FISH ECOLOGICAL STUDIES AND ITS APPLICATION IN...

FISH ECOLOGICAL STUDIES AND ITS APPLICATION IN ASSESSING ECOLOGICAL INTEGRITY OF

RIVERS IN NEPAL

By

Bibhuti Ranjan Jha

Thesis Submitted in partial fulfillment of the requirement

for the degree of

Doctor of Philosophy

in

The Department of Biological Sciences and Environmental Science School of Science

Kathmandu University Dhulikhel, Nepal

January 2006

FISH ECOLOGICAL STUDIES AND ITS APPLICATION IN ASSESSING ECOLOGICAL INTEGRITY OF

RIVERS IN NEPAL

By

Bibhuti Ranjan Jha

Supervisors:

Dr. Herwig Waidbacher & Dr. Subodh Sharma Ao. Univ. Professor Associate Professor Universität für Bodenkultur (BOKU) Kathmandu University (KU) Vienna, Austria Dhulikhel, Nepal

Kathmandu University

January 2006

ACKNOWLEDGEMENT

Writing thesis for me was indeed a long journey covering two continents Asia and Europe

and spanning almost three years. However, it was the first time I realized that I was

surrounded by wonderful people and institutions. Let me start with my two supervisors,

Prof. Dr. Herwig Waidbacher, Head of the Department of Water Atmosphere and

Environment, BOKU and Dr. Subodh Sharma, Department of Environmental Science and

Engineering, KU both of whom have given me all the support, guidance and confidence to

carry out this work. I would like to express my sincere gratitude and honor to them.

It was so nice to feel that I had a similar level of easiness in approaching Dr. Rana Bahadur

Chhetri, then Head of the Department of Biological and Environmental Sciences, KU and

now Associate Dean, and Prof. Dr. Mathias Jungwirth, Head of the Institute of

Hydrobiology, BOKU. I found both of them full of virtues.

I am also grateful to KU for providing all kinds of support including the equipment and

logistics to complete this work. The Dean of School of Science, Prof. Dr. Pushpa Raj

Adhikari was particularly after me to push into this work. Thank you so much sir. Dr.

Sanjay N. Khanal, my department head at KU not only gave me the tips on academic matter

but also on the life in Vienna. In addition I sincerely acknowledge the encouragement and

moral support received from the entire KU family. I am sure my colleague in the

department and other friends in KU are just waiting for me to host a party.

BOKU family, especially the members at the institute were equally inspiring. Prof. Moog,

Prof. Muhar and Prof. Schmutz were always friendly and ready to help in every matter. I

also remember the warm friendliness of benthos group upstairs and fish group downstairs.

The guys with whom I was working together in Keller are just amazing. Gü, Manu,

Frangez, Wiesel, Ande, Andreas, Thomas, Patrick, Gonzalo, Doris, Nicole, Catherine,

Helmut, Philipp and Jonathan were all wonderful friends and never allowed my spirit go

down. The songs of Berthold will always ring in my ears. All of you will remain in my

memory forever.

Franziska, the coordinator of the institute is a super lady. Not only she was helping me in all

office and domestic matters but also provided me motherly advices whenever we met.

Christian Dorninger is another person who has been seen always in helping mood.

I feel proud to name my sampling team members who helped me during the field trips.

Sujan, Arbinda, Shekhar, Bibhuti, Amul, Paras, Anil, Sushil, Amir, Keshab, Khadak, Paras,

Sujeet, Swastik, Diwas and Ramesh! I love you all. Pancha and Shiva, who also work in the

laboratory, were also integral part of the sampling team. Among colleagues Subhash, Bed,

Manoj and Dr. Sanjaya were always with me one time or another.

Among the institution, I always find the central department of Zoology of Tribhuvan

University very homely, may be because I used to be a student there. Prof. Dr. Jiwan

Shrestha particularly, provided me with unselfish help in identifying the sample. I would

like to express my heartfelt thanks to you, madam. Thanks also to Dr. Mana Wagley, who

helped me in developing the objectives of the study.

Dharani Man Singh is not only my close neighbor but was also closely watching my

progress during field studies. Many times I made use of his good office, Department of

Fisheries, Balaju for literature and taxonomy of fish. There I also got the opportunity to talk

with Dr. Swar and took some help from Ramola madam. Sincere thanks to all of you.

I would also like to acknowledge the cooperation of Department of National Parks and

Wildlife Conservation (DNPWC), Royal Chitwan National Park, Shivapuri National Park,

Department of Hydrology and Meteorology (DHM), World Conservation Union (IUCN),

Water and Energy Commission (WECS), National Agriculture Research Center (NARC)

and ICIMOD, Nepal.

Austrian Academic Exchange Service (ÖAD) and The World Conservation Union (IUCN,

Nepal) deserve very special thanks as the institutions providing scholarship and grant to

complete this research work.

One man from the Institute of Hydrobiology, BOKU stood very tall in terms of cooperation

to complete this work. Michael Straif (MUCH)! I am not finding words to express my

gratitude to you.

The Nepalese community in Vienna also deserves big thanks as it provided the homely

environment whenever I was homesick. Similarly thanks also to my friends and well-

wishers in Nepal. Haus Panorama 7th floor, where I was staying in Vienna was like a home

with a beautiful garden comprising wonderful people from all over the world.

I know there are many names missing in this text, who made valuable contributions to this

work. Let me acknowledge you all.

Finally, the members of my family who beared my absence many times during the studies

and waiting eagerly to receive me back naturally deserve a warm heart full of thanks.

And to my father I owe a debt of deepest gratitude, for the help I could not at the time

appreciate: his tireless urging and prodding towards the realization of this work was crucial,

and I as his son remain in his tutelage.

Bibhuti

ABSTRACT This work was, mainly, intended to assess the integrity of rivers in Nepal by some fish

community base parameters such as the number of species, composition and the abundance.

However, the variety of other information regarding fish resource and river morphology

such as spatial and temporal distribution and density of fish species, size structure of a

species, and substrate and physico-chemical parameters of the river are also well

documented.

Four different important disturbances, agriculture, urbanization, dams and weir, and

industries were studied here to assess if there were any impairments on the integrity of the

rivers by them. This work comprised nine rivers of Nepal in Central and Western

Development Region facing those disturbances. There were three case studies for each of

the four disturbances each having two sampling sites, the reference and the disturbed. Fish

sampling was done by standard wading method using backpack electro-fishing gear. Four

replicates of data corresponding to each major season were collected to give temporal

dimension to the study.

There were new findings regarding the range of distribution of many species as well as their

size. The seasonal variation in the distribution of fish species was also documented for all

the rivers, which were studied. In addition, the abundance and density of each species in

each river were calculated to help manage the fisheries resources. The classification of

rivers and river systems were also tried by using both fish community base variables and

abiotic factors using cluster analysis and discriminant analysis respectively. The results for

these were remarkable as both classifications corresponded to the age-old regional

classification of the Nepalese river systems.

Finally, it was seen that the fish population dynamics was sensitive to varieties of

disturbances the rivers are facing indicating that the fish base methods of assessing water

quality and river integrity could be developed for Nepalese rivers as well. It was found that

the impacts of all the disturbances on river integrity were not same and thus, could not be

generalized. Even the case studies of same disturbance produced mixed results pointing that

the regional and seasonal factors too modify the impacts.

It was found that high diversity and abundance of fish may not necessarily point toward a

good water quality. The impacts of agriculture in disturbed sites were quite visible

characterized by relatively higher diversity and abundance of fish indicating the nutrient

input in water by runoff through cultivated areas. It was found that the impacts of

agriculture also depend upon the river morphology and flow regime.

The impacts of the city on the integrity of river were not found to be big enough among the

cases studied. However, some trends were shown by fish community structure for this

disturbance indicating that it has potential to change the river conditions. On the other hand,

the impacts produced by dams and weirs were of mixed type. In general, the upstream sites

supposed to be the reference site was found to be more affected than the downstream sites

indicating that the upstream migration of some of the fish species was not possible due to

the fragmentation of the river.

Among the disturbance, the industrial disturbance was found to be the most serious one as it

clearly indicated a strong relationship of the industries and the water quality and integrity of

the rivers. It was even evident in Narayani River, one of the largest rivers of the country

with huge water discharge. In other cases, it showed seasonal fluctuations of the impact

pointing towards the biggest influential event, the monsoon, which truly rules over every

aspects of the river ecology.

Fish ecological studies and its numerous applications are very important to the country, as it

is extremely rich in both, the fish resource and the water resource. This work is just a

beginning in this direction. Once the sufficient fish base data of all the rivers and regions

are collected then a country level regional IBI metrics could be developed. It will then play

a significant role in conservation, management and monitoring of both the resources.

Abbreviations

AC Alternate Current AIC Agricultural Inputs Corporation BOD Biological Oxygen Demand BOKU Universität für Bodenkultur CA Cluster Analysis CBS Central Bureau of Statistics CDA Canonical Discriminant Analysis CDC Curriculumn Development Center CPUE Catch per Unit Effort DA Discriminant Analysis DC Direct Current DHM Department of Hydrology and Meteorology DNPWC Department of National Parks and Wildlife Conservation DO Dissolved Oxygen DOPP Directorate of Plant Protection EIA Environmental Impact Assessment EIFAC European Inland Fisheries Advisory Committee EU European Union FAO Food Agriculture Organization FPC Flood Impulse Concept GDP Gross Domestic Product GIS Geological Information System GLOF Glacial Lakes Outburst Floods GPS Geological Positioning System ha Hectare HAI Health Assessment Index HID Hetauda Industrial District HMG/N His Majesty’s Government /Nepal IBI Index of Biotic Integrity ID’s Industrial Districts IDM Industrial District Management Limited IE’s Industrial Estates INGO International Non Governmental Organization IUCN World Conservation Union KU Kathmandu University KW KilloWatt MASL Meter Above Sea Level MOIC Ministry of Information and Communication MOPE Ministry of Population and Environment MW Mega Watt NCAP Northwest Coalition for Alternatives to Pesticides NCS National Conservation Strategy NEA Nepal Electricity Authority NEPBIOS Nepalese Biotic Score NEPBIOS- brs Nepalese Biotic Score (Bagmati River system) NGO Non Governmental Organization NPB Nepal Pesticide Board NPC National Planning Commission

NPK Nitrogen Phosphorus Potassium ÖAD Österreichischer Austauschdienst RCC River Continuum Concept RCNP Royal Chitwan National Park RONAST Royal Nepal Academy of Science and Technology RPM River and Productivity Model SDC Serial Discontinuity Concept SNP Shivapuri National Park TL Total Length TSP Total Suspended Particle TSS Total Suspended Solid TU Tribhuvan University UNDP United Nation's Development Program WECS Water and Energy Commission Secretariat WFD Water Framework Directive

Chapter Index

S.N. Title Page

Chapter I

1. Introduction 1

1.1 Background 1

1.2 Rational of the work 6

1.3 Objectives 6

1.4 Hypothesis of the study 7

Chapter II

2. Integrity of the river system 8

2.1 Ecological integrity 8

2.2 Integrity and human beings 10

2.3 Integrity and economy 11

2.4 Integrity and sustainability 13

2.5 Integrity and health 15

2.6 Integrity, equilibrium and disequilibrium 16

2.7 Integrity revisited 18

2.8 Ecological integrity and the rivers 20

Chapter III

3. Fish as an indicator 25

3.1 Bioindication and bioindicators 25

3.2 Fish as bioindicators 27

3.2.1 History and development 27

3.2.2 Advantages of use of fish as bioindicator 29

3.2.3 The index of biotic integrity (IBI) 31

3.2.4 Modification of the index of biotic integrity (IBI) 34

Chapter IV

4. Electrofishing 37

4.1 Definition and history 37

4.2 Fish response 39

4.3 Factors affecting the efficiency of electrofishing 41

4.3.1 Abiotic factors 41

4.3.2 Biotic factors 43

4.3.3 Technical factors 44

4.4 The equipment 45

4.5 Uses and significance of electric fishing 46

4.6 Safety and precautions 47

4.7 Electric fishing in Nepal 48

Chapter V

5. Issues in context of Nepal 52

5.1 Rivers and river system 52

5.1.1 An overview 52

5.1.2 Geography and the rivers 53

5.1.3 Types of river 55

5.2 Scientific studies on Nepalese water 61

5.2.1 Early phase 62

5.2.2 Middle phase 63

5.2.3 Modern phase 65

5.3 Fishes of Nepal 68

5.4 River disturbances in Nepal 69

5.4.1 Agriculture 71

5.4.2 City (Urbanization) 75

5.4.3 Dams and weirs 78

5.4.4 Industries 82

Chapter VI

6. Materials and methods 85

6.1 Strategy 85

6.2 Types of disturbances 85

6.3 Site selection 85

6.4 Sampling 89

6.4.1 Time and duration 89

6.4.2 Fish collection and measurement 89

6.4.3 Physico-chemical parameters 90

6.4.4 Geo-morphology of the sampling sites 90

6.5 Data processing and analysis 91

6.6 Results and interpretation 91

Chapter VII

7. Description of the sites 92

7.1 Andhikhola 94

7.2 Arungkhola 95

7.3 Bagmati 96

7.4 Jhikhukhola 98

7.5 Karrakhola 99

7.6 Narayani 100

7.7 East Rapti 102

7.8 Seti 103

7.9 Tinau 104

Chapter VIII

8. Results 111

8.1 Distribution, abundance and density of fish 111

8.2 River classification based on biotic and abiotic factors 144

8.3 Study of the size structure of sucker head, Garra gotyla gotyla (Gray, 1830)

151

8.4 Assessment of ecological integrity of the rivers 187

8.4.1 Disturbances due to agriculture 187

8.4.2 Disturbances due to urbanization 194

8.4.3 Disturbances due to dams 201

8.4.4 Disturbances due to industries 208

8.5 Statistical verifications 216

8.5.1 Non parametric Kruskal Wallis Test 226

8.5.2 Parametric one way ANOVA (for seasonal variation of impacts)

227

8.5.3 Non parametric Mann Whitney Test (for impacts) 228

8.5.4 Parametric one way ANOVA (for impacts) 229

Chapter IX

9. Discussion 230

9.1 Distribution, abundance and density of fish 230

9.2 River classification based on biotic and abiotic factors 234

9.3 The size structure of sucker head Garra gotyla gotyla (Gray 1830)

236

9.4 Assessment of integrity of the river system 240

9.4.1 Disturbances due to agriculture 243

9.4.2 Disturbances due to urbanization (city) 247

9.4.3 Disturbances due to dams 251

9.4.4 Disturbances due to industries 256

Chapter X

10. Conclusions and recommendations

262

11. Executive summary 269

12. References 274

13. Appendix

Page

I Working time table 287

II Field protocol 288

III Field protocol (Fish base) 289

IV Checklist of fishes of Nepal 290

V Letter from Defense Ministry for safety during sampling 296

VI Letter from university for cooperation during sampling 297

VII Permission letter from DNPWC for sampling in RCNP 298

VIII Permission letter from DNPWC for sampling in SNP 299

IX Permission letter from SNP for sampling 300

X Permission letter from NEA for sampling 301

Map Index

S.N. Title Page7.1 Country map with sampling sites 937.2 Part of the country map enlarged with sampling sites 937.3 Showing sampling sites in Aandhikhola 1087.4 Showing sampling sites in Karrakhola, East Rapti, Narayani and

Arungkhola 108

7.5 Showing sampling sites in Bagmati river 1097.6 Showing sampling sites in Jhikhukhola 1097.7 Showing sampling sites in Seti river 1107.8 Showing sampling sites in Tinau river 110

Figure Index

S.N. Title Page5.4.1 Bioaccumulation and biomagnifications 758.1.1 Abundance of different fish species during one year of sampling 1418.2.1 Clusters of river 1458.2.2 Classification of the river system by CDA 1508.3.1 Length frequency of Garra species- Aandhikhola 1538.3.2 Length frequency of Garra species -Arungkhola 1538.3.3 Length frequency of Garra species- Jhikhukhola 1538.3.4 Length frequency of Garra species- Karrakhola 1538.3.5 Length frequency of Garra species- Narayani 1568.3.6 Length frequency of Garra species- East Rapti 1568.3.7 Length frequency of Garra species- Seti 1568.3.8 Length frequency of Garra species- Tinau 1568.3.9 Length frequency of Garra species- Spring 1588.3.10 Length frequency of Garra species- Premonsoon 1588.3.11 Length frequency of Garra species- Autumn 1588.3.12 Length frequency of Garra species- Winter 1588.3.13 Length-weight relationship of Garra gotyla gotyla in different seasons 1608.3.14 Length-weight relationship of Garra gotyla gotyla in different river

system - Premonsoon 162

8.3.15 Length-weight relationship of Garra gotyla gotyla in different river system - Postmonsoon

162

8.4.1 - 8.4.92

Distribution and abundances of fish species in all seasons and rivers for all disturbances

164-186

8.4.93 Impact of agriculture in Jhikhukhola- Upstream 1898.4.94 Impact of agriculture in Jhikhukhola- Downstream 1898.4.95 Impact of agriculture in East Rapti- Upstream 1918.4.96 Impact of agriculture in East Rapti- Downstream 1918.4.97 Impact of agriculture in Tinau- Upstream 1938.4.98 Impact of agriculture in Tinau- Downstream 1938.4.99 Impact of city in Narayani- Upstream 1968.4.100 Impact of city in Narayani- Downstream 1968.4.101 Impact of city on in Seti- Upstream 1988.4.102 Impact of city in Seti- Downstream 1988.4.103 Impact of city in Tinau- Upstream 2008.4.104 Impact of city in Tinau- Downstream 2008.4.105 Impact of dam in Aandhikhola- Upstream 2038.4.106 Impact of dam in Aandhikhola- Downstream 2038.4.107 Impact of dam in Bagmati- Upstream 2048.4.108 Impact of dam in Bagmati- Downstream 2048.4.109 Impact of dam in Tinau- Upstream 2078.4.110 Impact of dam in Tinau- Downstream 2078.4.111 Impact of industry in Arungkhola- Upstream 2108.4.112 Impact of industry in Arungkhola- Downstream 2108.4.113 Impact of industry in Karrakhola- Upstream 2128.4.114 Impact of industry in Karrakhola- Downstream 2128.4.115 Impact of industry in Narayani- Upstream 2158.4.116 Impact of industry in Narayani- Downstream 2158.5.1 Abundance of fish (CPUE) in all impacts in all seasons 2188.5.2 Number of fish species in all impacts in all seasons 2188.5.3 Abundance of fish (CPUE) in agricultural impacts 2198.5.4 Number of fish species in agricultural impacts 2198.5.5 Abundance of fish (CPUE) in impacts of city 2208.5.6 Number of fish species in impacts of city 2208.5.7 Abundance of fish (CPUE) in impacts of dam 2218.5.8 Number of fish species in impacts of dam 2218.5.9 Abundance of fish (CPUE) in impacts of industry 2228.5.10 Number of fish species in impacts of industry 222

Table Index S.N. Title Page3.2.1 Typical effects of environmental degradation on biotic assemblages 323.2.2 Parameters used in assessment of fish communities 323.2.3 Evaluation criteria for IBI 333.2.4 IBI modified from Karr (1981) 353.2.5 Fish based assessment of ecological integrity 364.3.1 Factors affecting electrofishing 414.7.1 Specification of the fishing gear used in this work 495.1.1 Estimated runoff of the rivers 535.1.2 Classification of the rivers studied in this work 615.4.1 Consumption of chemical fertilizers in Nepal by type 735.4.2 Growth of urban population and urban places in Nepal 765.4.3 Percent distribution of urban population 775.4.4 Urban densities in different regions of the country 775.4.5 List of the hydro power projects 79-815.4.6 Details of the industrial districts 835.4.7 Industrial pollution load in developing regions 846.1 Rivers and the locations of the sampling sites 866.2 Rivers and the disturbances studied 876.3 Rivers and details of the sampling sites 887.1.1 Details of Aandhikhola Hydel and Rural Electrification Project 957.3.1 Details of the Sundarijal Hydropower Plant 977.6.1 Material for production of 1 ton of paper 1017.9.1 Details of Tinau Hydropower Project 1068.1.1 List of fish species recorded in this study 111-1128.1.2 Distribution of fish species in sampled rivers and seasons 135-1378.1.3 Abundances of fish in different rivers (Number/10 minutes of fishing) 1398.1.4 Density of fish in different rivers (Number/100m²) 1438.2.1 Statistical details of the cluster analysis 1458.2.2 Valid and missing variables in CDA 1468.2.3 Summary of canonical discriminant functions 1478.2.4 Standardized canonical discriminant function coefficient 1478.2.5 Correlation details of the discriminant variables 1488.2.6 Classification processing summary 1488.2.7 Prior probabilities for groups 1488.2.8 Classification results 1498.3.1 The details of the statistics for each season for length weight

relationship 159

8.3.2 Summary of the statistics of three river systems in premonsoon and postmonsoon seasons

161

8.5.1 Abundances of fish in all impacts in all seasons 2238.5.2 Number of species in all impacts in all seasons 2238.5.3 Abundances of fish in agriculture impacts 2238.5.4 Number of species in agriculture impacts 2238.5.5 Abundances of fish in impacts of city 2248.5.6 Number of species in impacts of city 2248.5.7 Abundances of fish in impacts of dam 2248.5.8 Number of species in impacts of dam 2248.5.9 Abundances of fish in impacts of industry 2258.5.10 Number of species in impacts of industry 2258.5.11 Test of homogeneity of variance 2268.5.12 Tests of normality of variables 2268.5.13 Values of asymptotic significance from Kruskal-Wallis Test 2278.5.14 Values of significances in one way ANOVA 2288.5.15 Values of 2 tailed asymptotic significances from Mann Whitney test 2298.5.16 Significances in one way ANOVA 22910.1 Summary of the impacts in different rivers 266

Picture Index S.N. Title Page4.7.1 Electro fishing gear and its use in this research 514.7.2 Electro fishing gear and its use in this research 516.4.1 Length measuring instrument 916.4.2 Digital weighing machine 918.1.1 Gudusia chapra (Hamilton-Buchanan 1822) 1278.1.2 Neolissochilus hexagonolepis (McClelland 1839) 1278.1.3 Cirrhinus reba (Hamilton-Buchanan 1822) 1278.1.4 Labeo dero (Hamilton-Buchanan 1822) 1278.1.5 Puntius chola (Hamilton-Buchanan 1822) 1278.1.6 Puntius conchonius (Hamilton-Buchanan 1822) 1278.1.7 Puntius sophore (Hamilton-Buchanan 1822) 1288.1.8 Semiplotus semiplotus (McClelland 1839) 1288.1.9 Tor putitora (Hamilton-Buchanan 1822) 1288.1.10 Tor tor (Hamilton-Buchanan 1822) 1288.1.11 Naziritor chelynoides (McClelland 1839) 1288.1.12 Aspidoparia morar (Hamilton-Buchanan 1822) 1288.1.13 Barilius barila (Hamilton-Buchanan 1822) 1298.1.14 Barilius barna (Hamilton-Buchanan 1822) 1298.1.15 Barilius bendelisis (Hamilton-Buchanan 1822) 1298.1.16 Barilius shacra (Hamilton-Buchanan 1822) 1298.1.17 Barilius vagra (Hamilton-Buchanan 1822) 1298.1.18 Brachydanio rerio (Hamilton-Buchanan 1822) 1298.1.19 Danio aequipinnatus (McClelland 1839) 1308.1.20 Danio dangila (Hamilton-Buchanan 1822) 1308.1.21 Esomus danricus (Hamilton-Buchanan 1822) 1308.1.22 Crossocheilus latius (Hamilton-Buchanan 1822) 1308.1.23 Garra annandalei (Hora 1921) 1308.1.24 Garra gotyla gotyla (Gray 1830) 1308.1.25 Schizothorax richardsonii (Gray 1832) 1318.1.26 Schizothoraichthys progastus (McClelland 1839) 1318.1.27 Psilorhynchus pseudecheneis (Menon and Datta 1961) 1318.1.28 Nemacheilus corica (Hamilton-Buchanan 1822) 1318.1.29 Acanthocobitis botia (Hamilton-Buchanan 1822) 1318.1.30 Schistura beavani (Günther 1868) 1318.1.31 Schistura rupecula (McClelland 1839) 1328.1.32 Botia almorhae (Gray 1831) 1328.1.33 Botia lohachata (Chaudhuri 1912) 1328.1.34 Lepidocephalus guntea (Hamilton-Buchanan 1822) 1328.1.35 Amblyceps mangois (Hamilton-Buchanan 1822) 1328.1.36 Clupisoma garua (Hamilton-Buchanan 1822) 1328.1.37 Myersglanis blythii (Day 1870) 1338.1.38 Glyptothorax pectinopterus (McClelland 1842) 1338.1.39 Glyptothorax telchitta (Hamilton-Buchanan 1822) 1338.1.40 Glyptothorax trilineatus (Blyth 1860) 1338.1.41 Pseudecheneis sulcatus (McClelland 1842) 1338.1.42 Heteropneustes fossilis (Bloch 1794) 1338.1.43 Channa orientalis (Bloch & Schneider 1801) 1348.1.44 Channa punctatus (Bloch 1793) 1348.1.45 Glossogobius giuris (Hamilton-Buchanan 1822) 1348.1.46 Macrognathus pancalus (Hamilton-Buchanan 1822) 1348.1.47 Mastacembelus armatus (Lacepede 1800) 134

1 Introduction

-1-

CHAPTER I: INTRODUCTION

Background:

Global freshwater resources are not only over-exploited or poorly managed but also

ecologically degraded. Ecological degradation of fresh water bodies are mostly because of

encroachment along the river systems. Ironically, much of the degradation of fresh water

resources occur due to its tremendous utilities. The best source of water for humans, always,

has been rivers and streams as they are the symbol of freshness, continuity and eternity.

This is also a reason behind the establishment of most of the human civilization on the bank

of rivers. From ancient times rivers and streams are serving human beings for most of their

water requirements. In addition these water bodies have also served as a sink for mankind’s

wastes and sewerage.

With ever growing global population, increase in agriculture production, expansion of

industries and new demands for energy have to be met. All these involve the fresh water

and put tremendous pressure on this crucial resource. Thus, agricultural intensification,

urbanization, industrialization and the construction of dams and weirs, are considered as

some of the major human activities or disturbances potential to affect the ecological status

or integrity of the river system. Further, the human activities on water resources are usually

a local phenomenon but the impacts transcend the national boundaries.

On the other hand there are thousands of aquatic living organisms too, which spend their

entire lives in water and need this resource the most. Every life on earth constitutes a system

and no life is inherently superior to another. These living communities in aquatic systems

suffer more than human beings by degrading qualities of water resource. The living

communities in water include fish and other aquatic species all of which for our advantage

act as biological indicators of water quality and any alterations. They respond to the

cumulative effects of both physical and chemical disturbances to the water in which they

live.

The present work tries to assess the ecological integrity of the rivers and river systems by

using the information from fish ecological studies. The integrity of rivers is a very difficult

concept to define. The streams and rivers are complex ecosystems that take part in physical

1 Introduction

-2-

and chemical cycles that shape our planet and allow life to sustain. In general, the integrity

of the river system refers to its natural and wholesome state supporting all life forms;

aquatic and terrestrial, and capable of doing its usual geological functions.

Further, current ecological theories and concepts describe running waters as four-

dimensional systems, their longitudinal, lateral and vertical linkages, interactions and

exchange processes varying over time and over different scales (Jungwirth et al. 2000).

According to which, river systems are interactive at basically three spatial dimensions: in

the longitudinal (river/river or tributary), vertical (riverbed/aquifer) and lateral dimension

(riverbed/floodplain). The fourth dimension, the temporal scale is also crucial. The relative

importance of all these dimensions vary according to the terrain the river is passing through

but all are critical on themselves at their places.

There are various human activities and associated disturbances having potential to affect the

ecological status or integrity of the rivers and streams. This study has tried to analyze four

important disturbances in this regard such as agriculture, urbanization, dams and weirs, and

the industries. Pollution of water bodies is not restricted to urban and industrialized area

only. In our time even in rural areas the water pollution is common. The reason behind it is

the indiscriminate use of chemicals, both as a pesticide and fertilizer, which are then mixed

in the river system through run off.

In addition, the problem is not restricted to the developing countries alone but is present in

developed countries too from where these modern agricultural chemicals originated.

According to a U.S. Geological Survey (NCAP 1999), over 95% of river and stream

samples, as well as over 50% of well samples contained at least one pesticide and hence

they concluded, "Pesticides are widely found in rivers, streams, and wells". The rural areas,

mostly famous for the agriculture are more susceptible to this problem.

Thus, chemical intensive and faulty agricultural practices have become a threat to the

ecological integrity of the running waters. Some of the studies of selected areas in Nepal

show that deterioration of water quality through agricultural runoffs is quite alarming,

particularly in small rivers, streams and shallow groundwater. Hence, the study of the

impacts of agricultural disturbances in some of the Nepalese rivers has been chosen in this

work.

1 Introduction

-3-

In the same way, the process of urbanization is also one of the important causes that can

threat the normal ecology of the river. The relationship between human settlements and the

body of water, especially the river has always been intimate. The river in an urbanized area

could be seen used in many ways. Embankment and channelization for landscape

management, navigation and transportation, dumping of the wastes and recreation are only

some of them. And these, when put together with as the source of water supply, put

tremendous pressure on the ecological integrity of the river.

Urban areas in Nepal have increased and developed haphazardly without any plan and

projections creating wide range of problems that touch all sectors such as, environment,

economy and society. The urban population of Nepal according to the latest census stands at

14.2% of the total population (CBS 2001). This is not too much but what are alarming are

the rate and the way it is increasing. Therefore, the impacts of the cities or the urban areas

on the rivers also have been chosen for the analysis in this work.

The fragmentation of rivers through hydropower dams and other hydraulic measures is a

common phenomenon all over the world and the first thing it does by so is the disruption of

the longitudinal river continuum. These measures also fragment the population of many

species threatening their survivability. In addition, these engineering feats may also alter

some geo-morphological and physico-chemical characteristics of the river and that in turn

again adversely affect the living components.

The history of modern hydropower technology in Nepal dates back to 1911 AD, almost a

century before. Today Nepal produces about 526.44 MW of energy from hydropower and

many dams are under construction as the energy is in high demand (MOPE 2001). This

demands more and more assessments of the conditions of the Nepalese rivers. Most of the

dams are built in by bilateral assistance and hence carries design, operation and

maintenance from the donors or through their guidelines. This provides another series to

select from, as research sites and subsequent impacts. Thus, the disturbances due to dams

and weirs on rivers have also been selected for study in this work.

Another disturbance this research intended to work on is the effects of industrialization on

rivers. Nepal is not regarded as an industrialized country. In 1992 the total industrial units

were about 4271 of which 57% were only in the capital, Kathmandu (MOPE 2001). Also a

1 Introduction

-4-

very few of these total industrial units are big ones. Thus, superficially, there seems an

insignificant environmental problem coming out of these units. But different studies have

shown that the true pictures are quite different. Many of the studies in the field of chemistry

and toxicology of the effluents have revealed that the industries are putting tremendous

impacts on the rivers where they are drained.

All industrial wastes, in most cases, are directly discharged into local water bodies without

treatment. With innumerous types of effluents coming from them, we can be certain about

the grave impacts it adds to the water body, mostly the lotic one. The history is proof that

the industrialized nations too had serious problems on their rivers and streams from

industrial effluents. The impacts of industries are thus included in this work for the study.

There are altogether four types of disturbances, as described above, been selected to study

for their impacts. The impacts of agricultural disturbances are studied in the rivers

Jhikhukhola, East Rapti and Tinau, whereas the impacts of city are studied in the rivers

Narayani, Tinau and Seti. Similarly, the impacts of dams and weirs are studied in

Aandhikhola, Bagmati and Tinau, and the industrial impacts are studied in Arungkhola,

Karrakhola and Narayani. Thus altogether 12 case studies spreading over nine rivers are

included in this work.

The impacts of all these disturbances are studied by taking fish and their attributes as the

indicators. We can simply take fish as an example as its population and distribution clearly

reflect how much ecological integrity of rivers and streams has been compromised by

human actions. Assessment of river quality by taking fish as an indicator is a well

established and developed method in many parts of the world. For example, fish base index,

IBI (index of biotic integrity), is extensively used in United States and Europe.

However, in Nepal the fish based assessment of the river integrity is in premature stage.

Moreover, the water quality assessment by taking macrozoobenthos as an indicator is well

developed for Nepalese rivers and streams (Sharma 1996). Nepal is blessed by a very high

diversity of fresh water fishes and cannot afford to lose that. It possesses 182 fish species

belonging to 93 genera, under 31 families and 11 orders (Shrestha 2001). Thus, fish are not

just valuable as food resource but could also be utilized in many other ways. This work

1 Introduction

-5-

intends to assess the entire health or integrity of the river system by taking fish as a

fundamental indicator.

Assessing the integrity of rivers facing various disturbances is not the only goal of this

study. Fish being the important protein resource of the poor country like Nepal, some

aspects of the fisheries and fish ecological studies such as their diversity, spatial and

temporal distribution, abundance and a rough estimate of their densities in various rivers are

also included in this work. The technique of quantitative data acquired during this work

could be very helpful to calculate the biomass and productivity of the rivers as well as for

the conservation and management of fisheries resources. Thus, information collected and

the analysis done in this work would be very helpful to various sectors such as local people

and authority, the government and the institutions working in the field of management of

natural resources.

The example of size structure analysis, which is so important to evaluate the habitat

conditions, knowing the biology and estimating the crop, is also included in this study for

the benefit of society in general. In addition to that, another important application of fish

base and physico-chemical information collected during this work is the classification of the

rivers and river systems of Nepal. Two ways of classifying the rivers are included in this

work, one each utilizing biotic and abiotic variables.

The technique of using electrofishing gear for fish sampling, though common in fisheries

research elsewhere is relatively new technique in Nepal. The data acquired by this

technology are normally regarded as the standard data. A separate chapter is included in this

thesis to explain this sampling method. Thus, it is expected that many of the findings of this

work should not only be new but also authentic. It is expected that the findings of this work

are a valuable contribution to the database of the country regarding fish and water resources

and thereby to the general society.

The work was completed as planned without much constrains. The only major constrain

faced during the study was the political situation in the country. The administrative

procedures were increased so as to obtain permission letters from different departments and

organizations to carry the equipment and complete the sampling. The field visits were done

1 Introduction

-6-

rather in hurry due to the fear of unrest at some of the sites and thus, the socio-economic

linkages of the study could not be established as it was expected earlier.

Rational of the work: Water is the most important natural resource throughout the world and in case of Nepal it is

much more than that. It is regarded as the means pf prosperity for the country. The water

flowing through its more than six thousands rivers and streams, settled in numerous ponds

and lakes and reserved as snow in countless majestic peaks of Himalayas have been

subjected to multiple uses. Of these, rivers and streams, particularly, have been providing

water to the people for drinking, washing, industrial use, irrigation, hydropower generation,

subsistence fishing and various recreative activities.

Thus, it is of prime concern to all sectors to know the ecological constrains of this vital

resource thrusted upon by its multiple uses. It is also equally important to develop the tools

and techniques that express and quantify the extent of impact produced by various

disturbances so as to manage and conserve this resource. This work that uses the first

systematic application of electro fishing gear in Nepal is intended to give the fair picture of

the quality of the resource by using fish as an indicator. The result of this could be taken as

the guidelines for monitoring and conservation of this precious resource as well as for the

sustainable harvest of the fishery resource.

Objectives:

The broad objective of this work is to find wide varieties of information regarding the

impacts of modern agriculture, urbanization, hydropower dams and weirs, and the industries

in the selected rivers in Nepal by focusing on various aspects of fish and its population. The

information and results obtained are considered to be helpful to many sectors such as

government, academics, environmentalists, development planners, industrialists, farmers,

power companies, businessmen, NGO's and INGO’s, and above all the local communities.

The information and result obtained from this work could be categorized into two types: the

first type is scientific, technical and academic in nature while the second type is related with

general knowledge to link it with local community and local economy. The main objective

1 Introduction

-7-

of this research work is to put together these two sets of information so as to get a holistic

picture of situation of the selected rivers. However, this grand objective could be divisible

into the following constituents.

1. To study spatial and temporal distribution of fish diversity in selected rivers of

Nepal.

2. To calculate the abundance and density of fish species that helps in biomass

estimation and conservation measures.

3. To find out the methods to classify Nepalese rivers and river systems based on the

information of biotic and abiotic factors.

4. To show example of size structure analysis, which helps in understanding the

habitat conditions, knowing the biology of the species and estimating the crop.

5. To investigate the impacts of agriculture, cities, dams and industries on the rivers by

taking some fish attributes as indicator.

6. To put forward some recommendations in the basis of investigations for utilization

and management of the water and fisheries resources.

Hypothesis of the study: The fundamental hypothesis of this study is that the fish fauna is able to reflect the

differences influenced by variety of disturbances in river conditions and quality through the

change in their composition, diversity, and other population and community measures.

Matrices based on their population dynamics are able to show the picture of the impacts.

2 Integrity of the river system

-8-

CHAPTER II: INTEGRITY OF THE RIVER SYSTEM

2.1 Ecological Integrity: The term ‘ecological integrity’ is very widely used in environmental debate, discourse,

seminar, plans and in literature but is equally difficult to define in a single universal sense.

The definitions available so far are all subjective in nature and vary with individuals,

contexts and time. Integrity normally implies a condition, which is unimpaired or a state of

being complete or undivided. Ecosystems are usually made up of physical, chemical and

biological components and their interactions. In this background, one of the broadest

definitions of ecological integrity is given by Karr and Dudley (Karr and Chu 1995 and the

references therein) as the sum of physical, chemical and biological integrity.

The first reference to integrity in the environmental literature was Aldo Leopold’s (1949)

famous aphorism: “A thing is right when it tends to preserve the integrity, stability and

beauty of the biotic community. It is wrong when it tends otherwise” (Noss 1995 and the

references therein). But Leopold himself never explained the term integrity and the

generations of biologists and conservationists, since then, are still in search of the

unambiguous meaning of the term. The more they are trying, the more elaborate the

definition is becoming. For example, Westra (1995) has included the following in the

definition of ecological integrity: (1) ecosystem health, which may apply to some

nonpristine or degraded ecosystems provided that they function successfully; (2)

ecosystems’ abilities to regenerate themselves and withstand stress, specially

nonanthropogenic stress; (3) ecosystems’ optimum capacity for undiminished

developmental options; and (4) ecosystems’ abilities to continue their ongoing change and

development unconstrained by human interruptions past or present.

Kay and Schneider (Lemons and Westra 1995 and the references therein) have the similar

views on the concept of ecological integrity, which include three facets of ecosystems: (1)

the ability to maintain optimum operations under normal conditions; (2) the ability to cope

with changes in environmental conditions; and (3) the ability to continue the process of self-

organization on an ongoing basis, that is, the ability to continue to evolve, develop, and

proceed with the birth, death and renewal cycle. In one of the oldest concept, Cairns (in

Lemons and Westra 1995 and the references therein) defines ecological integrity as “the


-9-

maintenance of the community structure and function characteristics of a particular locale or

deemed satisfactory to society”.

Many have argued that the characteristics and essence of ecological integrity is found only

in nature or wild area or pristine area, without human activities. In yet another definition,

Westra (1995) has said that an ecosystem can be said to possess integrity when it is wild,

that is, free as much as possible today from human intervention, when it is an unmanaged

ecosystem, although not a necessarily pristine one. Karr and Chu (1995) also put integrity in

the similar way as the condition of sites with little or no influence from human actions; that

is, the resident biota is the product of evolutionary and biogeographic process at a site.

These types of ecologists see the wilderness or pristine nature as the entities having

ecological integrity.

To provide a space for humans and their activities, these scientists put forward a couple of

principles, that we must respect and protect core wild areas, and that we must view all our

activities as taking place within a buffer zone. To make it easy for human beings, some

ecologists have proposed some guidelines to leave some areas of wilderness without

interference. For example Naess (Westra et al. 2000 and the references therein), proposes a

30/30/30 percent guideline: 30% human activities, 30% carefully orchestrated activities

compatible with the wild (buffers) and 30% of wild areas of ecological integrity.

Among the components of ecological integrity, often the literature is biased towards the

biological integrity. According to Karr (2000), biological integrity refers to the condition of

places at one end of a continuum of human influence, places that support a biota that is the

product of evolutionary and biogeographic processes with little or no influence from

industrial society. This biota is a balanced, integrated, adaptive system having its full range

of elements (genes, species, assemblages) and processes (mutations, biotic interactions,

nutrient and energy dynamics, and metapopulation processes) expected in areas with

minimal human influence.

Brown et al. (2000) also put living being at the center of the concept. According to them,

ecosystems comprise thousands of species interacting in dynamic relationships, the

properties of which cannot be predicted from knowledge of the individual species in

isolation. Species invade or disappear, evolve or become extinct, and many systems


-10-

variables are in constant flux. Yet ecosystems have structure, pattern, and predictability

despite the radically contingent forces that may have created them. In the same vain, Noss

(1995) confesses that for him native biodiversity is one of the best expressions of ecological

integrity.

2.2 Integrity and human beings: Interestingly, there are conflicting views about and including human beings as a natural

being in the definition focusing biodiversity within ecological integrity. Lemon and Westra

(1995) define “natural” as a condition existing prior to human perturbation of ecosystems.

Many do not agree with this definition because it ignores the fact that human beings are part

of nature. However, human beings through their wisdom have made a tremendous progress,

according to Karr and Chu (1995), the consequences is the homogenization of global

society; human language, technology, and culture are becoming more homogenous as we

become more independent of the idiosyncrasies of local natural systems. They further add

that the legacy we inherit and the one we pass on, continue generations of toxic effluents,

destroyed and fragmented landscapes, depleted forests and fisheries and collapsing cultures

throughout the world. The failure to maintain human bonds with place, biology and culture

– our connections to living systems is what is emerging out.

Though past few decades were marked by tremendous increase in environmental awareness

the quality of the environment continues to decline. Today, human beings and the natural

world are on a collision course. Certainly, the world at present is very different from the one

during early human evolution and to add, this difference is not a natural one. This is also

explained by Karr and Chu (1995), when they say, “we have created a hybrid world – one

neither entirely natural nor entirely mechanical. The so called all round development

seemed to promise escape from dependence on, or even, connections with, other living

systems. Now the “information age” gives us “virtual reality”, completing our isolation

from the rest of the living world.

These are the reasons why many who believe and put forward some of the above definitions

of ecological integrity either ignore or reluctant to accept the fact that humans are part of a

nature and therefore need to be included. Only humans need to be blamed for this as we

have forgotten to live within the limitations of the physical environment. Thus, in many


-11-

biocentric views regarding integrity humans are treated differently. One of the criticisms

against biocentrism ethics is that they treat humans as superior than other creatures.

Biocentrists talk a lot about the equality of species, but when they get around to the

practical applications of their view, time and again, they show their bias in favor of the

human species (Sterba 1998).

However, Sterba is one of those who have well defended the concept of integrity with the

eye of biocentrism. He has proposed to distinguish between basic and nonbasic needs of

human. It is only when the basic needs of humans are not satisfied, they seriously endanger

their mental and physical well-being. The basic needs include food, shelter, medical care,

protection, companionship and self-development. These needs of life are also comparable to

the needs of other living being, and if humans can live within this they are very near to the

rest of the natural beings. Westra (1995) also is of the same view when she says that neither

humans nor panthers nor frogs have any place in wild systems, if they come riding Jeeps

and carrying computers and electrical generators and insist on using and then dumping

alien/toxic matters within the wild. It is a fallacy to assume that “human” equals

“technological human,” and it is only the latter who is not welcome in the wild.

2.3 Integrity and economy: Another aspect, which is closely linked with the ecological integrity, is the economy. The

field of economy normally covers the activities and relationships by which human beings

acquire, process, and distribute the material necessities and wants of life, including the

energy and material resources needed to power the industrial machine. It therefore

subsumes that subset of activities by which humankind interacts with the rest of the

ecosphere (Miller and Rees 2000). This also means that the essential goods and services for

human beings come only from the planet Earth and from nowhere else. The fact is also

explained by Karr (2000), when he says that for millennia, nature – specifically living

systems – provided food and fiber to nourish and clothe us and materials to build us homes

and transport. Living systems conditioned the air we breath, regulated the global water

cycle, and created the soil that sustained our developing agriculture. They decompose and

absorb our wastes. Beyond practicality, nature feeds the human spirit.


-12-

However, ever since the mankind became capable of using tools, and during most of the

industrial age, we have forgotten the fact that the Earth is finite and has limitations. The

“cowboy” mentality as explained by Herman Daly (Mark Sagoff 1995 and the references

therein) as the one that views nature as an unlimited frontier for exploitation, has played a

greater role for the impoverished condition of the planet. According to this view, there is no

need to worry about the “integrity” of nature – no need to recycle anything – because

technological progress makes resources essentially infinite.

In addition, the “cowboy” regards nature not only as an unlimited frontier to exploit but also

as a hostile foe to conquer. In ancient time, exploration of the nature always offered misery

to people in the form of heat and cold, hunger, disease and desolate wilderness. As the

nature was considered basically hostile to human purposes, it has been dammed, plowed,

blasted, cut, drained, dredged, poisoned, fenced, hunted, exterminated, genetically

reengineered, and in general controlled (Sagoff 1995). Interestingly, some economists still

believe that the destruction of nature in favor of industrial development is good and not bad

for human beings.

The economy is normally governed by money and market and its analysis ignores

biophysical conditions and the behavior of the ecosystem. For example, economists

virtually put zero marginal value on nonmarket species severing the concept of maintaining

biodiversity. Such analytic blindness creates a false sense of well-being even as economic

growth threatens disastrous ecological consequences (Miller and Rees 2000). In short,

economy separates human beings from rest of the species and the nature as a whole, similar

to ecology, which does this in a different way. Ecologists give a very high value on other

species, expending little effort on humans as ecological entities in their own right. They

study the impacts induced by humans, but ignore the impacts on humans as components of

affected ecosystems.

The conflict between the economy and ecological integrity mainly arises due to some

characteristics of former such as scale, equity and distribution. It is due to the huge growth

of economy that the life supporting system of the Earth is in serious state today. There are

several indicators to judge the scale of this growth – shrinking wild or natural space, rate of

depletion of tropical natural forest, amount of consumption of nonrenewable energy,

volume of greenhouse gases in the atmosphere, area of depletion of ozone layer, rate of


-13-

extinction of species, and the stocks of toxic and other wastes. The problem of equity and

distribution of the resources in modern market shows amusing picture as well. For example,

if the available world food supply for the past 20 years had been evenly divided and

distributed, each person would have received more than the minimum number of calories.

The reality is that a large section of the world population is under famine.

Similar example is put forward by Sterba (1998) when he says that presently the amount of

grain fed to American livestock is as much as all the people of China and India eat in a year.

These two countries constitute around one third of the world’s population. Yet, in another of

such example, it has been estimated that presently a North American uses fifty times more

resources than an Indian. This means that in terms of resource consumption the North

American continent’s population is the equivalent of 12.5 billion Indians. These examples

are mentioned here just to highlight the problem of equity and distribution in the modern

economy, which in turn are the threat to the integrity of natural systems.

However, there is an emergence of new breed of economists who see the earth with its

natural environment as a “spaceship” or a “lifeboat”, where the nature surrounds us with life

support systems minutely calibrated to our needs. They foresee an ecological disaster when

the global economy exceeds the limits of nature. Daly, who himself is this brand of

economists, imagines that the spaceman in a small capsule lives off tight material cycles

and immediate feedbacks, all under total control subservient to his needs (Sagoff 1995),

Thus, if for “cowboy” the integrity of ecosystem has no value, for the spaceman it is utmost.

2.4 Integrity and sustainability: Another concept with which the ecological integrity is often compared is the sustainability.

The last decade of the last century perhaps was the decade of the paradigm called

“sustainable development”. It was taken as a remedy for all environmental and

developmental issues especially after the World Summit of 1992 though the seed had been

planted way back in 1972 United Nations Stockholm Conference on the Human

Environment. Agenda 21, one of the most important outcomes of the summit, carries the

complete legacy of sustainable development. The legacy continued till recently, when

number of flaws appeared in it.


-14-

The flaws in sustainability starts right from the famous statement “yield the greatest

sustainable development to present generations while maintaining its potential to meet the

needs and aspirations of future generations.” But the question is whose generations.

According to Noss (1995), the “needs and aspiration” of present and future generations

considered in the World Conservation Strategy, were of human generations only. According

to this philosophy, the needs of nonhuman species can be ignored at least unless it can be

shown that the species in question benefit humans. Thus, the concept of sustainability was

proven to be too anthropocentric whereas that of integrity is much broader.

The other shortcomings of sustainability as noted by Irvine (Noss 1995 and the references

therein) include a failure of those who promote sustainability to consider environmental and

social limits to growth. This means the growth could be limitless as long as it is defendable

with general people and the society. For example, a housing company may justify the

draining of wetland as to provide more benefits. Likewise, other shortcomings include the

unwillingness to address the unsustainability of the current human population, much less its

expected growth and reluctance to confront the implications of the lifestyles of average

citizens of the more affluent societies. These two flaws appear as a bargaining point of

highly populated developing world and highly consumptive developed world not to provoke

each other.

An unrealistically optimistic faith in “alternative” technologies, institutional reform,

redistribution of wealth, decentralization, and personal empowerment is another

shortcoming of the sustainability concept, where the terms have become buzzwords of

politicians, economists, industrialists, development planner, and even some environmental

agencies. The last and perhaps the most important flaw of the concept is a failure to

recognize the claims of other species to their share of the planet's resources. Irvin himself

said that this failure is the most troubling one as it carries the belief that humans worth more

than other species. According to him this conclusion has no objective basis and is a

prejudice every bit as pernicious as the belief that whites are superior to blacks or males are

superior to females (or vice versa).

A good thing sustainability points toward is the sustainable use of resources, which no one

can deny. However, ecological integrity is a concept potentially broader and more

biocentric than sustainability. It not only includes sustainable use of resources, but also


-15-

sustenance of ecological and evolutionary processes, viable populations of native species,

and other non-human qualities of ecosystems, for their own sake. Brown et al. (2000) even

go further and say that in protecting ecosystem integrity, it is not individual species, the

quantities of stock and productivity, or resources used by humans that is of paramount

importance, but the ecological system they all depend upon that is the focus of concern.

2.5 Integrity and health: One of the concepts often confused with ecosystem integrity is ecosystem health. The two

terms do not contradict with each other but the former is much broader and within it

includes the latter. Health has been defined as the capacity to resist adverse environmental

impacts and as “the imputed capacity to perform tasks and roles adequately”. Also the

health paradigm is concerned with the present time and perhaps the immediate future,

whereas the integrity perspective poses no time limits and envisions birth, maturity, and

death cycles that may also produce different paths and trajectories, according to the largely

natural, evolutionary development of the system (Westra 1995).

Ecosystem health at its best connotes a stable state of well-being but does not speaks of

process of change, response to stress and self-organization, which are the features of

integrity. The integrity generally applies to the sites with little or no human interference,

while in contrast the health describes the preferred state of sites modified by human activity

(Westra 1995 and references therein). For example, the healthy conditions could be found in

cultivated areas, plantation forests and even in the cities but integrity in evolutionary sense

is nowhere there. Thus, a site may be considered healthy when their management neither

degrades the site for future use nor beyond their boundaries.

According to Karr and Chu (1995), health implies a flourishing condition, well-being,

vitality or prosperity. An organism is healthy when it performs all its vital functions

normally and properly with minimal outside care. And this concept of health applies to

individual organisms as well as to national or regional economies, industries and to natural

resources. Thus, an environment is regarded as healthy when the supply of goods and

services required by human and nonhuman residents is sustained. Interestingly, much of the

policymakers and scientists these days are addressing the problems of ecosystem health, and

this, in a way, is good because managed and supported ecosystems are the only ones we


-16-

should consider alternative for sustainable use such as alternative agriculture or sustainable

forestry.

2.6 Integrity, equilibrium and disequilibrium: The concept of ecological integrity was developed by keeping ecosystem in equilibrium.

Westra (Shrader-Frechette 1995 and the references therein) speaks of “integrity” together

with “health”, “wholeness”, “stability”, “balance” and “harmony". While Sagoff (1995)

emphasizes the interconnectivity within ecosystems, the interdependency of their parts and

their progress, toward increased stability and diversity, the literal meaning of integrity too

points toward a valuable whole, “the state of being whole, entire or undiminished” or “a

sound, unimpaired, or perfect condition”. In short, the ecosystems without human

interference are taken as the system in full equilibrium and integrity. However, many

modern scientists and philosophers have serious questions on these attributes of integrity.

The beginning of the questions perhaps started some 40 years before when we were able to

see the Earth from the space and found how we were isolated in a small piece of space

debris. From the distance of space, we saw ourselves and our planet exposed in an

unexpected fragility and vulnerability (Karr and Chu 1995). This could be the first time

humans have realized that our home is not so stable and powerfully balanced as we had

presumed. Further, the change and the disturbance are the norms and the environments do

not typically tend toward balanced, stable and integrated states. On the large scale, it is

marked by glacial and climatic changes that show little recurring pattern and tells that over

the long run natural environments will remain in constant flux. On a smaller scale, this is

evidenced by fires, storms, floods, droughts, invasion by exotic species and many more that

continually modify natural environments in ways that do not create the repeating patterns of

return to the same equilibrium state (Sterba 1998).

Thus Worster (Sterba 1998 and the references therein) claims that nature is fundamentally,

erratic, discontinuous and unpredictable. Similarly, systems ecologists and other systems

analysts now recognize that the behavior of most of the natural world is nonlinear,

discontinuous, irreversible, and characterized by lags and thresholds.


-17-

Often, the natural ecosystems are described as a complex and dynamic system with the

interrelationship of physical, chemical and biological factors. Scientifically and artistically

many have proved that the complexity of the ecosystem results in stability and balance and

its development has some predictable route. However, after chaos theory these facts too

look like vulnerable. The theory notes that any real dynamic system, even one described by

a set of deterministic equations, is ultimately not predictable because of the accumulation of

individually small interactions between its components. This applies to balls on a billiard

table and the planets in heavens. This means that our ability to forecast and predict will

always be limited regardless of how sophisticated our computers are or how much

information we have (Westra 1995 and the references therein).

It is difficult to characterize integrity in systems that are not static. Ecosystems changes

over time due to purely natural factors and their changes are often chaotic and unpredictable

(Noss 1995). He further adds that even over much shorter spans of time, natural ecosystems

are far from stable and unvarying. Natural disturbances occur at a variety of spatial and

temporal scales, so that a landscape is more of a shifting mosaic of patches than a

homogenous vegetation in equilibrium with its physical environment. Thus, it is difficult to

assign integrity to a system, which is continuously varying, frequently disturbed, unstable

and unpredictable. Van Valen and Pitelka (Sagoff 1995 and the references therein) even go

on to say that “ecology has no known regularities.” Likewise, an ecologist has said recently,

“whenever we seek to find consistency in nature, we discover change.”

Even if we consider the concept of evolution, the traditional definition of integrity has to

face a lot of criticisms. It has been observed that most species respond to environmental

change in an individualistic manner. As a result, the species composition of communities is

continuously changing. Species we see together today may have been separated for most of

their evolutionary histories (Noss 1995). Thus, he further adds that if communities are just

transient aggregations of species, how can they be said to possess integrity? In addition,

when we talk about adaptations, it is populations and not ecosystems that adapt. Adaptation

is restricted to heritable characteristics; no alleged knowledge of the past operates in natural

selection, and the individual, which is better adapted to the present environment, is the one

that leaves more offspring and hence transmits its traits (Shrader-Frechette 1995).


-18-

Every kind of organisms that we see today has reached this moment in time by threading

one needle after another, throwing up brilliant artifices to survive and reproduce against

nearly impossible odds (Sagoff 1995). It is the enormous and timeless labor of evolution

that invests its products – the plants and animals we encounter – with a dignity and

meaning. Their legitimacy is based not in any purpose they may serve – ours or that of some

superorganism that contains them – but in the circumstances of their coming hither.

Ecosystems do not have desires, aims or wants rather individuals have. Thus, it is difficult

to define good or bad for ecosystems, as they cannot experience pleasure or pain.

The complex systems like ecosystem response to the change or stress in a multitudes of

way, (1) the system could eventually continue to operate as before, or (2) it could operate

with a reduction or increase in species number, or (3) it could exhibit new paths in the food

web, or (4) it could take on a largely different structure with different species and food webs

(Shrader-Frechette 1995 and the references therein). Any of these changes are possible but

it is difficult to decide which one is the most natural and acceptable one, or which one

possess or lack of integrity. Similar view is expressed by Noss (1995) as he puts, “after

disturbance, an ecosystem may have multiple potential pathways of successional

development and multiple potential endpoints.” Thus an intermediate stage in forest

succession is not with less integrity than a climax forest.

In many cases it is even difficult to identify the climax stage as the communities continue

evolving. This is normally identified by those who carry equilibrium concept. In addition,

there is a general lack of empirically measurable conditions of integrity. Moreover, there are

confusions and vagueness in the words that describe the integrity. Like many other concepts

in science, the integrity too cannot be defined strictly in mechanistic way. All these facts

and arguments are on the side of those who believe the disequilibrium paradigm. However,

this paradigm leads to the path of inaction, as it believes nothing is certain. Equilibrium

concept on the other hand defines the goal and gives the guideline for governments and

policy makers to develop plans related with environment and natural resources.

2.7 Integrity revisited: It is generally accepted that ecological integrity is essential to maintain and protect life-

support systems, which are basic to both humans and nonhumans. The base of the


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economies and social sustainability is nature and its resources, without which neither of

them flourish.

Of course, change is the eternal law. Even some species such as fire-adapted pines and the

animals dependent on them, require frequent disturbance that brings change to cope

competition by fire-intolerant species. But accepting that change and disturbance is

necessary to keep ecosystems healthy and diverse does not require that we accept all

changes (Noss 1995). Let the changes be brought about by nature itself rather than by

humans, who are now equally capable of inducing a change of same magnitude. Botkin

(Noss 1995 and the references therein) too emphasized that the rate of change associated

with human disturbances are often far beyond what organisms are adapted to coping with.

It is not generally acceptable that the human activities do whatever to bring the change in

environment even though change is natural. This will be clearer if we see ecosystems in

functional and evolutionary context. Nature has functional constraints because organisms

have physiological limits to what they can tolerate. Human induced stresses often exceed

these limits. Likewise nature has evolutionary constraint as species are limited in how

quickly they can adapt the changing environment. Here too, the rate of change induced by

modern human activities exceeds rates experienced by species over their evolutionary

histories. Thus, those who believe integrity concept are right when they ask mankind to

restrict their activities below the functional and evolutionary limits the nature creates for

each ecosystem.

All natural changes are not deleterious to human beings. Nature is full of examples showing

miracles that could inspire and satisfy our needs and desire. Many will agree that the basic

requirement for these things to happen is the absence of human influence and

manipulations. One of the best examples we can mention here is about El Nino episode that

happened some years back in South America. The episode was vastly described as a very

bad climatological event, though it also showed how unmanipulated systems keep their

integrity intact. A desert area in Chile dramatically changed into a wonderland of flowers

and grasses due to the unusual rain brought in by El Nino.

This burst of life in once barren land has been interpreted in various ways by Westra et al.

(2000) to highlight the integrity of nature. The first conclusion they made was that the


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desert retained its biological potential because its vital state had not been reduced by human

disturbance. The area where the vital state has been changed by human activities is less

likely to experience such positive changes. The rapid bloom of desert organisms illustrates

in a dramatic fashion some of the autopoietic (self-creative) capacities of life to organize,

regenerate, reproduce, sustain, adapt, develop and evolve. This was their second conclusion.

Even a landscape like desert has such natural capacities to wonder how much capacity a

more fertile landscape might possess.

As another conclusion, they said that the self-creative capacities are dynamically temporal.

The display of new forms of life in the desert gains significance through its past and its

future. Thus, nature’s rhythms are displayed over time and no momentary snapshot captures

all of nature's potential. Finally they said that ecological integrity is valuable and valued.

The story of the Chilean desert is one simple example that provoked wonder and

appreciation. Some ecological communities, such as tropical forest show their marvels in a

more continuous, less seasonal or episodic fashion. More generally, the biological and

physical processes work together to give rise to the totality of life on Earth, including

ourselves, and maintain the conditions for the continuation of life.

Thus, natural ecosystems are valuable to themselves for their continuing support of life on

earth, as well as for the aesthetic value and the goods and services they provide to mankind.

This is why there is a growing concern about the policies and law regarding ecological

integrity. Ecological integrity is taken as an umbrella concept in the management and

conservation of nature and ecosystems. The concept joins natural science with the different

fields of social sciences including economy and very much helps in the formulation of

public policies. In addition, the works of Karr, Ulanowicz etc has made the measurement of

ecological integrity much easier and meaningful through creation of multimetric indices.

2.8 Ecological integrity and the rivers: Although rivers and streams represent only a small portion of a landscape, their state is

indicative of the condition of the whole watershed. Rivers, like blood samples from a

human, are indicative of the health of the landscape (Karr 1999). In addition, looking at the

rich biotic characteristics rivers are like lifelines of a continent with a picture of the

condition of surrounding landscapes and connecting landscapes over a great distance. Thus,


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integrity of the river system in many ways also contributes to the maintenance of the

integrity of the other ecosystems.

The integrity of the river system refers to its natural and wholesome state, supporting all life

forms; aquatic and terrestrial, and capable of doing its usual geological functions. The

streams and rivers are complex ecosystems that take part in physical and chemical cycles

that shape our planet and allow life to sustain. Thus, rivers and streams are not just a strip of

water cutting its way through the hills and mountains and finding its way downhill

meandering slowly toward the sea. It is much more than that. Certainly its bottom extends

beneath the ground and the sides into its floodplains. Because of its complexity series of

ecological concepts have evolved time to time regarding the river system. Khanal (2001)

has enumerated most of these concepts in his work that describe the function and structure

of river in time and space. These concepts are important in order to gauze the integrity of

the running waters.

Among these the Zonation Concept is one of the earliest river ecology concept and

according to this, along the longitudinal course of a river as and when the physiographic and

physiochemical conditions change the typical zone change as a phenomenon of spatial

succession. The features such as current and water temperature are particularly able to

distinguish the different zones. This subdivision of rivers into successive zones is also

characterized by biological inputs. Therefore in a typical river there is a clear trout zone or

barble zone etc. Similar zonation could also be obtained in the basis of benthic invertebrates

and other groups of organism as well.

The second river ecological concept is the river continuum concept (RCC), which describes

the structural and functional characteristics of aquatic communities along the whole length

of a river. According to this concept the biotic community of the stream adapts it structural

and functional characteristic to the abiotic environment, which forms a continuum with a

continuous gradient from headwaters to the river mouth (Vannote et al. 1980). Particularly,

this concept divides rivers into three parts based on the stream size such as headwaters

(stream orders 1-3), medium sized streams (stream orders 4-6) and large rivers (order above

6), which in turn is based on the size of particular organic matter and primary productivity.


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There is an intermediate concept between the first two concepts called the theory of stream

hydraulics (Statzner and Higler 1986). This concept states that there appears a distinct

change in species assemblages related with transitions in stream hydraulics. The stream

hydraulic is governed by geomorphological and hydrological characteristics such as current

velocity, depth, substrate and the slope.

Another ecological concept that explains a lotic system is resource spiraling concept. The

concept explains the processing of organic matter along the length of the river. According to

this concept, downstream flow of river results in downstream displacement of material

which creates a partially open cycle or ‘spiraling’. Spiraling can be measured with the unit

‘spiraling length’ (S), defined as the average distance along which the river flows during

one cycle of a nutrient element, such as carbon and shorter the spiraling length, the more

efficiently the nutrient is utilized.

Serial discontinuity concept (SDC) developed by Ward and Stanford (1983) describes about

the consequences of putting dams and weirs on rivers. Natural flow of river is a continuum

and the construction of dams and weirs disrupts this, which results in upstream-downstream

shifts in abiotic and biotic parameters and processes. The concept considers two parameters

to assess the relative impact of dams on river ecosystem. The discontinuity distance is the

first, which is the distance over which the values of physical or biological variable are

shifted upstream or downstream. And the second is the intensity, which is the change in the

values of variables as a result of these disruptive structures.

Another important concept regarding river systems is the flood-impulse concept (FPC) put

forward by Junk et al. (1989) and it describes the effects of floods on river channel as well

as in its floodplain in an unmodified river system. The nutrient cycle, that is, the release and

storage of nutrients in floodplains mainly depends on the flood cycle, vegetation cover and

in temperate regions also in the growth cycle of the vegetation. The fertility of the

floodplain is determined by the quality of the sediment. The river-floodplain system is

characterized by a variety of habitats from plains, bars, levees and swales to ox-bows,

backwaters and side-channels. Thus, a little fluctuation in flood cycle affects the diverse

habitats associated with it, which together form a rich biodiversity. FPC agrees that the

periodic floods in the rivers are vital for the survival of these large communities.


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Riverine productivity model (RPM) introduced by Thorpe and Delong (1994) also

highlights the productivity of the river system, but differs with RCC in that, the carbon in

constrained large rivers is not solely supplied from downstream transport but also from

local autochthonous production and inputs from riparian zone. The composition of

macroinvertebrates and the phytoplankton productivity measurements in large rivers

suggest that in-stream primary production is an important energy source in the downstream

part of the river, which is the main statement of this model.

Patch dynamic concept has received the inputs from Fisher et al. (1982), Power and Stewart

(1987), Pringle et al. (1988) etc. According to them the organisms in the streams exhibit

patchwork nature where different patch types are the result of different disturbances. A

‘patch’ could be defined as a spatial unit, which is determined, by both organisms and

disturbances. This concept mainly argues that the species with similar ecologies coexist in

stream systems. It also emphasizes that the community composition changes with such

patches and that there occurs a significant variation in community structure even in a small

spatial scales.

The next concept worthy regarding river system is the mosaic dynamic concept. Normally a

river shows a sequence of ecological gradient in terms of water flow, organic matter, fish

populations, and many other factors which change more or less gradually from head waters

to river mouth as a continuum (Frissell et al. 1986). However, there exists a relatively clear

boundaries for these characteristics and appear as a mosaic of series of unit. Thus, according

to this concept a river appears as a series of mosaic superimposed on the underlying

gradients.

Habitat templet theory is another important theory that explains the dynamics of a river

system. Proposed by Townsend and Heldrew (1994), the theory sees the river habitats as a

templet with axis of temporal and spatial heterogeneity. They explained that the temporal

variation bear a relationship with the disturbance regime to which organisms are subjected

while the spatial heterogeneity tends to ease or modify the influence of disturbances by

providing refugia where survival is more likely.

Yet, the broadest and perhaps among the widely accepted concepts regarding river is the

catchment concept. Several scientists have given argument in favor of catchment-oriented


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approach. Frissel et al. (1986) put forward a framework for stream habitat classification that

emphasizes a stream’s relationship to its watershed over a wide range of scales in time and

space. Similarly Gardiner (1990) came up with a manual for holistic appraisal of river on a

catchment scale. The structure and function of river is highly dependent on the

characteristics of whole catchment area.

Finally Petts (Khanal 2001 and the references therein) combined and integrated all the

important research on the functioning of river systems into a number of principles.

According to this rivers are: 1) three dimensional systems – longitudinal, vertical and

lateral; 2) driven by hydrology and fluvial geomorphology; 3) structured by food-webs; 4)

characterized by spiraling processes; and 5) dependent upon change – changing flows,

moving sediments and shifting channels. Thus, as any ecosystem, rivers too are a highly

complex system.

3 Fish as an indicator of ecological integrity

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CHAPTER III: FISH AS AN INDICATOR

3.1 Bioindication and bioindicators: Organisms, populations, biocoenoses and, ultimately, whole ecosystem are naturally

influenced by numerous biotic and abiotic stress factors such as fluctuations in climate,

varying radiation and food supply, predator-prey relationships, parasites diseases, and

competition within and between species (Markert et al. 2003). Naturally, the living

organisms react to such stressors and that’s how the ecosystem develops and together forms

the raw material of the evolution. Within one evolutionary epoch, the range of variation of

stress factors, generally, remains constant allowing the species to adjust to changing

environment.

In recent times, however, the environmental changes have increased in terms of both quality

and quantity. Through human activity the environment has been confronted with totally new

substances that did not previously exist (xenobiotics, radionuclides) and potentially harmful

substances (heavy metals) released in quantities unthinkable in the past (Markert et al.

2003). These new stressing factors together with the one occurring in nature result in a

multiplying effect, which often exceed the tolerance level of the organisms and diminish the

ability to cope or adjust. In the same time, the extent of effects on the living organisms

reflects the quantity and quality of different stress factors. The organisms then are called as

biomonitors and bioindicators, and the process bioindication.

There are some differences between the terms bioindicators and biomonitors as pointed out

by Markert et al. (2003). A bioindicators is an organism (or part of an organism or a

community of organisms) that contains information on the quality of the environment (or

part of the environment). A biomonitors on the other hand, is an organism (or part of an

organism or a community of organisms) that contains information on the quantitative

aspects of the quality of the environment. Though the term biomonitors is more inclusive,

bioindicators is more popular and is in extensive use. The bioindicators, also sometimes

called as indicator taxa or ecological indicators are species which are known to be sensitive

to processes or pollutants that lead to a change in biodiversity and are taken as surrogates


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for larger communities and act as a gauge for the condition of a particular habitat,

community or ecosystem (Markert et al. 2003).

Bioindication is the analysis of the informational structure of living systems, ranging from

single organisms to complex ecosystems, in order to define environmental quality or assess

environmental hazards and risks (Fränzle 2003). Thus, the bioindicators contribute to the

information need of ecosystem management. The organism has significance beyond what is

actually measured; in addition to the information of its presence and abundance, it provides

information on the occurrence of ecological processes (Lorenz 2003). For example,

occurrence and abundance of predator’s species indicate that the food web functions

sufficiently. According to Lorenz (2003), bioindicators can provide the following

information for ecosystem management:

• A description of ecosystem processes and structures

• The ecosystem condition by comparing the ecosystem with a reference level of good

ecological functioning.

• Cause-effect relationships within an ecosystem.

Besides those utilities, one of the important advantage of bioindication is that there are

different groups of living organism to chose from, such as bacteria, algae, plants and

animals, which can serve the purpose depending upon the objective and type of ecosystem

under investigation and monitoring. For example, plant species are very good bioindicator

of air pollution, whereas animals, generally with a greater arsenal of stress coping

mechanism, are perhaps best used in aquatic ecosystem. Another advantage of

biomonitoring approaches is the low cost in comparison to those of instrumental

measurements. Finally, species are spectacular and more appealing to the policymakers and

public and thus get a quick political acceptance and investment for investigation.

Many groups of organisms have been proposed as indicators of environmental quality, but

no single group has emerged as the favorite of most biologists (Karr 1981). He further says

that diatoms and benthic invertebrates have most frequently been cited as ideal organisms

for biological monitoring because of the availability of a theoretical structure that allows an

integrated ecological approach. However, their use in monitoring has many drawbacks, such


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as, it needs specialized taxonomists; life-history information is often lacking; difficult and

time consuming to sample, sort and identify; and the values less meaningful to the general

public (Karr 1981). Fish has clear advantages as indicator organisms for biological

monitoring program and thus its use for this purpose is ever increasing.

3.2 Fish as Bioindicators: 3.2.1 History and development:

Fish have been and remain a major part of any aquatic study designed to evaluate water

quality (Simon 1999). This sentence indicates that the use of fish as environmental

indicators has passed a considerable time and is continue to grow stronger. Simon (1999)

further adds that beginning around 1900 and accelerating greatly in about last 20 years, fish

community characteristics have been used to measure relative ecosystem health. In fact the

study of relationship between the fish and water bodies, arguably, started with human

civilization in ancient time. There are evidences in the form of stories that the fishermen

always knew the particular site or stretch of water bodies for desired type and amount of

fish.

The same approach, that is, the spatial changes of fish communities along the course of

river systems and the use of fish zonation patterns for river classification are examples of

some of the most traditional bioindication approaches as could be seen from the work of

Fritsch, 1872 and Thienemann, 1912 and 1925 (Chovanec 2003 and the references therein).

The use of fish communities as indicators of biological integrity was documented as early as

the turn of the last century on the Illinois River (Simon 1999). Simon (1999) further

documents the numerous studies on the changes in fish distribution as a result of pollution

plumes and sewerage outfalls such as Brinley 1942; Katz and Gaufin 1953; and Karr et al.

1985a.

Fish as a bioindicator, mainly, developed from the United States, where the fish have been

one of the most studied groups of aquatic organisms since 18th century. There are

documentation of earlier work on distribution and composition of the fish faunas of the

region’s rivers and streams, such as Rafinesque (1820), Kirtland (1838), Jordan (1890),

Kirsch (1895), and others. These works latter in 20th century led to the development of

inventories of composition and distribution of the fish faunas in many states. Fish fauna of


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Illinois (1920) was one of the first to appear followed by Indiana (1945), Ohio (1957;

1981), Missouri (1975), Kentucky (1975) etc. By now United States and Canada have

almost a complete list of composition and distribution of their fish according to regions and

rivers. These not only provided a baseline against which changes through the 19th and 20th

centuries were evaluated, but provided the impetus for future developments including the

routine use of fish assemblage as an indicator of the condition of water resources as a whole

(Yoder and Smith 1999).

Thus, starting from around 1800, gaining some movement from the beginning of 1900s and

accelerating tremendously in the last 25 years or so, fish community characteristics have

been used to measure relative ecosystem health. A variety of quantitative indices are now at

our disposal to measure the various impacts on the water bodies. Perhaps, the first of this

kind is the Index of Well-Being (Iwb) developed by Gamon (1973) to evaluate structural

components in numbers, biomass and species richness for assessing water resources (Simon

1999 and the references therein). Several modifications of this index called as Modified

Index of Well-Being (MIwb) also exists such as the one referred in Ohio EPA, 1987b where

the species designated as highly tolerant, exotic, and hybrid are eliminated from the

numbers and biomass components of the Iwb.

There is another index called Health Assessment Index (HAI), which is an extension and

refinement of a previously published field necropsy system developed by Goede and Barton

(1990) that provides a health profile of fish based on the percentages of anomalies observed

in the tissues and organs of individuals sampled from a population (Adams et al. 1993).

This index is based on the assumption that the biotic integrity of an ecological system is

often reflected by the health of organisms that reside in that system and in aquatic

ecosystems, fish, and particularly those species near the top of food chain, are generally

regarded as representative indicators of overall system health.

However, it is the Index of Biotic Integrity (IBI), first proposed and developed by Karr

(1981) is the most widely accepted and extensively used assessment method, where the fish

and their attributes are in center of investigation. The IBI is based on the hypothesis that

there are predictable relationships between fish assemblage structure and the physical,

chemical and biological condition of stream systems. The IBI was originally developed for

Midwestern US streams, and integrated 12 attributes of fish assemblages to determine biotic


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integrity or ‘health’ of the system (Hughes and Oberdorff 1999). Since its formulation, the

IBI has been modified almost annually and used in other regions and types of ecosystems

throughout the US and Canada.

Today, the fishery scientists and environmentalists all over the world use different types of

IBI, all with slight modifications in the original one to suit their own climatic and

geographic region. Hughes and Oberdorff (1999) have located at least 10 applications of the

IBI outside the US and Canada in small rivers and wadeable streams on six continents:

Europe (Oberdorff and Hughes, 1992; Oberdorff and Porcher, 1994; Oberdorff, 1996, in

France; Didier et al. 1996, in Belgium), Africa (Hugueny, 1996, in Guinea; Hocutt et al.

1994 in Namibia), Asia (Ganasan and Hughes, 1998, in India), South America (Gutierrez,

1994, in Venezuela), Australia (Harris, 1995), and North America (Lyons et al. 1995, in

Mexico).

Many parameters used in assessment of fish communities in IBI requires a sound

knowledge of physical and chemical characteristics of the stream, and the variables or

metrics like species composition and richness, trophic level of the species, fish abundance

and fish condition. Although originally developed for the Midwestern US, the IBI has been

adapted for use in a variety of other ecoregions and such adaptations usually necessitate the

substitution, addition, or deletion of metrics from the original IBI and the development of

new scoring criteria for some metrics because of zoogeographic, geological, or

climatological factors that affect faunal composition (Paller et al. 1996). The full fledged

application of this index in Nepalese condition still needs more studies on the fish fauna of

the country, however, the present work, which tests some of the metrics, marks the

beginning.

3.2.2 Advantages of use of fish as bioindicator:

There are several reasons why fish are widely used and accepted to describe natural

conditions as well as the alterations of aquatic systems. The advantages mentioned here are

the compilations of the advantages listed by many scientists working in this field such as

Karr (1981), Fausch et al. (1984), Leonard and Orth (1986), Hughes and Noss (1992),

Paller et al. (1996), Simon (1999), Yoder and Smith (1999), Hughes and Oberdorff (1999),

Chovanec et al. (2003), Fränzel (2003), Lorenz (2003).


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• Life-history information is extensive for most fish species.

• Fish communities generally include a range of species that represent a variety of

trophic levels (omnivores, herbivores, insectivores, planktivores, piscivores) and

include foods of both aquatic and terrestrial origin. Their position at the top of the

aquatic food web in relation to diatoms and invertebrates also helps to provide an

integrative view of the watershed environment.

• Fish are relatively easy to identify. Indeed, most samples can be sorted and

identified at the field site, with release of study organisms after processing.

• Both acute toxicity (missing taxa) and stressed effects (depressed growth and

reproductive success) can be evaluated. Careful examination of recruitment and

growth dynamics among years can help to pin point periods of unusual stress.

• Fish are typically present, even in the smallest streams and in all but the most

polluted waters.

• The general public can relate to statements about conditions of the fish community.

• A long tradition of ecological, physiological and ecotoxicological research on fish

has led to an advanced knowledge of the ecological requirements of a large number

of fish species. The effectiveness of bioindication approaches depends on the sound

knowledge of the indicator’s ecological demands and physiology.

• As migratory organisms fish are suitable indicators of habitat connectivity or

fragmentation.

• Due to the size of fish (and their organs) a great variety of analytical procedures can

be carried out.

• Due to the longevity of fish certain indication effects, e.g. accumulation processes

are increased and thus a long-term effects can be studied.

• The reconstruction of pristine reference communities is possible due to the existence

of historical information.

• Fish have larger ranges and are less affected by natural microhabitat differences than

smaller organisms. This makes fish extremely useful for assessing regional and

macrohabitat differences.

• While assessing the environmental quality by fish assemblage stock assessment also

goes side by side which is important for the sustainable harvest of this resource.


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• They have both economic and aesthetic values and thus help raise awareness of the

value of conserving aquatic systems.

However, there is a couple of drawback of using fish as a bioindicators.

• Fishery caused alterations, such as species transfer, stocking and overfishing make it

more difficult to discuss other man-induced degradations of aquatic ecosystems.

• The mobility of many species makes it difficult to identify not only the exact source

of pollution, but also the time and duration of exposure.

It is seen from the above list of advantages and disadvantages that the advantages distinctly

outweigh the drawbacks, and thus, the use of fish as a bioindicator is becoming more and

more popular all over the world.

3.2.3 The Index of Biotic Integrity (IBI):

There is an increasing demand for quantitative, easily applied and sensitive biological

measures of ecological integrity of aquatic system both in developed and developing

countries. A variety of quantitative indices using bio-criteria exist to assess the quality of

rivers and streams. Of these, the most commonly used and, arguably the most effective, has

been the Index of Biotic Integrity (IBI). The Index of Biotic Integrity (IBI) was first

developed by Karr (1981) for low gradient, small warm water streams affected by intense

agricultural activity, but was designed so its metrics could be modified to reflect species

differences in other stream types (Leonard and Orth 1986, Chovanec et al. 2003). When

Karr proposed this, he had a long experience of working with fish and water quality and had

the opinion that by carefully monitoring fishes, one can rapidly assess the ‘health’ (‘biotic

integrity’) of a local water resource. The IBI was developed to assess the biological

integrity of lotic systems effectively and directly (Karr 1981). The IBI applies features of

indigenous fish communities to assess watershed and stream quality, and is based on the

assumption that community features change with stream degradation.

Typical effects of environmental degradation on fish assemblage were compiled by

Margalef (1963) and Fausch et al. (1990) and were developed by Hughes and Noss (1992)

in a tabular form.


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Typical effects of environmental degradation on biotic assemblages The number of native species, and of those in specialized taxa or guilds, declines The percentage of exotic or introduced species or stocks increases The number of generally intolerant or sensitive species declines The percent of the assemblage comprising generally tolerant or insensitive species increases The percentage of trophic and habitat specialists declines The percentage of trophic and habitat generalists increases The abundance of the total number of individuals declines The incidence of disease and anomalies increases The percentage of large, mature, or old-growth individuals declines Reproduction of generally sensitive species decreases The number of size and age class declines Spatial or temporal fluctuations are more pronounced Table 3.2.1: Typical effects of environmental degradation on biotic assemblages

These knowledge of typical effects of environmental degradation on fish assemblage has

tremendously helped in the origin of IBI by Karr (1981) and latter on in its modifications by

different scientists. In addition, these effects have also allowed the proponents of IBI to

select the suitable variable or the metrics for their formula. These attributes of stream fish

communities are also relatively easy to measure and thus have helped in the development of

IBI. In his original work Karr (1981) had designed to assess the status of the community

using twelve fish community parameters, which could be roughly grouped into two sets –

species composition and richness, and ecological factors. These parameters are listed in the

following table.

Parameters used in assessment of fish communities Species Composition and Richness

• Number of Species • Presence of Intolerant Species • Species Richness and Composition of Darters • Species Richness and Composition of Suckers • Species Richness and Composition of Sunfish (except Green Sunfish) • Proportion of Green Sunfish • Proportion of Hybrid Individuals

Ecological Factors

• Number of Individuals in Sample • Proportion of Omnivores (Individuals) • Proportion of Insectivorous Cyprinids • Proportion of Top Carnivores • Proportion with Disease, Tumors, Fin Damage, and Other Anomalies

Table 3.2.2: Parameters used in assessment of fish communities. Source: Karr (1981)


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Karr (1981) argues that the choice of species richness and total number of individuals as

primary criteria for assessment, as long as those metrics are weighted by biogeographic,

season and stream-size considerations. This allows a freedom to modify the metrics

according to region, season and stream-size. In the same time, dynamics of production and

consumption of energy, reflected by the second set of parameters as it indicates the water

quality through changes in food availabilities or trophic levels.

Karr initially started assigning three values, (-), (0) and (+) for each metrics according to

their state but as a step forward to quantify the system, he replaced them with the values (1),

(3) and (5). These values are summed over all criteria for each site to provide an Index of

Biotic Integrity. Since there are twelve metrics, the highest possible score according to this

system would be 60. Six biotic integrity classes, such as ‘Excellent’, ‘Good’, ‘Fair’, ‘Poor’,

‘Very Poor’ and ‘No Fish’ are assigned according to score with some intermediate classes

as well. The table 3.2.3 illustrates the suggested boundaries for the classes.

Class Index

Number Excellent (E) 57 – 60 E – G 53 – 56 Good (G) 48 – 52 G – F 45 – 47 Fair (F) 39 – 44 F – P 36 – 38 Poor (P) 28 – 35 P – VP 24 – 27 Very Poor (VP) ≤ 23

Table 3.2.3: Evaluation criteria for IBI (Karr 1981) The class ‘Excellent’ relates to the best situations without influence of man with the

presence of all regionally expected species, including the most intolerant forms, with full

array of age and sex classes. The class ‘Good’ is characterized by somewhat less species

richness, mainly due to the loss of most intolerant forms. Here some species are represented

with less than optimal abundances or size distribution and trophic structure is in stress.

Similarly, the class ‘Fair’ indicates a further deterioration with fewer intolerant forms and

more abnormal trophic structure.


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The class ‘Poor’ is generally dominated by omnivores, pollution-tolerant forms and habitat

generalists with depressed growth rates increased frequency of hybrids and diseased fish.

‘Very Poor’ class on the other hand is characterized by the presence of few fish, that too

mostly introduced or tolerant species. Hybrids are common here, together with the fish with

disease, parasites, damaged fins and other anomalies. The last class, ‘No Fish’ perhaps is

the worst situation where a repetitive sampling fails to turn up any fish.

3.2.4 Modification of the Index of Biotic Integrity (IBI):

One of the important aspects of IBI is its flexibility for modification, an attribute on which

Karr himself is very proud of. The IBI is a multimetric indices that rates the existing

structure, composition and functional organization of the fish assemblage with regional and

habitat specific expectations derived from comparable high quality ecosystems (Lyons and

Wang 1996). Simon (1999) also considered IBI as a member of multimetric indices that

change structural characteristics depending on the geographic area. Thus, as the region of

application of IBI changes, its metrics also changes.

There are numerous modifications of IBI, particularly in North America for the use in

different regions (Fausch et al. 1984; Leonard and Orth 1986; Karr et al. 1987; Steedman

1988; Goldstein et al. 1994; Lyons et al. 1995; Lyons et al. 1996; Paller et al. 1996. Due to

its popularity, the application of IBI spread to all the continents with different versions for

different regions and different types of ecosystems. In Europe the IBI was modified and

used by Oberdorff and Hughes 1992; Oberdorff and Porcher 1994; Oberdorff 1996; Didier

et al. 1996, in Africa by Hugueny 1995, in Guinea; Hocutt et al. 1994 in Namibia, in Asia

by Ganasan and Hughes, 1998, in South America by Gutierrez, 1994, in Australia by Harris,

1995, and in North America by Lyons et al. 1995, in Mexico. These new versions have the

same multimetric structure, but they differ from the original IBI in number, identity and

scoring of metrics.

In most of the new versions of IBI, the number of metrics called community metrics are

selected, which fall broadly into three categories: species richness and composition, trophic

composition and fish abundance and condition. Each metrics are adjusted to reflect changes

in fish communities with the region and stream size. It is established that the natural

variation in species richness of fish communities is determined by two factors:

zoogeography and stream size. The prior knowledge of the natural condition and


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composition of the species of the streams under investigation is a must to choose the metrics

and to put numerical values in it. When human activities degrade the rivers and streams, the

aquatic communities they support are modified accordingly to various degrees. The IBI is

designed to assess and evaluate the differences between natural or reference condition and

the degree of disturbances. The following table lists metrics used in original IBI as well as

the areas that could be modified to suit the stream size and the region.

IBI Modified from Karr (1981). IBI = sum of the scores of metrics

Scoring criteria Category Metric 5 (best) 3 1 (worst)

Species richness and composition Trophic composition Fish abundance and condition

Total number of species Number and identity of darter species Number and identity of sunfish species Number and identity of sucker species Number and identity of intolerant species Proportion of individuals as green sunfish Proportion of individuals as omnivores Proportion of individuals as insectivorous cyprinids Proportion of individuals as top carnivores Number of individuals in sample Proportion of individuals as hybrids Proportion of individuals with disease, tumors, fin damage, and other anomalies

Varies with stream size and region <5% 5 – 20% >20% <20% 20 – 45% >45% >45% 20 – 45% <20% >5% 1 – 5% <1% Varies with stream size and region 0 0 – 1% >1% 0 0 – 1% >1%

Table 3.2.4.: IBI Modified from Karr (1981) IBI = sum of the scores of metrics Table source: Fausch et al. (1984)

Despite some examples of the application of traditional IBI for water quality monitoring,

the fish base assessment of ecological integrity in Europe at present is more guided by

Water Framework Directive (WFD) of European Union (EU). The main principle regarding

bioindication approach to assess the ecological status of surface waters mentioned in WFD,

EU (2000) calls for the assessment based on the investigation of the aquatic communities,

algae, macrophytes, benthic macroinvertebrates, and fish (Chovanec et al. 2003).

Subsequently, the ecological status of the water body is classified into five classes; high,

good, moderate, poor and bad. For example the classification scheme for fish-based

assessment of ecological integrity as developed by Schmutz et al. (2000) is given in the

following table.

}


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Levels of ecological integrity Criteria High Good Moderate Poor Bad

Type-specific species Self-sustaining species Fish region Number of guilds Guild composition Biomass and density Population age structure

None or nearly Some species Several species Many species Most species none missing missing missing missing missing None or some Several species Many species Most species Nearly all missing missing missing missing species missing No shift No shift Shift Shift Shift No guild No guild Single guild Many guilds Most guilds missing missing missing missing missing No alteration Slight Substantial Complete Complete alteration alteration alteration alteration No or nearly Slight Substantial Heavy Extremely no changes changes changes changes changed No or nearly Slight Substantial Heavy Extremely no changes changes changes changes changed

Table 3.2.5: Fish-based assessment of ecological integrity (after Schmutz et al. 2000)

It is possible to modify the above metrics as well as the classifying system of the status of

ecological integrity and apply to the Nepalese conditions once there is baseline information

regarding the composition of fish in the region. The easiest way is to find the key indicator

groups to substitute the metrics in the first category of the IBI. The second and third

category of the metrics simply requires the number and proportion or ratio of the sampled

fish.

However, the application of IBI in totality in Nepalese waters is not possible at present due

to the lack of adequate information regarding fish fauna. Only a very few rivers in Nepal

have been studied thoroughly in terms of biotic community. In addition, Nepal being one of

the most heterogeneous countries in terms of geography, it is very difficult to generalize the

information. Nevertheless, this study analyses and evaluates some of the metrics from the

first and third categories to assess the impacts of some important human-induced

disturbances in different rivers in Nepal. This study, with huge pool of data also opens the

study and research on the fish-based assessment of surface waters in Nepal.

4 Electrofishing

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CHAPTER IV: ELECTROFISHING

4.1 Definition and history: Electro-fishing is a contracted form of electric fishing, which simply means fishing with

electricity. In more technical definition, electro-fishing is the science of utilizing an

electrical current to stun fish momentarily or force them to swim involuntarily towards an

electrical field for collection. In this method, an electric current result in fish orienting

themselves to the anode and swimming towards it involuntarily thus facilitate the capture.

In this method, fish within the electric field are temporarily stunned and after a quick

examination they are returned to the water without any harm.

Electric fishing probably started after the discovery of electricity and man’s ability to

exploit this physical principal. Further evolution and development of this method of fishing

is rather confusing. Hartley (1990) writes that the electric fishing developed from different

origins in different environments and thus has a confusing history. Many of the events

described below are documented by Hartley (1990). There are enough stories in different

parts of the world about the use of electricity for fishing, even though it must have been in

crude form with uncontrolled amount of current and lack of precautions. The first evidence

or record of the electric fishing is the patent granted to Isham Baggs from London in 1863.

However, this patent must have been the result of a long practical approach and the

subsequent experience, indicating that the method is much older than that.

After Baggs’ work, there were a number of studies, mainly in Germany, regarding

orientation and movement of fish when exposed to the direct current, as is shown by the

work of Mach (1875) and Herman (1885). In England, in 1896, Loeb and Maxwell

demonstrated that the sensory reaction of fish were forced and not voluntary. Just before

that, Blasius and Schweitzer (1893) discovered the state called galvanonarcosis, in which

the fish seemed to sleep with a relaxed body if it faced the anode. Practical aspects of

electric fishing developed further in Germany as could be evident from the work of Holzer

(1932) and Scheminsky (1924).

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There are also records that the Japanese fishermen were using electricity to drive out eels

from their burrow into a net in the earlier part of the twentieth century. There was another

patent in 1912, claimed by Larssen that allowed him to use electricity to catch a variety of

aquatic creatures, which clearly indicates that he knew the potential of the method. The

earliest record of an electric fish screen is from United States when Burkey had the first of

his many patents in 1917. The work on the screens was later refined by MacMillan (1928)

and Tauti (1931). The use of electricity for capturing fish in production studies dates from

1920’s (Lagler 1978).

After the II World War, development of electric fishing continued, mainly in Germany and

US. Commercial production of electric fishing engines started at this time, which opened up

a new dimension in the field of fishery science. In US, initially there were construction of

small portable devices and the use of alternating current but later it was shifted towards

construction of larger fishing devices such as fish screens using more advanced pulse direct

current. With this, the days of experimental devices had passed and a whole lot of

formalities, especially in terms of precautions against fatal accidents emerged.

Development of electric fishing in UK after the war followed the pattern of both Germany

and US, but there were instances of some independent research elsewhere too. In the former

Soviet Union, Strakhov and Nusenbaum (1959) were developing electric screens and

Schentiakov (1960) electric trawling in lakes. In New Zealand, Burnet (1959) was testing

electric fishing. Among the congresses and conferences, 1957 FAO International Fishing

Gear Congress in Hamburg discussed the problems of electro-fishing, which was followed

by the second congress in 1963. In 1965, the European Inland Fisheries Advisory

Committee (EIFAC) arranged the meeting of various workers in the field and collected

papers to form a book ‘Fishing with Electricity’ (Vibert 1967a).

The working party again gathered in 1973 in Poland to discuss and compare different

aspects of fishing gear, which was compiled and published by Chmielewski (Hartley 1990

and the references therein). In the meantime, a book on general principles of electric fishing

was published by Sternin et al. (1972), which was updated by Halsband and Halsband

(1984). Lamarque, in collaboration with FAO did a study of electro-fishing in tropical

water, which allowed the choice of best current for fishing either on seawater or low

conductivity water. Two publications, Developments in Electric Fishing (Cowx 1990) and

4 Electrofishing

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Fishing with Electricity (Cowx and Lamarque 1990), are among the most widely circulated

books on electro-fishing so far. Now we are in the age, where due to advances in

electronics, the construction of lightweight fishing gear with many designs and any type of

current is possible.

Lamarque (1990) reported that between 1967 and 1987, there were 439 fishing operations in

15 countries in a range of biotopes including brooks, rivers, natural and fish farm ponds,

fresh and brackish lagoons, lakes, estuaries, mangroves and the sea. During these, a great

diversity of fish species (700) and crustacea (50) were caught at temperatures ranging

between 5 and 33°C and conductivity between 7 and 40,000 mS cm–¹. Since then, the

application of electric fishing is only increasing.

4.2 Fish response: The reaction or the response of fish in the electric field is related with the nervous system,

which is similar within themselves and also to those of other vertebrates. In a very simple

term, the nervous system constitutes of brain and the spinal cord from where the myomeres

come out and integrate the muscles. The objective in electrofishing is to interfere with this

neurological pathway between the brain and muscles of the fish (Reynolds 2002). Thus, by

disrupting the internal signal and overriding it with a signal from water, electric current

redirects the neurological signal and muscular reaction.

Fish show certain characteristics when in the presence of electricity. The reaction of fish to

electricity depends upon so many factors, such as, the type of current, field strength

(power), the fish length, the fish species and the orientation of the fish in relation to the

anode (www.fisheriesmanagement.co.uk/electrofishing.htm). There have been many

researches on how and why fish shows a particular response in presence of electricity. Only

the question of ‘how’ is established so far but there is not yet any established theory to

answer ‘why’ the fish react in a particular way. Probably, it may be because the responses

depend on so many things as mentioned before.

Response of fish to different current types is important things to know to select equipment

and field situation during electrofishing. According to Lamarque ((1990), DC has good

anodic galvanotaxis and induces tetanus only in the near vicinity of the electrode. Pulsed

4 Electrofishing

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DC has poorer anodic electrotaxis and tetanizes further from the anode preventing some

fishes from reaching the electrode. AC has no electrotaxis and fishes are tetanized at a

greater distance from the electrode than pulsed DC or DC. In general, DC is the least and

AC the most harmful electrical output with pulsed DC falling between the two. Thus,

electrofishing for research purpose utilizes DC or pulsed DC in most of the cases.

The description of the reaction of fish in presence of electricity could be explained in the

sequence of taxis, narcosis and tetanus (Lamarque 1990). The first reaction of the fish when

electric field is applied is a quivering motion of the body or dorsal fin. After that, the fish

move into the effective zone of the electrode and the responses correspond to increasing

voltage or proximity to the anode and the direction the fish is facing with respect to the

anode. The first thing that happens to the fish facing anode is the inhibited swimming,

which means the normal swimming of fish is retarded. As the voltage gradient increases, the

fish swims strongly towards the anode, which is also called as the first swimming towards

the anode. This is a forced swimming and is a component of electrotaxis or more

particularly, anodic galvanotaxis.

A further increase in voltage gradient results in galvanonarcosis where the fish become

motionless and its muscles are relaxed. At another increase of voltage, the fish begin to

swim again, this time in an unbalanced manner, called as second swimming to anode and is

the main component of anodic galvanotaxis. Here the fish is obliged to go towards the

anode. Above this voltage, anodic tetanus takes place, which is the state of muscular rigidity

as a result of direct excitation of the muscles by the current.

For the fish facing the cathode, increasing voltage induces two reactions of the fish,

cathodic galvanotaxis at a very low voltage followed by the turning of fish towards anode

on little more voltage. This mechanism is called half-turn towards the anode. However, if

fish fail to undergo the half-turn, cathodic tetanus of nervous origin takes place with rapid

increase of voltage. This is followed by cathodic tetanus of muscular origin characterize by

the absence of quivering in more voltage. And for the fish lying across the field, only one

response, anodic curvature is observed.

4 Electrofishing

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4.3 Factors affecting the efficiency of electric fishing: Though electric fishing as a sampling technique has emerged as one of the most important

tools in freshwater fisheries ecology and management, there are number of factors which

influence the efficiency and hence produce a biased result. A sound knowledge of these

factors help in obtaining a good data by applying optimal sampling strategy for a given

conditions. These factors can be mainly divided into environmental, biological and

technical according to origin (Zalewski and Cowx 1990). The table 4.3.1 lists all these

factors.

Environmental Biological Technical Abiotic Conductivity Water clarity Habitat Habitat structure Habitat dimensions Substrate and cover Water velocity Seasonality Temperature Weather

Community structure Taxocene structure Species diversity Species composition Population structure Density Fish size Age structure Species specific behavior, physiology color and morphology

Personnel Size of crew Crew experience Motivation and ability Equipment Equipment design Maintenance Organization Site selection Standardization of effort

Table 4.3.1: Factors affecting electrofishing Source: Zalewski and Cowx (1990) modified

The factors mentioned in the above table are described briefly here. 4.3.1 Abiotic factors: Conductivity: Conductivity of water is determined by the geology of the associated

watershed, but is also influenced by human activities, such as mining, agriculture practice,

soil erosion and effluent discharges. It is an important parameter that determines the

efficiency of electric fishing with a particular capacity of fishing gear. As for instance,

freshwater has a low conductivity; therefore a high field strength (Volts/cm) can be

achieved due to the reduction created in current flow (amps) caused by the increased

resistance (ohms). On the other hand, saline water is a better conductor of electricity, it has

a lower resistance and hence a better current flow. Thus, with everything remaining the

same, more power is required in salt water to achieve the same voltage as in freshwater.

Measurement of conductivity before sampling allows the chances to select the gear with

right electrical output.

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Water clarity: There is a clear relationship between the efficiency of electric fishing and

water transparency, but is very complex. It seems the fishing is more efficient in clear water

as the fish attracted and stunned are clearly seen so that they cannot escape the net.

However, on the other hand the same property also allows fish to see the fishing team from

distance and thus, they don’t come nearer into the electric field, especially in the water

without cover. In the similar way, in turbid water, bottom dwelling, camouflaged and small

fish are hard to see and catch even when immobilized.

Habitat structure and dimension: There are two basic freshwater habitat, fluvial and still

water with many differences between them resulting in the differences of fish community

and also the behavior of independent fish. Regarding the dimension, the most important

factor affecting the fishing efficiency is the channel width. This is because if the electric

field is inadequate to cover the whole width of the river fish are able to escape from the

periphery. Thus, there is an inverse relationship between the electro-fishing and river width

in general case. However, there are methods to increase the efficiency to a required level.

Substratum and cover: The bed or the bottom deposits also play a role in the fishing

efficiencies. Normally fine particles such as mud and silts and organic debris are more

conductive than coarse bottoms and thus cause problem by reduction in the current density

of an electric field. The covers, that include floated and submerged plant as well as trees,

have dual effect. These covers provide a shelter for many species and thus might increase

the efficiency, but on the other hand, dense cover affect visibility making it difficult to catch

the stunned fish. Thus, the purpose of the sampling has to be well defined to address the

problem of efficiency.

Water velocity: If the velocity of water is very high, it affects the performance of the

fishing team and there is also a chance of missing the stunned fish. On the contrary, in still

waters, tetanized fishes are close to the electrode but drown quickly due to tiredness unless

it is picked quickly. Thus, it is important to select suitable team and gear according to the

condition.

Seasons: The hydrological and thermal regimes of freshwater ecosystems change with

season and so do the behavior of fish. These changes are mainly guided by the purpose of

nutrition and breeding. These facts increase or decrease the efficiency of electric fishing

4 Electrofishing

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even in the same stretch of sampling in different seasons. Thus to overcome the problem of

seasonality as a factor for the efficiency of fishing, knowledge of autoecology of the species

is important.

Temperature: The information on the impact of temperature on fishing efficiency is also

full of contradictions. One study says that there is 40% reduction in conductivity when the

temperature is reduced from 20°C to 0°C and concludes that the colder water increases the

fishing efficiency (www.fisheriesmanagement.co.uk). While it has been shown that at

temperatures below 4°C fish tend to pass more quickly in to a state of immobilization,

which reduces the capture efficiency (Zalewski and Cowx, in Cowx and Lamarque 1990).

In any case, there is an optimum temperature range for each species where the efficiency is

highest.

4.3.2 Biotic factors: Fish size: It is normally accepted that the fishing efficiency of electro-fishing increases

exponentially with fish length. This means, longer the fish, bigger the effect of electric field

and this makes electro-fishing a size selective method. Thus, if target is to fish smaller fish,

an increase in the field strength decreases the selectivity. However, increase mortality will

take place due to the higher voltage gradient.

Species composition: In diverse communities, the fishing efficiency is less compare to non-

diverse community of one or two species. It is because, in diverse community all kind of

fish, large and small, adapted for different microhabitats with many adaptive features, and

also with variation in the internal conductivity may live together, which are not uniformly

affected by one electric field. Thus, the efficiency of fishing largely depends upon the

species composition of the fish community.

Fish density: The relationship of fish density and the fishing efficiency by electro-fishing is

also not straightforward. In low density, the fish are less and are easily caught with the

available effort. In high density, though the capture is more, efficiency declines because all

the stunned fish cannot be recovered. Often in high density, the focus is mainly on large

individuals and as the smaller ones are ignored, hence the lower efficiency.

4 Electrofishing

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Age structure: Normally, the juveniles and small fishes due to their size have a lower

probability of capture as discussed before regarding the fish size. However in lentic

condition like ponds and lakes, the juveniles dominate the shallow littoral zone due to

temperature preference and thus make them more vulnerable.

Behavior: Different life-style of the fish also influences the efficiency of sampling. For

instance, benthic forms, though less likely to escape the electric field, are difficult to pick

from betweens stones and roots, while nektonic may be able to escape the electric field, but

are easier to collect. Likewise, the fish showing territorial behavior are vulnerable to catch

while those showing schooling behavior, due to their fright response, escape the electric

field. Also predators are more vulnerable to capture than the prey.

4.3.3 Technical factors: Equipment: Efficiency of the fishing also depends upon the type of the fishing gear and its

maintenance. Electro-fishing gear these days come in several designs and with variable

output of electricity. Thus, efficiency can be vastly increased by choosing the specific

design and output matching the objective of the fishing. Similarly, the gear in poor working

condition can greatly reduce the efficiency and thus, a routine maintenance like cleaning the

electrodes, changing the engine oils, changing filters, stitching the nets if it is damaged, etc.

could help in the smooth running of machine during operation and hence increase the

efficiency.

Personnel: Skill, experience and the number of crewmembers have a big influence on the

efficiency of fishing. While the skill and experience always help in a good result, the

number of members too helps until it is crowded and lowers the efficiency. In addition, the

members should also be highly motivated to do the work to achieve best results.

Organization: Good organization and good planning always have a positive impact on the

fishing operation. For, example, the sampling objectives should be clear and pre-survey of

the sites must be done before the operation. Similarly, duration of the sampling, means of

transportation, accommodation, safety measures, cost etc. should be made clear before

going to the field. These things do have influence on the efficiency of fishing.

4 Electrofishing

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4.4 The equipment: The electro-fishing gears come in variety of types, designs and outputs and are

commercially produced these days. The main types of the fishing equipments that utilize the

electricity are:

1. Portable backpack shocking unit for classical wading

2. Boat mounted unit for classical boat fishing

3. Trawling, and

4. Screening/guiding

Regardless of type, an electrofishing system normally consists of following six sub-systems

according to Novotny (1990).

1. Power supply that provides electrical energy to the system.

2. Power conditioner that modifies raw energy to meet the requirements of the specific

application.

3. Instrumentation that provides knowledge of the electrical performance of the

system.

4. Interconnection system that safely carry the suitable power to the electrodes.

5. Electrodes, which properly couple the right electrical power to the water.

6. Auxiliary equipment that are necessary for successful electric fishing (nets, lights

etc)

The following is the complete list of electric fishing equipment that has been used in this

research (Pictures 4.7.1 and 4.7.2).

• A petrol powered portable backpack shocking unit with safety kill switch,

anode ring and rat tail cathode.

• Chest waders, elbow length rubber gloves and polarized sunglasses

• Dip nets of different sizes

• Small and large holding buckets

• Protocols and writing utensils

4 Electrofishing

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4.5 Uses and significances of electric fishing: Electro-fishing is one of the key tools available to fisheries management. This tool is

already in extensive use in developed countries, while the developing countries are just

beginning. The Environment Protection Agency (EPA 2004) of the United States puts

electro-fishing as an invaluable tool for fisheries biologists and aquatic scientists, which if

used properly can provide a wealth of information and insight for managing some of the

nations most precious resources. The agency further adds that this method of collecting fish

can be one of the best methods for non-lethal collections of resident fish species, allowing

the scientist to temporarily collect organisms and retain them in an aerated holding tank

until the right number, size, sex, or species have been collected.

Similarly, Burridge et al (1990) has reported that the electric fishing was established early

in the last century and has acknowledged that it has continued to grow in popularity. It is

used successfully in various habitats and environments, and is an accepted method for both

commercial fishing and fisheries research worldwide. Allen-Gil (2002) also asserts that

electrofishing is one of the most common techniques used in freshwater fisheries research.

Similar remark was made by Hickley et al, Malvestuto et al, Amiro, Penczak et al, Eloranta,

and Bird and Cowx (Cowx 1990 and the references therein). Lagler (1978) adds that this

method is one of the least selective of all active fishing methods.

Lamarque (1990) has reported that between 1967 and 1987, 439 fishing operations were

carried out in 15 countries in a range of biotopes including brooks, rivers, natural and fish

farm ponds, fresh and brackish lagoons, lakes estuaries, mangroves and the sea. During

these operations a great diversity of fish species (700) and crustacea (50) were encountered

at temperature ranging between 5 and 33°C and conductivity between 7 and 40,000μS/cm.

Such was his conclusion that with this the most efficient equipment and techniques for

fishing in different waters and catching different species were determined. Since then the

electro-fishing operations has been more intense, wide and more global, thus increasing the

horizon and amount of results by many folds.

Regarding the type of electric fishing method, still classical wading outscores other

methods. Steinmetz (1990) has also found that the classical wading is the most used method

followed by classical boat fishing, trawling and screening or guiding. This also suggests that

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streams, brooks and small rivers with suitable depth for wading are the sites where most of

the electric fishing operation is carried out. Steinmetz (1990) too, in his survey found that

the water types most frequently electric fished were brooks and rivers.

The main purposes for electro-fishing are stock assessment, sampling/health surveys, tag

fish, catching spawners, anaesthetizing or eliminating species. In US, EPA and most of the

other state agencies uses electrofishing as the primary methods for assessing fish

communities in stream monitoring programs. In his study, Steinmetz (1990) found that the

most important purpose of electric fishing is stock assessment followed by sampling/health

survey, tagging fish, catching spawners, anaesthetize and least for eliminating species. It

should be noted that all these activities could be needed to study the impacts of various

disturbances on water bodies and thus it can be concluded that the electric fishing is a major

operating method to evaluate biotic integrity or overall ecological integrity of the aquatic

habitat.

4.6 Safety and precautions: It is an age old saying, "never mix water with electricity". Obviously, electro-fishing can be

dangerous and hazardous if certain precautions and safety measures are not taken. The

electric fishing has evolved from homemade equipment, over 100 years back, primarily by

fishery workers with little or no electrical experience. Accidents were frequent then and

thus, the safety measures and precautions too have evolved to present state where the

accidents during the operations are minimized. Due to the growing concern of safety, the

equipment produced these days is designed to be accident free if handled according to the

prescription.

Not only the equipment, due to the ever-present dangers and continual reports of accidents

and close calls, many jurisdictions have started to police themselves (Goodchild 1990). As a

result, United States and many European countries where the electric fishing has become

indispensable, have formal policies, regulations and guidelines for the operation and

equipment. Some of these countries also have formal training programs for electric fishing

and associated first aid and some of them even have the provision of license for the

operation.

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The main hazard during electric fishing is the electric shock that results in ventricular

fibrillation (uncoordinated asynchronous contraction of the ventricular muscle fibers),

respiratory arrest and asphyxia (chest muscles contracting and not releasing) in the

descending order of severity. Besides the electric shock, another common risk is the

drowning in water that is facilitated by electric current in water. The third category of risk

are the secondary injury caused by the shock by making a person lose their footing and

balance, by fire and heat from the engine, and a kind of noise fatigue.

However, the risks and hazards associated with electric fishing is highly reduced and

minimized due to the advances in the equipment and policies as mentioned before. In fact

there is a specified Code of Practice reviewed by the Safety Requirements panel that was

presented in the 15th session of EIFAC in Gothenburg in 1988 (Cowx and Lamarque 1990).

In any case, Goodchild (1990) has made recommendations in three parts. The first part

concerns with the equipment and include designing and construction from qualified person,

generators with sufficient capacity and readable meters and gauges, easy control systems,

warning devices, specific plugs to avoid incorrect connection, right dip nets and hand-held

anodes, and with color codes and labels.

The second part concerns with the personnel and demands that the all persons involved in

electric fishing should be trained in the basic principles of electricity and operation of

electric fishing equipment and basic first aid. The crew leader must accept the fact that the

first important thing in an operation is the safety. The third part emphasizes the strict

following of safe operation procedures and guidelines and that includes a routine inspection

and maintenance of equipment, to keeping logbooks and instruction guides. If all these

recommendations are followed, electric fishing would be the safest operation with minimum

risk and hazards.

4.7 Electric fishing in Nepal: In Nepal, there is a rampant use of electricity for fishing in many parts of the country, but is

by a crude hand made gear utilizing the motorcar batteries. The efficiency of this kind of

fishing is in doubt, though there is increasing trend indicating that it is working well.

However, the electric fishing in Nepal so far is not for the studies and research, but for

taking. There is some information that some of the recent hydropower projects might have

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utilized electric fishing during the EIA period, but is not confirmed. Thus, this work could

be the first systematic application of electro-fishing gear in Nepal for research and studies

opening a new horizon for the studies of our streams, rivers, ponds and lakes.

The following is the description of electric fishing gear that has been used in this research.

Model GX50 Mechanic equipment description code GJAG Length Wide Height

249 mm 286 mm 225 mm

Weight (dry) 5,2 Kg Engine type 4 stroke, valve on top, 1 cylinder Cubic capacity 49 cm³ Caliber x run 41.8 x 36.0 mm Maxim engine capacity (Power) 1.8 kW (2.5 PS)/ 7.000 rpm Maxim torsion “par” 3.04 N.m (0.31 kgf-m)/ 4.500 rpm Fuel consumption 340 g/kWh (250 g/PSh) Cooling system Forced air Ignition system Magnetic ignition Axle direction Left Fuel tank capacity 0.5 l Oil tank capacity 0.25 l Engine oil SF or SG; SAE 10W-30 Spark plug NGK: C5HSB, CR5HSB

DENSO: U16FS-UB, U16FSR-UB Table 4.7.1: Specification of the fishing gear used in this work

This electro-fishing gear is a backpack unit and was used for classical wading. The

operation was carried out in 23 sites of 9 rivers in all the seasons spanning from 2003

February to 2004 January, with altitude varying from 140 masl to 1621 masl and

temperature from 8.9 to 31.9°C. During the entire sampling, 27,588 fishes of 47 species

were captured. The main purpose of the sampling is to analyze composition and population

dynamics of the fish to see whether they exhibit sensitivity to different disturbances. The

following pictures (4.7.1 and 4.7.2) show the electric fishing gear and its operation in

Nepalese water.

During all these sampling operations, the safety of the team member was the first priority.

The safety concern was also extended to all the passersby and onlookers who came to see

the sampling as well as the cattle in and around the sampling sites. This series of sampling

has also developed and trained a core group of about 8 persons who are now capable of

4 Electrofishing

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using electric fishing gears independently, at least, a backpack unit and around 20

individuals who are exposed to this sampling procedure sufficiently and these together

could be a valuable human resources to fisheries or any aquatic ecological studies and

research in Nepal.

4 Electrofishing

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Pic. 4.7.1: Electrofishing gear and its use in this research

Pic. 4.7.2: Electrofishing gear and its use in this research

5 Issues in context of Nepal

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CHAPTER V: ISSUES IN CONTEXT OF NEPAL

5.1 Rivers and river system: 5.1.1 An Overview: Being a landlocked country, Nepal consists of only freshwater or inland water resource.

However, Nepal is extremely rich in water resource as could be evident from some of the

forthcoming data. The inland water resource of Nepal includes natural waters such as rivers,

lakes and reservoirs, and also village ponds, marginal swamps and irrigated paddy fields

and equals 818500ha (Khanal 2001). Out of this, the network of rivers and streams, which

are more than 6000 in number alone covers around 395000ha of surface. There are about

1000 of them which are more than 11 km in length and as many as 100 of them that are

longer than 160 km. In total, the length of rivers and its tributaries in Nepal exceeds well

past 45000 km mark. This statistic is unique and amazing when we consider the size of the

country and by any standard, the drainage density of about 0.3 km/km², is very significant.

It is not only the number and area of the rivers and streams in Nepal that highlights the

richness of water resource but also the quantity of water. The total annual runoff from Nepal

including catchments in Tibet is about 222 billion m³/sec with a mean runoff coefficient of

0.777 (MOPE 2000) while the annual mean runoff of all rivers stands at 6,396 m³/sec. The

country is traversed by four major river systems and around 90% of the surface water is

concentrated in these basins. However, there is a big variation in flow as 70 –80% water is

available only during the monsoon mainly between June and September. In any case with

2.27% of the worlds freshwater (CBS 2003), Nepal is regarded as the second richest country

in the world in terms of water resource and the rivers play a significant role in it. The table

5.1.1 illustrates the runoff of the main rivers.


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Drainage Area (Km) Estimated Runoff (m³/sec) SN River Length Total In Nepal From All basins From Nepal 1 Mahakali 223 15260 5410 730 260 2 Karnali 507 44000 41550 1440 1360 3 Babai 190 3270 3270 95 95 4 West Rapti 257 6500 6500 160 160 5 Narayani 332 34960 30090 1820 1570 6 Bagmati 163 3610 3610 180 180 7 Sapta Koshi 513 60400 28140 1670 780 8 Kankai 108 1575 1575 83 83 9 Other Rivers 21432 21432 851 851 Total 1,91,007 1,41,577 7029 5339 Mean Specific Runoff (m³/sec/km²) Annual Runoff (billion m³) Converted Effective Precipitation (mm/year) Average Annual precipitation in Nepal (mm/year) Mean Runoff Coefficient

0,0368 222 1160

0,0377 169 1189 1530 0,777

5.1.1: Estimated Runoff of the Rivers (Source: JICA/DHM, 1993) 5.1.2 Geography and the Rivers: Corresponding to the unique geographical position and geophysical system of Nepal, the

rivers and streams here are diverse and dynamic. Geographically Nepal can be divided into

three regions, running east to west; the Mountain, the Hill and the Terai (Plains). The

mountains, which include high Himalayas with countless snowcapped peaks, constitute the

northern part of the country and occupies about one third (35%) of the land area. Almost all

big perennial rivers flowing through the country originate in this region. This region has a

very tough terrain and difficult climatic condition and thus, has the lowest population of the

entire region. According to the 2001 census, the region has only 7.3% population of the

country (CBS 2003). As such, the rivers in this region have very little anthropogenic

disturbances and appear as natural and pristine. However, natural disturbances cannot be

ruled out as being the youngest mountain chain and still in the process of mountain

formation, the region is very fragile due to the massive geological events.

Attractive peaks, fertile valleys and basins characterize the hill region or the middle

mountain zone. This region takes the largest share (42%) of the land area of the country

with about one tenth of its area being suitable for cultivation. This region being the center of

tradition and culture is inhabited by 44.3% of the total population and is ever increasing.

Even though the slopes of more than 30° are common in this area, people extensively use

land here for agriculture. The results of which are apparent in terms of erosion, slope


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failures, landslides, deforestation, etc. Also because of the easy availability of head due to

steep gradient, this region is also ideal for the construction of hydropower dams and weirs.

There are another sets of thousands of rivers originating from this region. Normally these

rivers are perennial with the source in groundwater but commonly called rain fed rivers as

they heavily depend on the precipitation for their average flow.

The narrow strip of flat alluvial plain, which is also the extension of Gangetic Plain, is the

third geographical region of Nepal. Popularly called as the Terai, it comprises 23% of the

land area of the country but accommodates the highest, 48.4% of the population. This is the

bread zone of the country and is also characterized by dense sub-tropical forest. There are

very few rivers originating here but every river of the country, perennial or seasonal has to

pass from this area before they drain to Ganges on Indian side. The rivers here assume slow

and meandering structure due to the negligible slope, which is less than 1%.

The three geographical division of Nepal appears very simple, but in reality it is much more

complex with at least two prominent transitional zones, one between Himalayas and

Midhills and the other between Midhills and Terai. They are respectively called as High

Mountain Region and Siwalik region. Another series of highly seasonal rivers and streams

originate from this Siwalik region also popularly called as the Churia range. These rivers

are dry most of the times but during monsoon they are very strong and create havoc in

lowland Terai.

In any case the morphology of Nepalese rivers is governed by the unique geo-physical

system and extreme climatic variation. The combination of high altitude, steep gradient and

the force of gravity are the factors for downward movement of materials on to the water

body and the subsequence is the high sediment load in Nepalese rivers. The rivers here,

particularly in hills and mountains are in high velocity cutting and eroding fragile and soft

rocks of the youngest mountain chain forming deep gorges and sharp ‘V’ shaped valleys.

Though the climate of Nepal is diverse with the world’s entire major climatic zone within a

small boundary, it is highly dominated by monsoon and this on its part controls the water

regime. The rainfall in Nepal is condensed into a four months monsoon period between

June to September, which accounts for about 80% of the annual rainfall. Though there are


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pockets of arid and semiarid regions in Nepal, the average annual precipitation is quite high

at 1530mm.

The rivers originating from glacier maintain a sound discharge all round the year because

of the permanent source; on the other hand many mid-hill rivers have to depend upon the

recharge by the rain to avoid drying. While the group of rivers originating from Churia is

more or less seasonal, they have a very high flow during monsoon period and rest of the

time they are dry. Thus these last two types of rivers are totally controlled by the monsoon

climate.

5.1.3 Types of river: The early systematic study on the type and classification of rivers in Nepal had been done in

1977 (Sharma 1977) and is further enhanced and documented by Shrestha (1990), Sharma

(1996), Sharma (1997) and Khanal (2001). According to information based on these work,

the rivers in Nepal can be classified on the basis of these criteria:

i. Origin ii. Availability of water iii. Location i. Rivers according to origin:

This type of classification is based on the age and different orogenies the Hindu-Kush

Himalayan region underwent in the geological age. Being the youngest mountain chain, its

formation can be traced back to a recent few geological ages with a complex method called

plate tectonic. According to this theory, the Eurasian plate was pushed hard by the Indian

plate along the prehistorical Tethys sea probably during late Cretaceous to Eocene period

and the landmass at the point of contact was subsequently raised marking the beginning of

Himalayan orogenies. There are geological evidences to show that some rivers were already

there draining to Tethys sea during this period and quite a few of them survived the tectonic

upheavals and are still continuing. While the other group of rivers originated immediately

after the first tectonic upliftment.

By the further pushing of tectonic plate, the lesser Himalayas, like Mahabharat and Churia,

were formed gradually in different geological ages at a place where the ancient sea was still

persisting and the first groups of rivers were still draining. The first to come into existence


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was the Mahabharat range during Oligocene to Miocene periods and that was the site for the

origin of second categories of rivers. It should also be noted that the typical monsoon

climate of the area was very much helpful in originating and shaping the structure of these

rivers. By then, the first groups of rivers had to increase their length and drainage area.

After this there was a formation of Churia hills during Pleistocene period, and along this

there was the formation of next categories of river channels and the increment of length and

drainage area of the first two. All these rivers from Himalayas in the North and Churia in

south started depositing materials into the sea, which latter on became the Gangetic plane

during the recent period. Thus, the rivers have originated and evolved at different time and

space in this part of the world and could be easily classified according to this criteria into

the following:

a) Antecedent rivers:

The rivers that were in existence before the Himalayas or originated during the beginning of

its formation in Cretaceous to Eocene period form this group. These rivers are normally

perennial with a long length, large drainage areas and a lot of tributaries. The main channels

of rivers such as Kosi, Narayani, Karnali and Mahakali are the example of these rivers in

Nepal.

b) Young post-Mahabharat rivers:

These rivers were formed along with the formation of Mahabharat range during Oligocene

to Miocene period. Bagmati, Babai, Kamala, and Rapti are some example of this kind of

rivers.

c) Younger post-Churia rivers:

These rivers are originated from the southern slope of Churia hills during Pleistocene

period. Aruwa, Ratuwa, Bakra, Handiya, Rate, Hardinath, Amari, Lalbakaya, Mainaha,

Pathraiya, Korah, Kateni etc. are all examples of this group.

d) New rivers:

This group includes rivers originating from Gangetic plain in recent times. They are

relatively short rivers with only first or second order channel in Nepal.


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ii. Rivers according to availability of water:

The basis of this classification is the availability of water during dry season and accordingly

following rivers are found in Nepal

a) The First Grade rivers:

These are perennial snow-fed rivers with their source in glaciers in the Himalayan region.

The big river system of the country, Kosi, Narayani, Karnali and Mahakali with their main

tributaries fall in this group. Since these rivers maintain steady flow throughout the year,

they have a high potential for hydropower and irrigation.

b) The Second Grade rivers:

These rivers are also perennial but originating below snowline with their source in spring or

groundwater. They have a very high fluctuation of flow; in dry season mainly in summer,

the flow is too low but soon in monsoon they swell into the highest level. These rivers too

have a good potential for hydropower and irrigation. Bagmati, Rapti, Babai, Tinau are some

examples of this group.

c) The Third Grade rivers:

These are intermittent and rain-fed rivers mostly originating from Churia range. Since they

dry up during summer and create havoc during monsoon, they have less potential for

hydropower and irrigation. Some examples of this group are Aruwa, Ratuwa, Bakra,

Handiya, Rate, Hardinath, Amari, Lalbakaya, Mainaha, Pathraiya, Korah, and Kateni etc.

iii. Rivers according to the location:

The rivers in Nepal are normally oriented into north – south axis dividing the country into a

number of zones. Broadly there are four major river systems at different places of Nepal

from east to west and another one group in the south. From east to west they are as follows

a) Koshi River System:

Kosi river system, popularly called as Saptakosi is made by the extensive network of seven

tributaries of which Arun, Sunkosi, Tamur, Dudhkosi and Tamakosi are the main elements.

This is the largest river system of Nepal in terms of drainage area and covers a very large

area in eastern Nepal through its tributaries and sub-tributaries. It is a transboundary river

originating from Tibet and draining into Ganges before innervating the major part of eastern


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Nepal. Out of 534 km of total length of the river 35% lies in Nepal and similarly out of

604000 km² catchment area, about 46% lie within Nepal.

b) Narayani River System:

Highly popular because of the social and religious region, the rivers in this system perforate

Central region of Nepal. The main rivers in this system are Kali Gandaki, Trishuli, Budhi

Gandaki, Marsyangdi, Seti and east Rapti. Some of the rivers in this system, like Trishuli

and Budhi Gandaki originate from Tibet while others from high mountains and middle

mountains. One of the main rivers, Kali Gandaki originates from cold and arid region of

Mustang in high mountains and passes through the deepest gorge in the world. 89% of total

catchment area of 34960 km² is in Nepal and almost entire of the 451 km length of the main

channel is within Nepal.

c) Karnali River System:

This river system lies in the western region of Nepal with the main constituents Humla

Karnali, Mugu Karnali, Bheri, Seti and Tila. With the exception of Humla Karnali, all other

river originates within Nepal in the Greater Himalayas. Catchment area of this river system

is 44000 km² and about 94% of this lie within Nepal. This is the longest rive system of all

the river systems in Nepal with main river measuring 550 km and 79% of this is in Nepal.

d) Mahakali River System:

This is the system of Far Western region of Nepal and the river has a status of Boundary

River as most part of it demarcates the western boundary of Nepal with India. The main

rivers of this system are Mahakali, Gauriganga, and Chamelia. The catchment area of this

system is spread into 15260 km² of which 34% lies within Nepal while the main channel is

223 km in length.

e) Southern River System:

This system normally includes all the rivers mainly originating from Mahabharat and

Siwalik range, which are not the members, or tributaries of the major river systems of Nepal

described above within the Nepalese territory. Some of the important southern rivers are,

Babai, Bagmati, Kamala, Kankai and west Rapti etc. When combined all, the catchment

area measures about 16000km².


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In addition to these three types of classification, there is couple of more types mainly

depending upon the biology and its diversity. Shrestha (1990) has classified Nepalese rivers

into the following, based on hydrobiology.

a) Fast streams:

These are torrential streams with high velocity (50cm/sec), rocky bottom with clear water,

and with high oxygen and cool temperature. Biological community here includes

Cladophora, Ulothrix, Caddis fly, snails, shrimps, larva of mayfly, stonefly and dragonfly,

and fishes such as loaches, carp minnows, sucker head fish with adhesive organ and reduced

air bladder.

b) Slow streams:

Deep with muddy, silt and sandy bottom, rate of flow and depth may vary; turbid water;

rooted vegetation in shore and shallow; oxygen lower and temperature higher. The living

world here includes snails and clams, bryzoans, crayfish, earthworms and fishes like

catfishes, murrels, carp minnows, garfishes, feather back and perches.

c) Intermittent streams:

They have very low flow at dry season; almost dry up except in the pools. The life here

includes crustaceans, Caddis fly, pupae and larvae of other insects and fishes like Channa,

Heteropneustes, Mungri, Clarius, Puntius etc. which have efficient air breathing

mechanisms.

d) Springs:

Chemical composition and water velocity constant, devoid of suspended matter and

temperature constant. The life normally includes producer like algae and submerged aquatic

plant, planktons etc.

Similarly, Nepal’s rivers could also be divided into number of zones according to the fish as

an indicator (Shrestha 1990). However this is an arbitrary zonation with no exact

demarcation between the zones with lot of overlapping. The different zones are:


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a) Snow trout zone:

This zone lies between 1800 – 3000 masl and the river is normally fast snow fed or glacier

fed cold water. This zone is dominated by trout (Schizothorax sps.), sucker heads (Garra

sps.) and loaches (Schistura sps.)

b) Stone carp or mixed zone:

This zone ranges between 1200 – 1800m and is truly a mixed zone with still fast flowing

cold water hill stream consisting of the above fishes mixed with stone carp (Psilorhynchus

sps.), catfish (Glyptothorax sps.) and trout (Schizothoraichthys sps.)

c) Hill barble zone:

This zone lies between 600 – 1200 m and the rivers here have slightly slow moving water

with moderate temperature. This zone is famous for sportive fishes like Mahaseer (Tor

sps.), and Katle (Neolissochilus sps.)

d) Major carp zone:

This zone ranges between 150 – 600 m mainly in the Terai characterize by slow and warm

water with dominant fishes such as Rohu (Labeo sps.), Mrigal (Cirrhinus sps.) etc.

Thus, judging by any parameter, the origin, the number, the length, the discharge, the

catchment area and the diversity, rivers are very prominent entity in Nepal. And to add that

with its multiple utilities they become Nepal’s the most important natural resource. Nepal

needs a lot of study and research in this field for its prosperity. The table 5.1.2 illustrates

where each of the rivers (sites) studied in this work stands according to those classifications.


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Classification → Rivers name ↓

Origin Availability of Water

Location Hydrobiology Fish as an indicator

Aandhikhola Young, Post-Mahabharat

Second Grade

Narayani River System

Fast Streams Hill barbed zone

Arungkhola Young, Post-Mahabharat

Second Grade


Fast Streams Major carp zone

Bagmati Young, Post-Mahabharat

Second Grade

Southern River System

Fast Streams Mixed zone

Jhikhukhola Young, Post-Mahabharat

Second Grade

Kosi River System


Karrakhola Young, Post-Mahabharat

Second Grade



Narayani Antecedent First Grade Narayani River System

Fast Streams to Slow Streams

Major carp zone

Rapti Young, Post-Mahabharat

Second Grade



Seti Antecedent First Grade Narayani River System


Tinau Young, Post-Mahabharat

Second Grade

Southern River System

Fast Streams Hill barbed zone to Major carp zone

Table 5.1.2: Classification of the rivers studied in this work 5.2 Scientific studies on Nepalese water: It would be a disregard to numerous scientists, researchers, academicians and explorers to

say that there have been a very little studies on the various aspects of the Nepalese rivers

and streams. With due recognition and appreciation to their contributions it would be

appropriate to conclude that the studies are little and highly concentrated to a certain rivers

or sections but also interesting and encouraging. Though Nepal is a small country, the

diversity of the climatic condition overrules every natural entity to be as diverse as it is. It

may be the physical features or it may be biological community, all are diverse making it

difficult but very interesting study. Extensive as well as intensive studies and investigation

of all the rivers and streams are still sought for but will occur in time with more people

involved.


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The scientific studies mentioned above include all aspects of aquatic system such as

hydrological features, fish and other aquatic lives, disturbances and pollutions, conservation

and development of water resource etc. Some works like those of Swar (1980), Rajbanshi

(1982), IUCN (1991), and Shrestha (1995) have comprehensively reviewed all available

work done in Nepal concerning different aspects of aquatic ecosystem. Sharma (1996) has a

list of biological expedition carried out in different time and places in Nepal and

surrounding areas. From those sources and also from the references by many others, these

studies can be broadly categorized into three phases belonging to different time frames.

5.2.1 Early phase: Here it includes all the initial studies of Nepalese water before Nepal opened up to the

outside world during 1950’s. Most of the work in this phase was restricted to historical,

cultural and religious account of Nepalese rivers and lakes. However, a few scientific

studies can still be traced back from this period. It is interesting to note that the initial

scientific studies of Nepalese water were mainly focused in the studies of fishes. The first

perhaps is the one by Hamilton (1822) where he studies the fishes found in river Ganges

and its branches and some of the important tributaries of this river flow from Nepal.

This work is followed by a list of Gunthur (1861) that enlists the cold-blooded vertebrates

from Nepal and includes large number of fishes. Then comes the works of Day (1878)

titled, “The Fishes of India” and another (1889) titled, “The Fauna of British India including

Ceylon and Burma”, which is a very comprehensive study of the number of fishes found in

this region including Nepal, incorporating both, the description and the diagrammatic

illustration. Such is the significance of this publication that even today all scientists

involved in fisheries in this region crosscheck their sample with this one for initial

taxonomic purpose. And also the present work has done so.

The other prominent works from this period are reports by Boulenger (1907) and Regan

(1907). The former report has a collection of batrachians, reptiles and fishes from Nepal and

the western Himalayas while the latter is concentrated on the fish but of the same

geographical region. Both of these reports are in records in Indian Museum. Perhaps, the

last work that could be mentioned from this phase is that of Menon (1949) in his study

called, “Notes on Fishes in India” where he has given account of the fishes from Kosi

Himalayas too.


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One thing interesting to note here is that Nepal first saw its hydroelectric plant during this

period. The first one with a small 500 kilowatt (KW) capacity was commissioned in 1911 at

Pharping in Kathmandu valley and the second one with similar capacity in 1936 at

Sundarijal again in the valley. There are no details of the study of hydrology and

environment prior to these setups except for some figures such as dates of commission,

dam’s length and height and the capacity of production. Since the ruler of Nepal at that time

had a good relationship with British India, it could be anticipated that these plants were

installed with British technical assistance. In any case, the main purpose of these plants at

that time was to light the palaces of the rulers, thus, as an element of luxury rather than that

of production.

Apart from those mentioned above not many literatures related with hydrobiology and

aquatic ecology regarding Nepal have been mentioned by authors from this time. In

addition, the work done on those subjects by Nepalese is not documented at all. This

indicates the overall academic and scientific scenario of the country at that time, which was

very poor. The entire country was a closed system with ruler suppressing the people and

with a very few educational institutions, that too only for ruling class and elites.

5.2.2 Middle phase: The middle phase of the studies on the Nepalese waters started from 1952, when the country

opened itself to the outside world following the downfall of a very long family governance

of Ranas. Until then the country was almost virgin and thus in the beginning there were a

series of scientific expeditions led by the foreign nationals. Sharma (1996) has a table

listing at least 17 large scales scientific expeditions carried out by the experts from different

countries during this phase. This was also the time when the government allowed and

initiated widespread studies on geography, population and some of its natural resources like

water and forest, as it was needed for planning and implementing developmental works.

This phase began with one of the all time most important studies of fishes in Nepal by Hora

(1952) in his work called “The Himalayan Fishes”. Taft (1955) had a survey of the fisheries

of Nepal through Nepal American Agriculture Co-operative Service. In the same year

Hirono (1955) had the result of the Japanese Expedition to Nepal Himalayas for Freshwater

Algae, Fauna and Flora. Another major contribution to the Ichthyology of Nepal comes

from De Witt (1960). The year 1961 is marked by two expeditions, Expedition of the


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Research Scheme Nepal Himalaya in the Khumbu Himal and German and Austrian

Expeditions to Nepal. Also Datta (1961) came up with the zoological results of the Indian

Cho-yu expedition.

Menon (1962) continued to his earlier work and published ‘A Distributional List of Fishes

of the Himalayas’. Meanwhile Zwelling (1962) sent a report to the Government of Nepal on

fish culture development. There was another Japanese expedition, Himalayan Expedition of

Chiba University, in the year 1963. Once again, Menon (1964) spotted Psilorhynchus

pseudecheneis, as a new cyprinid fish from Nepal. Then there were a couple of notable

expeditions till 1970, the one being the Canadian Expedition to Nepal (1967) while the

other, German and Austrian Expeditions to Nepal (1970).

Till this time there was hardly any contribution from Nepali scholar and scientists in this

field as could be evident from the works mentioned above. In fact, Nepalese scientists were

on making during this phase. However, the government was doing tremendous effort to

gather all possible information in these fields with collaborative works with foreign

nationals and organizations. Several new departments such as Department of Hydrology and

Meteorology, Department of Fisheries etc. were created. These departments on their part

started working by establishing the working stations at different places. Another major

achievement of this time was the documentation and quantification of rivers in Nepal and

their potentials for hydropower and irrigation. Thus, a number of studies on the major river

basins started in this time.

As hinted before, there is a solid emergence of Nepalese scholars and scientists in the field

of hydrology, fishery and aquatic ecosystem especially from the second half of the decade

of 70’s. But to begin with, Menon (1971) had the taxonomy of fishes of the genus

Schizothorax, which is a dominant fish of cold waters in Himalayas. The next year

Banarescu (1972) published, “A Contribution to the Knowledge of Cyprinoidei from Nepal,

Khumbu Himal. In the same time Majumdar (1972) together with Majupuria T.C. and

Shrestha J. had the New Records of Fish from Nepal. This could be perhaps the first entry

of Nepalese scientist in the literature list of fishery biology and could also be one of the

most dominant one. There were also two consecutive expeditions, “The Netherlands Center

for Alpine Biological Research” in the years 1972 and 1973 respectively that too

contributed in this field.


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The next year, Atkinson (1974) described the fish fauna of Nepal in his work titled, “Fauna

of the Himalayas containing species of Kumaon, Garhwal, Nepal and Tibet”. Then came the

work of Shrestha (1975) with his doctoral thesis, “Studies on the Structure and Seasonal

changes in the Gonads of Two fishes of Nepal”. Those two works, Shrestha (1972) and

Shrestha (1975) marked the beginning and dominance of Nepalese scientist in the field of

Fishery biology in Nepal. While the former focused herself on fish and has contributed

substantially in this field in Nepal, the latter has ventured to a wider area.

From production side, Woynarovich (1975) published an elementary guide to fish culture in

Nepal. One of the well-known fishery scientists of Nepal, Rajbanshi (1976) came up with

the work at species level in his work, “Looping of Snow Trout, Asala”. Next year Sharma

(1977) published the first comprehensive work on the River Systems of Nepal. This book,

probably the first one in its category is still a very handy one for a variety of information

regarding rivers in Nepal. This work has also opened the path for many scholars and

scientist to diversify their studies on water resource rather than limiting themselves to fish.

Sharma (1978) studied the quality of drinking water in Kathmandu. The same year Prosser

(1978) prepared an environmental report in Gandaki River Basin, Power Study. The study

on fish also went side by side with Shrestha (1978) continuing with seasonal changes in the

testes of Garra gotyla gotyla and Pradhan (1979) submitting report on cage fish culture in

Nepal to the Department of Fisheries. Finally there was another report by Shrestha (1979)

on aquatic ecology and the potential of fisheries development in Bagmati River for GTZ.

In short, the middle phase of the study on Nepalese water and aquatic ecosystem was very

important in many ways. There was a gathering of a lot of primary and baseline data on the

above field, emergence of Nepalese scholars and specialists on the field and the

diversification of the theme from mere fishery studies to geology, morphology, pollution,

and the conservation and development of the resources.

5.2.3 Modern Phase: All the work, research and publication, done in the field from 1980 onwards, could be put

together in this modern phase. The phase starts with Swar (1980) presenting the status of

limnological studies and research in Nepal at the conference in Kyoto. It is followed by

some monumental works on fisheries. Shrestha (1981) published Fishes of Nepal, a long


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wanted publication. Jayaram (1981) had the Freshwater Fishes of India, which is a good

taxonomical work where the species of Nepal too were included. The same year Shrestha

(1981) studied the pollution in river Bagmati with biological indicators, probably a first of

its kind in Nepal.

Then, Rajbanshi (1982) had another contribution to the nation on fisheries science with his

‘General Bibliography of Fish and Fisheries of Nepal. Another general but very useful

contribution regarding rivers of Nepal came from Shrestha (1983) published in Nepal

Digest. Terashima (1984) worked in a remote lake named Rara in Nepal and came up with

three new species of the Cyprinoid’s Genus Schizothorax, which were found to be

indigenous to Nepal and enriched the diversity of fishes in Nepal.

There was an ecological survey of the Narayani River within the Royal Chitwan National

Park by Edinburgh University Expedition to Nepal during 1984-1985 and the report was

submitted to the King Mahendra Trust for Nature Conservation. The new records of fishes

in Nepal continued with Edds (1985) and he also had the list of “The Fishes of Royal

Chitwan National Park (1986)”. The same year he also had ‘Fisheries of Kali

Gandaki/Narayani Rivers published. Shrestha (1988) worked on the important game fish of

Nepal, Tor sps. (Mahaseer) and published ‘Ranching Mahaseer in the Himalayan Water of

Nepal’, which includes important ecological and biological aspects of the fish.

Meanwhile, one of the great ichthyologists, Menon (1987) of the region was still

contributing to our knowledge about the fish with ‘The Fauna of India and Adjacent

Countries’, which is very helpful for taxonomy and quick information. Shrestha (1988)

came up with yet another diverse study, environment of Gangetic Dolphin in Kosi River.

Rai and Swar (1989) worked on a single species, Acrossocheilus hexagonolepis now

modified as Neolissochilus hexagonolepis and is published in FAO Fisheries Report. In the

similar way Sharma (1989) checked the status of Schizothorax sps. in Indian-Chinese

Subcontinent and is also published in FAO Fishery Report. The same year there was a

feasibility study of Karnali-Chisapani Multipurpose Project for Ministry of Water

Resources by Himalayan Power Consultants.

Shrestha (1990) came up with another couple of works, the first being the ‘Resources

Ecology of the Himalayan Waters’ and the next, ‘Rare fishes of Himalayan Waters of


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Nepal’. Shrestha (1991) submitted a report on cold water fish and fisheries of Nepal to

FAO. Talwar and Jhingran (1991) came up with their comprehensive taxonomic work,

Inland Fishes of India and Adjacent Countries in two volumes. This is one of the

publications most extensively used by the scientists in this region for the purpose of

identification of fishes. There are series of reports or papers by Shrestha for the next few

years - The role, scope and importance of natural Water Resources for increased fish

production in Nepal in 1992, Fisheries studies in Karnali River for Himalayan Power

Consultants in 1992 and Fish Biodiversity of Wetland System of Kosi Tappu Wildlife

reserve and Adjacent Areas for Department of National Park and Wildlife Conservation in

1993. In the meantime, Shrestha (1992) also contributed with his ‘Fishery Biology Study of

Melamchi River’.

Shrestha (1994) published ‘Fishes, Fishing Implements and Methods of Nepal’. This book

lists most of the species of fishes discovered so far in Nepal with diagrams and some color

photos and thus is handy to carry to the field for quick taxonomic purpose. The next year,

1995, she enumerated the fishes of Nepal for HMG/N and Govt. of Netherlands. During the

same period Subba (1995 and 1996) found the new record of hill stream fish, Olyra

longicaudata and pygmy barb, Puntius phuntunio from Nepal while Swar (1996) made a

taxonomic review of Katle, Neolissochilus hexagonolepis.

Sharma (1996) gave a new dimension to the studies of aquatic systems in Nepal. He was the

first to use macrozoobenthos to determine the water quality. He came up with NEPBIOS,

the first scientific water quality index applicable to Nepalese water and opened up a new

area of study. Swar and Shrestha (1997) had a paper on human impacts on aquatic

ecosystems and native fishes of Nepal, linking disturbances and biotic community of

aquatic systems. Pradhan (1998) picked the line of benthos and modified the NEPBIOS into

NEPBIO-brs while working on Bagmati River System. Meanwhile Sharma (1998)

published a list of aquatic insects of Nepal that could be used as bio-indicators of water

pollution.

Jayaram (1999) then published his latest book, ‘The Fresh Water Fishes of Indian Region’

that could be taken as the final work till now for the taxonomy of the fishes found in this

region. That is the reason Shrestha (2001) had a taxonomic revision of fishes of Nepal based

on the above publication and summed up with 182 species belonging to 93 genera under 31


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families and 11 orders respectively. With the advent of the new century Rajbanshi (2001)

published zoogeographical distribution and the status of coldwater fish in Nepal at river

system level. Likewise Khanal (2001) introduced disturbance ecology to Nepal and studied

different types of disturbances prevalent in Nepalese water by taking benthos as indicators.

Besides all these studies, there is a big series of literature on water resources regarding its

social, economical and political dimensions. These literatures emerged from middle phase

where messages mostly given were optimistic, like water is our wealth, our water is pure

and virgin, our water has a potential to rescue us from poverty as could be evident from

potential for energy and irrigation etc. But during the modern phase a lot of critical and

sensitizing thought also made appearance. Some important names expressing such thoughts

regarding water resources are Ajay Dixit, Dipak Gyawali, Bikash Thapa and A.B.Thapa

The reasons behind are acute water shortages at different parts of the country, pollution,

inability to generate the electricity demands of the country, people forced to pay one of the

highest tariff for electricity in the region, commissions and lack of far sightedness shown by

the planners and politicians in the treaties and contracts with other parties and, in general,

our inability to harness our vast water resource.

In short, there are a number of scientific studies and research done in Nepalese water, but

due to its volume and potential these studies look scant and with gaps. There should be

some authority responsible for gathering and building up of information and primary data.

They can start with collecting works from hundreds of graduate dissertations, which go

unnoticed after its defense. This will certainly bridge the gaps on information regarding our

resource. Likewise, the government or any competent authorities have to establish as many

monitoring center as possible so that there is uninterrupted supply of sufficient data. One

good trend is the increasing number of Nepalese scholars in this field and it should

continue.

5.3 Fishes of Nepal: Nepal is exceptionally rich in biodiversity and the diversity in fish is no exception. There

are many reasons for this. First, Nepal is very rich in water resource with more than 6000

rivers and streams together with numerous lakes and ponds. Second, Nepal has a very large

range of climatic zones, from subtropical to alpine, corresponding to its range of altitude


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that scales from about 50 masl to the worlds highest point. Third, Nepal is a meeting point

of two large biogeographical realms, Indo-Malayan and Palaearctic, and thus the species

from both converge here. Therefore, it is only natural that a large number of fish species are

found in Nepal. However, the only limitation is that being landlocked, the species occurring

here are freshwater type and not marine.

It is evident from the previous heading that fairly a good number of studies and research

have been carried out in the area of fish and fisheries in Nepal compare to the other fields of

hydrology and aquatic ecosystem. The fishes of Nepal have been recorded as early as in

1822 by Hamilton and have been included in the work of many scientists such as Gunther

(1861), Day (1889), Regan (1907), Menon (1949, 1987), Hora (1952), Jayaram (1981,

1999), Shrestha (1981, 1994, 1995, 1998, 2001), Shrestha (1994), Subba (1995), Talwar and

Jhingran (1991) and Rajbanshi (1982, 2001). However, the total number of fish reported

from Nepal varies in their works. Even the most reliable site on the internet

(www.fishbase.org) counts it to be 155 species, which is different from many authors. In

addition, there are some confusion also in the systematic position of some species, like the

orders, families and genera.

This situation has been improved mainly by the effort of Shrestha (2001) who did a

thorough taxonomic revision of her own earlier work (1995) where she had reported 185

species from Nepal. She has based her classification after the latest work of Jayaram (1999)

and came up with a total of 182 species belonging to 93 genera under 31 families and 11

orders. The list of fishes from Nepal appended (appendix IV) is mainly taken from this

work but are verified also with Day (1878), Talwar and Jhingran (1991), Rajbanshi (2001)

and the website, www.fishbase.org. Since, this work is not purely a taxonomic work and

also to make it simple, only the order, family and a genus is given to each species without

going into intermediate positions such as suborder and subfamily. The species, which were

caught during this research, is marked by the symbol *.

5.4 River disturbances in Nepal: In general, the rivers and streams in Nepal are so numerous that till now the disturbances on

them is not sufficiently documented. In fact, many rivers and streams and their sections are

still assumed to be pure, virgin and without any anthropological disturbances. This could be

http://www.fishbase.org/



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the reason that the rivers and streams are religiously referred to as a sacred place and also

worshipped as a mother Goddess. The predominant Hindu religion of the country observes

the rivers and streams as a symbol of freshness, continuity and eternity. It is believed that a

dip in the river, specially the one that has the established cultural and religious value, has a

potential to wash away all the dirts, sins and curses of a person.

From historical times, the rivers here are in multiple uses such as irrigation, water supply

for drinking and washing, recreation, subsistence fishing and transportation. In addition,

they have been used as a dumping site for industrial and household wastes probably because

the people had the crude knowledge about the carrying capacity and self-purification ability

of rivers. Despite all those uses from ancient time, the disturbances on Nepalese rivers with

some adverse effects are recent phenomena. This could be mainly attributed to a huge

population growth with increasing urban center, large-scale construction of dams and weirs

for electricity and irrigation, commencement of large and medium scale industries and the

evolution of chemical intensive modern agricultural practices.

Khanal (2001) distinguishes the river disturbances in Nepal into two types, Natural and

Anthropological. As mentioned before, Nepal is situated in a geologically active area where

the making of Himalayas is still on the process and thus it is natural that the rivers are not

sparred of the natural disturbances and disasters. This has also been confirmed by many

reports and studies regarding natural disasters in Nepal.

Some of the important natural events that lead to disaster are earthquakes, glacial lakes

outburst floods (GLOFs) and bursting of artificial landslide dam. The frequency of

earthquake is common with highly destructive one in about 50 years while the frequencies

of latter two are one in ten years. Likewise there are some annual events such as cloud

burst, heavy rainfall, landslides (rockslides, soil creep and debris flow), soil erosion, flood

and drought. All these are natural events in the country and they disturb the rivers and

streams.

While a little could be done to prevent these natural events except to take some precautions,

there is another type of disturbance, human disturbance, which is on the rise and a lot can be

done here to prevent massive disturbances. There is a wide list of human disturbances in

Nepalese rivers and streams identified by Khanal (2001). Hydraulic and hydrological


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disturbances include the construction of dams and impoundments, levees, canals, roads,

bridges, culverts and embankments for various purposes such as hydropower generation,

irrigation, water supply and transportation. Physical disturbances include substrate removal

from river bed, river bank and floodplain while chemical disturbances come from washing

(clothes, vehicles, carpets), mining practices, industrial waste, solid waste from

municipalities, modern agricultural practices (fertilizers and pesticides), and the banks used

in lieu of the public toilets.

There are even some disturbances coming from cultural/religious practice such as

cremation, and feast involving mass bathing and religious offerings on one hand and on the

other by the recreational activities such as picnic, fishing and rafting. But these disturbances

are highly localized to certain sections of certain rivers. At the catchment level, haphazard

settlements, overgrazing, intensive agriculture, deforestation and road constructions add to

the river disturbances. This work would focus on the following four types of human

disturbances on Nepalese rivers and streams.

5.4.1 Agriculture: Agriculture is the most important and dominant economic activity in Nepal. It contributes to

about 42% of the GDP and usually about one quarter of the country’s development budget

is allocated to this sector (MOPE 2001). Though, the land use pattern of the country shows

just 20.2% land under cultivation, over 80% of the total population still depends on

agriculture for subsistence of living. The paradox is that about 1.7 million ha. of agriculture

land, which accounts for almost 65% of the total cultivated land is still rainfed indicating

the general lack of irrigation facility and dependency on the monsoon.

The engagement of such a large chunk of Nepalese in agriculture is perhaps because

Nepalese society is predominantly a rural society with about 88% of them living in the rural

areas without industries, offices and business opportunities. Based on the estimated

population of 2001 (CBS 2003), Nepal has one of the highest population densities in the

world with respect to cultivable land at nearly eight persons per hectare. However, all this

population is not engaged in crop production. The people are also engaged in some of the

other agriculture sector such as livestock and fisheries. In any case, sometimes the three sub

sectors and most of the time at least two, go together.


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Out of total agricultural GDP, livestock contributes 31% and is thus very significant. In

addition to the production of milk and meat, it also provides animal power and manure to

farmland for maintenance of soil fertility. The country is also experiencing the increasing

trend of number of livestock. Between 1984 to 1998 there was an increment of 15% in their

number. This does not match with the area of pastureland, which remains more or less

constant at 1.7 million hectare and is thus, putting pressure to pastures and forests.

Likewise, the fish, which forms the major source of protein to the rural Nepalese, is too in

the increasing trend. The total production of fish in 1999/2000 was 31.7 thousand metric

tones compared to mere 4.3 thousand metric tones in 1982/83. About 55% of the total fish is

produced in rivers, lakes, paddy field, cage culture and reservoirs while the remaining is

produced in ponds. There are at present 22 thousand fish raising ponds in the country,

mostly in Terai and its total area has reached 8,840 ha.

Some of the important disturbances to the rivers and streams from agriculture come from

the landslides and soil erosion due to faulty agricultural practices on steep slopes, runoff of

chemicals such as fertilizers and pesticides and introduction of new and exotic species. Of

these, the second one is strictly man made disturbance, which is more harmful to Nepalese

rivers than the third, which too is a man made disturbance. The disturbance caused by the

new intensive agricultural practice has proliferated into our rural areas and is now a serious

threat to our once pure and virgin water. Some of the studies of selected areas in our region

show that deterioration of water quality is quite alarming, particularly in small rivers,

streams and shallow groundwater.

The main reason behind this is the chemical intensive so-called "Modern Agriculture" that

encourages the blind and indiscriminate use of chemical fertilizers, pesticides and broad-

spectrum antibiotics. The first introduction of mineral fertilizers in Nepal was in 1952 and

in 1954 the consumption was 10 tons. It was in 1965/66, with the establishment of

Agricultural Inputs Corporation (AIC), that organized supply of fertilizers, actually, began

in the kingdom. There is no domestic production of synthetic fertilizer in Nepal and thus, all

requirements are met through imports.

The use of chemical fertilizers (NPK) per hectare alone has increased tremendously from

7.6 kg in 1975 to 26.6 kg in1998 (MOPE 2001). However, after that it is in a decreasing


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trend. This could be evident from the other set of data that says the consumption of

chemical fertilizer was 2069 metric tonnes in 1965/66 and went up to 185,797 metric tonnes

in 1994/95 before declining to 148,187 metric tones. The forthcoming table illustrates the

import and consumption of chemical fertilizers in Nepal by type from 1997 to 2002 in

metric tonnes:

N (Nitrogen) P (Phosphorus) K (Potassium) Total Year Import Consumption Import Consumption Import Consumption Import Consumption

1997/98 51429 32629 5222 13124 - 1442 56651 47195 1998/99 28440 32314 17800 12097 - 1258 46240 45669 1999/2000 13800 25034 - 12031 - 185 13800 71460 2000/01 - 16397 - 7191 - 35 - 23623 2001/02 2250 11857 5750 9597 - 610 8000 21964

Table 5.4.1: Consumption of chemical fertilizers in Nepal by type Source: CBS 2003

Fertilizer usage in Nepal was very low at 35kg/ha/annum in 1997/1998 as maximum

national average consumption, which is the lowest after Bhutan in the South Asian region.

However, it increased remarkably to 57.9 Kg/ha/annum in 2000/2001 (ANZDEC 2001) and

the government plan is there to raise the overall average fertilizer use to 150 kg/ha/annum

by the year 2015. Thus, so far the amount of fertilizer use is not a problem in Nepal, but its

inappropriate use coupled with steep slope and torrential monsoon rain resulting in heavy

runoff, land slides and soil erosion has some effect on the rivers and streams as these

chemicals finally make their way into it.

Another group of agro-chemical that finds its usage in agriculture is the pesticides that are

generally poisonous substances for preventing, controlling, destroying, repelling or

mitigating pests. Pesticide use in Nepal has increased significantly in recent times due to the

access to the market and the farmer’s desire for high productivity. The national average

consumption of pesticide is estimated to be 650 g/ha (MOPE 1998) in commercial farming,

which is very high compare to the other countries in the region. According to the

Directorate of Plant Protection (DOPP), the country imported 33356 kg of insecticides,

15577 kg of fungicides/bactericides, 6748 kg of herbicides and 400 kg of rodenticides in the

year 1997. The total consumption of pesticides in the country is approximately 55 tonnes of

active ingredients per year (MOPE 2001). These figures could have been much more if

there were monitoring of trade between Nepal and India, which share an open border.


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At present, there is only one pesticides/insecticides factory in the country and is unable to

fulfill the country’s demand. AIC and other private dealers import and sell the items for

agricultural use. Nepal, also receives a large quantity of these toxic chemicals through

donation and international aid mechanisms in order to open markets. HMG of Nepal

adopted the Pesticides Act in 1991 and Pesticides regulation in 1993. In accordance of these

laws, Nepal has established the Nepal Pesticide Board (NPB) that will assist the government

in formulating pesticides policies and adopting regulatory measures for the safe use of

these. Among actions against toxic chemicals in the agriculture sector, Nepal has banned

the use of 12 of them including DDT, BHC and Aldrin through the Pesticides Act but

practical implementation is still questionable.

The pesticides, mostly insecticides, used in Nepal belong to highly persistent (Organo-

Chlorine) group. The commonly used insecticides in the country continue to include DDT,

BHC-dust, Aldrin and Endosulphers. Frequently these pesticides are either misused or

overused mainly due to the lack of knowledge. Rice being a traditional and an economically

important crop, farmers use the largest quantity of pesticides on it, but the number of

applications is more on vegetables. The residues of pesticides have been detected in various

crops such as rice, wheat, and pulse grains, and even in the milk.

These toxic chemicals, often called as the ‘chemicals of imperialism’ are produced in the

western market and are dumped in the developing countries when they realize the chemicals

are highly toxic and threat to health and environment. Some of these dangerous substances

like chlorinated organomercury compounds are found just on the outskirts of Kathmandu,

densely populated capital of Nepal, originate from German chemical company, Bayer and is

already banned for use in the European Union since 1988. This highlights how Nepal has

become a victim by becoming a dumping site of date expired, outdated and highly toxic

chemicals coming from multinational companies of developed countries.

Date-expired chemical pesticides are a serious problem in Nepal as it lacks the means of

disposal of these. A New Zealand based consulting company, ANZDEC Ltd. was

contracted to carry out the task of disposing 137 MT of pesticides and also to prepare

pesticides regulations for Nepal (NCS 1994). From AIC’s inventory of 137 MT of date-

expired pesticides, about 70 MT were buried or spread in Amlekhgunj, Siddarthnagar,

Nepalgunj and Biratnagar under the supervision of foreign consultants. But when a review


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of burial sites by another foreign consultants were done, it was revealed that the

Amlekhgunj burial was a public health hazard. In addition, there could be more than 20 MT

of chemical pesticides still in the godown at Amlekhgunj and another 67 tonnes are

stockpiled in unsafe conditions at various locations in the country (MOPE 2001)

While, there are agriculturists who relate the decreasing fertility of Nepalese soil with the

overuse of pesticides, the consequences of it on the water and aquatic lives are very little

studied and discussed. The water regime is the potential final place where these toxic

chemicals find their way. The most important way through which these chemicals are

transferred to water is by runoff. Washing vegetables in open water such as ponds and rivers

is also very common and through this also these pesticides find water. In addition, using

toxic chemicals directly in water for fishing by poisoning is also increasing. Just like in soil,

in water too, the bioaccumulation and biomagnifications of these chemicals take place and

affect the entire food chain. The following figure illustrates this process.

DDT in water DDT in Zooplankton DDT in small fish DDT in large fish DDT in fish-eating birds 0.000003 ppm 0.04 ppm 0.5 ppm 2 ppm 25 ppm

Fig. 5.4.1: Bioaccumulation and Biomagnifications Source: Cunningham and Saigo (1999)

Thus, two important agricultural inputs, fertilizers and the pesticides together with the weirs

constructed for irrigation, collectively, affect the rivers and its ecology. The most affected

aquatic life with these factors is obviously the fish. There has been very little study on this

area. As such, this field is a very important field and this study intends to facilitate the

further research in the field.

5.4.2 City (Urbanization): Urbanization generally refers to the process of growth in the proportion of population living

in the urban areas. Some characteristics of urbanization are the distinctive division of labor,

DDT accumulation in food chain


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technology based production of goods, trade of goods and services, high level of spatial and

economic interaction and relatively high density and diversity of population. There is a big

problem of definition in the study of Nepal’s urbanization as there is no consistency of it on

the areas designated as ‘urban’. This situation is more or less addressed by the Municipality

Act of 1992, and the Local Self Governance Act of 1999, which redefine and classify the

urban areas into three municipal areas, Metropolitan city, Sub-Metropolitan city and

Municipality (CBS 2003). Each category is classified by taking population size, annual

revenue and basic services and facilities into consideration.

Nepal is basically a rural society with most of the population living in villages. It remains

one of the least urbanized countries in the world and also in South Asia. According to the

latest census, around 3.2 million people live in urban areas, which is 13.9% of the total

population (CBS 2003). However, urban areas have increased and developed haphazardly

without any plan and projections creating wide range of problems that touch all sectors such

as, environment, economy and society. In 1952/54, when there was the first census in

Nepal, number of municipal areas in the country was just 10, which increased to 23 in 1981

and 58 in 2001. Similarly in the first census, urban population, as percent of rural

population, was 3 that jumped to 6.8 in 1981 and to 16.2 in 2001. The table next shows the

growth in urban population and urban places in Nepal from 1952 to 2001.

Census Year

Urban Population (in ‘000)

Number of Urban Places

Percent of Population Urban

Intercensal Increase (Percent)

1952/54 238.3 10 2.9 1961 336.2 16 3.6 41.1 1971 461.9 16 4.0 37.4 1981 956.7 23 6.4 107.1 1991 1695.7 33 9.2 77.2 2001 3227.9 58 13.9 90.4

Table 5.4.2: Growth of urban population and urban places in Nepal Source: Population Monograph of Nepal, Vol. 1, 2003

The pattern of urbanization in terms of three ecological regions (Mountains, Hills and Terai)

suggests that it is increasing steadily in hills and Terai where the lust valleys and the plains

constitute the landscape. The following table illustrates the percent distribution of urban

population (and places) by ecological regions from 1952 to 2001.


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Ecological regions ↓

1952/54 1961 1971 1981 1991 2001

Mountains -- -- -- -- -- 1.3 (2) Hills 82.4 (5) 69.7 (8) 65 (7) 51.8 (9) 51.2 (13) 53.2 (27) Terai 17.6 (5) 30.3 (8) 35 (9) 48.2 (14) 48.8 (20) 45.5 (29) Total 100.0 (10) 100.0 (16) 100.0 (16) 100.0 (23) 100.0 (33) 100.0 (58)

Table 5.4.3: Percent distribution of urban population Figures in parenthesis are number of urban places

Source: Population Monograph of Nepal, Vol. 1, 2003

Very high percent of urban population seen in the previous table is by virtue of the

population of Kathmandu valley, which has from historical time the largest share of Nepal’s

urban population. In 1952/54 about 83% of the country’s urban population was in

Kathmandu Valley. That has now declined but still 31% of urban population is in the valley.

In fact, over 39% of Nepal’s urban population at present reside in just 5 urban areas with a

population of over 100,000 and these include, Kathmandu and Lalitpur in Kathmandu

valley, Biratnagar and Birgunj in Terai and Pokhara in the hills.

The overall population density in urban areas in the country is 985/km² but there are

significant differences in terms of geographical regions. In general, the urban centers of

inner Terai and hill/ mountain regions have lower densities compared to Kathmandu Valley

and the Terai. The following table highlights the urban densities in different regions of the

country compared to rural density.

Regions Population 2001 Area (sq. km) Density (per sq. km) Hills/Mountains 576,024 1047 550 Kathmandu Valley 995,966 97 10265 Inner Terai 392,108 975 402 Terai 1,263,781 1158 1092 Urban Total 3,227,879 3276 985 Rural Total 19,509,055 143905 136

Table 5.4.4: Urban densities in different regions of the country Source: Population Monograph of Nepal, Vol.1, 2003

Though, Nepal’s urban population is still low at less that 15% of the total population, what

is alarming is the rate and the way it is growing despite the paucity of basic urban services

in most of the urban centers. For example, about 71% of urban households in Kathmandu

have water supply connection, which is the highest compare to 39% in Pokhara, 21% in

Biratnagar and 10% in Bharatpur. Likewise, about 25% of households in Kathmandu are


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connected to sewage facilities whereas in other municipal areas it is virtually lacking

(MOPE 1998).

Another problem that has emerged as a consequence of rapid growth of urban population is

that of solid wastes and garbage. Households are the main source of solid waste in Nepal

and the per capita waste generation is estimated to be 0.48 kg/day (MOPE 2001). About

three million urban residents in Nepal spread over 58 municipalities produced a total of

426,486 tonnes of waste in 1999 and of which the city of Kathmandu generated the highest

of 29%. Solid waste constitutes 83% of total waste generated by country followed by

agricultural waste at 11% and industrial waste at 6%.

Majority of the urban areas in Nepal, as is usual with other countries too, lie on the banks or

nearby some rivers and streams and put impacts on it in variety of ways. Not only there is a

massive encroachment of river banks due to unplanned and uncontrolled urban growth, but

also the rivers acts as an easy site for dumping of the wastes including the direct drainage of

the sewage if the city has any. Most of the cities, especially in the hills including

Kathmandu valley suffer from acute shortage of water for daily needs. This further adds

burden to the nearby rivers and streams, as people are forced to use it at least for cleaning,

cleansing and washing their clothes and pots to the raw vegetables and cattle. All these facts

lead to severe water pollution, which is a general sight around urban areas.

The polluted water has been the main source of many water borne diseases on one hand and

on the other hand it is diminishing aesthetic value and depleting aquatic biodiversity of all

water bodies around the cities. For example, there are virtually no fishes at all in river

Bagmati that passes through the heart of Kathmandu and Lalitpur during its course in the

cities. However there are some in headwater, before the river comes down to urbanized

locality and again reappear once the river leaves the valley. This indicates that the fishes are

sensitive to the various pressures put on the rivers by the process of urbanization and is an

important field of study.

5.4.3 Dams and weirs: The most important natural resource of Nepal is water resource. The prosperity of the

country largely depends upon the wise and sustainable utilization of this resource. For this a

wide varieties of hydraulic constructions mainly dams and weirs, impoundments, levees and


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embankments, culverts and bridges have been made and inevitably will be in increase for

variety of purposes such as hydropower generation, drinking water supply, irrigation, road

construction, flood control, wastewater treatment, fisheries development, water transport

and for many forms of recreation. Out of these, the dams and weirs particularly are more

important as it is the basic structure in hydropower development, which is the most

important source of energy for the country as well as well as in irrigation and water supply.

Nepal is a country of paradoxes. The country where a feasible hydropower potential

amounts well over 40,000 MW, only a small fraction, 527.7 MW (CBS 2003) of it is

produced so far. The statistics again say that only 15% population of the country has access

to this energy source leaving the rest in darkness. In addition, the people in Nepal pay one

of the highest electricity tariffs in the region. However, with ever-increasing energy demand

from all sectors has put tremendous pressure to the government to harness more and more

water resource for energy production. Consequently, numerous major and small

hydropower projects are either under construction or planned and proposed for the approval.

The following table lists the existing and upcoming hydropower projects from the country.

NO HYDRO PROJECT (EXISTING) CAPACITY (KW) 1 Trisuli 24,000 2 Sunkoshi 10,050 3 Gandak 15,000 4 Kulekhani I 60,000 5 Devighat 14,100 6 Kulekhani II 32,000 7 Marsyangdi 75,000 8 Puwa Khola 6,200 9 Modi Khola 14,800 10 Kali Gandaki A 144,000 11 Aandhi Khola (BPC)* 5,100 12 Jhimruk (BPC)* 12,300 13 Khimti Khola (HPL)* 60,000 14 Bhotekoshi (BKPC)* 36,000 15 Pharping 500 16 Panauti 2,400 17 Sundarijal 640 18 Phewa 1,088 19 Dhankuta 240 20 Tinau 1,024 21 Jhupra 345 22 Baglung 200 23 Doti 200 24 Phidim 240 25 Gorkhe 64 26 Jomsom 240 27 Jumla 200 28 Dhading 32 29 Syangja 80 30 Seti (Pokhara) 1,500 31 Helambu 50


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32 Salleri 400 33 Darchula I and II 300 34 Chame 45 35 Taplejung 125 36 Manang 80 NO HYDRO PROJECT (EXISTING) CAPACITY (KW) 37 Chaurjhari 150 38 Syarpudaha 200 39 Khandbari 250 40 Terhathum 100 41 Bhojpur 250 42 Ramechhap 150 43 Bajura 200 44 Bajhang 200 45 Arughat (Gorkha) 150 46 Tatopani I and II (Myagdi) 2,000 47 Okhaldhunga 125 48 Rupalgadh (dadeldhura) 100 49 Surnaiyagadh (Baitadi) 200 50 Namche 600 51 Achham 400 52 Dolpa 200 53 Chatara 3,200 54 Kalikot 500 55 Sange Khola (Sange HP) 183 56 Chilime (CPC) 20,000 NO HYDRO PROJECT UNDER CONSTRUCTION CAPACITY (KW) 1 Middle Marsyangdi 70,000 2 Gamgad 400 3 Heldung 500 4 Indrawati (NHPC) 7,500 5 Upper Modi 14,000 6 Piluwa Khola 3,000 NO PLANNED AND PROPOSED PROJECT CAPACITY (KW) 1 Seti (west) 750,000 2 Arun III 402,000 3 Budhi Gandaki 600,000 4 Kali Gandaki II 660,000 5 Lower Arun 308,000 6 Upper Arun 335,000 7 Karnali (Chisapani) 10,800,000 8 Upper Karnali 300,000 9 Chamelia 30,000 10 Pancheshwar 6,480,000 11 Thulodhunga 25,000 12 Tamur/Mewa 100,000 13 Dudh Koshi 300,000 14 Budhi Ganga 20,000 15 Rahughat Khola 27,000 16 Likhu 40,000 17 Kabeli A 30,000 NO PLANNED AND PROPOSED PROJECT CAPACITY (KW) 18 Upper Marsyangdi A 121,000 19 Kulekhani III 42,000 20 Aandhi Khola (storage) 180,000 21 Khimti II 27,000 22 Langtang Khola (storage) 218,000 23 Madi Ishaneshwar (storage) 86,000 24 Seti (storage) 122,000 25 Kankai (storage) 60,000 26 Upper Tama Koshi 250,000 27 Rawa Khola (Khotang) 2,300 28 Molung Khola (Okhaldhunga) 1,200 29 Naugargad (Darchula) 1,800


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30 Gandigad (Doti) 1,800 31 Phoigad (Dolpa) 150 32 Kolti (Bajura) 150 NO PRELIMINARY WORKS IN PROGRESS CAPACITY 1 Chaku Khola 910 2 Khudi 3,450 NO PRELIMINARY WORKS IN PROGRESS CAPACITY 3 Mailung 5,000 4 Daram Khola 5,000 5 Phema Khola 995 6 Sunkoshi Small 2,600 7 Langtang 10,000 8 Baramchi 999

Table 5.4.5: List of the hydropower projects Source: Nepal Electricity Authority, Fiscal Year 2001/02 – A Year in Review

(Modified) The table 5.4.5 illustrates that there are 56 large and small-scale hydropower projects

existing in Nepal and except for a few, all are in the operation. There are just six projects

under construction now probably due to a difficult socioeconomic and political situation in

the country. Once this phase of difficulty is over, many new projects would start

simultaneously as could be seen from the above table, which lists 32 planned and proposed

projects and at least 8 where the preliminary works are in the progress. Further, water being

the most abundant resource of the country in one hand and on the other hand due to the

demand of cheap, clean and renewable energy, Nepal Electricity Authority has a forecast of

average growth of energy at more than 7%. This means hydropower projects that inevitably

involve the construction of dams and weir will be a continuous process for the foreseeable

future.

In addition, there are number of established irrigation projects and many more will come up

in the future to reduce the dependency on monsoon as the country is predominantly

agricultural. With very few industries and in absence of other job opportunities more than

80 % of population still depend upon agriculture for subsistence living. The irony is, only

21% of the total land is under cultivation and out of these about 1.7 million ha. that amounts

to about 65% of the total cultivated land is still rainfed (MOPE 2000). This means, a

massive network of irrigation especially in midhills and Terai is sure to come in future and

these irrigation projects too involve the construction of some kind of dams and weirs.

There are multitudes of utilities of damming rivers but we must not forget that many times it

changes, the river ecology, forever. The same is pointed out by Jungwirth (1998) when he

says, ‘One of the central ecological problem of running water systems, which are subject to

multiple uses and therefore suffer disproportionate damage worldwide in comparison to


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other ecosystems, is the fragmentation of the longitudinal corridor by weirs of hydroelectric

power plants and other water engineering measures’. Further, current ecological theories

and concepts describe running waters as four-dimensional systems, their longitudinal,

lateral and vertical linkages, interactions and exchange processes varying over time and

over different scales (Jungwirth et al 2000).

The relative importance of all these dimensions vary according to the terrain the river is

passing through but all are critical on themselves at their places. Thus, the building of dams

and weirs has a potential to affect the ecological integrity of the river system and is

therefore, an important field of research especially in the country like Nepal.

5.4.4 Industries: Another possible threat to the rivers and streams comes from the industries. It may be true

that the all round development in general and economic development in particular is

associated with industrialization. The affluent western societies achieved this through

industrial revolution a few centuries ago. However, their development had a cost. History is

full of evidence that there were rampant air, water and soil pollution in Europe and

America. The present day clean environment in these regions is only due to a very high

price spent for cleaning the environment through regeneration and sophisticated technology.

In comparison, developing counties like Nepal has not paid that price as it is not an

industrialized nation now and never was in its history. There were around 4500

manufacturing units in different part of the country providing employment to over 0.2

million people (MOPE 1998). The Central Development Region has the highest number of

manufacturing establishments occupying about 55% of the total industries. Kathmandu

valley, which lies within this region, holds almost all of those units. However, the recent

data suggest that there is a large slump in the number of industries and the jobs at 3213 units

and 0.19 million jobs probably due to the current socio-political situation of the country

(CBS 2003).

Still, the total number of manufacturing units may look bigger without the knowledge of

type of industries operating in Nepal. Industries in Nepal are categorized into four types –

cottage industries, small industries with fixed capital up to Rs. 30 million, medium

industries with fixed capital from Rs. 30 to 100 million and large industries with fixed


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capital of above Rs. 100 million. Most of the industries in Nepal fall into the first two

categories with a very few in medium industries category and even less in large industries

category.

In the past, much of the industries in Nepal were established within a certain fixed area

commonly called as industrial districts IDs or industrial estates (IEs). It could be because

the basic infrastructure facilities, such as fence or boundary wall, industrial sheds, ware

houses, roads, drainage/culverts, electricity/water supply, bank, clinic, post office, child

care center, canteen and other required services for smooth operation of industries are easier

to provide in a specific area designated as IDs and IEs. Further, this concept has been

utilized by the government for regional economic development through establishment of

such units at 11 different parts of the country under the assistance from various donor

countries (Industrial Districts Management Limited, 2003).

The first industrial district to get established is Balaju Industrial District in Kathmandu way

back in 1960 under U.S. assistance. The following table highlights the characteristics of all

the industrial districts of the country.

Investment Rs.In million

IDs ↓

Established

Sponsor Area (Ropani)* HM

G Private

No. of industries

No. of Jobs

Power capacity (KVA)

Water supply Kl/hr

Roads (Km)

Balaju 1960 USA 696 13.2 2000.00

92 4000 4000 20 5.2

Patan 1963 India 293 14.3 408.1 106 1472 1100 1 5 Hetauda 1963 USU 2829 25.5 3124.7

2 54 4844 5000 92 11

Dharan 1973 India 202 7.7 162.9 25 566 750 1 2.3 Nepalgunj 1973 India 233 9.6

125.00 28 635 500 7.57 2.34

Pokhara 1974 HMG/N 501 14.7 500.00

73 1400 700 20 2.54

Butwal 1976 HMG/N 434 11.0 987.3 56 1300 1350 6 2.14Bhaktapur 1979 Germany 71 13.5 246.2 29 625 900 20 0.69Birendranagar

1981 Netherlands

90 7.4 5.00

19 70 50 4.1 0.91

Dhankuta** 1984 HMG/N 63 5.6 - 1 - - - Rajbiraj 1986 India 294 35.5

25.00 7 27 100 8 2

TOTAL 5706 158 7584.00

489 14985

14450 179.67

34.12

* 1 hectare = 19.65 Ropani ** Construction held up

Table 5.4.6: Details of the Industrial Districts Source: Industrial Districts Management Limited in Profile, 2003.


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Comparing the figures and the table above it is easy to make out that there is significant

number of industries established outside the industrial districts. Bulk of these industries is in

Kathmandu valley with a few scattered at different part of the country. Thus, except for the

valley there seems an insignificant environmental problem coming out of these units, but

the true pictures are different. Forty per cent of Nepal's total industrial units are related to

water pollution (MOPE 2001). All industrial wastes in most cases are directly discharged

into local water bodies, most commonly the lotic one, without any treatment.

The common type of wastes coming from the industrial effluent of Nepal include high load

of oxygen demanding wastes, disease causing agents, synthetic organic compounds, plant

nutrients, inorganic chemicals and minerals, and sediments (MOPE 1998). The following

table highlights not only the industrial pollution load but also their occurrence in different

development regions of the country.

Parameters Development

Regions ↓ TSP (ton) Waste Water Volume (m³)

BOD (ton) TSS (ton) Solid Waste (ton)

Kathmandu valley

37857 2100000 1150 1417 1421

Central excluding valley

19950 2160000 1284 2317 8622

Eastern

6626 3450000 1424 3614 9560

Western

5505 699000 1050 1350 1615

Mid Western

2610 43000 336 300 287

Far Western

3835 105000 493 593 378

Total

76,383 8,556,997 5,741 9,591 21,883

Table 5.4.7: Industrial pollution load in Development Regions Source: MOPE, 2000

The main problem of industrial pollution in Nepal lies not with the number of industries but

with the lack of environmental concerns and initiatives with them. However this is not to

blame the industrial sector alone as the environmental awareness and most of the related

legislations evolved much latter than their establishment in most of the cases. In addition, to

boost the country’s economic status, many more industries are sure to come with liberal

government policy. Thus, water pollution from industries would remain one of the

important environmental problems in Nepal for some time.

6 Materials and methods

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CHAPTER VI: MATERIALS AND METHODS 6.1 Strategy: The study of disturbances in streams and rivers in this work uses the comparative studies of

streams that have contrasting disturbance regimes. First the type of disturbances was

finalized and accordingly the rivers and streams were selected to represent those

disturbances. To give the study a temporal dimension, four replica of data set were collected

corresponding to different seasons. Finally a comparison of disturbed site with undisturbed

site was made for all the disturbances identified in different seasons to draw a conclusion.

The information regarding fish population and physico-chemical parameters collected

during the sampling were utilized for evaluating the magnetude of impairment. The same

information was also utilized for various related purposes.

6.2 Type of disturbances: Rivers in Nepal are subjected to different disturbances because of their varied uses. The

scale of impairment to the rivers and aquatic life done by these disturbances are ever-

growing. The type of disturbances this work wanted to focus was something that has to be

common or sure to increase in future, bigger in magnitude and of general interest. With that

view the following four types of disturbances were taken into consideration in this work.

• Agriculture

• Urbanization

• Dams and weirs

• Industries

6.3 Site selection: Selection of sites was done with main objective of including rivers and streams that are a

good representative of the disturbances mentioned above. However, as there are several

suitable sites to choose from, there were a number of factors considered.


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• Similarity in origin of the rivers: Almost all the rivers chosen were perennial having

water all the year round. This will allow a good comparison.

• Accessibility: Almost all the rivers were accessible by road. This was necessary in

order to carry the equipment.

• Socio-political situation: 2003 – 2004 was truly a difficult period in Nepal in terms

of political upheaval with almost no guarantee of safety. However, politically

sensitive localities were generally avoided. The permission letters for sampling are

included in the appendix.

• Public demand: At least the study on one disturbance in river Narayani that of a

paper mill was included as a part of this work as per the popular interest and

demand.

So with the main objective and the factors described above the following rivers were

selected for the study at the specified locations.

no river location 1 Aandhikhola Bayatari and Galyang (Shyangja) 2 Arungkhola Kusunde (Nawalparasi) 3 Bagmati Sundarijal (Kathmandu) 4 Jhikhukhola Paanchkhal (Kavre) 5 Karrakhola Hetauda (Makawanpur) 6 Narayani Narayanghat (Chitwan and Nawalparasi) 7 East Rapti Hetauda and Bhandara (Makawanpur and Chitwan) 8 Seti Pokhara (Kaski) 9 Tinau Maniphaant, Koldanda and Butwal (Palpa and Rupandehi)

Table 6.1: Rivers and the locations of the sampling sites with districts in parenthesis.

Among these rivers Aandhikhola, Bagmati and Tinau have been selected to study the

impact of hydropower dam while Arungkhola, Karrakhola and Narayani have been selected

to study the impact of industries. Similarly Jhikhukhola, East Rapti and Tinau are for

agricultural impacts as Narayani, Seti and Tinau are for the disturbance caused by

urbanization. The table 6.2 illustrates the rivers with respective disturbances identified.


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DISTURBANCES

RIVERS ↓ Dams/weirs Urbanization Industry Agriculture

Aandhikhola X Arungkhola X Bagmati X Jhikhukhola X Karrakhola X Narayani X X East Rapti X Seti X Tinau X X X

Table 6.2: Rivers and the disturbances identified for the study shown by ‘X’

For each disturbance in each river two sites were selected, one representing the reference or

upstream site while the other being the disturbed or downstream site. Thus, altogether 23

sampling sites were selected with the one in Narayani served as a reference site for both

industrial and urban disturbances. The table 6.3 highlights the geographical position of all

the sites.

The details of all the rivers studied and the corresponding sampling sites are described in

the next chapter.


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SITES DESCRIPTION

Rivers Sites - Upstream Sites – Downstream Sites - Downstream Aandhikhola Bayatari

27° 58' 29.6" lat. 83° 43' 1.6" long.

681 masl

Galyang 27° 56' 55.2" lat.

83° 40' 33.1" long. 670 masl

Arungkhola Kusunde 27° 37' 7.5" lat.

83° 57' 20" long. 148 masl

Kusunde 27° 36' 30.7" lat.

83° 57' 20.5" long. 140 masl

Bagmati Sundarijal 27° 46' 24.9" lat.

85° 25' 33.8" long. 1621 masl

Sundarijal 27° 46' 18.4" lat.

85° 25' 34.5" long. 1610 masl

Jhikhukhola Paanchkhal 27° 38' 55.3" lat.

85° 35' 28.5" long. 936 masl

Paanchkhal 27° 36' 24.4" lat.

85° 39' 33.4" long. 898 masl.

Karrakhola

Hetauda 27° 24' 30.8" lat.

85° 03' 09.6" long. 450 masl

Hetauda 27° 24' 53.7" lat. 85° 01' 09" long.

450 masl

Narayani

Narayanghat 27° 42 '16.1" lat. 84° 24' 50” long.

165 masl.

Narayanghat – city 27° 41' 51.1" lat. 84° 24' 50" long.

165 masl

Narayanghat -industry27° 41' 40.8" lat. 84° 24' 7.3" long.

162 masl Rapti Hetauda

27° 27' 10.9" lat. 85° 02' 19.5" long.

451 masl

Bhandara 27° 34' 14" lat.

84° 38' 54.8" long. 202 masl

Seti

Pokhara 28° 15' 12.8" lat. 83° 58' 4.5" long.

927 masl

Pokhara 28° 9' 39.4" lat.

84° 0' 56.1" long 630 masl

Tinau Maniphant - Agriculture 27° 49' 22.3" lat. 83° 36' 9.6" long.

680 masl

Koldanda - Agriculture 27° 47' 52.2" lat.

83° 31' 37.6" long. 616 masl

Tinau

Butwal – Dam 27° 44' 11.6" lat.

83° 27' 52.9" long. 282 masl

Butwal - Dam 27° 43' 32.8" lat. 83° 28' 6.3" long.

207 masl

Tinau Butwal – city 27° 43' 18.7" lat. 83° 28' 5.6" long.

171 masl

Butwal – city 27° 41' 37.5" lat.

83° 27' 38.3" long. 152 masl

Table 6.3: Rivers and exact coordinates of the sampling sites.


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6.4 Sampling: 6.4.1 Time and duration: The first set of field sampling of this study in selected river sections of Nepal began on the

third week of February 2003. Prior to that selection of appropriate sampling sites and testing

of some of the equipments were carried out since October 2002. After the first real

sampling, replicate of it were taken corresponding to all major seasons. Finally, four sets of

data representing each season, spring, summer/premonsoon, autumn/postmonsoon and

winter were collected spanning until the beginning of 2004. With 23 sites and four replicate

of these, there are altogether 92 samplings that constitute this work.

6.4.2 Fish collection and measurements: Fish sampling was done using electro fishing gear and this could be the first application of

electro fishing gear for fish sampling in Nepal, as the previous records could not be traced.

Fishing with electricity is a standard method of sampling all over the world at present

(Cowx 1990 and the references therein). The method followed here was a simple but

standard wading type where a person carries the generator fitted with motor on his back and

an anode fitted with net in the hands. He was assisted by two persons each carrying a long

dip nets to collect the shocked fish and a third person carrying a bucket to empty the nets.

For the safety all the persons involved in fishing were insulated by a long wading boots. In

addition, for the safety reason again, the local people and the onlookers around were well

informed about the electricity hazard and were requested not to enter the river section when

the sampling was in progress. Even the animals and cattle were guarded carefully from

entering the water body during this period (the detail of the gear is described in chapter iv).

In each site, the fish sampling was done in two runs, 1 and 2 respectively. The stretch of the

each sampling site was mostly between 50 to 100 meters but depending upon the conditions

sometimes it was less than that and a few times exceeded. The time span for each run were

taken separately and is even more important as it is a factor to calculate the catch per unit

effort (CPUE) which in turn is important tool to see other population dynamics of the fish.

CPUE in this work is defined as the number of fish captured in 10 minutes of electrofishing.

The time for each run were tried to be around 20 minutes and was never less than 30

minutes for the total of run 1 and 2 in any of the sample in all seasons. Different types of

readings were taken after the sampling and they included:


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i) Identification: The fishes were identified up to the species level as far as

possible in the field itself with the help of keys in the Nepalese context (Day

1878, Shrestha 1984, Talwar and Jhingran 1991, and Jayaram 1999). The

information given by the locals were also very valuable regarding the

identification. Those unidentified were preserved in 10% formalin solution

and were latter identified with the contribution from Central Department of

Zoology (TU), Dept. of Fisheries (HMG/Nepal), academicians and experts.

ii) Length measurement: The total length (TL) of all fishes was measured up to

the last 5 mm with the help of a specially constructed simple mechanical

devise. The measuring range of this tool is 0 – 1000 mm (Picture 6.4.1).

iii) Weight measurement: Several representative weights of the each length

group were also measured during the sampling using a standard weighing

machine with the range of 2 grams to 5 kilograms and not with decimals

(Picture 6.4.2).

6.4.3 Physico-chemical parameters: Several physico-chemical parameters like temperature, Ph, dissolved oxygen, conductivity,

stretch length, area, and water discharge of the rivers were noted down either before or after

the fishing in another protocol. Standard portable devices (from WTW, Germany) and

measuring tapes were used to collect this information and noted down in a separate

protocol. Also the data from Department of Hydrology and Metrology (DHM) were

obtained for comparison and correction.

6.4.4 Geo-morphology of the sampling sites: The information of this nature was mostly observatory. The riverbanks and substrates were

carefully observed and many times sketched in the protocol. The major substrate of each

river, mainly rock, boulder, cobbles, pebbles, gravel, sand and silt were taken account in

percentage. Number of digital photographs of each site highlighting its geology and

morphology were also taken in the spot. Altitude, latitude and longitude of each sampling

site were also measured by portable GPS (Global Positioning System) device.


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6.5 Data processing and analysis: Processing and analysis of data was done at Universität für Bodenkultur (BOKU), Austria

using standard software and statistical tools that are in use in modern research. All the data

regarding fish, physico-chemical parameters and geomorphology were initially recorded in

respective Excel spread sheets. The parameters analyzed included species diversity and

richness, leading species, density and abundance, and productivity. Correlations between

different parameters were examined and also some multivariate analysis was performed.

The main program used for the analysis was SPSS. The data obtained from electro fishing

are very much relevant and acceptable for all these tests and analysis (Cowx and Lamarque

1990).

Various kinds of books, journals and other information related with this work were studied,

reviewed and compared with the results. The main sources for these materials were the

number of libraries in the two universities involved, Kathmandu University (KU) and

Universität für Bodenkultur (BOKU). Besides, number of external sources such as

Ministries and Departments, private and public libraries and, NGO’s and INGO’s were also

consulted.

6.6 Results and interpretation: Results are produced in a numerical and graphical form to have better understanding.

Numbers of statistical analysis and tests such as cluster analysis, canonical discrimination

analysis, non parametric Kruskal–Wallis test, Mann-Whitney test and parametric one way

ANOVA were used to produce results. All the statictical analysis and tests were done using

SPSS version 11.0 software. Detail interpretation of these values and graphs has been done

in the chapter discussion.

Pic.6.4.1: Length measuring instrument Pic.6.4.2: Digital weighing machine

7 Description of the sites

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CHAPTER VII: DESCRIPTION OF THE SITES Nepal is more or less rectangular in shape with an average length of 885 km east to west

and non-uniform width of 193 km north to south. It covers an area of 147, 181 km² and lies

from sub-tropical to the alpine region at 26°22’ to 30°27’ N latitude and 80°4’ to 88°12’ E

longitude. It is a landlocked country between India and China and thus, rivers and the lakes

constitute the important water bodies. Politically, it is divided into 75 Districts within 14

Zones and 5 Developmental Regions. The sites of the present study lie in the Districts,

Kavrepalanchowk, Kathmandu, Makawanpur, Chitwan, Nawalparasi, Rupandehi, Palpa,

Shyangja and Kaski of Bagmati, Narayani, Lumbini and Gandaki Zone, which in turn are

part of Central and Western Development Regions.

This research involves the study of nine rivers from different parts of Nepal. The rivers that

were studied, in alphabetical order, are Aandhikhola, Arungkhola, Bagmati, Jhikhukhola,

Karrakhola, Narayani, East Rapti, Seti and Tinau. Among these rivers, Aandhikhola,

Arungkhola, Karrakhola, Narayani, East Rapti and Seti belong to Gandaki River System,

Jhikhukhola is a tributary of Koshi River System, and Tinau and Bagmati are river systems

draining to Ganges in India (Sharma 1977). A brief description of each river and sites are

given here.


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Map 7.1: Country map with sampling sites shown in square

Map 7.2: Part of the country map enlarged with sampling sites


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7.1 Aandhikhola: It is an important river of Shyangja district and originates from Dahare hill, southeast from

Karkineta (MOIC 1974). The district belongs to Gandaki Zone of Western Development

Region. It is a rainfed midhills river estimated to be 96 km long with catchment area of 195

km², which finally drain to Kali Gandaki just before the country’s largest hydropower dam.

The mean daily discharge of the river according to the latest record by Department of

Hydrology and Meteorology (DHM) varies from minimum of 8.58 m³/s in a day in May to

maximum of 696 m³/s in one day in August. The average annual flow of the river is 14.5

m³/s (DHM 2002).

Not only does this river fulfills the demand of water for agriculture and household activities

in the district, a power plant too is set up to generate 5 Megawatts (MW) of electric power

from this river. There is a provision of fish- pass in this hydropower project but its utility is

in question. Since the impact of hydropower dam on the fish population is studied from this

river, the details of this plant are also provided (table 7.1.1).

Two sampling sites were selected from this river. The upstream sampling site, also called as

the reference site is placed some kilometer before the dam in Bayatari. The downstream

sampling site lies immediately after the dam in the place called Galyang. The temperature

of water in upstream site varied from 14.7 to 25.4° C and the measure of dissolved oxygen

(DO) conductivity and pH reached up to 10 ppm, 51 µS/cm and 8.0 respectively. Similarly

the substrate in this site was observed to possess 20% rock, 20% boulder, 30% cobbles,

25% pebbles, 4% gravels and 1% each of sand and silt.

The temperature of water in downstream site varied from 14.9 to 23.5° C and the measure

of dissolved oxygen (DO) conductivity and pH reached up to 7.2 ppm, 52.2 µS/cm and 8.1

respectively. Similarly the substrate in this site was observed to possess 10% rock, 15%

boulder, 30% cobbles, 30% pebbles, and 15% gravels.


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Aandhikhola Hydel and Rural Electrification Project (AHREP): Basic Project Data Design output 5 MW Project Site South Syangja District River Diverted Aandhikhola Catchment Area 444 km² Minimum River Flow 1.4 m³/s Design Flood for Plant Operations 1000 m³/s Diversion Weir Type Concrete Gravity Weir Height 6 m Weir Length 65 m Daily Pondage with Flashboards 43,000 m³ Particles Removed by Silting Basin 0.3 mm and larger Headrace Tunnel Length 1340 m Headrace Tunnel Section 4 m² Surge Tank 12 m² Surface Area Vertical Entrance Shaft Depth 240 m Penstock Diameter 1.1 – 0.9 m Gross Head 246 m Design Head 238 m Design Flow 2.7 m³/s Power House Cavern Floor Area 250 m² Turbines 3 X 1.7 MW Pelton Alternators 3 X 2.2 MVA/5.3 KV Tailrace Tunnel Length 1040 m Tailrace Tunnel Section 5.2 m² High Tension Transmission Lines Approximately 80 km Access Road 1.6 km Total Project Cost Rs 51 million Table 7.1.1: Details of Aandhikhola Hydel and Rural Electrification Project (AHREP)

Source: Butwal Power Company Pvt. Ltd. (1982) 7.2 Arungkhola: It is an important river of Nawalparasi district, which originates from midhills in Palpa

district and drains to Narayani. The district belongs to Lumbini Zone of Western

Development Region. The catchment area of this river is 215 km² and has annual flow of

12.3 m³/s (DHM 2002). The river has one of the country’s important industries, Shree

Distillery (P) Ltd. along its bank. Established in 1985, the distillery has been producing

rectified spirit and blending and bottling different brands of high quality liquors.

The factory is situated in Kusunde, Nawalparasi at the bank of Arungkhola and occupies

about 65 ropanies of land. The company has sophisticated plants with capacity of 15,00,000

liter spirit per year and about 250 people work at the factory. The company has shown the


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environmental concern too. To ensure that the factory would not pollute the Arungkhola and

the surrounding areas, the company has fixed an effluent treatment plant. However, if it is

operational and efficient are yet to know. The pictures and the information from local

people indicate that the effluent from the distillery might be polluting the adjoining river if

not the entire area.

This work has studied the impacts of the factory on the river taking fish as an indicator.

There are two sampling sites for this purpose each before and after the industry on either

side of the East-West Highway. The site before the industry is called as upstream or

reference site and the one after is called as the downstream or disturbed site. The

temperature of water in upstream site varied from 17.4 to 28.5° C and the measure of

dissolved oxygen (DO) conductivity and pH reached up to 8.67 ppm, 72.5 µS/cm and 8.6

respectively. Similarly the substrate in this site was observed to possess 5% boulder, 25%

cobbles, 25% pebbles, 30% gravels, 10% sand and 5% silt.

The temperature of water in downstream site varied from 17 to 26° C and the measure of


respectively. Similarly the substrate in this site was observed to possess 15% boulder, 30%


7.3 Bagmati: This is the most important river of Kathmandu Valley, which originates from Baghdwar at

Shivapuri Hill as high as 2650 masl. It is a rainfed midhills river, which belongs to an

independent system and holds great religious and cultural value. The total length of the river

is 163 km with catchment area of 3610 km². The river flows around 30 km within

Kathmandu Valley. The mean daily discharge of the river at Sundarijal according to the

latest record by the Department of Hydrology and Meteorology (DHM) varies from 0.24

m³/s in April to 10 m³/s in someday in July with yearly mean of 1.37 m³/s. This river has

one of the country’s oldest hydropower plants at Sundarijal. The amount of power produced

by this plant is very insignificant, however, the diversion made by the dam is more

important in terms of drinking water supply to the huge population of the valley. The impact

of the dam in this river is studied in this work. The details of the studied hydropower plant


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are summarized in the following table. Since it is one of the oldest projects in Nepal, the

units are not consistent.

Project Site Kathmandu District River Diverted Bagmati Design Output 600 kW Minimum River Flow 1.2 m.l./h Design Flood for Plant Operation 2.4 m.l./h Diversion Weir Type Carbon Concrete Gravity Pipeline Weir Height 24 m Weir Length 6 m Headrace Tunnel Section 18 inch Surge Tank 1.5 m² Penstock Diameter 18 inch Design Head 950 feet Design Flow 2.6 m.l./h Power House Cavern Flow Area 1500 m² Turbines 2 X 300 kW Tailrace Tunnel Length 50 m Project Duration 1982 BS – 1991 BS Financed British Government

Table 7.3.1: Details of Sundarijal Hydropower Plant The impact of this dam in Bagmati River is studied in this work. Two sampling site were

fixed in this river. The upstream or the reference site was just before the impoundment and

the disturbed or the downstream site was immediately after the dam. Unlike Aandhikhola,

there is no provision of fish pass between upstream and downstream of this dam and thus,

the longitudinal corridor is completely disrupted. Both the reference and disturbed sites

were inside Shivapuri National Park and prior permissions were taken before each sampling

from the concerned authorities (see appendix for the permission letters).

The temperature of water in upstream site varied from 9.7 to 18.8° C and the measure of


respectively. Similarly the substrate in this site was observed to possess 5% rock, 20%

boulder, 25% cobbles, 25% pebbles, 20% gravels, 3% sand and 2% silt. The temperature of

water in downstream site varied from 8.9 to 15.9° C and the measure of dissolved oxygen

(DO) conductivity and pH reached up to 8.7 ppm, 24.3 µS/cm and 6.9 respectively.

Similarly the substrate in this site was observed to possess 20% rock, 40% boulder, 20%



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7.4 Jhikhukhola: This river is small in comparison with the other rivers of Kavrepalanchowk District, but is

famous for creating a very fertile agricultural valley in the district. The district belongs to

Bagmati Zone in the Central Development Region of the country. The river originates from

midhills bordering Bhakatapur and Kavrepalanchowk Districts and finally drains to

Sunkoshi River, which is an important tributary of the Koshi River System. The river covers

an area of 111.4 km². The water discharge was found to be fluctuating between minimums

of 9.0 m³/s to maximum of 93.6 m³/s (Gautam 1997).

The impact of agriculture on the river is studied in this river as it flows through a very

fertile valley, where people are engaged in intensive agricultural practice and the use of

fertilizers and pesticides are very high. According to the last census in 2001/02, there were

64570 holdings of land in Kavrepalanchowk district with an area of 44218.6 ha. Out of

these, total area of arable land amounts to 37404.7 ha of which 11406.1 ha are irrigated by

some means (CBS 2001). The quantity of mineral/chemical fertilizer used in the district was

found to be 10512953 kg with highest consumption of 4173168 kg only for maize. The

amount of this chemical input is in addition to the organic manure coming from a huge

stock of cattle, which numbers 88751 heads excluding buffaloes and goats which count

87389 and 224434 respectively. The number of holdings using pesticide is highest for

potato, which stands at 10363.

As usual, there are two sampling sites on this river around 12 km apart. The upstream, also

called as reference, is in the confluence of Jhikhukhola and Dhulikhelkhola at Dovan Pati

and the downstream or the disturbed site is at Baluwa. The temperature of water in upstream

site varied from 15.4 to 29° C and the measure of dissolved oxygen (DO) conductivity and

pH reached up to 6.9 ppm, 83.3 µS/cm and 7.5 respectively. The substrate in this site was

observed to possess 30% rock, 20% boulder, 20% cobbles, 15% pebbles, 10% gravels, 3%

sand and 2% silt. Similarly the temperature of water in downstream site varied from 14.6 to

29.3° C and the measure of dissolved oxygen (DO) conductivity and pH reached up to 10.9

ppm, 118.9 µS/cm and 8.6 respectively. The substrate in this site was observed to possess

1% rock, 20% boulder, 20% cobbles, 30% pebbles, 25% gravels, 3% sand and 1% silt.


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7.5 Karrakhola: The river originates from the northeast of Siwalik range in Makawanpur District, which

belongs to Narayani Zone of Central Development Region. From its origin the river flows

toward west, passes through Hetauda city and drains in East Rapti River. The total length of

the river was reported to be around 19.25 km with catchment area of 96 km² (Singh 1995).

The river flows nearby the country’s biggest industrial district called Hetauda Industrial

District (HID).

Established in 1963, with the help of United States of America, HID covers around 144

hectares of land with an investment of 25.5 million Rupees from the Government sector and

3124.72 million Rupees from the private sector (IDM 2003). The industrial district directly

employs 4844 person in 54 industries of which 44 are in operation. The power capacity of

the industrial district is 5000 KVA and has water supply of 92 kl/hr. There are varieties of

industries inside HID and the products include paints, plastic corks, electricity poles,

biscuits, tin containers, processed meats, carton boxes, ghee, toothpastes and soaps, plastic

pipes, processed foods, ball-point pen, stone powder and livestock feeds.

Similarly, other products include construction materials, vegetable oil, cigarette, furniture,

marble slab, leather, bone materials, plastic drums, dairy, beer, cotton fabrics, polyester, tea

packaging, tiles, hollow concrete, zippers and drugs. In addition, there are some laboratories

for quality control (IDM 2002). The effluents from all the industries inside the district are

collected together and are drained to the nearby Karrakhola. However, a new construction

for the effluent treatment is going on.

The impact of industries on this river was studied in this work. There were two sampling

sites for this purpose in this river. The upstream or the reference site was selected a few

kilometers before the industrial district and the downstream or disturbed site was about 1

km after the discharge of effluents from the industries. The temperature of water in

upstream site varied from 14 to 25.1° C and the measure of dissolved oxygen (DO)

conductivity and pH reached up to 8.4 ppm, 68 µS/cm and 7.33 respectively. The substrate

in this site was observed to possess 20% cobbles, 30% pebbles, 30% gravels, 10% sand and

10% silt. Similarly the temperature of water in downstream site varied from 17.2 to 27.4° C

and the measure of dissolved oxygen (DO) conductivity and pH reached up to 7.6 ppm, 115


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µS/cm and 7.28 respectively. The substrate in this site was observed to possess 10% rock,

30% boulder, 20% cobbles, 20% pebbles, 15% gravels, 3% sand and 2% silt.

7.6 Narayani: This river also called as Sapta Gandaki is the main channel of Gandaki River System, which

is one of the largest river systems of Nepal. The longest channel, Kali Gandaki of this river

system is antecedent (see chapter river and river system) and is drained by several glacial

rivers. Kali Gandaki originates from the other side of the Himalayas in Mustang area from

Photu pass where it is called Mustangkhola and (Sharma 1997). After reaching the plain in

Nepal, the system is popularly called as Narayani, which take southwestern direction from

Narayanghat and finally becomes confluent with the Ganges in India. The total length of the

river is 332 km with catchment area of 34960 km² of which 30090 km² lies within Nepal.

The average annual discharge of this river at Narayanghat is mentioned as 1576 m³/s

(DHM).

According to the last complete data of discharge of this river at Narayanghat, the minimum

daily discharge was measured as 212 m³/s and the maximum as 10900 m³/s (DHM). This

river is important for Nepal not only because of the size but also because of religious and

cultural attachment. This particular river has been selected for this study mainly due to the

popular demand. The impacts of both Bhrikuti Paper Mill and Narayanghat city, which lie

on the two different banks of the river, have been studied in this work.

Bhrikuti Pulp and Paper Mill, now a private company, situated on the bank of Narayani

River at Gaindakot, Nawalparasi was founded in 1982 by a mutual cooperation between

HMG of Nepal and the Government of the People’s Republic of China with a design output

of 10 tonnes/day of paper production. The first batch of paper was produced in 1986 and in

1989 the capacity of production was raised to 13 tonnes/day (Upadhaya 1994). The mill was

privatized in 1990 and as a result the capacity of production was massively raised to 128

tonnes/day within six years (Upadhaya 1996). In addition to the raw materials such as

wheat/rice straw and Sabai grass, the company uses large amounts of chemicals like caustic

soda (NaOH), talcum powder, resin, bleaching powder (CaOCl2, alum, soda ash (Na2CO3),

hydrochloric acid (HCl), CaO, Cl2 and the dyes for the production and maintenance (Kharel

and Thapa 2003). For every ton of the finished product, the plant needs 300 tonnes of water.


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The following table shows the input of different materials required to produce one ton of

paper in this mill.

One ton of paper Sabai grass 1465 Kg

Wheat straw 1562 Kg

Talcum powder 150 Kg

Resin 15 Kg

BleachingPowder 222 Kg

Alum 60 Kg

Soda ash 1.8 Kg

Soda Caustic 411 Kg

Table 7.6.1: Materials for production of one ton of paper Source: Bhrikuti Paper Mills Ltd. (Brochure 1982)

There are two kinds of interactions of this factory with Narayani River. First, the river is the

main source of huge volume of water the factory requires and second, the effluent from the

industry is directly discharged into the river without treatment. Considering the discharge

rate of the river, the impacts from first interaction might not be so significant. However, the

impacts from the second interaction are physically visible and chemically established

through various studies. This work studies these impacts by taking fish as an indicator.

Narayanghat city, which lies within Bharatpur Municipality of Chitwan district, is one of

the fastest growing urban centers of Nepal because of its strategic position. The city holds a

criss-cross of the longest highway of Nepal, the East-West Highway and the Highways

leading to the Capital, Kathmandu and the most important touristic city, Pokhara. In fact,

the major growth of the city started only after the construction of these highways. Bharatpur

was gazetted as municipal area just in 1981 with the population 27602, but by 2001, the

population had reached 89323 a three times growth (CBS 2003). Narayanghat is named

after the river Narayani on the bank of which the city is situated. The study of the impacts

of this rapid urbanization on Narayani River is also included in this work.

There were three sampling sites in this river for the study of impacts of two disturbances as

the reference site or the upstream site serves the purpose for both. The reference site was

fixed just before the section of the river from where the core urban area starts. The disturbed

site for the study of the impact of city was fixed on the left bank of the river immediately

after the city. As the city expands across the river and not along the river, the influence area

of the city on the river is very less. The disturb site for the impact of industry was fixed

about 100 m downstream from the place of effluent discharge on the right bank of the river.

Due to the large size, the river is unwadeable and thus, the sampling was restricted to the

banks of the river.


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The temperature of water in upstream site varied from 14 to 23.9° C and the measure of

dissolved oxygen (DO) conductivity and pH reached up to 8.8 ppm, 283 µS/cm and 8.2

respectively. The substrate in this site was observed to possess 20% boulder, 30% cobbles,

25% pebbles, 10% gravels, 10% sand and 5% silt. The temperature of water in downstream

site of the city varied from 16.2 to 28.3° C and the measure of dissolved oxygen (DO)


in this site was observed to possess 25% boulder, 25% cobbles, 25% pebbles, 20% gravels,

3% sand and 2% silt. Similarly, the temperature of water in downstream site for the impact

of industry varied from 16.4 to 26° C and the measure of dissolved oxygen (DO)


in this site was observed to possess 30% boulder, 30% cobbles, 25% pebbles, 5% gravels,

5% sand and 5% silt.

7.7 East Rapti: This is an important river of Makawanpur and Chitwan districts. The river originates from

midhills in Makawanpur district at a place called Chisapani Garhi and flows south up to

Hetauda and then takes westerly course and through a fertile valley of Makawanpur and

Chitwan districts before joining with Narayani River. The river has a catchment area of

about 3110 km² and runs for around 122 km (Sharma 1997). The average annual discharge

of the river measured at Bhandara in Chitwan is 61 m³/s. According to the last complete

data from DHM measured in this river at Rajaiya, the minimum daily discharge was 3.08

m³/s and the maximum 141 m³/s.

After a quick fall from its origin, the river meanders extensively in the low and fertile land

of the two districts and plays important role in the agriculture. According to the last census

in 2001/02, there were 59071 holdings of land in Makawanpur district with an area of

34256.1 ha. Out of these, total area of arable land amounts to 31740.3 ha of which 9130.7

ha are irrigated by some means (CBS 2001). The quantity of mineral/chemical fertilizer

used in the district was found to be 3663451 kg with highest consumption of 1789186 kg

only for maize. The amount of this chemical input is in addition to the organic manure

coming from a huge stock of cattle, which numbers 149712 heads excluding buffaloes and

goats which count 47440 and 243507 respectively. The number of holdings using pesticide

in paddy alone stands highest at 9325.


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Similarly, according to the last census in 2001/02, there were 71429 holdings of land in

Chitwan district with an area of 42113.2 ha. Out of these, total area of arable land amounts

to 38348.9 ha of which 28442.0 ha are irrigated by some means (CBS 2001). The quantity

of mineral/chemical fertilizer used in the district was found to be 4203056 kg with

consumption of 2856863 kg only for paddy. The amount of this chemical input is in

addition to the organic manure coming from a huge stock of cattle, which numbers 89333

heads excluding buffaloes and goats which count 91970 and 160873 respectively. The

numbers of holdings using pesticides are 7341 in the district. The number of holdings using

pesticide in paddy alone stands at 22287.

There were two sampling sites for the study of the impacts of agriculture on this river. The

upstream or the reference site was fixed in the river in Makawanpur district few kilometers

before Hetauda immediately after the river comes down from the midhills. The downstream

or the disturbed site was set up in Bhandara, Chitwan district some 50 km away from the

reference site. The site was just on the boundary of Royal Chitwan National Park and the

special permissions were taken from the concerned authorities before each sampling (see

appendix for permission letters).

The temperature of water in upstream site varied from 17.8 to 24.1° C and the measure of

dissolved oxygen (DO) conductivity and pH reached up to 8.2 ppm, 174 µS/cm and 8.3

respectively. The substrate in this site was observed to possess 2% rock, 10% boulder, 30%

cobbles, 30% pebbles, 20% gravels, 3% sand and 5% silt. Similarly the temperature of

water in downstream site varied from 16.4 to 30° C and the measure of dissolved oxygen

(DO) conductivity and pH reached up to 9.4 ppm, 420 µS/cm and 8 respectively. The

substrate in this site was observed to possess 5% boulder, 40% cobbles, 30% pebbles, 20%

gravels, 2% sand and 3% silt.

7.8 Seti: This river is glacial in origin and comes from Annapurna range. This is the most important

river of Kaski district and flows through the heart of Pokhara city where it cuts the ground

deep and appears almost underground for some distance. It is a tributary of Gandaki River

System with a catchment area of 3000 km², length 125 km and annual average discharge of


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52 m³/sec (Sharma 1997). According to the last complete yearly data of this river by DHM,

the minimum flow was recorded as 11.5 m³/s and the maximum as 169 m³/s.

As the river passes through Pokhara, one of the most important urban center of the country,

the impacts of urbanization on this river is studied in this work. Pokhara is a beautiful

touristic city in the midhills of Kaski district of Western Development Region of Nepal,

which is very close to very high Annapurna ranges of Himalayas. The rank of the city as an

urban center of Nepal has improved tremendously from 13th in 1961 to 4th in 2001 (CBS

2003). The population of this city has grown at steady rate from 5413 in 1961 to 156312 in

2001. The strategic position and the touristic value of this city are the main reason of its

growth and are expected to continue like this in future as well. It is natural to expect some

disturbances of this growth on the river, which flows, through the center of the city.

Two sampling sites, upstream and downstream or the reference and disturbed were fixed on

this river to study the impacts of urbanization. The reference site was fixed on the river

along the Pokhara – Baglung Highway some distances before it enters the city. While, the

disturbed site was fixed after the river emerges out of the city near Phulbari area. The

temperature of water in upstream site varied from 12.8 to 21° C and the measure of


respectively. The substrate in this site was observed to possess 20% rock, 30% boulder,

25% cobbles, 15% pebbles, 8% gravels, 1% sand and 1% silt. Similarly the temperature of

water in downstream site varied from 14.3 to 20.5° C and the measure of dissolved oxygen

(DO) conductivity and pH reached up to 9.4 ppm, 63.7 µS/cm and 7.9 respectively. The

substrate in this site was observed to possess 10% rock, 30% boulder, 30% cobbles, 10%

pebbles, 10% gravels, 5% sand and 5% silt.

7.9 Tinau: Tinau River is one of the most important rivers of Palpa and Rupandehi districts of Lumbini

Zone in Western Development Region of Nepal. The river originates from midhills above

Maniphant in Palpa district and flows south to Rupandehi district. It is interesting to note

that except during the flood period, the river goes underground just near Butwal city and

emerges out only after about 10 km in the south (MOIC 1974). The river does not belong to

any of the three major river systems of Nepal and runs about 95 km between an altitude of


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100 – 800 masl (Sharma and Shrestha 2001). The drainage area of the river is estimated to

be 544 km² (Sharma 1977). According to the last complete annual data of the mean daily

discharge of the river by DHM, the minimum was 2.58 m³/s and the maximum was 92.8

m³/s.

This river is the most important river in this work as the impacts of three different

disturbances; agriculture, dam and the urbanization were studied here. The river after

origination flows through a highly fertile valley called Maniphant (sometimes also called as

Mariphant). The valley, which is irrigated naturally by Tinau River is suitable for the

cultivation of varieties of crops, pulses and vegetables and as such is under intensive

agricultural practices. This makes it an ideal site for the investigation of the impacts of

agricultural practices on the river by taking fish as an indicator.

According to the last census in 2001/02, there were 44406 holdings of land in Palpa district

with an area of 31623.5 ha. Out of these, total area of arable land amounts to 22734.9 ha of

which 8372.0 ha are irrigated by some means (CBS 2001). The quantity of

mineral/chemical fertilizer used in the district was found to be 759442 kg with highest

consumption of 302627 kg only for paddy. The amount of this chemical input is in addition

to the organic manure coming from a huge stock of cattle, which numbers 86660 heads

excluding buffaloes and goats which count 77868 and 126657 respectively. The number of

holdings using pesticide in paddy alone stands highest at 3123.

The same river has a hydropower project called Tinau Hydropower Project which was

constructed by Butwal Power Company at about 3 km north of Butwal on the right bank in

Palpa district (WECS 1997). Construction started in 2023 B.S. and completed in 2034, this

is among the oldest hydropower projects of the country with mere 1 MW of installed

capacity, but the dam constructed across this river for power generation completely disrupts

the longitudinal corridor of the river. In addition, unlike Aandhikhola, there is no provision

of fish pass either. This makes this river ideal for the study of the impact of dams on the

river and thus it is a part of the study in this work.


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The details of Tinau Hydropower Project are summarized in the following table. 1 Minimum Flow in Tinau River 2.4 m³/s 2 Average Discharge 54 m³/s 3 Design Discharge 2.4 m³/s 4 Gross Head 50 m

Size of Powerhouse Cavern L: 88 m, H: 6 m Engine Hall L: 32 m, B: 4.5 m

5

Corridor L: 56 m, B: 3 m 6 X – Section of Main Tunnel 2.1 m² 7 X – Section of Tailrace Tunnel 3.85 m² 8 Dam Length 65 m 9 Dam Height 8 m 10 Dam Type R.C.C. and Stone Masonry 11 Length of Tunnel 2462 m 12 Construction Period 11 Years 13 Turbines 2 X 250 kW and 1 X 500kW 14 Cost of Project Rs 102,00,000

Table 7.9.1: Details of Tinau Hydropower Project Source: WECS (1997) modified

Downstream from the hydropower plant the river also supports one of the important urban

centers of the country called Butwal. The city is strategically placed in Bhanwar region as a

door to the people of the hills of all Western Development Regions for their business and

other interactions with Terai as well as with India. The city is also head quarter of Lumbini

Zone and its importance is enhanced by the country’s longest highway, East-West Highway,

which passes through the middle of the city and also by the link with another, Siddhartha

Highway. Butwal Industrial District, a prestigious name in the commerce and industrial

sector, is also situated in this urban center.

Butwal was gazetted as urban center in 1959, is not and was not a very crowded area in

comparison with some other major municipal areas of the country. The census of 1971

recorded the population of the city as 12, 815. The population increased to 22,583 in 1981,

44,272 in 1991 and 75,384 in 2001 (CBS 2003). However, it is not the population as such,

but its growth is simply alarming as could be seen from the above figure. The impact of this

urbanization is ever increasing on the nearby Tinau River and is thus included in this study.

There were six sampling sites in Tinau river, two each for the three disturbances,

agriculture, dam and urbanization. To study the agricultural impact, the upstream or the

reference site was fixed just near the beginning of the valley, Maniphant in Palpa district.


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The downstream or the disturbed site for this purpose was selected in the place called

Koldanda also in Palpa. Similarly, for the impact of dam, the upstream or the reference site

was made about 100 m before the dam and the disturbed or downstream was about 500 m

after the dam, both in Palpa district. The sampling sites for the study of the impact of

urbanization however were in Rupandehi district. The upstream or the reference site was

about 1 km before the city and the downstream was just before the river disappears

underground.

The temperature of water in reference site for agriculture varied from 17 to 31.9° C and the

measure of dissolved oxygen (DO) conductivity and pH reached up to 9.2 ppm, 25.6 µS/cm

and 7.2 respectively. The substrate in this site was observed to 30% cobbles, 40% pebbles,

25% gravels, 3% sand and 2% silt. Similarly the temperature of water in downstream site

for agriculture varied from 12.2 to 22.5° C and the measure of dissolved oxygen (DO)

conductivity and pH reached up to 8.15 ppm, 72.3 µS/cm and 8.24 respectively. The

substrate in this site was observed to possess 30% rock, 25% boulder, 20% cobbles, 20%

pebbles, 3% gravels, 1% sand and 1%.

The temperature of water in reference site for city varied from 16 to 24.5° C and the

measure of dissolved oxygen (DO), conductivity and pH reached up to 8.8 ppm, 70 µS/cm

and 8.4 respectively. The substrate in this site was observed to 20% rock, 30% boulder,

20% cobbles, 20% pebbles, 8% gravels, 1% sand and 1% silt. Similarly the temperature of

water in downstream site for city varied from 14.2 to 23.8° C and the measure of dissolved

oxygen (DO) conductivity and pH reached up to 7.5 ppm, 68 µS/cm and 8.5 respectively.

The substrate in this site was observed to possess 10% boulder, 10% cobbles, 30% pebbles,

30% gravels, and 20% sand.

The temperature of water in reference site for dam varied from 15 to 28.8° C and the

measure of dissolved oxygen (DO), conductivity and pH reached up to 8 ppm, 68 µS/cm

and 8.2 respectively. The substrate in this site was observed to possess 10% rock, 10%

boulder, 10% cobbles, 10% pebbles, 30% gravels, 25% sand and 5% silt. Similarly the

temperature of water in downstream site for dam varied from 15.4 to 26.4° C and the

measure of dissolved oxygen (DO) conductivity and pH reached up to 7.6 ppm, 68.8 µS/cm

and 8.2 respectively. The substrate in this site was observed to possess 15% rock, 15%

boulder, 20% cobbles, 30% pebbles, 10% gravels, 5% sand and 5% silt.


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Map 7.3: Showing Sampling Sites in Aandhikhola

Map 7.4: Showing Sampling Sites in Karrakhola, East Rapti, Narayani and Arungkhola


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Map 7.5: Showing Sampling Sites in Bagmati River

Map 7.6: Showing Sampling Sites in Jhikhukhola


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Map 7.7: Showing Sampling Sites in Seti River

Map 7.8: Showing Sampling Sites in Tinau River

8 Results

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CHAPTER VIII: RESULTS 8.1: Distribution, abundance and density of fish: The following are the details of the fishes captured and studied in this research, which are

presented systematically, according to Shrestha (2001) who in turn had followed Jayaram

(1999). In addition, Day (1889), Rajbanshi (1982), Rahman (1989), Shrestha (1990), Talwar

and Jhingran (1991), Shrestha (1994), Shrestha (1994) and Shrestha (1995) have also been

consulted to work out this part of the result.

NO ORDER FAMILY GENUS SPECIES

1 Clupeiformes Clupeidae Gudusia Gudusia chapra Hamilton-Buchanan 1822

2 Cypriniformes Cyprinidae Neolissochilus Neolissochilus hexagonolepis McClelland 1839

3 Cirrhinus Cirrhinus reba Hamilton-Buchanan 1822

4 Labeo Labeo dero Hamilton-Buchanan 1822

5 Puntius Puntius chola Hamilton-Buchanan 1822

6 Puntius Puntius conchonius Hamilton-Buchanan 1822

7 Puntius Puntius sophore Hamilton-Buchanan 1822

8 Semiplotus Semiplotus semiplotus McClelland 1839

9 Tor Tor putitora Hamilton-Buchanan 1822

10 Tor Tor tor Hamilton-Buchanan 1822

11 Naziritor Naziritor chelynoides McClelland 1839

12 Aspidoparia Aspidoparia morar Hamilton-Buchanan 1822

13 Barilius Barilius barila Hamilton-Buchanan 1822

14 Barilius Barilius barna Hamilton-Buchanan 1822

15 Barilius Barilius bendelisis Hamilton-Buchanan 1822

16 Barilius Barilius shacra Hamilton-Buchanan 1822

17 Barilius Barilius vagra Hamilton-Buchanan 1822

18 Brachydanio Brachydanio rerio Hamilton-Buchanan 1822

19 Danio Danio aequipinnatus McClelland 1839

20 Danio Danio dangila Hamilton-Buchanan 1822

21 Esomus Esomus danricus Hamilton-Buchanan 1822

22 Crossocheilus Crossocheilus latius Hamilton-Buchanan 1822

23 Garra Garra annandalei Hora 1921

8 Results

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NO ORDER FAMILY GENUS SPECIES 24 Garra Garra gotyla gotyla

Gray 1830 25

Schizothorax Schizothorax richardsonii

Gray 1832 26 Cypriniformes Cyprinidae Schizothoraichthys Schizothoraichthys progastus

McClelland 1839 27 Psilorhynchidae Psilorhynchus Psilorhynchus pseudecheneis

Menon and Datta 1961 28 Balitoridae Nemacheilus Nemacheilus corica

Hamilton-Buchanan 1822 29 Acanthocobitis Acanthocobitis botia

Hamilton-Buchanan 1822 30 Schistura Schistura beavani

Günther 1868 31 Schistura Schistura rupecula

McClelland 1839 32 Cobitidae Botia Botia almorhae

Gray 1831 33 Botia Botia lohachata

Chaudhuri 1912 34 Lepidocephalus Lepidocephalus guntea

Hamilton-Buchanan 1822 35 Siluriformes Amblycipitidae Amblyceps Amblyceps mangois

Hamilton-Buchanan 1822 36 Schilbeidae Clupisoma Clupisoma garua

Hamilton-Buchanan 1822 37 Sisoridae Myersglanis Myersglanis blythii

Day 1870 38 Glyptothorax Glyptothorax pectinopterus

McClelland 1842 39 Glyptothorax Glyptothorax telchitta

Hamilton-Buchanan 1822 40 Glyptothorax Glyptothorax trilineatus

Blyth 1860 41 Pseudecheneis Pseudecheneis sulcatus

McClelland 1842 42 Heteropneustidae Heteropneustes Heteropneustes fossilis

Bloch 1794 43 Perciformes Channidae Channa Channa orientalis

Bloch & Schneider 1801 44 Channa Channa punctatus

Bloch 1793 45 Gobiidae Glossogobius Glossogobius giuris

Hamilton-Buchanan 1822 46 Synbranchiformes Mastacembelidae Macrognathus Macrognathus pancalus

Hamilton-Buchanan 1822 47 Mastacembelus Mastacembelus armatus

Lacepede 1800 Table 8.1.1 : List of fish species recorded in this study

1. Gudusia chapra: This fish, commonly known as river shad or Suiya in Nepal has been

listed by Day (1889), Chaudhuri (1912), Taft (1955), DeWitt (1960), Menon (1962),

Shrestha (1978), Rajbanshi (1982), Rahman (1989), Shrestha (1990), Talwar and Jhingran

(1991) and Shrestha (2001) under the same name or different synonyms. It is reported from

India, Pakistan, Bangladesh, Burma, Malaya and Nepal. In Nepal, it has been reported from

up to 373 masl altitudes and measures up to 200 mm total length (TL). The fish is not

included in IUCN red list and the status is described as common. The present study has

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found this fish only once in Karra Khola at 450 masl (new record) during spring and, thus, it

could be a threatened species, at least, at this altitude. (Picture:8.1.1)

2. Neolissochilus hexagonolepis: This fish, commonly known as Katle in Nepal, has been

listed by McClelland (1839), Day (1889), Hora (1937), Taft (1955), Mishra (1959), DeWitt

(1960), Menon (1962), Shrestha (1978), Rajbanshi (1982), Shrestha (1990), Talwar and

Jhingran (1991) and Shrestha (2001) under the same name or different synonyms. It is

distributed in India, Nepal, Bangladesh, Burma, China, Thailand, Malaysia and Indonesia.

In Nepal, this fish has been recorded from up to the altitude of 1700 masl with maximum

size recorded is 610 mm. The fish is not included in IUCN red list though it is described as

‘vulnerable’ in the country may be because of its great commercial importance. This study

finds the species occurring from the altitude 162 masl to 927 masl with some sections of

river Aandhikhola, Tinau, Seti and East Rapti still holding a good number. (Picture: 8.1.2)

3. Cirrhinus reba: This fish, commonly known as Rewa in Nepal, has been listed by

Hamilton-Buchanan (1822), Günther (1861), Day (1889), Taft (1955), DeWitt (1960),

Menon (1962), Shrestha (1978), Rajbanshi (1982), Rahman (1989), Shrestha (1990), Talwar

and Jhingran (1991) and Shrestha (2001) under the same name or different synonyms. It is

reported from Pakistan, India, Nepal, Bangladesh and Burma. In Nepal it has been found up

to 373 masl with maximum size of 305 mm. It is not included in IUCN red list and in Nepal

its status is reported to be ‘common’. This study finds the species occurring in Karrakhola at

450 masl (new record) and it could be a threatened species at this altitude. (Picture: 8.1.3)

4. Labeo dero: Commonly known as Gardi, Rohu or Shahi in Nepal, this fish has been

mentioned by Hamilton-Buchanan (1822), Day (1889), Chaudhuri (1912), Hora (1937),

Taft (1955), DeWitt (1960), Menon (1962), Shrestha (1978), Rajbanshi (1982), Rahman

(1989), Shrestha (1990), Talwar and Jhingran (1991), and Shrestha (2001) under the same

name or different synonyms. It is reported from Iran, Afghanistan, Pakistan, India, Nepal,

Bhutan Bangladesh, Burma, China and Sri Lanka. In Nepal it has been found up to 1424

masl with maximum size of 300 mm. It is not included in IUCN red list and in Nepal its

status is reported to be ‘common’. This study finds the species occurring in rivers Narayani,

East Rapti, Arungkhola and Tinau at the altitude ranging from 148 to 207 masl with

maximum total length of 320 mm (new record). Its distribution seems much more limited

than reported in the past. It has a significant commercial value. (Picture: 8.1.4)

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5. Puntius chola: This fish, commonly known as Sidre or Pothi in Nepal has been listed by

Hamilton-Buchanan (1822), Day (1889), Taft (1955), DeWitt (1960), Menon (1962),


(1991) and Shrestha (2001) under the same name or different synonyms. This fish is

reported from Pakistan, India, Nepal, Bangladesh, Sri Lanka, Burma and Bhutan. In Nepal

it has been reported from up to 300 masl with maximum size of 80 mm. It is not included in

IUCN red list though in Nepal it is mentioned as ‘rare’. This study finds this fish in rivers

Aandhikhola and Karrakhola, and also confirms it to be rare but the distribution is wider up

to 670 masl (new record). (Picture. 8.1.5)

6. Puntius conchonius: Commonly known as Sidre or Pothi again, this fish has been listed

by Hamilton-Buchanan (1822), Day (1889), Taft (1955), DeWitt (1960), Menon (1962),

Shrestha (1978), Jayaram (1982), Rajbanshi (1982), Rahman (1989), Shrestha (1990),

Talwar and Jhingran (1991) and Shrestha (2001) under the same name or different

synonyms. This fish is reported from Afghanistan, Pakistan, India, Nepal and Bangladesh.

In Nepal it has been reported from up to 1800 masl with maximum size of 80 mm. It is not

included in IUCN red list and the status is described as ‘common’. The present study finds

this fish in rivers Arungkhola, Karrakhola, Narayani, East Rapti, Seti and Tinau and

confirms it as common at least in the altitude 140 to 927masl with the maximum size

reaching up to 85 mm (new record). (Picture: 8.1.6)

7. Puntius sophore: Commonly known as Sidre or Chandanpothi, this fish has been listed

by Hamilton-Buchanan (1822), Day (1889), Fowler (1924), Taft (1955), DeWitt (1960),

Menon (1962), Tilak (1970), Shrestha (1978), Rajbanshi (1982), Rahman (1989), Shrestha

(1990), Talwar and Jhingran (1991) and Shrestha (2001) under the same name or different

synonyms. It is reported from Afghanistan, Pakistan, India, Nepal, Bangladesh, Bhutan,

Burma and China. In Nepal it has been reported from up to 1460 masl with maximum size

of 100 mm. It is not included in IUCN red list and the status is described as ‘common’. The

present study finds this fish in rivers Arungkhola, Karrakhola, Narayani, East Rapti, Seti

and Tinau and confirms it as common. (Picture: 8.1.7)

8. Semiplotus semiplotus: This fish, commonly known as Chepti in Nepal has been listed

by McClelland (1839), Day (1889), Hora (1939), Chaudhuri (1919), Hora (1937), Taft

(1955), DeWitt (1960), Menon (1962), Shrestha (1978), Rajbanshi (1982), Shrestha (1990),

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synonyms. It is reported from India, Nepal, Burma, and Bhutan. In Nepal it has been

reported from up to 463 masl with maximum size of 300 mm. It is not included in IUCN red

list and the status is described as ‘common’ in the country. This study finds this fish from

the rivers Aandhikhola, Arungkhola and Narayani up to 670 masl (new record), but seems

threatened unlike previously reported. (Picture: 8.1.8)

9. Tor putitora: This fish, commonly known as Sahar or Mahseer in Nepal has been listed

by Hamilton-Buchanan (1822), Day (1889), Hora (1939), Taft (1955), Mishra (1959),

DeWitt (1960), Menon (1962), Shrestha (1978), Rajbanshi (1982), Rahman (1989),

Shrestha (1990), Talwar and Jhingran (1991) and Shrestha (2001) under the same name or

different synonyms. It is reported from Afghanistan, Pakistan, India, Nepal, Bangladesh and

Bhutan. In Nepal it has been reported from up to 1891 masl with maximum size of 1800

mm. Though it is not included in IUCN red list, it is reported ‘vulnerable’ in the country. It

is a big commercial game fish. The present study finds this fish in rivers Aandhikhola,

Arungkhola, Narayani, East Rapti and Tinau up to 681 masl and confirms that it is

vulnerable. (Picture: 8.1.9)

10. Tor tor: This fish, commonly known as Sahar in Nepal has been listed by Hamilton-

Buchanan (1822), Day (1889), Mirza (1967) Shrestha (1978), Rajbanshi (1982), Rahman

(1989), Shrestha (1990), Talwar and Jhingran (1991) and Shrestha (2001) under the same

name or different synonyms. It is reported from Pakistan, India, Nepal, Bangladesh, Bhutan

and Burma. In Nepal it has been reported from up to 1891 masl with maximum size of 1200

mm. Though it is not included in IUCN red list, it is reported as ‘endangered’ in the

country. It is a big game fish with high commercial value. The present study finds this fish

in rivers Narayani and Tinau up to 282 masl and confirms that it is endangered. (Picture:

8.1.10)

11. Naziritor chelynoides: This fish, commonly known as Karange in Nepal, has been listed

by McClelland (1839), Day (1889), Shrestha (1990), Talwar and Jhingran (1991) and

Shrestha (2001) under the same name or different synonyms. It is reported from Pakistan,

India and Nepal. In Nepal it has been reported from up to 1700 masl with maximum size of

250 mm. It is not included in IUCN red list and reported as ‘fairly common’ in the country.

The present study however finds this fish only in river Aandhikhola at 681 masl with

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maximum size of 210 mm and thus fish seems less than common than reported earlier.

(Picture: 8.1.11)

12. Aspidoparia morar: This fish, commonly known as Harda, Bhegna or Chepwa in

Nepal, has been listed by Hamilton-Buchanan (1822), Day (1889), Hora (1937), Taft

(1955), DeWitt (1960), Menon (1962), Shrestha (1978), Rajbanshi (1982), Rahman (1989),


different synonyms. It is reported from Iran, Afghanistan, Pakistan, India, Nepal,

Bangladesh, Burma and Thailand. In Nepal it has been reported from up to 850 masl with

maximum size of 145 mm. It is not included in IUCN red list and reported as ‘common’ in

the country. The present study however finds this fish only in rivers Narayani and East

Rapti, that too less in number and with restricted altitudinal range up to 202 masl. (Picture:

8.1.12)

13. Barilius barila: This fish, commonly known as Fageta or Khasre in Nepal, has been

listed by Hamilton-Buchanan (1822), Day (1889), Chaudhuri (1912), Taft (1955), DeWitt

(1960), Menon (1962), Shrestha (1978), Rajbanshi (1982), Rahman (1989), Shrestha


synonyms. It is reported from India, Nepal, Bangladesh and Burma. In Nepal it has been

reported from up to 1424 masl with maximum size of 125 mm. It is not included in IUCN

red list and reported as ‘common’ in the country. The present study also finds this fish as

very common and is caught in all the rivers studied except Bagmati, up to 936 masl with

maximum size of 130 mm (new record). (Picture:8.1.13)

14. Barilius barna: This fish, commonly known as Fageta in Nepal, has been listed by




India, Nepal, Bangladesh and Burma. In Nepal it has been reported from up to 1891 masl

with maximum size of 150 mm. It is not included in IUCN red list and reported as

‘common’ in the country. However, the present study found only one of these specimens at

the altitude of 452 masl in Karrakhola indicating that this species might be highly

threatened. (Picture: 8.1.14)

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15. Barilius bendelisis: This fish, commonly known as Fageta in Nepal, has been listed by

Hamilton-Buchanan (1822), Day (1889), Hora (1937), Taft (1955), DeWitt (1960), Menon

(1962), Shrestha (1978), Rajbanshi (1982), Rahman (1989), Shrestha (1990), Talwar and


reported from Pakistan, India, Nepal, Bangladesh, Bhutan and Sri Lanka. In Nepal it has

been reported from up to 1891 masl with maximum size of 180 mm. It is not included in

IUCN red list and reported as ‘common’ in the country. The present study also finds this

species as quite common and is recorded from all the rivers studied except Bagmati up to

the altitude 936 masl. (Picture: 8.1.15)

16. Barilius shacra: This fish, commonly known as Fageta in Nepal, has been listed by


(1962), Tilak (1971), Shrestha (1978), Rajbanshi (1982), Rahman (1989), Shrestha (1990),


synonyms. It is reported from India, Nepal, and Bangladesh. In Nepal it has been reported

from up to 850 masl with maximum size of 130 mm. It is not included in IUCN red list and

reported as ‘common’ in the country. However, the present study finds the species only in

rivers Arungkhola, Narayani and East Rapti, and is not so common as reported though the

same altitudinal range has been explored. (Picture: 8.1.16)

17. Barilius vagra: This fish, commonly known as Fageta or Khasre in Nepal, has been

listed by Hamilton-Buchanan (1822), Day (1889), Hora (1937), Taft (1955), Mishra (1959),

DeWitt (1960), Menon (1962), Mirza and Sadiq (1978), Shrestha (1978), Rajbanshi (1982),

Rahman (1989), Shrestha (1990), Talwar and Jhingran (1991) and Shrestha (2001) under

the same name or different synonyms. It is reported from Afghanistan, Pakistan, India,

Nepal, Bangladesh and Sri Lanka. In Nepal it has been reported from up to 1500 masl with

maximum size of 150 mm. It is not included in IUCN red list and reported as ‘common’ in

the country. The present study too finds it common and it is caught in all rivers except

Bagmati among the rivers studied. (Picture: 8.1.17)

18. Brachydanio rerio: This fish, commonly known as Zebra in Nepal, has been listed by




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Pakistan, India, Nepal, Bangladesh, Bhutan and Burma. In Nepal it has been reported from

up to 1350 masl with maximum size of 25 mm. It is not included in IUCN red list but

reported as ‘vulnerable’ in the country. The present study finds this fish up to the height of

898 masl with maximum size of 50 mm (new record), and though reported vulnerable, there

are certain sections of river like Tinau where they are found in abundance. (Picture: 8.1.18)

19. Danio aequipinnatus: This fish, commonly known as Bhitti or Patale Sidre in Nepal,

has been listed by McClelland (1839), Day (1889), Regan (1907), Taft (1955), DeWitt

(1960), Menon (1962), Shrestha (1978), Rajbanshi (1982), Rahman (1989), Shrestha


synonyms. It is reported from India and Nepal. In Nepal it has been reported from up to

1460 masl. It is included in IUCN red list as the species with Data Deficient (DD) and

reported as ‘insufficiently known’ in the country. The present study finds this species from

Arungkhola and Jhikhukhola from up to 936 masl with the maximum size of 85 mm, and

the exact status has to be studied further as it is not so common. (Picture: 8.1.19)

20. Danio dangila: This fish, commonly known as Nepti in Nepal, has been listed by


(1962), Rajbanshi (1982), Rahman (1989), Talwar and Jhingran (1991) and Shrestha (2001)

under the same name or different synonyms. It is reported from India, Nepal, Bangladesh,

Bhutan and Burma. In Nepal it has been reported from up to 300 masl. It is not included in

IUCN red list but reported as ‘occasional’ in the country. The present study finds this

species only in Seti river at 630 masl with maximum size of 75 mm (new records) and

seems to be a highly threatened species. (Picture: 8.1.20)

21. Esomus danricus: This fish, commonly known as Dhedawa or Darai in Nepal, has been

listed by Hamilton-Buchanan (1822), Day (1889), Chaudhuri (1912), Taft (1955), DeWitt

(1960), Menon (1962), Rao and Sharma (1972), Shrestha (1978), Rajbanshi (1982),


the same name or different synonyms. It is reported from Afghanistan, Pakistan, India,

Nepal, Bangladesh, Sri Lanka and Burma. In Nepal it has been reported from up to 1460

masl with maximum size of 75 mm. It is not included in IUCN red list and reported as

‘common’ in the country. The present study finds it only in the river Tinau, Karrakhola and

Arungkhola up to 680 masl and also not so common. (Picture: 8.1.21)

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22. Crossocheilus latius: This fish, commonly known as Lohari, Petfora, Besuro or Kaundi

in Nepal, has been listed by Hamilton-Buchanan (1822), Day (1889), Hora (1937), Taft

(1955), DeWitt (1960), Menon (1962), Rao and Sharma (1972), Shrestha (1978), Rajbanshi

(1982), Rahman (1989), Shrestha (1990), Talwar and Jhingran (1991) and Shrestha (2001)

under the same name or different synonyms. It is reported from India, Nepal and

Bangladesh. In Nepal it has been reported from up to 850 masl with maximum size of 220

mm. It is not included in IUCN red list and reported as ‘common’ in the country. The

present study finds its distribution limited to within 202 masl and was caught in river

Narayani, Arungkhola, Rapti and Tinau. (Picture: 8.1.22)

23. Garra annandalei: This fish, commonly known as Buduna in Nepal, has been listed by


(1962), Ganguly and Dutta (1973), Shrestha (1978), Rajbanshi (1982), Rahman (1989),


different synonyms. It is reported from India, Nepal, Bangladesh and Bhutan. In Nepal it

has been reported from up to 1891 masl with maximum size of 150 mm. It is not included in

IUCN red list and reported as ‘common’ in the country. The present work finds it in all the

rivers studied except Bagmati and Narayani (but found in the tributaries), up to 936 masl

with maximum size of 165 mm (new record) and is quite common. (Picture: 8.1.23)

24. Garra gotyla gotyla: This fish, commonly known as Buduna in Nepal, has been listed

by Gray (1832), Day (1889), Prashad (1912), Hora (1921), Taft (1955), DeWitt (1960),

Menon (1962), Ganguly and Dutta (1973), Shrestha (1978), Rajbanshi (1982), Rahman


name or different synonyms. It is reported from Afghanistan, Pakistan, India, Nepal,

Bangladesh, Bhutan and Burma. In Nepal it has been reported from up to 1560 masl with

maximum size of 150 mm. It is not included in IUCN red list and reported as ‘fairly

common’ in the country. The present work finds it in all the rivers studied except river

Bagmati with maximum size of 180 mm (new record) and is perhaps the most common

species. (Picture: 8.1.24)

25. Schizothorax richardsonii: This fish, commonly known as Buchhe Asla in Nepal, has

been listed by Gray (1832), Günther (1861), Heckel (1877), Day (1889), Regan (1907),

Chaudhuri (1913), Hora (1921), Taft (1955), DeWitt (1960), Menon (1962), Mirza and

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Awan (1978), Shrestha (1978), Rajbanshi (1982), Terashima (1984), Shrestha (1990),


synonyms. It is reported from Afghanistan, Pakistan, India, Nepal and Bhutan. In Nepal it

has been reported from up to 2810 masl 600 mm. It is not included in IUCN red list but

reported as ‘vulnerable’ in the country. The present study finds it in river Bagmati,

Narayani, East Rapti and Aandhikhola up to 1621 masl. It is an important game fish with

high commercial value and is found sufficiently only in river Bagmati during this research.

(Picture: 8.1.25)

26. Schizothoraichthys progastus: This fish, commonly known as Chuche Asla in Nepal,

has been listed by McClelland (1839), Günther (1861), Day (1889), Shrestha (1978),

Rajbanshi (1982), Tilak and Sharma (1982), Shrestha (1990), Talwar and Jhingran (1991)

and Shrestha (2001) under the same name or different synonyms. It is reported from India,

Nepal and Bhutan. In Nepal it has been reported from up to 1820 masl with maximum size

of 300 mm. It is not included in IUCN red list but reported as ‘vulnerable’ in the country.

The present study finds this commercially valuable game fish in only river Seti up to 927

masl, thus, indicating a very restricted distribution. (Picture: 8.1.26)

27. Psilorhynchus pseudecheneis: This fish, commonly known as Tite Machha in Nepal,

has been listed by Menon and Datta (1962), Shrestha (1978), Rajbanshi (1982), Shrestha

(1990), Talwar and Jhingran (1991) and Shrestha (2001). This species is endemic to Nepal

and has been reported from up to 2950 masl with maximum size of 200 mm. It is not

included in IUCN red list but reported as ‘vulnerable’ in the country. The present study

finds this species only in rivers Narayani and East Rapti, up to 202 masl and that too in very

limited number. (Picture: 8.1.27)

28. Nemacheilus corica: This fish, commonly known as Gadela in Nepal, has been listed

by Hamilton-Buchanan (1822), Day (1889), Taft (1955), DeWitt (1960), Menon (1962),



Afghanistan, Pakistan, India, Nepal and Bangladesh. In Nepal, it has been reported from up

to 1460 masl with maximum size of 75 mm. It is not included in IUCN red list but reported

as ‘insufficiently known’ in the country. The present study finds it in rivers Aandhikhola,

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Jhikhukhola, Karrakhola, Narayani, East Rapti and Tinau, though not in good number.

(Picture: 8.1.28)

29. Acanthocobitis botia: This fish, commonly known as Dhade Goira in Nepal, has been

listed by Hamilton-Buchanan (1822), Blyth (1861), Day (1889), Chaudhuri (1910), Taft



different synonyms. It is reported from Pakistan, India, Nepal, Bangladesh, China, Burma

and Thailand. In Nepal, it has been reported from up to 1380 masl with maximum size of

100 mm. It is not included in IUCN red list and is reported as ‘common’ in the country. The

present study finds it in rivers Arungkhola, Karrakhola, Narayani, East Rapti, Seti and

Tinau, up to 680 masl and in good number. (Picture: 8.1.29)

30. Schistura beavani: This fish, commonly known as Pate Goira or Gadela in Nepal, has

been listed by Günther (1868) Taft (1955), DeWitt (1960), Menon (1962), Shrestha (1978),

Rajbanshi (1982), Rahman (1989), Shrestha (1990), Talwar and Jhingran (1991) and

Shrestha (2001) under the same name or different synonyms. It is reported from India,

Nepal and Bangladesh. In Nepal, it has been reported from up to 1560 masl with maximum

size of 75 mm. It is not included in IUCN red list and is reported as ‘common’ in the

country. The present study finds it in all rivers that is studied, up to 1610 masl with

maximum size of 100 mm (new records), and is very common. (Picture: 8.1.30)

31. Schistura rupecula: This fish, commonly known as Tele Goira or Gadela in Nepal, has

been listed by McClelland (1838), Day (1889), DeWitt (1960), Shrestha (1978), Rajbanshi


name or different synonyms. It is reported from India, Nepal and Bangladesh. In Nepal, it

has been reported from up to 2810 masl with maximum size of 100 mm. It is not included

in IUCN red list and is reported as ‘common’ in the country. The present study finds it in all

the rivers that are studied, up to 1621 masl and is very common. (Picture: 8.1.31)

32. Botia almorhae: This fish, commonly known as Baghi in Nepal, has been listed by

Gray (1831), Day (1889), Taft (1955), DeWitt (1960), Menon (1962), Shrestha (1978),

Rajbanshi (1982), Rahman (1989), Shrestha (1990), Talwar and Jhingran (1991) and

Shrestha (2001) under the same name or different synonyms. It is reported from India and

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Nepal. In Nepal, it has been reported from up to 300 masl with maximum size of 150 mm. It

is not included in IUCN red list and is reported as ‘insufficiently known’ in the country. The

present study finds it in Narayani and Rapti rivers, up to 202 masl with maximum size of

170 mm (new record) and recommends a further study for its exact status. (Picture: 8.1.32)

33. Botia lohachata: This fish, commonly known as Baghi in Nepal, has been listed by

Chaudhuri (1912), Taft (1955), DeWitt (1960), Menon (1962), Shrestha (1978), Rajbanshi

(1982), Rahman (1989), Shrestha (1990), Talwar and Jhingran (1991) and Shrestha (2001)

under the same name or different synonyms. It is reported from Pakistan, India, Nepal and

Bangladesh. In Nepal, it has been reported from up to 850 masl with maximum size of 100

mm. It is not included in IUCN red list and is reported as ‘common’ in the country. The

present study finds it in rivers Arungkhola, Narayani, East Rapti and Tinau, up to 207 masl

with maximum size of 140 mm (new record) and in fair number. (Picture: 8.1.33)

34. Lepidocephalus guntea: This fish, commonly known as Chuinke or Goira in Nepal, has

been listed by Hamilton-Buchanan (1822), Day (1889), Smith (1945), Rendahl (1948), Taft



different synonyms. It is reported from Pakistan, India, Nepal, Bangladesh, Burma and

Thailand. In Nepal, it has been reported from up to 76 masl with maximum size of 85 mm.

It is not included in IUCN red list and is reported as ‘common’ in the country. The present

study finds it in Arungkhola, Karrakhola, Narayani, East Rapti and Tinau rivers, up to 452

masl with maximum size of 95 mm (new records), and is quite common in some of these

rivers. (Picture: 8.1.34)

35. Amblyceps mangois: This fish, commonly known as Chilwai, Pichhi or Bindhar in

Nepal, has been listed by Hamilton-Buchanan (1822), Day (1889), Chaudhuri (1919), Taft



different synonyms. It is reported from Pakistan, India, Nepal, Bangladesh, Burma and

Thailand. In Nepal, it has been reported from up to1372 masl with maximum size of 150

mm. It is not included in IUCN red list and is reported as ‘rare’ in the country. The present

study finds it in Arungkhola, Karrakhola, Narayani, East Rapti and Tinau rivers, up to 616

masl, and is still fairly common in some of those rivers. (Picture: 8.1.35)

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36. Clupisoma garua: This fish, commonly known as Jalkapur or Bainkhe in Nepal, has

been listed by Hamilton-Buchanan (1822), Day (1889), Hora (1937), Taft (1955), Mishra



different synonyms. It is reported from Pakistan, India, Nepal and Bangladesh. In Nepal, it

has been reported from up to 570 masl with maximum size of 609 mm. It is not included in

IUCN red list and is reported as ‘fairly common’ in the country. A good commercial fish,

this study finds it in only river Narayani up to 165 masl and in very low number, thus,

seems to be threatened. (Picture: 8.1.36)

37. Myersglanis blythii: This fish, commonly known as Tilkabre in Nepal, has been listed

by Day (1869), Regan (1907), Hora (1952), Menon (1962), Shrestha (1978), Rajbanshi


name or different synonyms. It is an endemic fish to Nepal and has been reported up to

2960 masl with maximum size of 100 mm. It is not included in IUCN red list and is

reported as ‘rare’ in the country. This study finds it in Arungkhola and Seti rivers, up to 927

masl and in very little number indicating that it should be rare. (Picture: 8.1.37)

38. Glyptothorax pectinopterus: This fish, commonly known as Karasingha in Nepal, has

been listed by McClelland (1842), Hora (1923), Taft (1955), DeWitt (1960), Menon (1962),

Shrestha (1978), Rajbanshi (1982), Shrestha (1990), Talwar and Jhingran (1991) and

Shrestha (2001) under the same name or different synonyms. It is reported from Pakistan,

India and Nepal. In Nepal, it has been reported from up to 1820 masl with maximum size of

150 mm. It is not included in IUCN red list and is reported as ‘fairly common’ in the

country. This study finds it in East Rapti and Tinau rivers, up to 616 masl and in very little

number indicating that it should be highly threatened or rare. (Picture: 8.1.38)

39. Glyptothorax telchitta: This fish, commonly known as Kotel or Kavre in Nepal, has

been listed by Hamilton-Buchanan (1822), Day (1889), Hora (1949), Taft (1955), DeWitt

(1960), Menon (1962), Bashir and Mirza (1975), Shrestha (1978), Rajbanshi (1982),


the same name or different synonyms. It is reported from Pakistan, India, Nepal and

Bangladesh. In Nepal, it has been reported from up to 1424 masl with maximum size of 125

mm. It is not included in IUCN red list and is reported as ‘rare’ in the country. This study

8 Results

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finds it in Narayani, East Rapti and Tinau rivers, up to 616 masl with the maximum size of

130 mm (new record) and in not very high number indicating that it should be highly

threatened or rare. (Picture: 8.1.39)

40. Glyptothorax trilineatus: This fish, commonly known as Kavre in Nepal, has been

listed by Blyth (1861), Day (1889), Regan (1907), Shrestha (1978), Rajbanshi (1982),


different synonyms. It is reported from India, Nepal, Burma and Thailand. In Nepal, it has

been reported from up to 1820 masl with maximum size of 150 mm. It is not included in

IUCN red list and is reported as ‘rare’ in the country. This study finds it in Narayani, East

Rapti and Tinau rivers, up to 282 masl and in very low number indicating that it should be

highly threatened or rare. (Picture: 8.1.40)

41. Pseudecheneis sulcatus: This fish, commonly known as Kabre in Nepal has been listed

by McClelland (1842), Taft (1955), DeWitt (1960), Menon (1962), Tilak and Husain

(1973), Shrestha (1978), Rajbanshi (1982), Rahman (1989), Shrestha (1990), Talwar and


reported from India, Nepal, Bangladesh and Tibet. In Nepal, it has been reported from up to

1891 masl with maximum size of 175 mm. It is not included in IUCN red list and is

reported as ‘occasional’ in the country. This study finds it in Arungkhola, Karrakhola, Seti

and Tinau rivers, up to 927 masl and in very low number indicating that it should be highly

threatened or rare or could be occasional as reported before. (Picture: 8.1.41)

42. Heteropneustes fossilis: This fish, commonly known as Singhe in Nepal, has been listed

by Bloch (1794), Günther (1861), Day (1889), Regan (1907), Taft (1955), DeWitt (1960),

Menon (1962), Mishra (1976), Shrestha (1978), Rajbanshi (1982), Rahman (1989), Shrestha


synonyms. It is reported from Pakistan, India, Nepal, Bangladesh, Burma and Sri Lanka. In

Nepal, it has been reported from up to 1400 masl with maximum size of 175 mm. This

stinging fish is not included in IUCN red list and is reported as ‘common’ in the country.

This study finds it in Aandhikhola, Karrakhola, East Rapti, Jhikhukhola, Seti and Tinau

rivers, up to 898 masl with maximum size of 205 mm (new record) and in very low number

indicating that it should be a highly threatened species if not rare. (Picture: 8.1.42)

8 Results

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43. Channa orientalis: This fish, commonly known as Bhoti or Hile in Nepal, has been

listed by Bloch and Schneider (1801), Hamilton-Buchanan (1822), Day (1889), Chaudhuri

(1919), DeWitt (1960), Menon (1962), Rajbanshi (1982), Rahman (1989), Shrestha (1990),


synonyms. It is reported from Iran, Afghanistan, Pakistan, India, Nepal, Bangladesh, Burma

and Sri Lanka up to Indonesia. In Nepal, it has been reported from up to 1400 masl with

maximum size of 180 mm. This fish is not included in IUCN red list and is reported as

‘common’ in the country. This study finds it in Arungkhola, Karrakhola, Narayani, East

Rapti, Seti and Tinau rivers, up to 680 masl with maximum size of 220 mm (new record),

and is fairly common. (Picture:8.1.43)

44. Channa punctatus: This fish, commonly known as Bhoti or Hile in Nepal, has been

listed by Bloch (1793), Günther (1861), Day (1889), Regan (1907), Taft (1955), Mishra



different synonyms. It is reported from Afghanistan, Pakistan, India, Nepal, Bangladesh,

Burma and China. In Nepal, it has been reported from up to 1350 masl with maximum size

of 304 mm. This fish is not included in IUCN red list and is reported as ‘common’ in the

country. This study finds it in Aandhikhola, Arungkhola, Jhikhukhola, Karrakhola,

Narayani and Tinau rivers, up to 936 masl and is quite common. (Picture: 8.1.44)

45. Glossogobius giuris: This fish, commonly known as Bulla in Nepal, has been listed by

Hamilton-Buchanan (1822), Day (1889), Koumans (1941), Taft (1955), DeWitt (1960),



reported from Africa to Oceania encompassing Indian sub continent and South of China. In

Nepal, it has been reported from up to 300 masl with maximum size of 175 mm. This fish is

not included in IUCN red list and is reported as ‘common’ in the country. This study finds it

in Narayani and East Rapti rivers, up to 202 masl and its number indicates that it is a highly

threatened species in Nepal. (Picture: 8.1.45)

46. Macrognathus pancalus: This fish, commonly known as Kath Gainchi or Malanga

Bam in Nepal, has been listed by Hamilton-Buchanan (1822), Day (1889), Menon (1962),


8 Results

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Pakistan, India, Nepal and Bangladesh. In Nepal, it has been reported from up to 300 masl

with maximum size of 250 mm. This fish is not included in IUCN red list and is reported as

‘common’ in the country. This study finds it only in Arungkhola at 202 masl and its number

indicates that it is not as common as reported earlier. (Picture: 8.1.46)

47. Mastacembelus armatus: This fish, commonly known as Bam in Nepal, has been listed

by Lacepede (1800), Günther (1861), Day (1889), Hora (1921), Taft (1955), DeWitt (1960),



reported from Pakistan, India, Nepal, Bangladesh up to Vietnam and Indonesia. In Nepal, it

has been reported from up to 784 masl with the maximum size of 300 mm. This fish is not

included in IUCN red list and is reported as ‘common’ in the country. This study finds it in

Aandhikhola, Arungkhola, Karrakhola, Narayani, East Rapti and Tinau rivers, up to 681

masl with maximum size of 675 mm (new record) and is fairly common. (Picture: 8.1.47)

8 Results

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Pic.8.1.1: Gudusia chapra (Hamilton-Buchanan

1822) Source: www.fishbase.org

Pic.8.1.2: Neolissochilus hexagonolepis (McClelland 1839)

Pic.8.1.3: Cirrhinus reba (Hamilton-Buchanan 1822) Source: www.fishbase.org

Pic.8.1.4: Labeo dero (Hamilton-Buchanan 1822)

Pic.8.1.5: Puntius chola (Hamilton-Buchanan 1822) Source: Talwar and Jhingran (1991)

Pic.8.1.6: Puntius conchonius (Hamilton-Buchanan 1822)



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Pic.8.1.7: Puntius sophore (Hamilton-Buchanan 1822)

Pic.8.1.8: Semiplotus semiplotus (McClelland 1839)

Pic.8.1.9: Tor putitora (Hamilton-Buchanan 1822)

Pic.8.1.10: Tor tor (Hamilton-Buchanan 1822)

Pic.8.1.11: Naziritor chelynoides (McClelland 1839)

Source: www.images.google.com

Pic.8.1.12. Aspidoparia morar (Hamilton-Buchanan 1822)

http://www.images.google.com/

8 Results

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Pic.8.1.13: Barilius barila (Hamilton-Buchanan 1822) Source: Talwar and Jhingran (1991)

Pic.8.1.14: Barilius barna (Hamilton-Buchanan 1822)

Pic.8.1.15: Barilius bendelisis (Hamilton-Buchanan 1822)

Pic.8.1.16: Barilius shacra (Hamilton-Buchanan 1822)

Pic.8.1.17: Barilius vagra (Hamilton-Buchanan 1822)

Pic.8.1.18: Brachydanio rerio (Hamilton-Buchanan 1822)

8 Results

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Pic.8.1.19: Danio aequipinnatus (McClelland 1839)

Pic.8.1.20: Danio dangila (Hamilton-Buchanan 1822)

Pic.8.1.21: Esomus danricus (Hamilton-Buchanan 1822)

Pic.8.1.22: Crossocheilus latius (Hamilton-Buchanan

1822)

Pic.8.1.23: Garra annandalei (Hora 1921)

Pic.8.1.24: Garra gotyla gotyla (Gray 1830)

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Pic.8.1.25: Schizothorax richardsonii (Gray 1832)

Pic.8.1.26:Schizothoraichthys progastus (McClelland 1839)

Pic.8.1.27:Psilorhynchus pseudecheneis (Menon and Datta 1961)Source: www.fishbase.org

Pic.8.1.28: Nemacheilus corica (Hamilton-Buchanan 1822)

Source: www.fishbase.org

Pic.8.1.29: Acanthocobitis botia (Hamilton-Buchanan 1822)

Pic.8.1.30: Schistura beavani (Günther 1868)



8 Results

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Pic.8.1.31: Schistura rupecula (McClelland 1839)

Pic.8.1.32: Botia almorhae (Gray 1831)

Pic.8.1.33: Botia lohachata (Chaudhuri 1912)

Pic.8.1.34: Lepidocephalus guntea (Hamilton-Buchanan 1822)

Pic.8.1.35 : Amblyceps mangois (Hamilton-Buchanan 1822)

Pic.8.1.36: Clupisoma garua (Hamilton-Buchanan 1822) Source: Shrestha (1995)

8 Results

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Pic.8.1.37: Myersglanis blythii (Day 1870) Source: Shrestha (1994)

Pic.8.1.38: Glyptothorax pectinopterus (McClelland 1842)

Source: Shrestha (1994)

Pic.8.1.39: Glyptothorax telchitta (Hamilton-Buchanan 1822)

Pic.8.1.40: Glyptothorax trilineatus (Blyth 1860)

Pic.8.1.41: Pseudecheneis sulcatus (McClelland 1842)

Pic.8.1.42: Heteropneustes fossilis (Bloch 1794)

8 Results

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Pic.8.1.43: Channa orientalis (Bloch & Schneider 1801)

Pic.8.1.44. Channa punctatus (Bloch 1793)

Pic.8.1.45: Glossogobius giuris (Hamilton-Buchanan 1822)

Source: www.fishbase.org

Pic.8.1.46: Macrognathus pancalus (Hamilton-Buchanan1822)

Pic.8.1.47: Mastacembelus armatus (Lacepede 1800)


8 Results

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Altogether 27588 fishes were captured during the entire sampling period lasting one

complete year and encompassing nine rivers in Central and Western Developmental Region

of Nepal. The captured fish represented 5 orders, 12 families, 33 genus and 47 species.

Table 8.1.2, below not just only shows the different species captured in the different rivers

that were sampled but also the seasons in which they were captured. The mark ‘S’, ‘P’, ‘A’

and ‘W’ mentioned in the table denotes the four seasons – spring, premonsoon or summer,

postmonsoon or autumn and winter respectively. While, the table 8.1.3 shows the yearly

average of the abundance in catch per unit effort (CPUE) of fish species in the sampled

rivers. CPUE in this study is defined as the number of species captured in 10 minutes of

electrofishing.

Rivers→ species↓

Aandhi Arung Bagmati Jhikhu Karra Narayani East Rapti

Seti Tinau

Gudusia chapra Hamilton-Buchanan 1822

S

Neolissochilus hexagonolepis McClelland 1839

S P A W

S A W

S P W

S P A W

S P AW

S P A W

Cirrhinus reba Hamilton-Buchanan 1822

A

Labeo dero Hamilton-Buchanan 1822

A W

P A

P A

A W

Puntius chola Hamilton-Buchanan 1822

P

S

Puntius conchonius Hamilton-Buchanan 1822

S P A W

P A W

S P A W

S P A

S W

S P A W

Puntius sophore Hamilton-Buchanan 1822

S P A W

S P A W

S P A

S P A

S A

S P A W

Semiplotus semiplotus McClelland 1839

S

A W

A

Tor putitora Hamilton-Buchanan 1822

S P W

S A W

S P

S W

S P A W

Tor tor Hamilton-Buchanan 1822

A

S

Naziritor chelynoides McClelland 1839

S

Aspidoparia morar Hamilton-Buchanan 1822

P

P A

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Seti Tinau

Barilius barila Hamilton-Buchanan 1822

S P A

S P A W

S P A W

S P A W

P A W

S P A W

P A W

S P A W

Barilius barna Hamilton-Buchanan 1822

W

Barilius bendelisis Hamilton-Buchanan 1822

S P W

S P A W

S P A W

S P A W

S P A W

S P A W

S

S A W

Barilius shacra Hamilton-Buchanan 1822

S

S P

S P W

Barilius vagra Hamilton-Buchanan 1822

S P A W

S A W

S

S P A W

S P A W

S P A W

S P W

S A W

Brachydanio rerio Hamilton-Buchanan 1822

S

P A W

A

S P A W

S P A

S P

S P A W

Danio aequipinnatus McClelland 1839

W

S P A W

Danio dangila Hamilton-Buchanan 1822

S P

Esomus danricus Hamilton-Buchanan 1822

S W

A

S P A W

Crossocheilus latius Hamilton-Buchanan 1822

A

P A

A

A W

Garra annandalei Hora 1921

S P A W

P

S P

S P

S P

S P AW

S P

Garra gotyla Gray 1830

S P A W

S P A W

S P A W

S P A W

S P A W

S P A W

S A W

S P A W

Schizothorax richardsonii Gray 1832

S P A W

S P A W

S W

P A W

Schizothoraichthys progastus McClelland 1839

S P AW

Psilorhynchus pseudecheneis Menon and Datta 1961

W

W

Nemacheilus corica Hamilton-Buchanan 1822

P

A

A

P A W

P

A

Acanthocobitis botia Hamilton-Buchanan 1822

S P A W

S P A W

S P W

S P A W

S P A

S

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Seti Tinau

Schistura beavani Günther 1868

S P A W

S P A W

P

S P W

S P A W

S P A W

S P A W

S P A

S P A W

Schistura rupecula McClelland 1839

S P A W

S P A W

A

S P A W

S P A W

S P A W

S P A W

S P AW

S P A W

Botia almorhae Gray 1831

P A W

A

Botia lohachata Chaudhuri 1912

A W

S P A W

A W

S A W

Lepidocephalus guntea Hamilton-Buchanan 1822

S P A W

S P A W

S P A W

S

P A W

Amblyceps mangois Hamilton-Buchanan 1822

S P A W

S P A W

P W

S P A W

S A W

Clupisoma garua Hamilton-Buchanan 1822

S

Myersglanis blythii Day 1870

A

S P A

Glyptothorax pectinopterus McClelland 1842

W

S

Glyptothorax telchitta Hamilton-Buchanan 1822

S P A

S A

A W

Glyptothorax trilineatus Blyth 1860

A

A

S A

Pseudecheneis sulcatus McClelland 1842

W

P

A W

A

Heteropneustes fossilis Bloch 1794

S

S P W

S

S

S

S A W

Channa orientalis Bloch & Schneider 1801

S P A W

S P A

P

A

S P

S P A W

Channa punctatus Bloch 1793

A

S P A W

S P A W

S A W

P A W

S P A W

Glossogobius giuris Hamilton-Buchanan 1822

A

S

Macrognathus pancalus Hamilton-Buchanan 1822

P A W

Mastacembelus armatus Lacepede 1800

S P A W

P A W

S P A W

S P A W

S P A W

S P A W

TOTAL SPECIES

18

27

3

12

25

32

30

18

29

Table 8.1.2: Distribution of fish species in sampled rivers and seasons

8 Results

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River Aandhikhola accounted for 18 different species in total with only 9 of them in all

seasons, 3 of them in three seasons and 6 of them showed up only in one season. Out of

these six species of single season, Naziritor chelynoides was not found in any other rivers

sampled in any seasons. Garra gotyla gotyla and Neolissochilus hexagonolepis had a good

abundance, while Barilius vagra, Garra annandalei, Schistura beavani and Schistura

rupecula had a fair abundance. Another thing to note in this river is the highest abundance

of Mastacembelus armatus among the rivers sampled. The average abundance of fish in this

river was found to be 71.89 / 10 mins.

Arungkhola showed a good diversity of fish with 27 species. Among them 12 species were

present in all the seasons, 5 species were present in three seasons, 4 of them showed up in

only two seasons and 6 of them sneaked in only one season. Schistura beavani had the

highest CPUE in this river followed by Garra gotyla gotyla. Acanthocobitis botia, Barilius

barila, Lepidocephalus guntea, Puntius conchonius and Puntius sophore had a fair

abundance. Macrognathus pancalus was recorded only from here among the sampled

rivers. The average abundance of fish in this river was found to be 96.10 / 10 mins.

Only 3 species were found in Bagmati River during the sampling time of which

Schizothorax richardsonii was the only species found in all the seasons. Schistura beavani

and Schistura rupecula were recorded only once and that too in the separate seasons.

However, the abundance of S. richardsonii was found to be good at over 30/10mins. The

average abundance of fish in this river was found to be 30.61 / 10 mins, lowest among the

rivers sampled. Jhikhukhola on the other hand was relatively richer than Bagmati with 12

species and half of them were present in all seasons. 2 species were recorded from here in

three seasons and another 1 from two seasons. Still, 3 species showed up just in one season.

The river was characterized by high abundance of Barilius barila, while the abundance of

B. vagra, Channa punctatus, G. gotyla and S. rupecula were fair and sufficient. The average

abundance of fish in this river was found to be 79.17 / 10 mins.

8 Results

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Fish species Aandhikhola Arungkhola Bagmati Jhikhukhola Karrakhola Narayani East Rapti Seti Tinau Average

Acanthocobitis botia 0.00 3.31 0.00 0.00 22.81 1.23 12.24 0.80 1.24 4.63

Amblyceps mangois 0.00 2.76 0.00 0.00 6.66 0.10 1.25 0.00 0.04 1.20

Aspidoparia morar 0.00 0.00 0.00 0.00 0.00 1.06 1.19 0.00 0.00 0.25

Barilius barila 1.32 3.59 0.00 41.77 2.42 2.24 10.16 1.34 4.71 7.51

Barilius barna 0.00 0.00 0.00 0.00 0.03 0.00 0.00 0.00 0.00 0.00

Barilius bendelisis 0.30 1.10 0.00 2.75 1.88 0.18 3.06 0.05 0.60 1.10

Barilius shacra 0.00 0.04 0.00 0.00 0.00 0.12 0.34 0.00 0.00 0.06

Barilius vagra 4.94 2.53 0.00 6.71 2.17 0.51 9.83 1.19 2.14 3.33

Botia almorhae 0.00 0.00 0.00 0.00 0.00 1.05 0.09 0.00 0.00 0.13

Botia lohachata 0.00 0.78 0.00 0.00 0.00 5.03 0.57 0.00 0.16 0.73

Brachydanio rerio 0.13 0.31 0.00 0.09 5.32 0.13 0.00 0.10 6.65 1.42

Channa orientalis 0.00 1.18 0.00 0.00 0.39 0.08 0.08 0.06 0.39 0.24

Channa punctatus 0.03 1.77 0.00 3.13 0.66 0.15 0.00 0.00 1.80 0.84

Cirrhinus reba 0.00 0.00 0.00 0.00 0.03 0.00 0.00 0.00 0.00 0.00

Clupisoma garua 0.00 0.00 0.00 0.00 0.00 0.47 0.00 0.00 0.00 0.05

Crossocheilus latius 0.00 0.03 0.00 0.00 0.00 1.81 0.06 0.00 0.02 0.21

Danio aequipinnatus 0.00 0.09 0.00 1.26 0.00 0.00 0.00 0.00 0.00 0.15

Danio dangila 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.06 0.00 0.01

Esomus danricus 0.00 0.19 0.00 0.00 0.79 0.00 0.00 0.00 0.44 0.16

Garra annandalei 4.27 0.44 0.00 1.31 0.38 0.00 1.13 16.03 0.54 2.68

Garra gotyla 23.82 14.71 0.00 7.13 5.47 8.63 20.22 2.82 22.12 11.66

Glossogobius giuris 0.00 0.00 0.00 0.00 0.00 0.03 0.04 0.00 0.00 0.01

Glyptothorax pectinopterus 0.00 0.00 0.00 0.00 0.00 0.00 0.03 0.00 0.03 0.01

Glyptothorax telchitta 0.00 0.00 0.00 0.00 0.00 0.47 0.14 0.00 0.22 0.09

Glyptothorax trilineatus 0.00 0.00 0.00 0.00 0.00 0.02 0.28 0.00 0.06 0.04

Gudusia chapra 0.00 0.00 0.00 0.00 0.03 0.00 0.00 0.00 0.00 0.00

Heteropneustes fossilis 0.06 0.00 0.00 0.56 0.14 0.00 0.03 0.07 0.09 0.11

Labeo dero 0.00 0.34 0.00 0.00 0.00 0.88 0.94 0.00 0.08 0.25

Lepidocephalus guntea 0.00 6.33 0.00 0.00 19.91 0.80 0.04 0.00 0.08 3.02

Macrognathus pancalus 0.00 0.16 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.02

Mastacembelus armatus 2.08 0.94 0.00 0.00 0.66 0.60 0.63 0.00 0.50 0.60

Myersglanis blythii 0.00 0.03 0.00 0.00 0.00 0.00 0.00 0.21 0.00 0.03

Naziritor chelynoides 0.16 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.02

Nemacheilus corica 0.10 0.00 0.00 0.03 0.09 1.72 0.13 0.00 0.01 0.23

Neolissochilus hexagonolepis 17.88 0.00 0.00 0.00 0.32 0.29 1.56 4.69 0.85 2.84

Pseudecheneis sulcatus 0.00 0.03 0.00 0.00 0.03 0.00 0.00 0.31 0.06 0.05

Psilorhynchus pseudecheneis 0.00 0.00 0.00 0.00 0.00 0.08 0.14 0.00 0.00 0.02

Puntius chola 0.03 0.00 0.00 0.00 0.16 0.00 0.00 0.00 0.00 0.02

Puntius conchonius 0.00 3.56 0.00 0.00 10.15 3.78 2.88 0.14 3.71 2.69

Puntius sophore 0.00 7.15 0.00 0.00 5.22 3.00 2.38 0.21 21.09 4.34

Schistura beavani 7.72 41.70 0.06 0.43 19.97 6.54 30.46 2.21 20.24 14.37

Schistura rupecula 6.33 2.48 0.03 13.99 4.47 5.95 19.59 11.79 7.75 8.04

Schizothoraichthys progastus 0.00 0.00 0.00 0.00 0.00 0.00 0.00 18.34 0.00 2.04

Schizothorax richardsonii 1.09 0.00 30.51 0.00 0.00 0.21 1.53 0.00 0.00 3.71

Semiplotus semiplotus 0.06 0.13 0.00 0.00 0.00 0.02 0.00 0.00 0.00 0.02

Tor putitora 1.55 0.41 0.00 0.00 0.00 0.15 0.41 0.00 0.30 0.31

Tor tor 0.00 0.00 0.00 0.00 0.00 0.02 0.00 0.00 0.02 0.00

Grand Total 71.89 96.10 30.61 79.17 110.16 47.35 121.44 60.41 95.95 79.23

Table 8.1.3: Abundance of fish in different rivers (number/10 minutes of fishing)

8 Results

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Quite a high number of fish species were recorded from Karrakhola. Out of 25 species

recorded 12 of them were found in all the seasons, 4 in three seasons, 1 in two seasons and

the rest accounted for only one season. The river was characterized by the good abundance

of A. botia, Lepidocephalus guntea, Puntius conchonius, and S. beavani. The abundance of

Amblyceps mangois, Brachydanio rerio, G. gotyla, Puntius sophore and S. rupecula were

also found to be in fair condition. The species Cirrhinus reba and Gudusia chapra were

recorded only from this river during the sampling. The average abundance of fish in this

river was found to be 110.16 / 10 mins.

Narayani, the biggest river sampled for this study was found to be harboring of the highest

number of fish species. Altogether 32 fish species were recorded from this river in this

study, which is still less than recorded by many authors. Among the species recorded 9 were

found in all seasons, 9 were present in three seasons, 6 were in two seasons and 8 of them in

at least one season. The river was found to hold a good number of G. gotyla gotyla, while

Botia lohachata, P. conchonius, S. beavani and S. rupecula were found to be in fair number.

One of the most highly threatened species, Tor tor was also recorded from this river. The

total abundance of fish in this river was calculated to be 47.35 / 10 mins.

East Rapti was another river studied for this purpose and 30 fish species were recorded from

here. Out of them, 10 species were present in all seasons, 4 species were recorded from

three seasons, 6 were accounted from two seasons, and remaining 10 were present at least in

one of the seasons. The river showed a high abundance of Acanthocobitis botia, B. barila,

B. vagra, G. gotyla, S. beavani and S. rupecula. The species with fair abundance in this

river were found to be P. conchonius and P. sophore. Among some of the least common

species identified during this sampling schedule, Glossogobius giuris, Glyptothorax

pectinopterus and Psilorhynchus pseudecheneis were also recorded from this river. The

total fish abundance in this river was found to be highest among the river studied at 121.44

/10 mins.

Seti River accounted for 18 species in this study. Among them only 4 species were recorded

throughout the year while, 6 species each were present in three seasons and two seasons,

and only 2 species were present only in one season. Two fishes, Danio dangila and

Schizothoraichthys progastus were recorded only from this river during the entire sampling

period. The river showed a high abundance of Garra annandalei, S. rupecula and S.

8 Results

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progastus, while G. gotyla gotyla and N. hexagonolepis were in fair number. The total

abundance of fish in this river was found to be 60.41 / 10 mins.

Tinau is perhaps the most important river in this study. The total number of species

recovered from this river was also quite high with 29 species. Out of these, 13 species were

recorded from all seasons, 6 species from three seasons, 5 species from two seasons and

another 5 species were present only once. Some of the least common species according to

this study recorded from this river includes Esomus danricus, G. pectinopterus and T. tor.

The species with a good abundance in this river identified were G. gotyla, P. sophore and S.

beavani while, B. barila, Brachydanio rerio, P. conchonius and S. rupecula were also found

to be in fair numbers. The total abundance of fishes in this river was also found to be quite

high at 95.95 / 10 mins.

The Fig.8.1.1 shows the total average abundance of each fish calculated during this study.

Average abundance of fish

0,00

2,00

4,00

6,00

8,00

10,00

12,00

14,00

16,00

Aca

ntho

cobi

tis b

otia

Am

blyc

eps

man

gois

Asp

idop

aria

mor

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ariliu

s ba

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Bar

ilius

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ariliu

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Bar

ilius

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Bot

ia a

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Bot

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Bra

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Cha

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Cirr

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Cro

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Dan

io a

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atus

Dan

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som

us d

anric

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ann

anda

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Gar

ra g

otyl

aG

loss

ogob

ius

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Gly

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x tri

linea

tus

Gud

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Het

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Lepi

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alus

Mas

tace

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atus

Mye

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bly

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Naz

irito

r che

lyno

ides

Nem

ache

ilus

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aN

eolis

soch

ilus

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lepi

sPs

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chen

eis

sulc

atus

Psi

lorh

ynch

us p

seud

eche

neis

Pun

tius

chol

aP

untiu

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nius

Pun

tius

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ore

Sch

istu

ra b

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niS

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tura

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Sch

izot

hora

icht

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prog

astu

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ax ri

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lotu

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lotu

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itora

Tor t

or

fish name

CPU

E (c

atch

/10

min

)

Total abundance: 79.23Number of species: 47

Fig. 8.1.1: Abundance of different fish species during one year of sampling

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This figure illustrates the average abundance (CPUE) of all the fish species recorded during

this work in all the rivers studied and in all the seasons. The total average abundance for all

fish was found to be 79.23 and among these the abundance of S. beavani, G. gotyla gotyla,

S. rupecula and B. barila was found to be fairly good. On the other hand the species such as

B. barna, C. reba, D. dangila, G. giuris, G. chapra, M. pancalus, M. blythii, N. chelynoides,

P. pseudecheneis, P. chola, S. semiplotus and T. tor were found to have very low

abundance.

Table 8.1.4, shows the density of the fish in different rivers, which were studied in this

work. It was calculated as the number of fish in 100 m² areas. It was found that Jhikhukhola

had the highest density of fish at 24.11/100m² and Narayani had the lowest at less than one

in the same area. However, Narayani is one of the biggest river of the country and the

fishing was possible only on the shoreline of the river. Tinau was found to have a good

density of fish at 23.51/100m² followed by Arungkhola, Karrakhola, East Rapti,

Aandhikhola, Bagmati and Seti in the decreasing order of the density.

8 Results

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Fish species Aandhi Arung Bagmati Jhikhu Karra Narayani Rapti Seti Tinau average

Acanthocobitis botia 0,00 0,45 0,00 0,00 2,84 0,03 0,96 0,04 0,25 0,51

Amblyceps mangois 0,00 0,49 0,00 0,00 0,93 0,00 0,08 0,00 0,02 0,17

Aspidoparia morar 0,00 0,00 0,00 0,00 0,00 0,02 0,06 0,00 0,00 0,01

Barilius barila 0,14 0,79 0,00 11,05 0,30 0,03 0,80 0,10 1,18 1,60

Barilius barna 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00

Barilius bendelisis 0,03 0,17 0,00 1,04 0,29 0,00 0,26 0,01 0,22 0,22

Barilius shacra 0,00 0,01 0,00 0,00 0,00 0,00 0,03 0,00 0,00 0,00

Barilius vagra 0,50 0,35 0,00 1,65 0,24 0,01 0,84 0,05 0,37 0,45

Botia almorhae 0,00 0,00 0,00 0,00 0,00 0,02 0,00 0,00 0,00 0,00

Botia lohachata 0,00 0,10 0,00 0,00 0,00 0,08 0,03 0,00 0,02 0,03

Brachydanio rerio 0,01 0,06 0,00 0,01 0,47 0,00 0,00 0,00 1,88 0,27

Channa punctatus 0,00 0,00 0,00 0,20 0,00 0,00 0,00 0,00 0,00 0,02

Channa gachua 0,00 0,15 0,00 0,00 0,04 0,00 0,01 0,00 0,11 0,03

Channa punctatus 0,00 0,28 0,00 0,46 0,04 0,00 0,00 0,00 0,54 0,15

Cirrhinus reba 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00

Clupisoma garua 0,00 0,00 0,00 0,00 0,00 0,01 0,00 0,00 0,00 0,00

Crossocheilus latius 0,00 0,00 0,00 0,00 0,00 0,03 0,00 0,00 0,00 0,00

Danio aequipinnatus 0,00 0,01 0,00 0,32 0,00 0,00 0,00 0,00 0,00 0,04

Danio dangila 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00

Esomus dandricus 0,00 0,05 0,00 0,00 0,03 0,00 0,00 0,00 0,14 0,02

Garra annandalie 0,43 0,05 0,00 0,44 0,05 0,00 0,11 1,43 0,23 0,30

Garra gotyla 2,70 1,92 0,00 2,61 0,72 0,15 1,70 0,16 4,25 1,58

Glossogobius giuris 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00

Glyptothorax pectinopterus 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,01 0,00

Glyptothorax telchitta 0,00 0,00 0,00 0,00 0,00 0,01 0,01 0,00 0,03 0,01

Glyptothorax trilineatus 0,00 0,00 0,00 0,00 0,00 0,00 0,02 0,00 0,01 0,00

Gudusia chapra 0,00 0,00 0,00 0,00 0,01 0,00 0,00 0,00 0,00 0,00

Heteropneustes fossilis 0,00 0,00 0,00 0,08 0,03 0,00 0,00 0,00 0,03 0,02

Labeo dero 0,00 0,03 0,00 0,00 0,00 0,02 0,05 0,00 0,01 0,01

Lepidocephalus guntea 0,00 0,87 0,00 0,00 2,14 0,01 0,00 0,00 0,01 0,34

Macrognathus pancalus 0,00 0,02 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00

Mastacembelus armatus 0,21 0,11 0,00 0,00 0,08 0,01 0,04 0,00 0,13 0,07

Myersglanis blythii 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,02 0,00 0,00

Naziritor chelynoides 0,02 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00

Nemacheilus corica 0,01 0,00 0,00 0,01 0,01 0,03 0,01 0,00 0,00 0,01

Neolissochilus hexagonolepis 2,15 0,00 0,00 0,00 0,05 0,00 0,16 0,30 0,24 0,32

Pseudecheneis sulcatus 0,00 0,01 0,00 0,00 0,00 0,00 0,00 0,03 0,01 0,01

Psilorhynchoides pseudecheneis 0,00 0,00 0,00 0,00 0,00 0,00 0,01 0,00 0,00 0,00

Puntius chola 0,00 0,00 0,00 0,00 0,03 0,00 0,00 0,00 0,00 0,00

Puntius conchonius 0,00 0,50 0,00 0,00 1,48 0,06 0,23 0,01 0,94 0,36

Puntius sophore 0,00 0,99 0,00 0,00 0,58 0,05 0,17 0,01 5,73 0,84

Schistura beavani 0,87 7,08 0,02 0,16 2,88 0,11 2,27 0,14 4,67 2,02

Schistura rupecula 0,74 0,41 0,01 6,08 0,72 0,09 1,45 0,86 2,45 1,42

Schizothoraichthys progastus 0,00 0,00 0,00 0,00 0,00 0,00 0,00 1,86 0,00 0,21

Schizothorax richardsonii 0,10 0,00 7,71 0,00 0,00 0,00 0,20 0,00 0,00 0,89

Semiplotus semiplotus 0,01 0,01 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00

Tor putitora 0,15 0,07 0,00 0,00 0,00 0,00 0,04 0,00 0,03 0,03

Tor tor 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00

Grand Total 8,07 14,98 7,74 24,11 13,98 0,79 9,55 5,05 23,51 11,98 Table 8.1.4: Density of fish in different rivers (number/100m²)

8 Results

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8.2 River classification based on biotic and abiotic factors: A) Cluster analysis (CA):

Classification can be defined as a process where a set of objects, systems or entities are

divided into a number of discrete groups on the basis of some measure of their similarities

or differences with respect to one or more pre-defined criteria. But classification of

ecological systems like rivers is difficult due to complexities because the systems are

generally characterized by indistinct boundaries and their characteristics vary continuously

rather than discretely. However there are numbers of precise statistical tools such as cluster

analysis (CA) and discriminant analysis (DA), which process varieties of variables to give a

meaningful classifications of the system.

This study has tried to classify the different rivers and river systems that were sampled by

using both biotic and abiotic factors. CA was performed to classify the rivers by using some

fish attributes such as the number of species and their abundance, whereas several abiotic

factors such as altitude, temperature, dissolved oxygen and the substrates were included in

discriminant analysis.

In this work, hierarchical cluster analysis has been applied by using Ward’s method for

river classification. This method was used because it processes a small space distorting

effect, uses more information on cluster contents than other methods, and has been proved

to be an extremely powerful grouping mechanism (Lambrakis et al. 2004). In the basis of

total number of species and their abundance a cluster analysis to group and classify the

different rivers that were sampled was also done. The table 8.2.1 shows the details of this

analysis, while Fig.8.2.1 shows the relationships among the rivers and rivers systems that

were studied in this work. The relative similarities between the rivers in the group or the

cluster could be seen by the values of coefficients in the table or by the distance at which

the cluster combined.

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Agglomeration Schedule

Cluster Combined Stage Cluster First

Appears

Stage Cluster 1 Cluster 2 Coefficients Cluster 1 Cluster 2 Next

Stage 1 1 6 682.300 0 0 3 2 2 7 1373.232 0 0 4 3 1 8 2417.669 1 0 5 4 2 5 4026.153 2 0 5 5 1 2 6671.631 3 4 6 6 1 9 10409.027 5 0 7 7 1 3 15311.099 6 0 8 8 1 4 24188.286 7 0 0

Table 8.2.1: Statistical details of the cluster analysis This analysis has put Aandhikhola and Narayani rivers in one group with Seti River joining

them to form a first cluster indicating that the three share some common features. Similarly,

Arungkhola and Rapti formed another group with Karrakhola joining them to form a second

cluster. Here too, the result indicated that there exist some common features between them.

These two clusters joined before any other rivers join them, indicating further that the two

clusters belonged to one larger group or system. Tinau was found to be quite far from this

group though Bagmati and Jhikhukhola were found to be at more and most distant from the

group.

Fig. 8.2.1: Clusters of river

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B) Canonical Discrimination Analysis (CDA):

After looking at the remarkable results of cluster analysis to group different rivers and river

systems in the basis of the abundance and number of fish species, it was felt that whether

the series of abiotic factors, which were recorded during this study, have the same potential.

For this ‘ canonical discriminant analysis’ was done. In another words, the cluster analysis

was done in the basis of biotic factors, whereas the discriminant analysis was done in the

basis of abiotic factors. The data of abiotic factors utilized in this analysis were altitude,

temperature, dissolved oxygen, pH, conductivity, and the substrates such as rock, boulder,

cobbles, pebbles, gravels, silt and sand. All these abiotic factors were used as independent

variables in this analysis. As each run of sampling was referred as one case, there were 184

cases altogether in this work. The table below shows the details of valid and missing

variables.

Analysis Case Processing Summary

Unweighted Cases N Percent Valid 184 100.0

Missing or out-of-range group codes 0 .0

At least one missing

discriminating variable

0 .0

Both missing or out-of-range group codes and at least

one missing discriminating

variable

0 .0

Excluded

Total 0 .0 Total 184 100.0

Table 8.2.2: Valid and missing variables in CDA

The discriminant analysis uses the function, f(x) = a.X + b.Y + c.Z + ----------------- where a, b and c’s are the coefficients and X, Y and Z’s are the variables. Each variable get their own coefficients and the value of each of them are pooled together to form group matrices. The values of each variable are weighted against each other and are correlated. Three such functions are initially used but the analysis chooses the best two functions in the basis of canonical correlation to produce results. The table 8.2.3 summarizes the canonical discriminant functions and also illustrates why the first two functions were chosen particularly based on canonical correlation.

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Eigenvalues

Function Eigenvalue % of Variance Cumulative % Canonical Correlation

1 6.563(a) 77.7 77.7 .932 2 1.608(a) 19.0 96.7 .785 3 .277(a) 3.3 100.0 .466

a First 3 canonical discriminant functions were used in the analysis. Table 8.2.3: Summary of Canonical Discriminant Functions The standardized canonical discriminant function coefficients for each variable in all three functions are illustrated in the forthcoming table.

Function 1 2 3

altitude -1.287 .320 -.110 boulder -.458 -.002 .951 pebbles 1.053 .765 1.177 cobbles -.271 -.749 .588

rock 1.548 .769 .659 silt -.341 -.267 .181

oxygen .169 -.054 -.226 conductivity .006 .114 -.315 temperature .194 .107 -.709

sand .352 .450 1.458 Ph .167 .110 -.560

Table 8.2.4: Standardized Canonical Discriminant Function Coefficients When all these standardized canonical discriminant functions pooled together within the

groups to derive correlations between discriminating variables, it gave an interesting result

(Table 8.2.5). In function 1, the variables having largest absolute correlation were found to

be altitude and two morphological features, boulders and pebbles. The same in function 2

were found to be some additional morphological features such as cobbles, rock and silt, and

two physico-chemical parameters, dissolved oxygen (DO) and conductivity. The function 3

had temperature, sand, pH and gravels having some correlation, though the last variable is

not used in the further analysis.

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Structure Matrix

Function 1 2 3

altitude -.583(*) .556 -.178 boulder -.155(*) .016 .016 pebbles .104(*) -.072 -.021 cobbles -.060 -.651(*) -.129

rock -.014 .326(*) -.109 silt .027 -.259(*) .121

oxygen .015 -.149(*) -.122 conductivity .048 -.118(*) -.061 temperature .160 -.038 -.476(*)

sand .113 .173 .390(*) Ph .060 .008 -.292(*)

gravels(a) .058 .050 -.081(*) Pooled within-groups correlations between discriminating variables and standardized canonical discriminant

functions Variables ordered by absolute size of correlation within function. * Largest absolute correlation between each variable and any discriminant function

a This variable not used in the analysis. Table 8.2.5: Correlation details of the discriminant variables

Processed 184 Missing or out-of-

range group codes 0 Excluded

At least one missing discriminating

variable 0

Used in Output 184

Table 8.2.6: Classification Processing Summary

cd_riversystem Prior Cases Used in Analysis

Unweighted Weighted Bagmati .087 16 16.000Gandaki .565 104 104.000Koshi .087 16 16.000Tinau .261 48 48.000Total 1.000 184 184.000

Table 8.2.7: Prior Probabilities for Groups With these functions and correlations of the variables, the classification of the river systems

were done using all 184 cases and all the cases were used in both the ways, weighted and

unweighted in the analysis. Among the cases used, Bagmati had 16 cases, Gandaki had 104

cases, Koshi had 16 cases and Tinau had 48 cases (Table 8.2.6). The results of the

classification of the rivers system were amazing, perfectly matching the regional differences

of the country. This indicated that the group of abiotic factors such as morphological and

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physico-chemical features was able to discriminate among themselves to represent regional

and physico-geographic group of the rivers and river systems of Nepal.

The figure 8.2.2 showed how the different variables in each rivers and river systems

discriminated each other and how close they were to their group centroids, which were

remarkably apart from each other and distinct. In Bagmati, the variables were found to be

100% distinct and totally discriminated the variables of other rivers (Table 8.2.8). Similarly

in Gandaki system, the variables were 98.1% distinct whereas only 1.9 % of them were not

distinct and that too from only one river system, Koshi. The Koshi system on the other hand

showed 100% distinct variables completely discriminating the group of variables from other

systems. Finally Tinau River showed 83.3% distinct variables and all those variables, which

were not able to discriminate the system, were found to be mixed with the variables of

Gandaki system only.

Thus, the morphological features and the physico-chemical parameters of different rivers

and river system studied in this work were found to be very good variables, which were able

to classify the rivers and river system of Nepal. The result of the classification showed that

it is very much in terms with the age-old classification of the Nepalese rivers (Sharma 1977

and 1997) in terms of region, origin and geology.

Predicted Group Membership

cd_river system Bagmati Gandaki Koshi Tinau Total Bagmati 16 0 0 0 16Gandaki 0 102 2 0 104Koshi 0 0 16 0 16

Count

Tinau 0 8 0 40 48Bagmati 100.0 .0 .0 .0 100.0Gandaki .0 98.1 1.9 .0 100.0Koshi .0 .0 100.0 .0 100.0

Original

%

Tinau .0 16.7 .0 83.3 100.0Bagmati 16 0 0 0 16Gandaki 0 100 4 0 104Koshi 0 0 16 0 16

Count

Tinau 0 8 0 40 48Bagmati 100.0 .0 .0 .0 100.0Gandaki .0 96.2 3.8 .0 100.0Koshi .0 .0 100.0 .0 100.0

Cross-validated(a)

%

Tinau .0 16.7 .0 83.3 100.0

Table 8.2.8: Classification results

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In the cross validation of above grouping where each case was classified by the functions

derived all cases other than that case, the group variable for Bagmati River and Koshi

system were again found to be 100% distinct. While 96.2% in Gandaki system and 83.3% in

Tinau were able to discriminate the respective river and system. Here too even when they

were not discriminate cent percent, the group variables were mixed with only one other

river or system. The classification system was found to be so accurate that 94.6% originally

grouped cases and 93.5% of cross-validated grouped cases were classified correctly.

-8 -6 -4 -2 0 2 4

Function 1

-4

-2

0

2

4

Func

tion

2 Bagmati

Gandaki

KoshiTinau

cd_riversystemBagmatiGandakiKoshiTinauGroup Centroid

Canonical Discriminant Functions

Fig. 8.2.2: Classification of the river system by CDA

Thus, the morphological features and the physico-chemical parameters of different rivers

and river system studied in this work were found to be very good variables, which were able

to classify the rivers and river system of Nepal. The result of the classification showed that

it is very much in terms with the age-old classification of the Nepalese rivers (Sharma 1977

and 1997) in terms of region, origin and geology.

8 Results

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8.3: STUDY OF THE SIZE STRUCTURE OF SUCKER HEAD, Garra gotyla gotyla (Gray, 1830) Length and weight data are useful and standard results of fish sampling programs (Morato

et al. 2001). Such data are essential for a wide number of studies, for example estimating

growth rates, age structure and other aspects of fish population dynamics. Study of the size

structure (length frequency) in riverine fish reveals many ecological and life-history traits

such as the river health, stock conditions and breeding period of the fish. The size structure

of a fish population at any point in time can be considered a ‘snapshot’ that reflects the

interactions of the dynamic rates of recruitment, growth and mortality (Neumann 2001).

From length frequency distributions of fish there are methods to determine the ages

(Bagenal and Tesch 1978), which together with the weight and abundance (catch per unit

effort) give details of the different disturbance regime of the rivers, breeding ground and

breeding seasons, the general health of the stock, density and biomass, and the status of the

species. Length-weight regressions have been extensively used to estimate weight from

length because of technical difficulties and the amount of time required to record weight in

the field (Morato et al. 2001). Therefore, the size structure analysis is one of the most

commonly used fisheries assessment tools.

Although size structure analysis is a standard and regular method to evaluate the conditions

of both rivers and stocks in developed countries of North America and Europe, it has just

started in the developing countries. Nepal, with a huge amount of water resource, has a

tremendous potential for fisheries development. Some information on ecological and

population characteristics of the fish, such as region and altitude of occurrence, habitat

preference, temperature range, maximum length, feeding habit, life history and a crude

status of many of the fish species are available. However, the size structure analysis, which

is so important in fisheries management is clearly lacking in the Nepalese fish species. This

could be the first work of its kind in Nepal.

This work analyzed the size structure and length-weight relationship of sucker head, Garra

gotyla gotyla (Gray 1830), a widely distributed and important fish species of the region.

This fish, commonly known as Buduna in Nepal, has been listed by Gray (1832), Day

(1889), Prashad (1912), Hora (1921), Taft (1955), DeWitt (1960), Menon (1962), Ganguly

8 Results

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and Dutta (1973), Shrestha (1978), Rajbanshi (1982), Rahman (1989), Shrestha (1990),

Talwar and Jhingran (1991), Shrestha (1994) and Shrestha (2001) under the same name or

different synonyms. It is reported from Afghanistan, Pakistan, India, Nepal, Bangladesh,

Bhutan and Burma. In Nepal the species has been reported from up to 1560 masl with

maximum size of 150 mm. It has been included as coldwater fish of Nepal by Shrestha

(1999) and Swar (2001). It is not included in IUCN red list and reported as ‘fairly common’

in the country. The present work finds it in all the rivers studied except river Bagmati and is

perhaps one of the most common species. It is a harmless fish feeding on algae, plants and

detritus (www.fishbase.org).

The importance of the fish has been mentioned as minor commercial by Talwar and

Jhingran (1991). However, due to high value as a food fish as well as its distribution, this

species has a potential to become important protein source to the poverty-ridden population

of Nepal. But there is hardly any method developed to assess the population dynamic of the

species nor is there any example of using it as an indicator for the impact of various

disturbances. This is the first description of length frequency distribution and length-weight

relationship of Garra gotyla gotyla. In Nepalese context, even a basic work regarding size

structure description and distribution is of great value for reference as well as for

comparison for future studies.

A. Length frequency distribution:

Out of nine river sampled in this study, the species Garra gotyla gotyla was recorded from

all except Bagmati river at Sundarijal in Kathmandu. There were altogether 4567 numbers

of the species captured from eight of the remaining rivers from all seasons. The total length

of the species varied from minimum of 20 mm to the maximum of 180 mm, and there were

all the length groups in between. The length of 180 mm of the species is perhaps the new

record. Similarly the weight of the fish varied from minimum of 2 gm to maximum of 73

gm. The mean length of the fish species in each case is rounded to a whole number. The

result of the length frequency distribution in each river, that is the spatial variation of length

frequency, is shown in the following figures (note the scale).

8 Results

-153-

Fig. 8.3.1: Length frequency of Garra sps. Fig. 8.3.2: Length frequency of Garra sps.

Fig. 8.3.3: Length frequency of Garra sps. Fig. 8.3.4: Length frequency of Garra sps. Aandhikhola: This river has one of the best length frequency distribution (Fig.8.3.1).

Altogether 711 number of the fish species were captured in all season in this river with

minimum total length of 30 mm and the maximum of 180 mm. Looking at the length

frequency distribution in this river, it can be said that it holds a very healthy population of

the species. There are sizable numbers of the species with the length 50 mm and under,

while the largest numbers are with the length category of 80 to 100 mm, the size already

capable of breeding. There are also abundant of the species with length category 105 – 150

mm indicating the favorable habitat condition for the mature adults. In addition, the

presence of the species even longer than that and up to 180 mm just indicates the river

8 Results

-154-

provides the optimum suitable conditions for all the stages in the life cycle of the species.

The mean length of the species in this river was found to be 85 mm, highest of the entire

river studied.

Arungkhola: Total number of this species caught in Arungkhola was 458 with minimum

total length of 20 mm to the maximum of 115 mm from all seasons (Fig.8.3.2). The length

frequency distribution of the species in this river shows a different picture than that of

Aandhikhola. In this river too, there are abundant of number of the length category 20 – 50

mm, suggesting that it provides a good spawning ground for the species. However, the peak

of the number was in the length category 55 – 80 mm, which is less than before. There were

some number with the length category of 85 – 115 mm, but longer than that were absolutely

missing. The mean length of the species was also clearly less than before at 58 mm.

Jhikhukhola: Total number of this species captured in Jhikhukhola was 214 with the

minimum total length of 30 mm to the maximum of 120 mm (Fig.8.3.3). There were few

numbers of the fish with less than 50 mm of total length suggesting the decline of the

breeding ground. However, there were large numbers of this fish in the length category of

50 – 90 mm suggesting a similar situation as in Arungkhola. There were some numbers of

the fish of total length category 95 mm up to 120, which is also similar to Arungkhola. The

large matured fishes were missing here too, though the mean total length of the species was

little higher than before at 68 mm.

Karrakhola: The number of this species caught in Karrakhola was 172. Among the

captured, the minimum total length was 20 mm and the maximum was 120 mm (Fig.8.3.4).

The highest numbers of fish in this river were of the length category 20 – 50 mm indicating

the condition of breeding ground to be normal. There were slump of numbers of the length

categories between 55 –100 mm. There were very few numbers of the length categories 105

–120 mm and after that all large adult fishes were missing. The mean total length of the

species here was 53 mm.

Narayani: It is one of the biggest rivers of Nepal, but the total number of the sucker head

captured in this river was moderate at 415 (Fig.8.3.5). The total length of the species in this

river varied from 40 mm minimum to the maximum of 175 mm. The distribution of length

frequency of the species here gives a very different picture. The total length category, 50

8 Results

-155-

mm or less of this species was almost missing in this river indicating that it is not suitable

for spawning. However, there were abundant of length categories from 55 mm to 100 mm

suggesting a suitable habitat for fresh adults. There were also many fishes of length group

105 mm – 150 mm and a few even up to 175 mm suggesting that the conditions are suitable

for very large adults. The mean of the total length was also relatively higher at 81 mm.

East Rapti: The total number of this fish species caught here were 636. Among the

captured, the minimum total length was 30 mm whereas the maximum was 140 mm

(Fig.8.3.6). Compare to Narayani, there were more number of fish with length categories

less than 50 mm indicating a good conditions for the fries. However, the bulk of the number

of this fish here was made up of the length categories between 50 mm to 95 mm. There

were relatively few numbers of the fish higher than those length categories, but available

length group was moderately longer up to 140 mm. The mean of the total length of the

species in this river was 67 mm.

Seti: The lowest numbers of this species were caught from Seti River. Out of 84 number of

sucker head captured from here, the minimum total length of the fish was 40 mm and the

maximum was 130 mm (Fig.8.3.7). There were very few numbers of lesser length

categories and also many of these categories missing. It indicates that the conditions for

spawning are not favorable. However, there were steady numbers of them in the categories

from 55 mm to 100 mm suggesting that the conditions are not so bad for fresh adults. There

were some fishes longer than those categories up to 130 mm, but some groups are missing

indicating the population may not be healthy. Nevertheless, the mean total length of the

species in this river stands at 74 mm.

Tinau: In terms of abundance as well as the distribution of length frequency, the population

of sucker heads was the healthiest in this river. The total number of the fish accounted here

were 1877, and that with a very unpleasant situation during premonsoon when a massive

poisoning of the river was reported just a few days before the sampling. The total length of

the species varied from minimum of 20 mm to the maximum of 145 mm (Fig.8.3.8). There

were a good number of the fish of the length categories 20 mm to 50 mm suggesting good

conditions for spawning and initial growth. The majority of the population was composed of

the length categories 55 mm to 100 mm indicating a right habitat conditions for the growth

and maturation of the species. The numbers of fish more than 100 mm in total length were

8 Results

-156-

few but there were a presence of continuous length categories up to 145 mm. The mean of

total length of the population of sucker heads in Tinau River was found to be 62 mm.



The length frequencies of the sucker head were also found to vary in temporal basis. There

are different pictures and the mean total length of the species in the four seasons, when they

were sampled. The temporal variation of the length frequency normally gives insight to the

attributes such as the time of spawning, migration if any, and the growth status of the stock.

Here are the findings of all year around divided into four seasons in a clockwise series.

Spring: The total number of sucker head captured in this season was 1326 with the total

length varying from 30 mm to 180 mm (Fig.8.3.9). The absence of the fish of 20 mm length

categories indicates that this season might not be the spawning season. There were some

8 Results

-157-

fish of the length categories 30 mm to 45 mm and these could be the fish hatched in the last

breeding season. There are large numbers of fish of length categories 50 mm – 100 mm.

Though the numbers slump above this length categories, there abundance were consistent

till length category 150 mm and there were some even longer than that up to 180 mm.

Presence of all ranges of fish suggest that they are resident fish. Also the highest mean of

the total lengths, 72 mm was due to the less number of fries indicating spring is not a

breeding season.

Premonsoon: The total number of the fish caught in this season was remarkably low

because of the poisoning of Tinau River just before the sampling as mentioned before. In

addition no fish were recorded from Seti River as well. 608 sucker heads were captured in

this season ranging from 20 mm to 140 mm (Fig.8.3.10). Presence of some numbers of 20

mm category indicated that the season should be the starting point of spawning. There were

many fishes up to 45 mm length group. The peak of the numbers however were of the

length categories 50 mm to 90 mm. Above those length groups the numbers slumped till the

140 mm length groups and there were even some groups entirely missing. The mean total

length of the assemblage was lowest at 61 mm. The absence of some higher length groups

and large mature adults indicate there might be some migration after spawning.

Autumn: The numbers of fish captured in this season were the highest at 1371 with lot of

juveniles, which indicate that it followed the breeding time (Fig.8.3.11). Also important was

the remarkable recovery of the numbers of sucker heads in Tinau River. The lengths of the

captured fishes varied almost a full range from 20 mm to 175 mm indicating a good and

healthy assemblage. There were many fishes of the length groups 20 mm to 35 mm

indicating the time of breeding. However, the peaks of the numbers were of the length

groups 40 mm to 95 mm. There was a gradual slump of numbers from 100 mm to 150 mm

length categories, which is a characteristic of a normal healthy population. There were even

some numbers of sucker heads above 150 mm up to 175 mm. The mean of the total length

in this season was found to be 66 mm.

8 Results

-158-

→

Fig. 8.3.9: Length frequency of Garra sps. Fig. 8.3.10: Length frequency of Garra sps. ↑ ↓

←


Winter: The numbers of sucker heads captured in this season were 1262 ranging from 30

mm to 170 mm length groups (Fig.8.3.12). The distribution of length frequencies was

almost continuous except for some very large mature adults. There were less fishes with the

length group 30 mm to 45 mm compared to autumn may be because of the mortality or

other factors. However, there were steady numbers of them from 50 mm to 95 mm length

8 Results

-159-

class. The number declines gradually from 100 mm to 160 mm and there was fish even up

to 170 mm an indication of a normal healthy population. There was no indication of

migration as well in this season. The mean total length of the species in this season stands at

69 mm.

B. Length – weight relationship:

The length-weight relationship, which is an important attribute in assessing the health of the

fish, to calculate the biomass and to manage the stock was also formulated for the Garra

species using nonlinear regression and was compared for the seasons and river systems.

Among the eight rivers from Nepal where the species was recorded, Aandhikhola,

Arungkhola, Karrakhola, East Rapti, Narayani and Seti rivers constitute the Gandaki

system; Jhikhukhola belongs to the Koshi system, whereas Tinau is taken as an independent

system. The details of the regression of seasonal variations of length-weight relationship are

shown in the table 8.3.1.

Seasons▬►

Details Spring Premonsoon or

summer Postmonsoon or

Autumn Winter

Regression Nonlinear Nonlinear Nonlinear Nonlinear Equation f = exp(a*x) f = exp(a*x) f = exp(a*x) f = exp(a*x)

R 0.94697814 0.92296271 0.89885934 0.94971944 R² 0.89676761 0.85186016 0.80794811 0.90196702

Tolerance 0.000100 0.000100 0.000100 0.000100 Stepsize 100 100 100 100

‘‘Iterations 1000 1000 1000 1000 Coefficient (a) 0.0241 0.0260 0.0227 0.0245

Std. Error 0.0002 0.0002 0.0001 0.0001

Table 8.3.1: The Details of the Statistics for Each Season for length-weight relationship Seasonal variation of length-weight relationship of this species gives very interesting

picture corresponding to its life history as well as physiological stress (Fig.8.3.13). Looking

at the regression, the healthiest fish or the highest biomass was found in premonsoon or

summer season while the least biomass was in autumn. The details of the statistics for each

season are given in table 8.3.1.

8 Results

-160-

0

20

40

60

80

100

120

0 20 40 60 80 100 120 140 160 180 200total length [mm]

wei

ght [

gm]

autumnpremonsoonwinterspring

Fig. 8.3.13 Length-Weight Relationship of Garra gotyla gotyla in Different Seasons The relationship has the highest coefficient in premonsoon or summer (0.0260) and lowest

in postmonsoon or autumn (0.0227). Thus, the curve is sharpest or steepest in premonsoon

while opposite in postmonsoon or autumn. Between these seasons there is an interval of just

about 3 or 4 months, but perhaps the event monsoon in this interval time seems a very big

factor in determining the health and biomass of the fish. For example, according to this

regression, a sucker head measuring 180 mm in length measured 60 gm in autumn whereas

the same size weighed as much as 110 gm in summer or premonsoon. The coefficients were

intermediate in spring and in winter, and hence the curves too were moderate and lied

between the curves of premonsoon and postmonsoon.

The relationship of length and weight of sucker heads also varied between different river

systems of Nepal. Since the coefficient of the curve was found to be highest in premonsoon

and lowest in autumn, the length-weight relationship of the species in these two seasons are

compared here. The details of the statistics for all three river systems are given in table

8.3.2. Another reason to compare the length-weight relationship between these seasons is

because the number of sucker heads collected was highest in autumn/postmonsoon and

lowest in summer/premonsoon. In premonsoon, the coefficient of curve was highest in

Gandaki System at 0.0261 whereas both the Koshi and Tinau System had a same lower

value of 0.0241. The regression showed that until the length 95 mm the sucker heads in all

8 Results

-161-

the river systems had the same growth and biomass as they measured same around 10 gm.

However the growth seemed to differ from that point in this season and in Gandaki System

it is more rapid. For example, the sucker head measuring 180 mm in this season was found

to measure as much as 110 gm, while in the other systems it was lowly 76 gm (Fig. 8.3.14).

Koshi Tinau Gandaki River

Systems▬► Details

premonsoon postmonsoon premonsoon postmonsoon premonsoon postmonsoon

Regression Nonlinear Nonlinear Nonlinear Nonlinear Nonlinear Nonlinear Equation f = exp(a*x) f = exp(a*x) f = exp(a*x) f = exp(a*x) f = exp(a*x) f = exp(a*x) R 0.89734577 0.95172228 0.82110163 0.85992448 0.92624661 0.90389843 R² 0.80522944 0.90577530 0.67420788 0.73947011 0.85793277 0.81703237 Tolerance 0.000100 0.000100 0.000100 0.000100 0.000100 0.000100 Stepsize 100 100 100 100 100 100 ‘‘Iterations 1000 1000 1000 1000 1000 1000 Coefficient (a) 0.0241 0.0257 0.0241 0.0240 0.0261 0.0226 Std. Error 0.0004 0.0002 0.0010 0.0003 0.0002 0.0001 Table 8.3.2: Summary of the statistics of three river systems in premonsoon and postmonsoon seasons. Interestingly, the coefficient of the curve was found to be highest in Koshi River System at

0.0257, while it was lowest in Gandaki system at 0.0226 in postmonsoon season. The value

was intermediate in Tinau System where it was found to be 0.0240. Thus, the curve is

highest in Koshi System and lowest in Gandaki System with Tinau fitting in between the

two. Until the length 80 mm, the corresponding weights were found to be more or less same

in all the river systems at around 7 gm, but after that the weight gradually fell apart. For

example, the sucker head measuring 180 mm in Koshi System was calculated to be 102 gm

while the same total length in Gandaki System was around 58 gm. The weight for the same

length in Tinau however was found to be intermediate between those two at around 75 gm.

Thus, the length-weight relationship of the species in three river systems was found to be

significantly different (Fig. 8.3.15).

8 Results

-162-

Premonsoon/summer

0

20

40

60

80

100

120

0 20 40 60 80 100 120 140 160 180 200

total length [mm]

wei

ght [

gm]

GandakiKoshiTinau

Fig. 8.3.14 : Length-weight Relationship of Garra gotyla gotyla in Different River Systems

Postmonsoon/autumn

0

20

40

60

80

100

120

0 20 40 60 80 100 120 140 160 180 200

total length [mm]

wei

ght [

gm]

GandakiKoshiTinau

Fig. 8.3.15 : Length-weight Relationship of Garra gotyla gotyla in Different River Systems The length-weight relationship of the same river system in these two seasons also showed

interesting trends. The Koshi System was found to have higher coefficient of the curve in

postmonsoon season (0.0257) in comparison with premonsoon (0.0241). On the other hand,

the Gandaki System has higher coefficient in premonsoon (0.0261) compared to

8 Results

-163-

postmonsoon (0.0226). The growth in Tinau System was found to be more or less

consistence in the two seasons.

The regression showed that a sucker head with total length of 180 mm measured around 76

gm in premonsoon in contrast to 102 gm in postmonsoon in Koshi System. Similarly the

species with the same length measured around 110 gm in premonsoon and around 58 gm in

postmonsoon, a remarkable difference. The sucker heads of Tinau System for the same

length, however, measured around 75 gm in both the seasons.

8 Results

-164-

Fig.8.4.1 Impact of agriculture Fig.8.4.2 Impact of agriculture


Jhikhukhola upstream in spring (Agriculture)

0

20

40

60

80

100

120

140

160

180

Bariliu

s bari

laBari

lius b

ende

lisis

Bariliu

s vag

raCha

nna p

uncta

tusDan

io ae

quipi

nnatu

sGarr

a ann

anda

leiGarr

a goty

la

Heterop

neus

tes fo

ssilis

Schist

ura be

avan

iSch

istura

rupe

cula

Fish species

Abu

ndan

ce (C

PUE)

Total abundance:32 Number of species:7

Jhikhukhola upstream in Premonsoon/summer (Agriculture)

020406080

100120140160180

Bariliu

s bari

laBari

lius b

ende

lisis

Chann

a pun

ctatus

Danio

aequ

ipinn

atus

Garra a

nnan

dalei

Garra g

otyla

Heterop

neus

tes fo

ssilis

Schist

ura be

avan

iSch

istura

rupe

cula

Fish species

Abu

ndan

ce (C

PUE) Total abundance:48.33

Number of species:7

Jhikhukhola downstream in Premonsoon/summer (Agriculture)

0

20

40

60

80

100

120

140

160

180

Bariliu

s bari

laBari

lius b

ende

lisis

Chann

a pun

ctatus

Danio

aequ

ipinn

atus

Garra a

nnan

dalei

Garra g

otyla

Heterop

neus

tes fo

ssilis

Schist

ura be

avan

iSch

istura

rupe

cula

Fish species

Abu

ndan

ce (C

PUE)

Total abundance:71.67Number of species:6

Jhikhukhola downstream in spring (Agriculture)

020406080

100120140160180

Bariliu

s bari

laBari

lius b

ende

lisis

Bariliu

s vag

raCha

nna p

uncta

tusDan

io ae

quipi

nnatu

sGarr

a ann

anda

leiGarr

a goty

la

Heterop

neus

tes fo

ssilis

Schist

ura be

avan

iSch

istura

rupe

cula

Fish species

Abu

ndan

ce (C


Number of species:7

8 Results

-165-



Jhikhukhola upstream in autumn (Agriculture)

020406080

100120140160180

Bariliu

s bari

laBari

lius b

ende

lisis

Brachy

danio

rerio

Chann

a pun

ctatus

Danio

aequ

ipinn

atus

Garra g

otyla

Nemac

heilu

s cori

caSch

istura

rupe

cula

Fish species

Abu

ndan

ce (C


Number of species:6

Jhikhukhola downstream in autumn (Agriculture)

0

20

40

60

80

100

120

140

160

180

Bariliu

s bari

laBari

lius b

ende

lisis

Brachy

danio

rerio

Chann

a pun

ctatus

Danio

aequ

ipinn

atus

Garra g

otyla

Nemac

heilu

s cori

caSch

istura

rupe

cula

Fish species

Abu

ndan

ce (C

PUE)

Total abundance:39.5 Number of species:8

Jhikhukhola upstream in winter (Agriculture)

0

20

40

60

80

100

120

140

160

180

Bariliu

s bari

laBari

lius b

ende

lisis

Chann

a pun

ctatus

Danio

aequ

ipinn

atus

Garra g

otyla

Heterop

neus

tes fo

ssilis

Schist

ura be

avan

iSch

istura

rupe

cula

Fish species

Abu

ndan

ce (C


Number of species:7

Jhikhukhola downstream in winter (Agriculture)

0

20

40

60

80

100

120

140

160

180

Bariliu

s bari

laBari

lius b

ende

lisis

Chann

a pun

ctatus

Danio

aequ

ipinn

atus

Garra g

otyla

Heterop

neus

tes fo

ssilis

Schist

ura be

avan

iSch

istura

rupe

cula

Fish species

Abu

ndan

ce (C

PUE)


8 Results

-166-



East Rapti upstream in spring (Agriculture)

0102030405060708090

100

Acanth

ocob

itis bo

tia

Amblyce

ps m

ango

is

Bariliu

s Bari

la

Bariliu

s ben

delis

is

Bariliu

s sha

craBari

lius v

agra

Garra a

nnan

dalei

Garra g

otyla

Glosso

gobiu

s giur

is

Glyptot

horax

telch

itta

Heterop

neus

tes fo

ssilis

Lepid

ocep

halus

gunte

a

Mastac

embe

lus ar

matus

Neoliss

ochil

us he

xago

nolep

is

Puntiu

s con

chon

ius

Puntiu

s sop

hore

Schist

ura be

avan

i

Schist

ura ru

pecu

laTor

putito

ra

Fish species

Abu

ndan

ce (C


Number of species:16

East Rapti downstream in spring (Agriculture)

0102030405060708090

100

Acanth

ocob

itis bo

tia

Amblyce

ps m

ango

is

Bariliu

s Bari

la

Bariliu

s ben

delis

is

Bariliu

s sha

craBari

lius v

agra

Garra a

nnan

dalei

Garra g

otyla

Glosso

gobiu

s giur

is

Glyptot

horax

telch

itta

Heterop

neus

tes fo

ssilis

Lepid

ocep

halus

gunte

a

Mastac

embe

lus ar

matus

Neoliss

ochil

us he

xago

nolep

is

Puntiu

s con

chon

ius

Puntiu

s sop

hore

Schist

ura be

avan

i

Schist

ura ru

pecu

laTor

putito

ra

Fish species

Abu

ndan

ce (C



East Rapti upstream in P remonsoon/ summer (Agriculture)

0102030405060708090

100

F is h s pe c ie s

Tot al abundance:151.5Number of species:13

East Rapti downstream in Premonsoon/summer (Agriculture)

0102030405060708090

100

Acanth

ocob

itis bo

tia

Amblyce

ps m

ango

is

Aspido

paria

mora

rBari

lius b

arila

Bariliu

s ben

delis

isBari

lius s

hacra

Bariliu

s vag

ra

Garra a

nnan

dalei

Garra g

otyla

Labe

o dero

Mastac

embe

lus ar

matus

Nemac

heilu

s cori

ca

Neolis

soch

ilus h

exag

onole

pis

Puntiu

s con

chon

ius

Puntiu

s sop

hore

Schist

ura be

avan

i

Schist

ura ru

pecu

la

Schizo

thorax

richa

rdson

ii

Fish species

Abu

ndan

ce (C



8 Results

-167-



East Rapti upstream in autumn (Agriculture)

0102030405060708090

100

Acanth

ocob

itis bo

tia

Amblyce

ps m

ango

is

Aspido

paria

mora

r

Bariliu

s bari

la

Bariliu

s ben

delis

is

Bariliu

s vag

ra

Botia a

lmorh

ae

Botia l

ohac

hata

Chann

a orie

ntalis

Crosso

cheil

us la

tius

Garra g

otyla

Glyptot

horax

telch

itta

Glyptot

horax

trilin

eatus

Labe

o dero

Mastac

embe

lus ar

matus

Neoliss

ochil

us he

xago

nolep

is

Puntiu

s con

chon

ius

Puntiu

s sop

hore

Schist

ura be

avan

i

Schist

ura ru

pecu

la

Schizo

thorax

richa

rdson

ii

Fish species

Abu

ndan

ce (C

PUE) Total abundance:71


East Rapti downstream in autumn (Agriculture)

0102030405060708090

100

Acanth

ocobit

is bo

tia

Amblyce

ps m

ango

is

Aspido

paria

mora

r

Barilius b

arila

Barilius b

ende

lisis

Barilius v

agra

Botia al

morhae

Botia lo

hach

ata

Channa

orien

talis

Crosso

cheilu

s lati

usGarr

a goty

la

Glyptot

horax t

elchit

ta

Glyptot

horax t

rilinea

tusLa

beo d

ero

Mastac

embelus

armatu

s

Neoliss

ochil

us hex

agon

olepis

Puntius

conch

onius

Puntius

sopho

re

Schist

ura be

avan

i

Schist

ura ru

pecu

la

Schizo

thorax

richa

rdson

ii

Fish species

Abu

ndan

ce (C

PUE)


East Rapti upstream in winter (Agriculture)

0102030405060708090

100

Acan

thoc

obitis

bot

ia

Ambly

ceps

man

gois

Barili

us ba

rilaBa

rilius

ben

delis

isBa

rilius

shac

raBa

rilius

vagr

aBo

tia lo

hach

ata

Garra

got

yla

Glyptot

hora

x pec

tinop

teru

s

Mas

tacem

belus

arm

atus

Neolis

soch

ilus h

exag

onol.

..

Psilo

rhyn

chus

pseu

dech

e...

Schis

tura

beav

ani

Schis

tura

rupe

cula

Schiz

otho

rax r

ichar

dson

iiTo

r puti

tora

Fish species

Abu

ndan

ce (C



East Rapti downstream in winter (Agriculture)

0102030405060708090

100

Acan

thoco

bitis

botia

Ambly

ceps

man

gois

Barili

us b

arila

Barili

us be

ndeli

sisBa

rilius

shac

raBa

rilius

vagr

aBo

tia lo

hach

ataGar

ra go

tyla

Glyptot

hora

x pec

tinop

teru

s

Mastac

embe

lus ar

matus

Neolis

soch

ilus h

exag

onol.

..

Psilo

rhyn

chus

pseu

dech

e...

Schis

tura

beav

ani

Schis

tura r

upec

ula

Schiz

otho

rax r

ichar

dson

iiTo

r puti

tora

Fish species

Abu

ndan

ce (C



8 Results

-168-



Tinau upstream in spring (Agriculture)

020406080

100120140160

Acanth

ocob

itis bo

tia

Amblyce

ps m

ango

is

Bariliu

s bari

la

Bariliu

s ben

delis

is

Bariliu

s vag

ra

Botia l

ohac

hata

Brachy

danio

rerio

Chann

a orie

ntalis

Chann

a pun

ctatus

Esomus

danri

cus

Garra a

nnan

dalei

Garra g

otyla

Glyptot

horax

pecti

nopte

rus

Glyptot

horax

trilin

eatus

Heterop

neus

tes fo

ssilis

Mastac

embe

lus ar

matus

Neoliss

ochil

us he

xago

nolep

is

Puntiu

s con

chon

ius

Puntiu

s sop

hore

Schist

ura be

avan

i

Schist

ura ru

pecu

laTor

putito

raTor

tor

Fish species

Abu

ndan

ce (C



Tinau downstream in spring (Agriculture)

020406080

100120140160

Acanth

ocob

itis bo

tia

Amblyce

ps m

ango

is

Bariliu

s bari

la

Bariliu

s ben

delis

is

Bariliu

s vag

ra

Botia l

ohac

hata

Brachy

danio

rerio

Chann

a orie

ntalis

Chann

a pun

ctatus

Esomus

danri

cus

Garra a

nnan

dalei

Garra g

otyla

Glyptot

horax

pecti

nopte

rus

Glyptot

horax

trilin

eatus

Heterop

neus

tes fo

ssilis

Mastac

embe

lus ar

matus

Neolis

soch

ilus h

exag

onol.

..

Puntiu

s con

chon

ius

Puntiu

s sop

hore

Schist

ura be

avan

i

Schist

ura ru

pecu

laTor

putito

raTor

tor

Fish species

Abu

ndan

ce (C



Tinau upstream in Premonsoon/summer (Agriculture)

020406080

100120140160

Bariliu

s bari

la

Brachy

danio

rerio

Chann

a orie

ntalis

Chann

a pun

ctatus

Esomus

danri

cus

Garra a

nnan

dalei

Garra g

otyla

Lepid

ocep

halus

gunte

a

Mastac

embe

lus ar

matus

Neolis

soch

ilus h

exag

onole

pis

Puntiu

s con

chon

ius

Puntiu

s sop

hore

Schist

ura be

avan

i

Schist

ura ru

pecu

laTor

putito

raFish species

Abu

ndan

ce (C



Tinau downstream in Premonsoon/summer (Agriculture)

020406080

100120140160

Bariliu

s bari

la

Brachy

danio

rerio

Chann

a orie

ntalis

Chann

a pun

ctatus

Esomus

danri

cus

Garra a

nnan

dalei

Garra g

otyla

Lepid

ocep

halus

gunte

a

Mastac

embe

lus ar

matus

Neolis

soch

ilus h

exag

onole

pis

Puntiu

s con

chon

iusPun

tius s

opho

re

Schist

ura be

avan

i

Schist

ura ru

pecu

laTor

putito

ra

Fish species

Abu

ndan

ce (C


Number of species:5

8 Results

-169-

Tinau upstream in autumn (Agriculture)

020406080

100120140160

Amblyce

ps m

ango

is

Bariliu

s bari

la

Bariliu

s ben

delis

is

Bariliu

s vag

ra

Botia l

ohac

hata

Brachy

danio

rerio

Chann

a orie

ntalis

Chann

a pun

ctatus

Crosso

cheil

us la

tius

Esomus

danri

cus

Garra g

otyla

Glyptot

horax

telch

itta

Glyptot

horax

trilin

eatus

Heterop

neus

tes fo

ssilis

Labe

o dero

Lepid

ocep

halus

gunte

a

Mastac

embe

lus ar

matus

Nemac

heilu

s cori

ca

Neolis

soch

ilus h

exag

onole

pis

Pseud

eche

neis

sulca

tus

Puntiu

s con

chon

ius

Puntiu

s sop

hore

Schist

ura be

avan

i

Schist

ura ru

pecu

laTor

putito

ra

Fish species

Abu

ndan

ce (C



Tinau downstream in autumn (Agriculture)

020406080

100120140160

Amblyce

ps m

ango

is

Bariliu

s bari

la

Bariliu

s ben

delis

is

Bariliu

s vag

ra

Botia l

ohac

hata

Brachy

danio

rerio

Chann

a orie

ntalis

Chann

a pun

ctatus

Crosso

cheil

us la

tius

Esomus

danri

cus

Garra g

otyla

Glyptot

horax

telch

itta

Glyptot

horax

trilin

eatus

Heterop

neus

tes fo

ssilis

Labe

o dero

Lepid

ocep

halus

gunte

a

Mastac

embe

lus ar

matus

Nemac

heilu

s cori

ca

Neolis

soch

ilus h

exag

onole

pis

Pseud

eche

neis

sulca

tus

Puntiu

s con

chon

ius

Puntiu

s sop

hore

Schist

ura be

avan

i

Schist

ura ru

pecu

laTor

putito

ra

Fish species

Abu

ndan

ce (C




Tinau upstream in winter (Agriculture)

020406080

100120140160

Amblyce

ps m

ango

is

Bariliu

s bari

la

Bariliu

s ben

delis

is

Bariliu

s vag

ra

Botia l

ohac

hata

Brachy

danio

rerio

Chann

a orie

ntalis

Chann

a pun

ctatus

Crosso

cheil

us la

tius

Esomus

danri

cus

Garra g

otyla

Glyptot

horax

telch

itta

Heterop

neus

tes fo

ssilis

Labe

o dero

Lepid

ocep

halus

gunte

a

Mastac

embe

lus ar

matus

Neolis

soch

ilus h

exag

onole

pis

Puntiu

s con

chon

ius

Puntiu

s sop

hore

Schist

ura be

avan

i

Schist

ura ru

pecu

laTor

putito

ra

Fish species

Abu

ndan

ce (C



Tinau downstream in winter (Agriculture)

0

20

40

60

80

100

120

140

160

Amblyceps m

angois

Barilius b

arila

Barilius b

endelisis

Barilius v

agra

Botia lo

hachata

Brachyd

anio rerio

Channa orientalis

Channa punctatus

Crossoch

eilus latiu

s

Esomus d

anricus

Garra gotyla

Glyptothorax t

elchitta

Heteropneustes f

ossilis

Labeo dero

Lepidocephalus g

untea

Mastace

mbelus arm

atus

Neolissoch

ilus hexa

gonolepis

Puntius c

onchonius

Puntius s

ophore

Schistu

ra beavani

Schistu

ra rupecu

la

Tor putito

ra

Fish species

Abu

ndan

ce (C




8 Results

-170-

Fig.8.4.25 Impact of city Fig.8.4.26 Impact of city


Narayani upstream in spring (City and Industry)

05

10152025303540

Acan

thoc

obitis

bot

iaBa

rilius

ben

delis

isBa

riliu

s sh

acra

Baril

ius

vagr

aBo

tia lo

hach

ata

Brac

hyda

nio

rerio

Clup

isom

a ga

rua

Gar

ra g

otyla

Glyp

toth

orax

telch

itta

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Neoli

ssoc

hilu

s he

xago

...Pu

ntiu

s co

ncho

nius

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Schi

zoth

orax

rich

ards

onii

Tor p

utito

ra

Fish species

Abu

ndan

ce (C



Narayani downstream in spring (City)

05

10152025303540

Acan

thoc

obitis

bot

iaBa

riliu

s ben

delis

isBa

riliu

s sha

cra

Baril

ius v

agra

Botia

loha

chat

aBr

achy

dani

o re

rioCl

upiso

ma

garu

aG

arra

got

ylaG

lypto

thor

ax te

lchitt

a

Lepi

doce

phalu

s gu

ntea

Mas

tace

mbe

lus

arm

atus

Neol

issoc

hilu

s he

xago

...Pu

ntius

con

chon

ius

Punt

ius s

opho

reSc

histu

ra b

eava

niSc

histu

ra ru

pecu

la

Schiz

otho

rax

richa

rdso

niiTo

r put

itora

Fish species

Abu

ndan

ce (C



Narayani upstream in Premonsoon/summer (City and Industry)

05

10152025303540

Acan

thoc

obitis

bot

ia

Ambl

ycep

s m

ango

is

Aspid

opar

ia m

orar

Baril

ius b

arila

Baril

ius b

ende

lisis

Baril

ius s

hacr

aBa

riliu

s vag

raBo

tia a

lmor

hae

Botia

loha

chat

aBr

achy

dani

o re

rioCh

anna

orie

ntali

s

Chan

na p

unct

atus

Cros

soch

eilu

s lat

ius

Gar

ra g

otyla

Glyp

toth

orax

telch

itta

Labe

o de

ro

Lepi

doce

phalu

s gu

ntea

Mas

tace

mbe

lus

arm

atus

Nem

ache

ilus c

orica

Neol

issoc

hilu

s he

xago

...

Punt

ius c

onch

oniu

sPu

ntius

sop

hore

Schis

tura

bea

vani

Schis

tura

rupe

cula

Tor p

utito

ra

Fish species

Abu

ndan

ce (C



Narayani downstream in Premonsoon/summer (City)

05

10152025303540

Acan

thoc

obitis

bot

ia

Ambl

ycep

s m

ango

is

Aspid

opar

ia m

orar

Baril

ius b

arila

Baril

ius b

ende

lisis

Baril

ius s

hacr

aBa

riliu

s vag

raBo

tia a

lmor

hae

Botia

loha

chat

aBr

achy

dani

o re

rioCh

anna

orie

ntali

s

Chan

na p

unct

atus

Cros

soch

eilu

s lat

ius

Gar

ra g

otyla

Glyp

toth

orax

telch

itta

Labe

o de

ro

Lepi

doce

phalu

s gu

ntea

Mas

tace

mbe

lus

arm

atus

Nem

ache

ilus c

orica

Neol

issoc

hilu

s he

xago

...

Punt

ius c

onch

oniu

sPu

ntius

sop

hore

Schis

tura

bea

vani

Schis

tura

rupe

cula

Tor p

utito

ra

Fish species

Abu

ndan

ce (C



8 Results

-171-



Narayani upstream in autumn (City / Industry)

05

10152025303540

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

vagr

aBo

tia a

lmor

hae

Botia

loha

chat

aBr

achy

dani

o re

rioCh

anna

pun

ctat

us

Cros

soch

eilu

s la

tius

Gar

ra g

otyla

Glo

ssog

obiu

s gi

uris

Glyp

toth

orax

telch

itta

Glyp

toth

orax

trilin

eatu

sLa

beo

dero

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Nem

ache

ilus

coric

a

Punt

ius

conc

honi

usPu

ntiu

s sop

hore

Schi

stur

a be

avan

i

Schi

stur

a ru

pecu

la

Sem

iplo

tus

sem

iplo

tus

Tor t

or

Fish species

Abu

ndan

ce (C



Narayani downstream in autumn (City)

05

10152025303540

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

vagr

aBo

tia a

lmor

hae

Botia

loha

chat

aBr

achy

dani

o re

rio

Chan

na p

unct

atus

Cros

soch

eilu

s la

tius

Gar

ra g

otyla

Glo

ssog

obiu

s gi

uris

Glyp

toth

orax

telch

itta

Glyp

toth

orax

trilin

eatu

sLa

beo

dero

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Nem

ache

ilus

coric

a

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

la

Sem

iplo

tus

sem

iplo

tus

Tor t

or

Fish species

Abu

ndan

ce (C



Narayani upstream in winter (City / Industry)

05

10152025303540

Acan

thoc

obitis

bot

ia

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisi

sBa

riliu

s va

gra

Botia

alm

orha

eBo

tia lo

hach

ata

Chan

na p

unct

atus

Gar

ra g

otyla

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Nem

ache

ilus

coric

a

Neol

issoc

hilu

s he

xag.

..

Psilo

rhyn

chus

pse

ud...

Punt

ius

conc

honi

usSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

la

Schi

zoth

orax

rich

ards

...

Fish species

Abu

ndan

ce (C



Narayani downstream in winter (City)

05

10152025303540

Acan

thoc

obitis

bot

ia

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisi

sBa

riliu

s va

gra

Botia

alm

orha

eBo

tia lo

hach

ata

Chan

na p

unct

atus

Gar

ra g

otyla

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Nem

ache

ilus

coric

a

Neol

issoc

hilu

s he

xag.

..

Psilo

rhyn

chus

pse

ud...

Punt

ius

conc

honi

usSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

la

Schi

zoth

orax

rich

ards

...

Fish species

Abu

ndan

ce (C


Number of species:8

8 Results

-172-



Seti upstream in spring (City)

05

1015202530354045

Acan

thoc

obitis

bot

iaBa

riliu

s be

ndel

isis

Baril

ius

vagr

aBr

achy

dani

o re

rioCh

anna

orie

ntal

isDa

nio

dang

ilaG

arra

ann

anda

lei

Gar

ra g

otyla

Hete

ropn

eust

es fo

ssilis

Mye

rsgl

anis

blyt

hii

Neol

issoc

hilu

s he

xa...

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

la

Schi

zoth

orai

chth

ys ..

.

Fish species

Abu

ndan

ce (C



Seti downstream in spring (City)

05

1015202530354045

Acan

thoc

obitis

bot

iaBa

riliu

s be

ndel

isis

Baril

ius

vagr

aBr

achy

dani

o re

rioCh

anna

orie

ntali

sDa

nio

dang

ilaG

arra

ann

anda

leiG

arra

got

yla

Hete

ropn

eust

es fo

ssilis

Mye

rsgl

anis

blyt

hii

Neol

issoc

hilus

hex

agon

...Pu

ntiu

s co

ncho

nius

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Schi

zoth

orai

chth

ys p

rog.

..

Fish species

Abu

ndan

ce (C



Seti upstream in Premonsoon/summer (City)

05

1015202530354045

Acan

thoc

obitis

bot

iaBa

riliu

s ba

rila

Baril

ius

vagr

aBr

achy

dani

o re

rioCh

anna

orie

ntal

isDa

nio

dang

ilaG

arra

ann

anda

lei

Mye

rsgl

anis

blyt

hii

Neol

issoc

hilu

s he

xag.

..Sc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laSc

hizo

thor

aich

thys

p...

Fish species

Abu

ndan

ce (C


Number of species:7

Seti downstream in Premonsoon/summer (City)

05

1015202530354045

Acan

thoc

obitis

bot

iaBa

riliu

s ba

rila

Baril

ius

vagr

aBr

achy

dani

o re

rioCh

anna

orie

ntal

isDa

nio

dang

ilaG

arra

ann

anda

lei

Mye

rsgl

anis

blyt

hii

Neol

issoc

hilu

s he

xa...

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Schi

zoth

orai

chth

ys ..

.

Fish species

Abu

ndan

ce (C



8 Results

-173-



Seti upstream in autumn (City)

05

1015202530354045

Acan

thoc

obitis

bot

iaBa

riliu

s ba

rila

Gar

ra a

nnan

dale

iG

arra

got

ylaM

yers

glan

is bl

ythi

iNe

oliss

ochi

lus

hexa

g...

Pseu

dech

enei

s su

lcatu

sPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laSc

hizo

thor

aich

thys

p...

Fish species

Abu

ndan

ce (C


Number of species:8

Seti downstream in autumn (City)

05

1015202530354045

Acan

thoc

obitis

bot

iaBa

riliu

s ba

rila

Gar

ra a

nnan

dale

iG

arra

got

ylaM

yers

glan

is bl

ythi

iNe

oliss

ochi

lus

hexa

g...

Pseu

dech

enei

s su

lcatu

sPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laSc

hizo

thor

aich

thys

p...

Fish species

Abu

ndan

ce (C


Number of species:9

Seti upstream in winter (City)

05

1015202530354045

Baril

ius

baril

a

Baril

ius

vagr

a

Gar

ra a

nnan

dale

i

Gar

ra g

otyla

Neol

issoc

hilu

s he

xa...

Pseu

dech

enei

s su

lcatu

sPu

ntiu

s co

ncho

nius

Schi

stur

a ru

pecu

laSc

hizo

thor

aich

thys

p...

Fish species

Abu

ndan

ce (C


Number of species:6

Seti downstream in winter (City)

05

1015202530354045

Baril

ius

baril

a

Baril

ius

vagr

a

Gar

ra a

nnan

dale

i

Gar

ra g

otyla

Neol

issoc

hilu

s he

xag.

..Ps

eude

chen

eis

sulca

tus

Punt

ius

conc

honi

usSc

hist

ura

rupe

cula

Schi

zoth

orai

chth

ys p

...

Fish species

Abu

ndan

ce (C


Number of species:7

8 Results

-174-



Tinau upstream in spring (City)

0

25

50

75

100

125

150

Acan

thoc

obitis

bot

ia

Ambly

ceps

man

gois

Baril

ius

baril

aBa

rilius

ben

delis

isBa

riliu

s va

gra

Botia

loha

chat

aBr

achy

dani

o re

rioCh

anna

orie

ntal

is

Chan

na p

unct

atus

Esom

us d

anric

usG

arra

ann

anda

lei

Gar

ra g

otyla

Glyp

toth

orax

pec

tinop

t...

Glyp

toth

orax

trilin

eatu

s

Hete

ropn

eust

es fo

ssilis

Mas

tace

mbe

lus

arm

atus

Neoli

ssoc

hilu

s he

xago

...

Punt

ius

conc

honiu

sPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laTo

r put

itora

Tor t

or

Fish species

Abu

ndan

ce (C

PUE)


Tinau downstream in spring (City)

0

25

50

75

100

125

150

Acan

thoc

obitis

bot

ia

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisi

sBa

riliu

s va

gra

Botia

loha

chat

a

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Esom

us d

anric

usG

arra

ann

anda

lei

Gar

ra g

otyla

Glyp

toth

orax

pec

tinop

...

Glyp

toth

orax

trilin

eatu

s

Hete

ropn

eust

es fo

ssilis

Mas

tace

mbe

lus

arm

atus

Neol

issoc

hilu

s he

xag.

..

Punt

ius

conc

honi

usPu

ntiu

s so

phor

e

Schi

stur

a be

avan

i

Schi

stur

a ru

pecu

laTo

r put

itora

Tor t

or

Fish species

Abu

ndan

ce (C


Number of species:7

Tinau upstream in Premonsoon/summer (City)

0

25

50

75

100

125

150

Baril

ius

baril

aBr

achy

dani

o re

rioCh

anna

orie

ntal

isCh

anna

pun

ctat

usEs

omus

dan

ricus

Gar

ra a

nnan

dale

iG

arra

got

ylaLe

pido

ceph

alus

gun

tea

Mas

tace

mbe

lus

arm

atus

Neoli

ssoc

hilu

s he

xago

...Pu

ntiu

s co

ncho

nius

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Tor p

utito

ra

Fish species

Abu

ndan

ce (C


Number of species:5

Tinau downstream in Premonsoon/summer (City)

0

25

50

75

100

125

150

Baril

ius

barila

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Esom

us d

anric

usG

arra

ann

anda

lei

Gar

ra g

otyla

Lepi

doce

phalu

s gu

ntea

Mas

tace

mbe

lus a

rmat

us

Neol

issoc

hilus

hex

ago.

..Pu

ntiu

s co

ncho

nius

Punt

ius s

opho

reSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laTo

r put

itora

Fish species

Abu

ndan

ce (C


Number of species:5

8 Results

-175-



Tinau upstream in autumn (City)

0

25

50

75

100

125

150

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisi

sBa

riliu

s va

gra

Botia

loha

chat

a

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Cros

soch

eilu

s la

tius

Esom

us d

anric

usG

arra

got

yla

Glyp

toth

orax

telch

itta

Glyp

toth

orax

trilin

eatu

s

Hete

ropn

eust

es fo

ssilis

Labe

o de

ro

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Nem

ache

ilus

coric

a

Neol

issoc

hilu

s he

xag.

..

Pseu

dech

enei

s su

lcatu

s

Punt

ius

conc

honi

usPu

ntiu

s so

phor

e

Schi

stur

a be

avan

i

Schi

stur

a ru

pecu

laTo

r put

itora

Fish species

Abu

ndan

ce (C



Tinau downstream in autumn (City)

0

25

50

75

100

125

150

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisi

sBa

riliu

s va

gra

Botia

loha

chat

a

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Cros

soch

eilu

s la

tius

Esom

us d

anric

usG

arra

got

yla

Glyp

toth

orax

telch

itta

Glyp

toth

orax

trilin

eatu

s

Hete

ropn

eust

es fo

ssilis

Labe

o de

ro

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

...

Nem

ache

ilus

coric

a

Neol

issoc

hilu

s he

xa...

Pseu

dech

enei

s su

lcatu

s

Punt

ius

conc

honi

usPu

ntiu

s so

phor

e

Schi

stur

a be

avan

i

Schi

stur

a ru

pecu

laTo

r put

itora

Fish species

Abu

ndan

ce (C



Tinau upstream in winter (City)

0

25

50

75

100

125

150

Ambly

ceps

man

gois

Barili

us b

arila

Barili

us b

ende

lisis

Barili

us va

gra

Botia

loha

chat

a

Brac

hyda

nio re

rio

Chan

na o

rient

alis

Chan

na p

uncta

tus

Cros

soch

eilus

latiu

s

Esom

us d

anric

usGar

ra g

otyla

Glypto

thor

ax te

lchitta

Hete

ropn

euste

s fos

silis

Labe

o de

ro

Lepid

ocep

halus

gun

tea

Mas

tace

mbe

lus a

rmat

us

Neoli

ssoc

hilus

hex

agon

o...

Punt

ius co

ncho

nius

Punt

ius so

phor

e

Schis

tura

bea

vani

Schis

tura

rupe

cula

Tor p

utito

ra

Fish species

Abu

ndan

ce (C



Tinau downstream in winter (City)

0

25

50

75

100

125

150

Ambl

ycep

s m

ango

isBa

riliu

s ba

rilaBa

riliu

s be

ndel

isis

Baril

ius

vagr

aBo

tia lo

hach

ata

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Cros

soch

eilu

s lat

ius

Esom

us d

anric

usG

arra

got

yla

Glyp

toth

orax

telch

itta

Hete

ropn

eust

es fo

ssilis

Labe

o de

ro

Lepi

doce

phalu

s gu

ntea

Mas

tace

mbe

lus a

rmat

us

Neol

issoc

hilus

hex

ago.

..

Punt

ius

conc

honi

usPu

ntiu

s sop

hore

Schi

stur

a be

avan

i

Schi

stur

a ru

pecu

laTo

r put

itora

Fish species

Abu

ndan

ce (C


Number of species:5

8 Results

-176-

Fig.8.4.49 Impact of dam Fig.8.4.50 Impact of dam


Aandhikhola upstream in spring (Dam)

05

1015202530354045

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

vagr

aBr

achy

dani

o re

rioG

arra

ann

anda

lei

Gar

ra g

otyla

Hete

ropn

eust

es fo

ssilis

Mas

tace

mbe

lus

arm

...Na

zirito

r che

lynoi

des

Neol

issoc

hilu

s he

xa...

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Schi

zoth

orax

rich

ar...

Sem

iplo

tus

sem

iplo

tus

Tor p

utito

ra

Fish species

Abu

ndan

ce (C



Aandhikhola downstream in spring (Dam)

05

1015202530354045

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

vagr

aBr

achy

dani

o re

rioG

arra

ann

anda

lei

Gar

ra g

otyla

Hete

ropn

eust

es fo

s...

Mas

tace

mbe

lus

a...

Nazir

itor c

helyn

oide

sNe

oliss

ochi

lus

he...

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Schi

zoth

orax

rich

a...

Sem

iplo

tus

sem

ipl..

.To

r put

itora

Fish species

Abu

ndan

ce (C

PUE)


Aandhikhola upstream in Premonsoon/summer (Dam)

05

1015202530354045

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

vagr

aG

arra

ann

anda

lei

Gar

ra g

otyla

Mas

tace

mbe

lus

arm

...Ne

mac

heilu

s co

rica

Neol

issoc

hilu

s he

xa...

Punt

ius

chol

aSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laSc

hizo

thor

ax ri

char

d...

Tor p

utito

ra

Fish species

Abu

ndan

ce (C

PUE) Total abundance: 47.39

Number of species:9

Aandhikhola downstream in Premonsoon/summer (Dam)

05

1015202530354045

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

vagr

aG

arra

ann

anda

lei

Gar

ra g

otyla

Mas

tace

mbe

lus

arm

atus

Nem

ache

ilus

coric

aNe

oliss

ochi

lus

hexa

g...

Punt

ius

chol

aSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laSc

hizo

thor

ax ri

char

ds...

Tor p

utito

ra

Fish species

Abu

ndan

ce (C



8 Results

-177-



Aandhikhola upstream in autumn (Dam)

05

1015202530354045

Baril

ius

baril

a

Baril

ius

vagr

aCh

anna

pun

ctat

usG

arra

ann

anda

lei

Gar

ra g

otyla

Mas

tace

mbe

lus

arm

atus

Neol

issoc

hilu

s he

xago

...Sc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laSc

hizo

thor

ax ri

char

dson

ii

Fish species

Abu

ndan

ce (C


Number of species:9

Aandhikhola downstream in autumn (Dam)

05

1015202530354045

Baril

ius

baril

a

Baril

ius

vagr

aCh

anna

pun

ctat

us

Gar

ra a

nnan

dale

i

Gar

ra g

otyla

Mas

tace

mbe

lus

arm

...Ne

oliss

ochi

lus

hexa

...

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Schi

zoth

orax

rich

ard.

..

Fish species

Abu

ndan

ce (C


Number of species:6

Aandhikhola upstream in winter (Dam)

05

1015202530354045

Baril

ius

bend

elisi

s

Baril

ius

vagr

aG

arra

ann

anda

lei

Garra

got

ylaM

asta

cem

belus

arm

atus

Neol

issoc

hilus

hex

ago.

..Sc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laSc

hizo

thor

ax ri

char

dson

ii

Tor p

utito

ra

Fish species

Abu

ndan

ce (C


Number of species:9

Aandhikhola downstream in winter (Dam)

05

1015202530354045

Baril

ius

bend

elisi

s

Baril

ius

vagr

aG

arra

ann

anda

lei

Gar

ra g

otyla

Mas

tace

mbe

lus

arm

atus

Neol

issoc

hilu

s he

xag.

..Sc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laSc

hizo

thor

ax ri

char

ds...

Tor p

utito

ra

Fish species

Abu

ndan

ce (C


Number of species:8

8 Results

-178-



Bagmati upstream in spring (Dam)

0

10

20

30

40

50

60

70

80

90

100

Schizothorax richardsonii

F ish species


Bagmati downstream in spring (Dam)

0

10

20

30

40

50

60

70

80

90

100


F ish species

Tot al abundance:15.29 Number of species:1

Bagmati upstream in Premonsoon/summer (Dam)

0

10

20

30

40

50

60

70

80

90

100

Schi

stur

abe

avan

i

Schi

zoth

orax

richa

rdso

nii

Fish species

Abu

ndan

ce (C

PUE)


Bagmati downstream in Premonsoon/summer (Dam)

0

10

20

30

40

50

60

70

80

90

100

Schistura beavani Schizothorax richardsonii

F ish species


8 Results

-179-



Bagmati upstream in autumn (Dam)

0

10

20

30

40

50

60

70

80

90

100

Schistura rupecula Schizothorax richardsonii

Fish species

Abu

ndan

ce (C

PUE)

Total abundance:43.47Number of species2:

Bagmati downstream in autumn (Dam)

0

10

20

30

40

50

60

70

80

90

100

Schistura rupecula Schizothorax richardsonii

Fish species

Abu

ndan

ce (C

PUE)


Bagmati upstream in winter (Dam)

0

10

20

30

40

50

60

70

80

90

100


Fish species

Abu

ndan

ce (C

PUE)


Bagmati downstream in winter (Dam)

0

10

20

30

40

50

60

70

80

90

100


Fish species

Abu

ndan

ce (C

PUE)


8 Results

-180-



Tinau upstream in spring (Dam)

05

1015202530354045

Acan

thoc

obitis

bot

ia

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisi

sBa

riliu

s va

gra

Botia

loha

chat

a

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Esom

us d

anric

usG

arra

ann

anda

lei

Gar

ra g

otyla

Glyp

toth

orax

pec

tinop

...

Glyp

toth

orax

trilin

eatu

s

Hete

ropn

eust

es fo

ssilis

Mas

tace

mbe

lus

arm

atus

Neol

issoc

hilu

s he

xag.

..

Punt

ius

conc

honi

usPu

ntiu

s so

phor

e

Schi

stur

a be

avan

i

Schi

stur

a ru

pecu

laTo

r put

itora

Tor t

or

Fish species

Abu

ndan

ce (C



Tinau downstream in spring (Dam)

05

1015202530354045

Acan

thoc

obitis

bot

ia

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisi

sBa

riliu

s va

gra

Botia

loha

chat

a

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Esom

us d

anric

usG

arra

ann

anda

lei

Gar

ra g

otyla

Glyp

toth

orax

pec

tinop

...

Glyp

toth

orax

trilin

eatu

s

Hete

ropn

eust

es fo

ssilis

Mas

tace

mbe

lus

arm

atus

Neol

issoc

hilu

s he

xag.

..

Punt

ius

conc

honi

usPu

ntiu

s so

phor

e

Schi

stur

a be

avan

i

Schi

stur

a ru

pecu

laTo

r put

itora

Tor t

or

Fish species

Abu

ndan

ce (C



Tinau upstream in Premonsoon/summer (Dam)

05

1015202530354045

Baril

ius

barila

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Esom

us d

anric

usG

arra

ann

anda

lei

Gar

ra g

otyla

Lepi

doce

phalu

s gu

ntea

Mas

tace

mbe

lus a

rmat

us

Neol

issoc

hilus

hex

ago.

..Pu

ntiu

s co

ncho

nius

Punt

ius s

opho

reSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laTo

r put

itora

Fish species

Abu

ndan

ce (C


Number of species:6

Tinau downstream in Premonsoon/summer (Dam)

05

1015202530354045

Baril

ius

baril

aBr

achy

dani

o re

rioCh

anna

orie

ntal

isCh

anna

pun

ctat

usEs

omus

dan

ricus

Gar

ra a

nnan

dale

iG

arra

got

yla

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Neol

issoc

hilu

s he

xag.

..Pu

ntiu

s co

ncho

nius

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Tor p

utito

ra

Fish species

Abu

ndan

ce (C


Number of species:3

8 Results

-181-



Tinau upstream in autumn (dam)

05

1015202530354045

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisi

sBa

riliu

s va

gra

Botia

loha

chat

a

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Cros

soch

eilu

s lat

ius

Esom

us d

anric

usGa

rra g

otyla

Glyp

toth

orax

telch

itta

Glyp

toth

orax

trilin

eatu

s

Hete

ropn

eust

es fo

ssilis

Labe

o de

ro

Lepi

doce

phalu

s gu

ntea

Mas

tace

mbe

lus a

rmat

us

Nem

ache

ilus

coric

a

Neol

issoc

hilus

hex

ago.

..

Pseu

dech

enei

s sul

catu

s

Punt

ius

conc

honi

usPu

ntiu

s so

phor

e

Schi

stur

a be

avan

i

Schi

stur

a ru

pecu

laTo

r put

itora

Fish species

Abu

ndan

ce (C



Tinau downstream in autumn (dam)

05

1015202530354045

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisi

sBa

riliu

s va

gra

Botia

loha

chat

a

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Cros

soch

eilu

s la

tius

Esom

us d

anric

usG

arra

got

yla

Glyp

toth

orax

telch

itta

Glyp

toth

orax

trilin

eatu

s

Hete

ropn

eust

es fo

ssilis

Labe

o de

ro

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Nem

ache

ilus

coric

a

Neol

issoc

hilu

s he

xag.

..

Pseu

dech

enei

s su

lcatu

s

Punt

ius

conc

honi

usPu

ntiu

s so

phor

e

Schi

stur

a be

avan

i

Schi

stur

a ru

pecu

laTo

r put

itora

Fish species

Abu

ndan

ce (C


Number of species:9

Tinau upstream in winter (Dam)

05

1015202530354045

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisi

sBa

riliu

s va

gra

Botia

loha

chat

aBr

achy

dani

o re

rioCh

anna

orie

ntal

is

Chan

na p

unct

atus

Cros

soch

eilu

s la

tius

Esom

us d

anric

usG

arra

got

yla

Glyp

toth

orax

telch

itta

Hete

ropn

eust

es fo

ssilis

Labe

o de

ro

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Neol

issoc

hilu

s he

xag.

..

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laTo

r put

itora

Fish species

Abu

ndan

ce (C

PUE)


Tinau downstream in winter (Dam)

05

1015202530354045

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisi

sBa

riliu

s va

gra

Botia

loha

chat

aBr

achy

dani

o re

rioCh

anna

orie

ntal

is

Chan

na p

unct

atus

Cros

soch

eilu

s la

tius

Esom

us d

anric

usG

arra

got

yla

Glyp

toth

orax

telch

itta

Hete

ropn

eust

es fo

ssilis

Labe

o de

ro

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Neol

issoc

hilu

s he

xag.

..

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laTo

r put

itora

Fish species

Abu

ndan

ce (C

PUE)


8 Results

-182-

Fig.8.4.73 Impact of the industry Fig.8.4.74 Impact of the industry


Arungkhola upstream in spring (Industry)

0102030405060708090

100110

Acan

thoc

obitis

bot

iaAm

blyc

eps

man

gois

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

shac

raBa

riliu

s va

gra

Chan

na o

rient

alis

Chan

na p

unct

atus

Esom

us d

anric

usG

arra

got

yla

Lepi

doce

phal

us g

unte

aPu

ntiu

s co

ncho

nius

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Tor p

utito

ra

Fish species

Abu

ndan

ce (C



Arungkhola downstream in spring (Industry)

0102030405060708090

100110

Acan

thoc

obitis

bot

iaAm

blyc

eps

man

gois

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius s

hacr

aBa

riliu

s va

gra

Chan

na o

rient

alis

Chan

na p

uncta

tus

Esom

us d

anric

usG

arra

got

yla

Lepid

ocep

halu

s gu

ntea

Punt

ius c

onch

oniu

sPu

ntiu

s so

phor

eSc

histu

ra b

eava

niSc

histu

ra ru

pecu

laTo

r put

itora

Fish species

Abu

ndan

ce (C



Arungkhola upstream in Premonsoon/summer (industry)

0102030405060708090

100110

Acan

thoc

obitis

bot

iaAm

blyc

eps m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisis

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Gar

ra a

nnan

dale

iG

arra

got

yla

Lepi

doce

phal

us g

unte

a

Mac

rogn

athu

s pa

ncal

us

Mas

tace

mbe

lus

arm

atus

Punt

ius

conc

honi

usPu

ntius

sop

hore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Fish species

Abu

ndan

ce (C



Arungkhola downstream in Premonsoon/summer (industry)

0102030405060708090

100110

Acan

thoc

obitis

bot

iaAm

blyc

eps

man

gois

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Garra

ann

anda

lei

Gar

ra g

otyla

Lepi

doce

phal

us g

unte

a

Mac

rogn

athu

s pa

ncal

us

Mas

tace

mbe

lus

arm

atus

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stura

rupe

cula

Fish species

Abu

ndan

ce (C

PUE)

Total abundance: 12.25Number of species:14

8 Results

-183-



Arungkhola upstream in autumn (Industry)

0102030405060708090

100110

Acan

thoc

obitis

bot

ia

Ambl

ycep

s man

gois

Baril

ius

baril

aBa

riliu

s be

ndeli

sisBa

riliu

s va

gra

Botia

loha

chat

aBr

achy

dani

o re

rioCh

anna

orie

ntal

isCh

anna

pun

ctat

us

Cros

soch

eilus

latiu

sG

arra

got

ylaLa

beo

dero

Lepi

doce

phal

us g

unte

a

Mac

rogn

athu

s pa

ncal

us

Mas

tace

mbe

lus

arm

atus

Mye

rsgl

anis

blyth

ii

Punt

ius

conc

honi

usPu

ntius

sop

hore

Schi

stur

a be

avan

i

Schi

stur

a ru

pecu

la

Sem

iplo

tus

sem

iplo

tus

Tor p

utito

ra

Fish species

Abu

ndan

ce (C



Arungkhola downstream in autumn (Industry)

0102030405060708090

100110

Acan

thoc

obitis

bot

ia

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisi

sBa

riliu

s va

gra

Botia

loha

chat

aBr

achy

dani

o re

rioCh

anna

orie

ntal

is

Chan

na p

unct

atus

Cros

soch

eilu

s la

tius

Gar

ra g

otyla

Labe

o de

ro

Lepi

doce

phal

us g

unte

a

Mac

rogn

athu

s pa

ncal

us

Mas

tace

mbe

lus

arm

...M

yers

glan

is bl

ythi

i

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

la

Sem

iplo

tus

sem

iplo

tus

Tor p

utito

ra

Fish species

Abu

ndan

ce (C



Arungkhola upstream in winter (Industry)

0102030405060708090

100110

Acan

thoc

obitis

bot

ia

Ambl

ycep

s m

ango

isBa

riliu

s bar

ilaBa

riliu

s be

ndel

isis

Baril

ius

vagr

aBo

tia lo

hach

ata

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Dani

o ae

quipi

nnat

usEs

omus

dan

ricus

Gar

ra g

otyla

Labe

o de

ro

Lepi

doce

phal

us g

unte

a

Mac

rogn

athu

s pa

ncal

us

Mas

tace

mbe

lus

arm

atus

Pseu

dech

enei

s su

lcatu

s

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

la

Sem

iplo

tus

sem

iplo

tus

Tor p

utito

ra

Fish species

Abu

ndan

ce (C



Arungkhola downstream in winter (Industry)

0102030405060708090

100110

Acan

thoc

obitis

bot

ia

Ambl

ycep

s m

ango

isBa

rilius

bar

ilaBa

rilius

ben

delis

isBa

rilius

vag

raBo

tia lo

hach

ata

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Dani

o ae

quip

inna

tus

Esom

us d

anric

usG

arra

got

ylaLa

beo

dero

Lepi

doce

phal

us g

unte

a

Mac

rogn

athu

s pa

ncal

us

Mas

tace

mbe

lus

arm

atus

Pseu

dech

enei

s su

lcatu

s

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

la

Sem

iplo

tus

sem

iplo

tus

Tor p

utito

ra

Fish species

Abu

ndan

ce (C

PUE)


8 Results

-184-



Karrakhola upstream in spring (Industry)

05

1015202530354045

Acan

thoc

obitis

bot

ia

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisi

sBa

riliu

s va

gra

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Gar

ra a

nnan

dale

iG

arra

got

ylaG

udus

ia c

hapr

a

Hete

ropn

eust

es fo

ssilis

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Neol

issoc

hilu

s he

xag.

..Pu

ntiu

s ch

ola

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Fish species

Abu

ndan

ce (C



Karrakhola downstream in spring (Industry)

05

1015202530354045

Acan

thoc

obitis

bot

iaAm

blyc

eps

man

gois

Baril

ius

baril

aBa

rilius

ben

delis

isBa

riliu

s va

gra

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Garra

ann

anda

lei

Gar

ra g

otyla

Gud

usia

cha

pra

Hete

ropn

euste

s fo

ssilis

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Neol

issoc

hilu

s he

xago

...Pu

ntiu

s ch

ola

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Fish species

Abu

ndan

ce (C



Karrakhola downstream in Premonsoon/summer (Industry)

05

1015202530354045

Acan

thoc

obitis

bot

iaAm

blyc

eps m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisis

Baril

ius

vagr

aBr

achy

dani

o re

rioCh

anna

orie

ntal

isG

arra

ann

anda

lei

Gar

ra g

otyla

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Pseu

dech

enei

s su

lcatu

sPu

ntiu

s co

ncho

nius

Punt

ius s

opho

reSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

la

Fish species

Abu

ndan

ce (C



Karrakhola upstream in Premonsoon/summer (Industry)

05

1015202530354045

Acan

thoc

obitis

bot

iaAm

blyc

eps m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisis

Baril

ius

vagr

aBr

achy

dani

o re

rioCh

anna

orie

ntal

isG

arra

ann

anda

lei

Gar

ra g

otyla

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Pseu

dech

enei

s su

lcatu

sPu

ntiu

s co

ncho

nius

Punt

ius s

opho

reSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

la

Fish species

Abu

ndan

ce (C



8 Results

-185-



Karrakhola upstream in autumn (Industry)

05

1015202530354045

Acan

thoc

obitis

bot

ia

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisi

sBa

riliu

s va

gra

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Cirrh

inus

reba

Esom

us d

anric

usG

arra

got

yla

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Nem

ache

ilus

coric

a

Neol

issoc

hilu

s he

xag.

..Pu

ntiu

s co

ncho

nius

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Fish species

Abu

ndan

ce (C



Karrakhola downstream in autumn (Industry)

05

1015202530354045

Acan

thoc

obitis

bot

ia

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elisi

sBa

riliu

s va

gra

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Cirrh

inus

reba

Esom

us d

anric

usG

arra

got

yla

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Nem

ache

ilus

coric

a

Neol

issoc

hilu

s he

xag.

..Pu

ntiu

s co

ncho

nius

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Fish species

Abu

ndan

ce (C



Karrakhola upstream in winter (Industry)

05

1015202530354045

Acan

thoc

obitis

bot

iaAm

blyc

eps

man

gois

Baril

ius

barila

Baril

ius

barn

aBa

riliu

s ben

delis

isBa

riliu

s va

gra

Brac

hyda

nio

rerio

Chan

na p

unct

atus

Gar

ra g

otyla

Lepi

doce

phalu

s gu

ntea

Mas

tace

mbe

lus

arm

atus

Neol

issoc

hilus

hex

ago.

..Pu

ntiu

s co

ncho

nius

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Fish species

Abu

ndan

ce (C



Karrakhola downstream in winter (Industry)

05

1015202530354045

Acan

thoc

obitis

bot

iaAm

blyc

eps

man

gois

Baril

ius

barila

Baril

ius

barn

aBa

riliu

s ben

delis

isBa

riliu

s va

gra

Brac

hyda

nio

rerio

Chan

na p

unct

atus

Gar

ra g

otyla

Lepi

doce

phalu

s gu

ntea

Mas

tace

mbe

lus a

rmat

us

Neol

issoc

hilus

hex

ago.

..Pu

ntiu

s co

ncho

nius

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Fish species

Abu

ndan

ce (C



8 Results

-186-

Fig.8.4.89 Impact of industry Fig.8.4.90 Impact of industry

Fig.8.4.91 Impact of industry Fig.8.4.92 Impact of industry

Narayani downstream in spring (industry)

05

10152025303540

Acan

thoc

obitis

bot

iaBa

riliu

s be

ndel

isis

Baril

ius

shac

raBa

riliu

s va

gra

Botia

loha

chat

aBr

achy

dani

o re

rioCl

upiso

ma

garu

aG

arra

got

yla

Glyp

toth

orax

telch

itta

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Neol

issoc

hilu

s he

xag.

..Pu

ntiu

s co

ncho

nius

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Schi

zoth

orax

rich

ards

...To

r put

itora

Fish species

Abu

ndan

ce (C


Number of species:8

Narayani downstream in Premonsoon/summer (Industry)

05

10152025303540

Acan

thoc

obitis

bot

ia

Ambl

ycep

s m

ango

is

Aspi

dopa

ria m

orar

Baril

ius

barila

Baril

ius

bend

elisi

sBa

riliu

s sh

acra

Baril

ius

vagr

aBo

tia a

lmor

hae

Botia

loha

chat

a

Brac

hyda

nio

rerio

Chan

na o

rient

alis

Chan

na p

unct

atus

Cros

soch

eilu

s la

tius

Gar

ra g

otyla

Glyp

toth

orax

telch

itta

Labe

o de

ro

Lepi

doce

phalu

s gu

ntea

Mas

tace

mbe

lus a

rmat

us

Nem

ache

ilus

coric

a

Neol

issoc

hilus

hex

ago.

..

Punt

ius

conc

honi

usPu

ntiu

s so

phor

e

Schi

stur

a be

avan

i

Schi

stur

a ru

pecu

laTo

r put

itora

Fish species

Abu

ndan

ce (C


Number of species:8

Narayani downstream in autumn (Industry)

05

10152025303540

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

vagr

aBo

tia a

lmor

hae

Botia

loha

chat

aBr

achy

dani

o re

rioCh

anna

pun

ctat

us

Cros

soch

eilu

s la

tius

Gar

ra g

otyla

Glo

ssog

obiu

s gi

uris

Glyp

toth

orax

telch

itta

Glyp

toth

orax

trilin

eatu

sLa

beo

dero

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

atus

Nem

ache

ilus

coric

a

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

la

Sem

iplo

tus

sem

iplo

tus

Tor t

or

Fish species

Abu

ndan

ce (C



Narayani downstream in winter (industry)

05

10152025303540

Acan

thoc

obitis

bot

iaAm

blyc

eps

man

gois

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

vagr

aBo

tia a

lmor

hae

Botia

loha

chat

aCh

anna

pun

ctat

usG

arra

got

yla

Lepi

doce

phal

us g

unte

a

Mas

tace

mbe

lus

arm

...Ne

mac

heilu

s co

rica

Neol

issoc

hilu

s he

xa...

Psilo

rhyn

chus

pse

u...

Punt

ius

conc

honi

usSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

la

Schi

zoth

orax

rich

ard.

..

Fish species

Abu

ndan

ce (C



8 Results

-187-

8.4 Assessment of ecological integrity of the rivers: There were four types of disturbances having potential to affect the integrity of the river

system chosen for study in this work. The four types of disturbances include agricultural

practices, urbanization, construction of dams and weirs, and industrialization. The extent

and importance of these disturbances in river systems of Nepal have, already, been

discussed in the chapter, “Issues in context of Nepal.” For each disturbance three rivers

were considered as case studies. For each disturbances, two sampling sites, the upstream or

the reference and the downstream or the disturbed sites indicating different disturbance

regime has been compared in terms of assemblage and population dynamics of fish. The

abundance of the fish in all cases was measured in CPUE, which is ‘catch per unit effort’

and the unit effort in this study is the 10 minutes of electrofishing by general wading

method. Here are the results of these comparisons according to the disturbances.

8.4.1. Disturbances due to agriculture:

The three rivers studied for agricultural disturbances, mainly, due to agricultural inputs such

as fertilizers and pesticides include Jhikhukhola in Kavre district, East Rapti in

Makawanpur and Chitwan districts, and Tinau in Palpa district. The details of the amount of

these agricultural inputs have, already, been discussed in earlier chapters. To examine

thoroughly the each case, seasonal variations in impacts have been studied. The results of

the study in each river and in each season are directly presented here. The statistical

significances of this disturbance in Nepalese river will be presented latter.

a) Jhikhukhola:

This river in a broad view showed some differences between two disturbances regime

indicating the potential of this disturbance to affect the integrity of the river system. There

were not much difference between upstream and downstream in terms of the number of the

species, but the composition of the species showed some variations and the total abundance

showed a huge variations. The number of species upstream in reference site was 7 in spring

and the same number of species was present in the downstream or the disturbed site as well

in this season (Fig. 8.4.1 and 8.4.2). Total abundance of fish (CPUE) in upstream was 32

whereas the same was as high as 134.33 in downstream, a big difference. The common

species between the two sites in this season were B. barila, C. punctatus, G. annandalei,

and S. beavani but the other three species varied between two sites. D. aequipinnatus, G.

8 Results

-188-

gotyla gotyla and S. rupecula were found only in reference site while B. bendelisis, B. vagra

and H. fossilis were present only in disturbed site.

Total numbers of species in both the sites were more or less similar in premonsoon or

summer season as well at 7 and 6, respectively (Fig.8.4.3 and 8.4.4). During this season, the

total abundance of fish increased in upstream to 48.33 while there was a big slump in

downstream to 71.67, though the downstream abundance was still higher. B bendelisis, and

S rupecula showed up in upstream this season but C. punctatus disappeared. Likewise, B.

bendelisis, B. vagra and S. beavani were absent from downstream while G. gotyla gotyla

and S. rupecula appeared.

The results in autumn season were found remarkably different compared to those two

seasons. Though the total number of species in upstream and downstream remained more or

less constant at 6 and 8, there was a big difference in the abundance of fish (Fig. 8.4.5 and

8.4.6). Surprisingly, the upstream abundance this time was higher than the downstream at

45.5 and 39.5 respectively. Interestingly, the species showed the similar composition in

upstream, the downstream recorded two new species, B. rerio and N. corica. The

disappearance of H. fossilis was another remarkable feature in this season.

The results for winter season in this river once again were similar to spring and

premonsoon. The total number of species in both the sites remained same at 7 (Fig. 8.4.7

and 8.4.8). The abundance of fish is once again in favor of downstream at perhaps highest at

202.72 compared to upstream at 59.28. There is not much difference in the species

composition though the absence of G. annandalei since autumn and reappearance of H.

fossilis was noteworthy.

8 Results

-189-

Fig. 8.4.93: Impact of agriculture


The total yearly differences in the number, composition and abundance of fish species are

shown in fig. 8.4.93 and 8.4.94 between the two sites. There were distinct differences

between upstream and downstream sites in terms of the number of species and the total

abundance in the yearly data. The number of species in upstream all round the year was 8

while in the disturbed site was 12. Similarly, the total yearly abundance of the fish in

upstream was 46.28 while that in the downstream site were more than double at 112.05. In

addition, the difference of the composition of fish species in the assemblage between two

Jhikhukhola upstream in all seasons

0

10

20

30

40

50

60

70

80

Bar

ilius

bar

ila

Baril

ius

bend

elis

is

Bar

ilius

vag

ra

Bra

chyd

anio

rerio

Cha

nna

punc

tatu

s

Dan

ioae

quip

inna

tus

Gar

raan

nand

alei

Gar

ra g

otyl

a

Het

erop

neus

tes

foss

ilis

Nem

ache

ilus

coric

a

Schi

stur

abe

avan

i

Schi

stur

aru

pecu

la

Fish species

Abu

ndan

ce (C


Number of species: 8

Jhikhukhola downstream in all seasons

0

10

20

30

40

50

60

70

80

Bar

ilius

bar

ila

Bar

ilius

bend

elis

is

Bar

ilius

vagr

a

Bra

chyd

anio

rerio

Cha

nna

punc

tatu

s

Dan

ioae

quip

inna

tus

Gar

raan

nand

alei

Gar

ra g

otyl

a

Het

erop

neus

tes

foss

ilis

Nem

ache

ilus

coric

a

Sch

istu

rabe

avan

i

Sch

istu

raru

pecu

la

Fish species

Abu

ndan

ce (C



8 Results

-190-

sites were B. vagra, B. rerio, H. fossilis and N. corica, which were never found in the

reference site throughout the year.

b) East Rapti:

Impact of agriculture in East Rapti River was found to be least in terms of fish species

number and their abundance. In spring season, the total numbers of species present in

upstream and downstream were 16 and 15, respectively (Fig. 8.4.9 and 8.4.10). The total

abundance of fish in this season, too, showed a little difference at 179.80 and 187.17 in

upstream and downstream respectively. However there were some differences in species

composition. G. giuris, G. telchitta and L. guntea were absent in the reference site while B.

shacra, H. fossilis, N. hexagonolepis and T. putitora were absent from the disturbed site.

The remaining fish species were common in the two sites. About half of the total abundance

of fish in downstream was made up of a single species, S. beavani.

The premonsoon season had the similar characteristic in both of the sites except that there

was significant decline in the abundance in the disturbed site. The total numbers of species

in upstream and downstream were found to be 13 and 16 respectively (Fig. 8.4.11 and

8.4.12). Similarly the total abundance was 151.5 and 77.25 on the two sites respectively.

The species missing from the reference site in this season were A. morar, B. shacra, L. dero,

M. armatus and P. conchonius, and those missing from the disturbed site were N.

hexagonolepis and S. richardsonii.

The autumn season was marked by the big drop of fish abundance in upstream site. The

total numbers of species in upstream and downstream site in this season were 13 and 17

respectively (Fig. 8.4.13 and 8.4.14). Similarly the total abundance was 71 and 78.25 on the

two sites respectively. The species missing from the reference site in this season were A.

morar, B. almorhae, B. lohachata, C. latius, G. telchitta, G. trilineatus and L. dero and

those missing from the disturbed site were A. botia, C. orientalis, N. hexagonolepis and S.

richardsonii. The number of species in downstream site in this season is the highest with

some species specialized for low land water.

The winter season was again characterized by high abundance of fish in reference site and

decrease in species number in disturbed site. The total numbers of species in upstream and

downstream site in this season were 13 and 10 respectively (Fig. 8.4.15 and 8.4.16).

8 Results

-191-

Similarly the total abundance was 138.75 and 87.78 on the two sites respectively. The

species missing from the reference site in this season were G. pectinopterus and P.

pseudecheneis and those missing from the disturbed site were A. mangois, B. shacra, M.

armatus, N. hexagonolepis, S. richardsonii and T. putitora. A big number of the species is

missing from downstream site in this season though many of the missing species mentioned

above were missing permanently.



East Rapti upstream in all seasons

05

101520253035

Acan

thoc

obiti

s bo

tiaAm

blyc

eps

man

gois

Aspi

dopa

ria m

orar

Baril

ius

Baril

aBa

riliu

s be

ndel

isis

Baril

ius

shac

raBa

riliu

s va

gra

Botia

alm

orha

eBo

tia lo

hach

ata

Cha

nna

orie

ntal

isC

ross

oche

ilus

latiu

sG

arra

ann

anda

lei

Gar

ra g

otyl

aG

loss

ogob

ius

giur

isG

lypt

otho

rax

pect

inop

teru

sG

lypt

otho

rax

telc

hitta

Gly

ptot

hora

x tri

linea

tus

Het

erop

neus

tes

foss

ilisLa

beo

dero

Lepi

doce

phal

us g

unte

aM

asta

cem

belu

s ar

mat

usN

emac

heilu

s co

rica

Neo

lisso

chilu

s he

xago

nole

Psilo

rhyn

chus

pse

udec

hen

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laSc

hizo

thor

ax ri

char

dson

iiTo

r put

itora

Fish species

Abu

ndan

ce (C

PUE)

Total abundance: 135.26


East Rapti downstream in all seasons

05

101520253035

Acan

thoc

obiti

s bo

tiaAm

blyc

eps

man

gois

Aspi

dopa

ria m

orar

Baril

ius

Baril

aBa

riliu

s be

ndel

isis

Baril

ius

shac

raBa

riliu

s va

gra

Botia

alm

orha

eBo

tia lo

hach

ata

Cha

nna

orie

ntal

isC

ross

oche

ilus

latiu

sG

arra

ann

anda

lei

Gar

ra g

otyl

aG

loss

ogob

ius

giur

isG

lypt

otho

rax

pect

ino.

..G

lypt

otho

rax

telc

hitta

Gly

ptot

hora

x tri

linea

tus

Het

erop

neus

tes

foss

ilisLa

beo

dero

Lepi

doce

phal

us g

unte

aM

asta

cem

belu

s ar

mat

usN

emac

heilu

s co

rica

Neo

lisso

chilu

s he

xago

noPs

ilorh

ynch

us p

seu.

..Pu

ntiu

s co

ncho

nius

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Schi

zoth

orax

rich

ar...

Tor p

utito

ra

Fish species

Abu

ndan

ce (C

PUE)



8 Results

-192-

The total yearly difference in the number, composition and abundance of fish species in this

river is shown in fig. 8.4.95 and 8.4.96. There were some minor differences between

upstream and downstream sites in terms of the number of species and the total abundance in

the yearly data. The number of species in upstream at least once in the year was 19 while in

the disturbed site was more at 25. Similarly, the total yearly abundance of the fish in

upstream was 135.26 while that in the downstream site were slightly less at 107.61. Among

the differences between composition includes species such as A. morar, B. almorhae, B.

lohachata, C. latius, G. giuris, G. pectinopterus, G. telchitta, G. trilineatus, L. dero, L.

guntea, P. pseudecheneis, C. orientalis, H. fossilis, N. hexagonolepis, S. richardsonii and T.

Putitora where the first eleven species were found completely missing from the upstream

while the remaining five were missing from the disturbed site.

c) Tinau:

Tinau River is the last example of the agricultural impact in this study. The number of

species was found to be more or less same in two different sites though the abundance was

quite high in the reference site unlike the agricultural impact on the rivers mentioned above.

In spring the total numbers of the species present in upstream and downstream sites were 14

and 16, respectively (Fig. 8.4.17 and 8.4.18). The total abundance of fish in this season, too,

showed a little difference at 225.94 and 198.25 in upstream and downstream, respectively.

However there were some differences in species composition as A. mangois, G.

pectinopterus, H. fossilis, N. hexagonolepis, P. conchonius and T. putitora were absent in

the reference site while, B. rerio, E. danricus, M. armatus and P. sophore, were absent from

the disturbed site.

The premonsoon season was characterized by a big drop in both the number of species and

the abundance in the downstream site. In this season, the numbers of species present in

upstream and downstream were 11 and 5, respectively (Fig. 8.4.19 and 8.4.20). The total

abundance of fish in this season was found to be 250.36 and just 23.75, respectively. The

species missing from downstream site compared to the reference were B. rerio, C.

punctatus, E. danricus, G. annandalei, M. armatus, P. conchonius and P. sophore.

However, S. rupecula was found in downstream site and not in reference site.

The autumn season marked some recovery in downstream site. The number of species in

this season at reference and disturbed sites were 12 and 10 respectively (Fig. 8.4.21 and

8 Results

-193-

8.4.22). Similarly the total abundance of fish in those sites was found to be 310.39 and 55.9

respectively. The differences in the composition of the species were brought about by A.

mangois, B. vagra, B. rerio, C. punctatus, E. danricus, H. fossilis, M. armatus, N.

hexagonolepis, P. sophore, and T. putitora.


Fig. 8.4.98: Impact of agriculture The winter season was marked by some slump in the abundance of fish in the reference site.

The number of species in this season at reference and disturbed sites were 14 and 11

Tinau upstream in all seasons

0

20

40

60

80

100

120

Acan

thoc

obiti

s bo

tiaAm

blyc

eps

man

gois

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

vagr

aBr

achy

dani

o re

rioC

hann

a or

ient

alis

Cha

nna

punc

tatu

sEs

omus

dan

ricus

Gar

ra a

nnan

dale

iG

arra

got

yla

Gly

ptot

hora

x pe

ctin

opte

rG

lypt

otho

rax

telc

hitta

Het

erop

neus

tes

foss

ilisM

asta

cem

belu

s ar

m...

Neo

lisso

chilu

s he

xa...

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laTo

r put

itora

Fish species

Abu

ndan

ce (C



Tinau downstream in all seasons

020406080

100120

Acan

thoc

obiti

s b.

..Am

blyc

eps

man

...Ba

riliu

s ba

rila

Baril

ius

bend

elis

isBa

riliu

s va

gra

Brac

hyda

nio

rerio

Cha

nna

orie

ntal

isC

hann

a pu

ncta

tus

Esom

us d

anric

usG

arra

ann

anda

lei

Gar

ra g

otyl

aG

lypt

otho

rax

pect

ino

Gly

ptot

hora

x te

lc...

Het

erop

neus

tes

foss

Mas

tace

mbe

lus

arm

Neo

lisso

chilu

s ...

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laTo

r put

itora

Fish species

Abu

ndan

ce (C

PUE)

Total abundance: 83.33Number of species: 18

8 Results

-194-

respectively (Fig. 8.4.23 and 8.4.24). Likewise, the total abundance of fish in those sites in

this season was found to be 200.5 and 55.43 respectively. The differences in composition in

those sites in this season were A. mangois, C. punctatus, E. danricus, G. telchitta, H.

fossilis, M. armatus, N. hexagonolepis, P. conchonius and P. sophore.


river is shown in fig. 8.4.97 and 8.4.98. There were some marked differences between

upstream and downstream sites not in terms of the number of species but in the total

abundance in the yearly data. The number of species in upstream at least once in the year

was 16 while in the disturbed site was more at 18. Similarly, the total yearly abundance of

the fish in upstream was 246.8 while that in the downstream site were much less at 83.33.

Among the differences between compositions includes species such as A. mangois, G.

pectinopterus, G. telchitta, N. hexagonolepis, T. putitora, E. danricus, M. armatus, and P.

sophore, where the first five species were found completely missing from the upstream

while the remaining three were missing from the disturbed site.

8.4.2 Disturbances due to urbanization:

The three rivers studied for disturbances due to urbanization, mainly, due to the haphazard

growth of the cities or the urban centers, include Narayani in Chitwan district, Seti in Kaski

district and Tinau in Butwal district. The three cities, of which the impacts were studied

here, are Narayanghat, Pokhara and Butwal, respectively. The details of the extent of urban

growth and populations of these cities have been already discussed in earlier chapters. To

examine thoroughly the each case, seasonal variations in impacts have been studied. The

results of the study in each river and in each season are directly presented here. The

statistical significances of this disturbance in Nepalese river will be presented latter.

a) Narayani:

Narayani River is one of the largest rivers of Nepal and two types of disturbances,

urbanization and industrialization, were studied in this river. First, the impacts due to the

city are described here. The spring season showed a little difference between the reference

site and the downstream disturbed site in terms of the number of species and the abundance

of the fish. The total numbers of species in upstream and downstream in this season were 14

and 10 respectively (Fig. 8.4.25 and 8.4.26). Similarly the total abundance of fish in these

sites in spring was 37.31 and 47.90 respectively. The differences in the composition

8 Results

-195-

between two sites in this season were the species, B. bendelisis, B. shacra, B. vagra, C.

garua, G. telchitta, M. armatus, P. conchonius and S. richardsonii, which were present in

only one of the either sites.

The premonsoon season showed increase of both the number of species and the abundance

in both of the site with even less differences between the two. The numbers of species in

upstream and downstream site in this season were 20 each in both (Fig. 8.4.27 and 8.4.28).

Similarly, the total abundance of fish in these two sites was 83.11 and 79.25 respectively.

There was a very minute difference in the composition of the species. The upstream site was

lacking A. botia, L. guntea and N. hexagonolepis while the downstream was found missing

of B. rerio, G. telchitta and T. putitora.

The autumn season marked a decrease in the number of fish species and the abundance in

disturbed site. The number of species in reference and the disturbed sites in this season were

17 and 14 respectively (Fig. 8.4.29 and 8.4.30). Similarly, the total abundance of fish in

these two sites was 97.75 and 58.25 respectively in this season. There were few variations

in the species composition. The upstream site was found missing of G. trilineatus only

while the downstream was found missing of B. bendelisis, P. sophore, S. semiplotus and T.

tor.

The winter season showed a substantial decrease in the number of species and the

abundance of fish in both the sites. The numbers of species in the two sites were 10 and 8

respectively in this season (Fig. 8.4.31 and 8.4.32). Similarly, the total abundance of fish in

these two sites was 38.83 and 31.5 respectively. There were some variations in the

composition of the species in two sites. The upstream was found missing of B. bendelisis

and L. guntea compared to downstream while the downstream was found missing of A.

botia, B. vagra, B. almorhae and P. pseudecheneis compared to upstream.


river is shown in fig. 8.4.99 and 8.4.100. There were some small differences between


the yearly data. The number of species in upstream at least once in the year was as high as

28 while in the disturbed site was little less at 23. Similarly, the total yearly abundance of

the fish in upstream was 64.25 while that in the downstream site were again a little less at

8 Results

-196-

54.22. The fish species missing in the reference site compared to disturbed site included G.

trilineatus only while the species missing in disturbed site compared to reference site

included, B. rerio, C. garua, P. pseudecheneis, S. richardsonii, S. semiplotus and T. tor.

Fig. 8.4.99: Impact of city

Fig. 8.4.100: Impact of city b) Seti:

The river Seti flows through the heart of the city called Pokhara and thus is taken as a good

site for the study of the impacts of urbanization on the river. The spring season is

Narayani downstream in all seasons

02468

101214161820

Acan

thoc

obiti

s bo

tiaAm

blyc

eps

man

gois

Aspi

dopa

ria m

orar

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

shac

raBa

riliu

s va

gra

Botia

alm

orha

eBo

tia lo

hach

ata

Brac

hyda

nio

rerio

Clu

piso

ma

garu

aC

ross

oche

ilus

latiu

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got

yla

Gly

ptot

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x te

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ttaG

lypt

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rax

trilin

e...

Labe

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ceph

alus

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Mas

tace

mbe

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arm

atus

Nem

ache

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coric

aN

eolis

soch

ilus

hexa

gono

Psilo

rhyn

chus

pse

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ntiu

s co

ncho

nius

Punt

ius

soph

ore

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stur

a be

avan

iSc

hist

ura

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cula

Schi

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orax

rich

a...

Sem

iplo

tus

sem

ipl..

.To

r put

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Tor t

or

Fish species

Abu

ndan

ce (C


Number os species: 23

Narayani upstream in all seasons

02468

101214161820

Acan

thoc

obiti

s bo

tiaAm

blyc

eps

man

gois

Aspi

dopa

ria m

orar

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

shac

raBa

riliu

s va

gra

Botia

alm

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tia lo

hach

ata

Brac

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Clu

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ma

garu

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latiu

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Tor t

or

Fish species

Abu

ndan

ce (C



8 Results

-197-

characterized by a relatively better condition in downstream site rather than upstream. The

total numbers of species in upstream and downstream in this season were 10 and 13

respectively (Fig. 8.4.33 and 8.4.34). Similarly the total abundance of fish in these sites in

spring was 50.16 and 62.73 respectively. The species missing in downstream in this season

compared to reference site were B. bendelisis, B. vagra and M. blythii while the missing

ones in the reference site were A. botia, B. rerio, C. orientalis, D. dangila, H. fossilis and P.

conchonius.

The premonsoon season marked the increase of abundance in the reference section though

the number of species declined. The total numbers of species in upstream and downstream

in this season were 7 and 11 respectively (Fig. 8.4.35 and 8.4.36). Similarly the total

abundance of fish in these sites in premonsoon was 79 and 51.67 respectively. The species

missing in downstream in this season compared to reference site was only M. blythii while

the missing ones in the reference site were A. botia, B. rerio, C. orientalis, D. dangila and

N. hexagonolepis.

The autumn season was characterized by the decline in the abundance of fish in upstream

and little increase in downstream with almost the same number of the species. The total

numbers of species in upstream and downstream in this season were 8 and 9 respectively

(Fig. 8.4.37 and 8.4.38). Similarly the total abundance of fish in these sites in autumn was

38.25 and 64.25 respectively. The species missing in downstream in this season compared

to reference site were M. blythii and P. sophore while the missing ones in the reference site

were A. botia, G. gotyla gotyla and S. beavani.

The winter season showed almost similar conditions in both reference and disturbed site

with only minor differences in all fish based parameters. The total numbers of species in

upstream and downstream in this season were 6 and 7 respectively (Fig. 8.4.39 and 8.4.40).

Similarly the total abundance of fish in these sites in winter was 70.25 and 67 respectively.

The species missing this time in downstream compared to reference site were B. barila, and

P. conchonius while the missing ones in the reference site were B. vagra, G. gotyla gotyla

and P. sulcatus.


river is shown in fig. 8.4.101 and 8.4.102. There were some small differences between

8 Results

-198-

Fig. 8.4.101: Impact of the city

Fig. 8.4.102: Impact of the city


the yearly data. The number of species in upstream that showed up at least once in the year

was 13 while in the disturbed site was little higher at 16. Similarly, the total yearly

abundance of the fish in upstream was 59.41 while that in the downstream site were a little

higher at 61.41. The fish species missing in the disturbed site compared to the reference site

included B. bendelisis and M. blythii only while the species missing in reference site

Seti upstream in all seasons

0

5

10

15

20

25

30Ac

anth

ocob

itis

botia

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

vagr

aBr

achy

dani

o re

rioC

hann

a or

ient

alis

Dan

io d

angi

laG

arra

ann

anda

lei

Gar

ra g

otyl

aH

eter

opne

uste

s fo

ssilis

Mye

rsgl

anis

bly

thii

Neo

lisso

chilu

s he

xago

noPs

eude

chen

eis

sulc

atus

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laSc

hizo

thor

aich

thys

...

Fish species

Abu

ndan

ce (C



Seti downstream in all seasons

05

1015

2025

30

Acan

thoc

obiti

s bo

tiaBa

riliu

s ba

rila

Baril

ius

bend

elis

isBa

riliu

s va

gra

Brac

hyda

nio

rerio

Cha

nna

orie

ntal

isD

anio

dan

gila

Gar

ra a

nnan

dale

iG

arra

got

yla

Het

erop

neus

tes

fos.

..M

yers

glan

is b

lyth

iiN

eolis

soch

ilus

he...

Pseu

dech

enei

s su

...Pu

ntiu

s co

ncho

nius

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Schi

zoth

orai

chth

ys p

rog

Fish species

Abu

ndan

ce (C

PUE)



8 Results

-199-

compared to the disturbed site included A. botia, B. rerio, C. orientalis, D. dangila and H.

fossilis.

c) Tinau:

Impact of Butwal city in Tinau River was studied in this work. Spring season showed

tremendous differences between the reference and the disturbed site in this river in terms of

both the number of species and the total abundance. The total numbers of species in

upstream and downstream in this season were 14 and 7 respectively (Fig. 8.4.41 and

8.4.42). Similarly the total abundance of fish in these sites in spring was 184.54 and 54.1

respectively. The species missing in downstream in this season compared to reference site

were B. barila, B. lohachata, B. rerio, G. gotyla gotyla, G. pectinopterus, N. hexagonolepis

and T. putitora while the missing ones in the reference site were none.

The premonsoon season was marked by a huge decrease in both the number of species and

the total abundance particularly in the upstream site. The total numbers of species in

upstream and downstream in this season were 5 in each respectively (Fig. 8.4.43 and

8.4.44). Similarly the total abundance of fish in these sites in premonsoon was 18.75 and

39.75 respectively. The species missing in downstream in this season compared to reference

site included just one species, S. rupecula; likewise, the missing one in the reference site too

was just a one species L. guntea.

The autumn season showed a good recovery both in terms of the number of species and the

total abundance particularly in the upstream site. The total numbers of species in upstream

and downstream in this season were 13 and 12 respectively (Fig. 8.4.45 and 8.4.46).

Similarly the total abundance of fish in these sites in autumn was 107.5 and 40.5

respectively. The species missing in downstream in this season compared to reference site

were C. latius, G. telchitta, N. corica, N. hexagonolepis, and P. sulcatus while the missing

ones in the reference site were B. barila, B. bendelisis, C. punctatus and M. armatus.

The winter season again marked the decline of the abundance and to some extent the

species as well. The total numbers of species in upstream and downstream in this season

were 12 and 5 respectively (Fig. 8.4.47 and 8.4.48). Similarly the total abundance of fish in

these sites in winter was 73 and 27.5 respectively. The species missing in downstream in

this season compared to reference site were B. vagra, B. rerio, C. latius, L. dero, M.

8 Results

-200-

armatus, L. guntea, N. hexagonolepis and P. sophore, while the missing one in the reference

site was a single species, B. barila.

Fig. 8.4.103. Impact of the city

Fig. 8.4.104 Impact of the city


river is shown in fig. 8.4.103 and 8.4.104. There were considerable differences between




05

10152025303540455055

Acan

thoc

obiti

s bo

tiaBa

riliu

s ba

rila

Baril

ius

bend

elis

isBa

riliu

s va

gra

Botia

loha

chat

aBr

achy

dani

o re

rioC

hann

a pu

ncta

tus

Cro

ssoc

heilu

s la

tius

Gar

ra g

otyl

aG

lypt

otho

rax

pect

ino.

..G

lypt

otho

rax

telc

hitta

Labe

o de

roLe

pido

ceph

alus

gun

tea

Mas

tace

mbe

lus

arm

atus

Nem

ache

ilus

coric

aN

eolis

soch

ilus

hexa

gono

Pseu

dech

enei

s su

lc...

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laTo

r put

itora

Fish species

Abu

ndan

ce (C

PUE)




05

10152025303540455055

Acan

thoc

obiti

s bo

tiaBa

riliu

s ba

rila

Baril

ius

bend

elis

isBa

riliu

s va

gra

Botia

loha

chat

aBr

achy

dani

o re

rioC

hann

a pu

ncta

tus

Cro

ssoc

heilu

s la

tius

Gar

ra g

otyl

aG

lypt

otho

rax

pect

ino.

..G

lypt

otho

rax

telc

hitta

Labe

o de

roLe

pido

ceph

alus

gun

tea

Mas

tace

mbe

lus

arm

atus

Nem

ache

ilus

coric

aN

eolis

soch

ilus

hexa

gono

Pseu

dech

enei

s su

lc...

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laTo

r put

itora

Fish species

Abu

ndan

ce (C



8 Results

-201-

was 21 while in the disturbed site was comparably low at 13. Similarly, the total yearly

abundance of the fish in upstream was 95.96 while that in the downstream site was less than

half at 40.46. The composition of the assemblage too showed some differences in the two

sites. The fish species missing in the disturbed site compared to the reference site included

B. rerio, C. latius, G. pectinopterus, G. telchitta, L. dero, N. corica, N. hexagonolepis, P.

sulcatus and T. putitora, while the species missing in reference site compared to the

disturbed site included a single species, C. punctatus.

8.4.3 Disturbances due to dams:

The three rivers studied for disturbances due to the construction of dams and weirs include

Aandhikhola in Syangja district, Bagmati in Kathmandu district and Tinau in Palpa district.

The technical and other details of the dams constructed on these rivers have been already

discussed in earlier chapters. To examine thoroughly the each case, here too, seasonal

variations, in impacts, have been studied. The results of the study in each river and in each

season are directly presented here. The statistical significances of this disturbance in

Nepalese river will also be presented latter.

a) Aandhikhola:

Impact of the dam constructed for the 5 MW Aandhikhola Hydro Electricity Project on the

river Aandhikhola was studied in this work. In spring season there were very few

differences in the number of species and the total abundance of the fish in upstream

reference site and the downstream disturbed site. The total numbers of species in upstream

and downstream in this season were 11 and 13 respectively (Fig. 8.4.49 and 8.4.50).

Similarly the total abundance of fish in these sites in spring was 84.02 and 75.98

respectively. However, there were some differences in the species composition. The fish

species missing in the disturbed site compared to the reference site included B. vagra and N.

chelynoides while the species missing in reference site compared to the disturbed site

included B. rerio, H. fossilis, S. semiplotus and T. putitora.

Premonsoon season marked the decrease in the both number of species and the abundance

in the reference site but the downstream rather improved. The total numbers of species in

upstream and downstream in this season were 9 and 12 respectively (Fig. 8.4.51 and

8.4.52). Similarly the total abundance of fish in these sites in premonsoon was 47.39 and

123 respectively. The fish species missing in the disturbed site compared to the reference

8 Results

-202-

site included just a single species, T. putitora, while the species missing in reference site

compared to the disturbed site included B. bendelisis, N. corica, P. chola and S.

richardsonii.

The autumn characterized the unfavorable condition particularly in the downstream as

shown by the abundance and the number of species. The total numbers of species in

upstream and downstream in this season were 9 and 6 respectively (Fig. 8.4.53 and 8.4.54).

Similarly the total abundance of fish in these sites in autumn was 46.25 and 42 respectively.

The fish species missing in the disturbed site compared to the reference site included B.

barila, C. punctatus, G. annandalei and N. hexagonolepis, while the species missing in

reference site compared to the disturbed site included just a single species, S. richardsonii.

The winter season showed an improvement in both the site particularly in terms of the

abundance of fish. The total numbers of species in upstream and downstream in this season

were 9 and 8 respectively (Fig. 8.4.55 and 8.4.56). Similarly the total abundance of fish in

these sites in winter was 71 and 85.5 respectively. The fish species missing in the disturbed

site compared to the reference site included B. bendelisis and S. richardsonii, while the

species missing in reference site compared to the disturbed site included just a single

species and this time, T. putitora.


river is shown in fig. 8.4.105 and 8.4.106. There were some differences between upstream

and downstream sites in terms of the number of species and the total abundance in the

yearly data and was in favor of downstream. The number of species in upstream that

showed up at least once in the year was 12 while in the disturbed site was comparably high

at 16. Similarly, the total yearly abundance of the fish in upstream was 62.16 while that in

the downstream site was more than that at 81.62. The composition of the assemblage too

showed some differences in the two sites. The fish species missing in the disturbed site

compared to the reference site included C. punctatus and N. chelynoides, while the species

missing in reference site compared to the disturbed site included B. rerio, H. fossilis, N.

corica, P. conchonius and S. semiplotus.

8 Results

-203-

Fig. 8.4.105 Impact of dam


b) Bagmati:

The study made in this river was at Sundarijal in Kathmandu where the river is disrupted by

one of the oldest dam construction in the country. There was just one dominating species in

both upstream and a downstream site in this river and thus, the differences between the sites

is in just the abundance of that species. In spring, just 1 species, S. richardsonii was

recorded on the either side of the dam. The abundance of the species in upstream was 36.76

while that in the disturbed site was just 15.29 (Fig.8.4.57 and 8.4.58). In premonsoon, 1

Aandhikhola upstream in all seasons

05

1015202530

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

vagr

aBr

achy

dani

o re

rioC

hann

a pu

ncta

tus

Gar

ra a

nnan

dale

iG

arra

got

yla

Het

erop

neus

tes

foss

ilisM

asta

cem

belu

s ar

...N

aziri

tor c

hely

noid

esN

emac

heilu

s co

rica

Neo

lisso

chilu

s he

xago

nPu

ntiu

s ch

ola

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Schi

zoth

orax

rich

ards

onSe

mip

lotu

s se

mip

lotu

sTo

r put

itora

Fish species

Abu

ndan

ce (C



Aandhikhola downstream in all seasons

05

1015202530

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

vagr

aBr

achy

dani

o re

rioC

hann

a pu

ncta

tus

Gar

ra a

nnan

dale

iG

arra

got

yla

Het

erop

neus

tes

foss

ilisM

asta

cem

belu

s ar

m...

Naz

irito

r che

lyno

ides

Nem

ache

ilus

coric

aN

eolis

soch

ilus

hexa

...Pu

ntiu

s ch

ola

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Schi

zoth

orax

rich

ard.

..Se

mip

lotu

s se

mip

lotu

sTo

r put

itora

Fish species

Abu

ndan

ce (C



8 Results

-204-

more species S. beavani was recorded on both the site, but the abundance of fish in

upstream declined considerably. Thus, there were 2 species on both the sites in this season

with the total abundance of 21.8 and 20.95 in upstream and downstream respectively

(Fig.8.4.59 and 8.4.60).


Fig. 8.4.108 Impact of dam In autumn 1 different species, S. rupecula showed up in the reference site whereas the

downstream site was left with just the same dominant species, S. richardsonii (Fig.8.4.61

Bagmati upstream in all seasons

0

10

20

30

40

50

60

Schistura beavani Schistura rupecula Schizothorax richardsonii

Fish species

Abu

ndan

ce (C

PUE)



Bagmati downstream in all seasons

0

10

20

30

40

50

60

Schistura beavani Schistura rupecula Schizothorax richardsonii

Fish species

Abu

ndan

ce (C

PUE)



8 Results

-205-

and 8.4.62). The total abundance of fish in this season in upstream too increased to 43. 47,

but the abundance in the disturbed site was one of the lowest of the entire study at 2.32. In

winter season, both the upstream and downstream site was with only the same single

dominant species but the abundance particularly in the upstream was highest of all the

season (Fig.8.4.63 and 8.4.64). The abundance of fish in this season was 97.75 and 6.5 in

upstream and downstream respectively.


river is shown in fig. 8.4.107 and 8.4.108. There were not many differences between

upstream and downstream sites in terms of the number of species but the total abundance in

the yearly data showed significant differences and was in favor of upstream. The number of

species in upstream that showed up at least once in the year was 3 while in the disturbed site

was 2. Similarly, the total yearly abundance of the fish in upstream was 49.95 while that in

the downstream site were much less at 11.26. The composition of the assemblage did not

show much difference in the two sites. The fish species missing in the disturbed site

compared to the reference site was just a single species S. rupecula.

c) Tinau:

This river too holds one of the very old dams under Tinau Small Hydropower Project and

the impact of this dam is studied in this work. In spring season there were no differences in

the number of species and few in the total abundance of the fish in upstream reference site

and the downstream disturbed site. The total numbers of species in upstream and

downstream in this season were 12 each (Fig. 8.4.65 and 8.4.66). Similarly the total

abundance of fish in these sites in spring was 74.17 and 89.28 respectively. However, there

were some differences in the species composition. The fish species missing in the disturbed

site compared to the reference site included N. hexagonolepis and T. putitora while the

species missing in reference site compared to the disturbed site included B. barila, B. rerio

and M. armatus.

The premonsoon characterized a huge drop in both the species number and the abundance

of fish on either side of the dam. The total numbers of species in upstream and downstream

in this season were 6 and 3 respectively (Fig.8.4.67 and 8.4.68). Similarly the total

abundance of fish in these sites in premonsoon was 13.32 and 38.5 respectively. There were

minor differences in the species composition. The fish species missing in the disturbed site

8 Results

-206-

compared to the reference site included G. gotyla gotyla, N. hexagonolepis, S. rupecula and

T putitora, while the species missing in reference site compared to the disturbed site

included P. sophore only.

The autumn season marked a good recovery in both the number of species and the

abundance of fish on either side of the dam. The total numbers of species in upstream and

downstream in this season were 10 and 9 respectively (Fig.8.4.69 and 8.4.70). Similarly the

total abundance of fish in these sites in autumn was 61.91 and 54.23 respectively. There

were some differences in the species composition. The fish species missing in the disturbed

site compared to the reference site included B. barila, N. hexagonolepis and T. putitora,

while the species missing in reference site compared to the disturbed site included G.

trilineatus and L. dero.

The winter season showed difficult conditions for the fish particularly in the upstream of the

dam as was shown by their abundance and composition. The total numbers of species in

upstream and downstream in this season were 7 and 9 respectively (Fig.8.4.71 and 8.4.72).

Similarly the total abundance of fish in these sites in winter was 28.25 and 77.02

respectively. There were some differences in the species composition as well. The fish

species missing in the disturbed site compared to the reference site included P. conchonius

and T. putitora, while the species missing in reference site compared to the disturbed site

included B. vagra, B. lohachata, L. dero and P. sophore.


river is shown in fig. 8.4.109 and 8.4.110. There were some differences between upstream

and downstream sites in terms of the number of species and the total abundance in the

yearly data and was in slightly favor of downstream. The number of species in upstream

that showed up at least once in the year was 15 while in the disturbed site was comparably

high at 17. Similarly, the total yearly abundance of the fish in upstream was 44.41 while

that in the downstream site was more than that at 64.76. The composition of the assemblage

too showed some differences in the two sites. The fish species missing in the disturbed site

compared to the reference site included T. putitora and T. tor, while the species missing in

reference site compared to the disturbed site included B. lohachata, B. rerio, L. dero, and

M. armatus.

8 Results

-207-


Fig.8.4.110 Impact of dam


05

101520253035

Acan

thoc

obiti

s bo

tiaBa

riliu

s ba

rila

Baril

ius

bend

elis

isBa

riliu

s va

gra

Botia

loha

chat

aBr

achy

dani

o re

rioG

arra

got

yla

Gly

ptot

hora

x te

lchi

ttaG

lypt

otho

rax

trilin

e...

Labe

o de

roM

asta

cem

belu

s ar

mat

usN

eolis

soch

ilus

hexa

gono

Pseu

dech

enei

s su

lcat

usPu

ntiu

s co

ncho

nius

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Tor p

utito

ra

Tor t

or

Fish species

Abu

ndan

ce (C

PUE)




05

101520253035

Acan

thoc

obiti

s bo

tiaBa

riliu

s ba

rila

Baril

ius

bend

elis

isBa

riliu

s va

gra

Botia

loha

chat

aBr

achy

dani

o re

rioG

arra

got

yla

Gly

ptot

hora

x te

lchi

ttaG

lypt

otho

rax

trilin

eatu

sLa

beo

dero

Mas

tace

mbe

lus

a...

Neo

lisso

chilu

s he

...Ps

eude

chen

eis

su...

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laTo

r put

itora

Tor t

or

Fish species

Abu

ndan

ce (C



8 Results

-208-

8.4.4 Disturbances due to industries:

The three rivers studied for disturbances due to the industries include Arungkhola in

Nawalparasi district, Karrakhola in Makawanpur district and Narayani in Chitwan and

Nawalparasi districts. The technical and other details of the industries on the bank of these

rivers have been already discussed in earlier chapters. To examine thoroughly the each case,

here too, seasonal variations in impacts, have been studied. The results of the study in each

river and in each season are directly presented here. The statistical significances of this

disturbance in Nepalese rivers will also be presented latter.

a) Arungkhola:

This river holds one of the important distilleries called ‘Shree Distillery’ on its bank and the

present work studied the impact of this industry on this river. The spring season showed big

differences between reference and disturbed site particularly in terms of the abundance of

fish. The total numbers of species in upstream and downstream in this season were 16 and

13 respectively (Fig.8.4.73 and 8.4.74). Similarly, the total abundance of fish in these sites

in spring was 129.85 and 39.93 respectively. There were some minor differences in the

species composition as well. The fish species missing in the disturbed site compared to the

reference site included A. mangois, B. shacra and E danricus, while the species missing in

reference site compared to the disturbed site were none.

The premonsoon season was characterized by a big jump in the abundance of fish in

downstream site particularly by a single species, S. beavani. The total numbers of species in

upstream and downstream in this season were 15 and 14 respectively (Fig.8.4.75 and

8.4.76). Similarly, the total abundance of fish in these sites in premonsoon was 82.25 and

126.25 respectively. There were some minor differences in the species composition as well.


rerio and M. pancalus, while the species missing in reference site compared to the disturbed

site was just one, B. bendelisis.

The autumn marked the decline in the abundance of fish in both the site, however there was

a considerable increase in the number of species in the reference site. The total numbers of

species in upstream and downstream in this season were 21 and 14, respectively (Fig.8.4.77

and 8.4.78). Similarly, the total abundance of fish in these sites in autumn was 50.5 and 32

respectively. There were considerable differences in the species composition in this season.

8 Results

-209-


rerio, C. latius, L. dero, L. guntea, M. pancalus, M. blythii, S. semiplotus and T. putitora,

while the species missing in reference site compared to the disturbed site was just one S.

rupecula.

The winter season was characterized by the high abundance of fish in both the sites as well

as by a highest number of species. The total numbers of species in upstream and

downstream in this season were 22 and 19, respectively (Fig.8.4.79 and 8.4.80). Similarly,

the total abundance of fish in these sites in winter was 128.25 and 179.75, respectively.

There were some differences in the species composition in this season as well. The fish

species missing in the disturbed site compared to the reference site included D.

aequipinnatus, L. dero, M. pancalus and S. semiplotus, while the species missing in

reference site compared to the disturbed site included P. sulcatus only.


river is shown in fig. 8.4.111 and 8.4.112. There were not any substantial differences


abundance in the yearly data and was slightly in favor of upstream. The number of species

in upstream that showed up at least once in the year was 26 while in the disturbed site was a

little less at 20. Similarly, the total yearly abundance of the fish in upstream was 97.71

while that in the downstream site were marginally less at 94.48. The composition of the

assemblage however, showed some differences in the two sites. The fish species missing in

the disturbed site compared to the reference site included B. shacra, C. latius, D.

aequipinnatus, L. dero, M. pancalus, M. blythii and S. semiplotus, while the species missing

in reference site compared to the disturbed site included just a single species, P. sulcatus.

8 Results

-210-

Fig.8.4.111 Impact of industry

Fig. 8.4.112 Impact of industry b) Karrakhola:

The river receives all the effluent from the most important industrial district; ‘Hetauda

Industrial District’ of the country in Hetauda and thus, the impacts of industries in this river

were studied here. In spring season, there was a big difference in the abundance of fish

between upstream and downstream sites but in terms of the number of species the two sites

were almost same. The total numbers of species in upstream and downstream in this season

Arungkhola downstream in all seasons

0

10

20

30

40

50

60

Acan

thoc

obiti

s bo

tiaAm

blyc

eps

man

gois

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

shac

raBa

riliu

s va

gra

Botia

loha

chat

aBr

achy

dani

o re

rioC

hann

a or

ient

alis

Cha

nna

punc

tatu

sC

ross

oche

ilus

latiu

sD

anio

aeq

uipi

nnat

usEs

omus

dan

ricus

Gar

ra a

nnan

dale

iG

arra

got

yla

Labe

o de

roLe

pido

ceph

alus

gun

tea

Mac

rogn

athu

s pa

ncal

usM

asta

cem

belu

s ar

mat

usM

yers

glan

is b

lyth

iiPs

eude

chen

eis

sulc

atus

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laSe

mip

lotu

s se

mip

lotu

sTo

r put

itora

Fish species

Abu

ndan

ce (C



Arungkhola upstream in all seasons

0

10

20

30

40

50

60Ac

anth

ocob

itis

botia

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

bend

elis

isBa

riliu

s sh

acra

Baril

ius

vagr

aBo

tia lo

hach

ata

Brac

hyda

nio

rerio

Cha

nna

orie

ntal

isC

hann

a pu

ncta

tus

Cro

ssoc

heilu

s la

tius

Dan

io a

equi

pinn

atus

Esom

us d

anric

usG

arra

ann

anda

lei

Gar

ra g

otyl

aLa

beo

dero

Lepi

doce

phal

us g

unte

aM

acro

gnat

hus

panc

alus

Mas

tace

mbe

lus

arm

atus

Mye

rsgl

anis

bly

thii

Pseu

dech

enei

s su

lcat

usPu

ntiu

s co

ncho

nius

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Sem

iplo

tus

sem

iplo

tus

Tor p

utito

ra

Fish species

Abu

ndan

ce (C



8 Results

-211-

were 16 and 17, respectively (Fig.8.4.81 and 8.4.82). Similarly, the total abundance of fish

in these sites in spring was 112.77 and 62.25, respectively. There were some minor

differences in the species composition as well. The fish species missing in the disturbed site

compared to the reference site included B. vagra and C. punctatus, while the species

missing in reference site compared to the disturbed site were G. chapra, N. hexagonolepis

and P. conchonius.

The season premonsoon was characterized by the reverse trend in the abundance of fish

compared to spring between the two sites as well as the absence of few species. The total

numbers of species in upstream and downstream in this season were 13 and 15 respectively

(Fig.8.4.83 and 8.4.84). Similarly the total abundance of fish in these sites in premonsoon

was 82.25 and 128.75, respectively. There were some minor differences in the species

composition as well. The fish species missing in the disturbed site compared to the

reference site included P. sulcatus only while the species missing in reference site compared

to the disturbed site were B. rerio, C. orientalis and M. armatus.

The autumn season indicated favorable conditions in both the sites in terms of abundance as

well as the number of species. The total numbers of species in upstream and downstream in

this season were 17 and 16, respectively (Fig.8.4.85 and 8.4.86). Similarly the total

abundance of fish in these sites in autumn was 146.78 and 118 respectively. There were

some minor differences in the species composition as well. The fish species missing in the

disturbed site compared to the reference site included B. bendelisis, C. punctatus and E.

danricus, while the species missing in reference site compared to the disturbed site were C.

reba and N. corica.

In winter, the abundance of fish in upstream remained more or less constant but in disturbed

site there was a decreasing trend. The total numbers of species in upstream and downstream

in this season were 16 and 13, respectively (Fig.8.4.87 and 8.4.88). Similarly the total

abundance of fish in these sites in winter was 139 and 88.5, respectively. There were again

some minor differences in the species composition. The fish species missing in the

disturbed site compared to the reference site included B. barna, C. punctatus and M.

armatus, while the species missing in reference site compared to the disturbed site were

none.

8 Results

-212-

Fig. 8.4.113 Impact of industry



river is shown in fig. 8.4.113 and 8.4.114. There were not any substantial differences


abundance in the yearly data. The number of species in upstream that showed up at least

Karrakhola upstream in all seasons

0

5

10

15

20

25

30Ac

anth

ocob

itis

botia

Ambl

ycep

s m

ango

isBa

riliu

s ba

rila

Baril

ius

barn

aBa

riliu

s be

ndel

isis

Baril

ius

vagr

aBr

achy

dani

o re

rioC

hann

a or

ient

alis

Cha

nna

punc

tatu

sC

irrhi

nus

reba

Esom

us d

anric

usG

arra

ann

anda

lei

Gar

ra g

otyl

aG

udus

ia c

hapr

aH

eter

opne

uste

s fo

ssilis

Lepi

doce

phal

us g

unte

aM

asta

cem

belu

s ar

mat

usN

emac

heilu

s co

rica

Neo

lisso

chilu

s he

xago

nole

Pseu

dech

enei

s su

lcat

usPu

ntiu

s ch

ola

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

la

Fish species

Abu

ndan

ce (C



Karrakhola downstream in all season

0

5

10

15

20

25

30

Acan

thoc

obiti

s bo

tiaAm

blyc

eps

man

gois

Baril

ius

baril

aBa

riliu

s ba

rna

Baril

ius

bend

elis

isBa

riliu

s va

gra

Brac

hyda

nio

rerio

Cha

nna

orie

ntal

isC

hann

a pu

ncta

tus

Cirr

hinu

s re

baEs

omus

dan

ricus

Gar

ra a

nnan

dale

iG

arra

got

yla

Gud

usia

cha

pra

Het

erop

neus

tes

foss

ilisLe

pido

ceph

alus

gun

tea

Mas

tace

mbe

lus

arm

atus

Nem

ache

ilus

coric

aN

eolis

soch

ilus

hexa

gono

lePs

eude

chen

eis

sulc

atus

Punt

ius

chol

aPu

ntiu

s co

ncho

nius

Punt

ius

soph

ore

Schi

stur

a be

avan

iSc

hist

ura

rupe

cula

Fish species

Abu

ndan

ce (C



8 Results

-213-

once in the year was 21 while in the disturbed site it was 21 too. Similarly, the total yearly

abundance of the fish in upstream was 120.2 while that in the downstream site were

marginally less at 100.12. The composition of the assemblage however, showed some

differences in the two sites. The fish species missing in the disturbed site compared to the

reference site included B. barna, C. punctatus, E. danricus and P. sulcatus while the species

missing in reference site compared to the disturbed site included C. reba, G. chapra, N.

corica and P. conchonius.

c) Narayani:

There is a big industry called Bhrikuti Pulp and Paper Mill on the bank of Narayani River at

Gaindakot in Nawalparasi district. The factory not only depends on the river for its entire

water requirement but also discharges its effluents in the same river. The impact of this

industry in the river was studied here in this work. The impact of the industry was quite

visible in spring season as there was a big difference in the abundance of fish and the

species richness between upstream reference site and downstream disturbed sites. The total

numbers of species in upstream and downstream in this season were 14 and 8, respectively

(Fig.8.4.25 and 8.4.89). Similarly, the total abundance of fish in these sites in spring was

37.31 and 18.33 respectively. There were also considerable differences in the species


reference site included B. bendelisis, B. shacra, B. vagra, B. lohachata, G. gotyla gotyla, G.

telchitta, N. hexagonolepis, S. rupecula, S. richardsonii and T. putitora while the species

missing in reference site compared to the disturbed site were B. rerio, M. armatus, P.

conchonius and P. sophore.

The premonsoon season also showed a big difference between upstream and downstream

site though there was a good increase in the abundance of fish in both the sites. The total

numbers of species in upstream and downstream in this season were 20 and 8, respectively

(Fig.8.4.27 and 8.4.90). Similarly, the total abundance of fish in these sites in premonsoon

was 83.11 and 35.33, respectively. There were also tremendous differences in the species


reference site included A. mangois, B. bendelisis, B. shacra, B. vagra, B. almorhae, B.

lohachata, B. rerio, C. latius, G. gotyla gotyla, G. telchitta, L. dero, M. armatus, N. corica,

S. beavani, S. rupecula and T. putitora while the species missing in reference site compared

to the disturbed site were C. orientalis, C. punctatus, L. guntea and N. hexagonolepis.

8 Results

-214-

The autumn season marked some increase in the species number in the disturbed site but as

before there were noticeable differences between the two sites yet again. The total numbers

of species in upstream and downstream in this season were 17 and 11, respectively

(Fig.8.4.29 and 8.4.91). Similarly the total abundance of fish in these sites in autumn was

97.75 and 20.83, respectively. There were good differences in the species composition as

well. The fish species missing in the disturbed site compared to the reference site included

B. bendelisis, B. vagra, C. latius, G. gotyla gotyla, G. telchitta, L. dero, L. guntea, S.

beavani, S. semiplotus and T. tor while the species missing in reference site compared to the

disturbed site were B. barila, B. rerio, C. punctatus and G. giuris.

The winter season was found to show the least impact of the industry mainly due to a huge

drop in the abundance as well as in the number of species in the reference site and not

because of the improvement in the disturbed site. The total numbers of species in upstream

and downstream in this season were 10 each in both (Fig.8.4.31 and 8.4.92). Similarly, the

total abundance of fish in these sites in winter was 38.83 and 19.75, respectively. However,

there were some differences in the species composition. The fish species missing in the

disturbed site compared to the reference site included A. botia, B. bendelisis, G. gotyla

gotyla, M. armatus, N. corica, P. pseudecheneis, S. beavani and S. rupecula while the

species missing in reference site compared to the disturbed site were A. mangois, B. barila,

C. punctatus, L. guntea, N. hexagonolepis P. conchonius and S. richardsonii.


river is shown in fig. 8.4.115 and 8.4.116. There were substantial differences between



was 28 while in the disturbed site it was 21. Similarly, the total yearly abundance of the fish

in upstream was 64.25 while that in the downstream site were much less at 23.56. The

composition of the assemblage too showed some differences in the two sites. The fish

species missing in the disturbed site compared to the reference site included B. bendelisis,

B. shacra, C. latius, G. gotyla gotyla, G. telchitta, L. dero, P. pseudecheneis, S. semiplotus,

T. putitora and T. tor while the species missing in reference site compared to the disturbed

site included C. orientalis, C. punctatus and G. giuris.

8 Results

-215-



Narayani upstream in all seasons

02468

101214161820

Acan

thoc

obiti

s bo

tiaAm

blyc

eps

man

gois

Aspi

dopa

ria m

orar

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

shac

raBa

riliu

s va

gra

Botia

alm

orha

eBo

tia lo

hach

ata

Brac

hyda

nio

rerio

Cha

nna

orie

ntal

isC

hann

a pu

ncta

tus

Clu

piso

ma

garu

aC

ross

oche

ilus

latiu

sG

arra

got

yla

Glo

ssog

obiu

s gi

uris

Gly

ptot

hora

x te

lchi

ttaLa

beo

dero

Lepi

doce

phal

us g

unte

aM

asta

cem

belu

s ar

mat

usN

emac

heilu

s co

rica

Neo

lisso

chilu

s he

xago

nole

Psilo

rhyn

chus

pse

udec

hen

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laSc

hizo

thor

ax ri

char

dson

iiSe

mip

lotu

s se

mip

lotu

sTo

r put

itora

Tor t

or

Fish species

Abu

ndan

ce (C



Narayani downstream in all seasons

02468

101214161820

Acan

thoc

obiti

s bo

tiaAm

blyc

eps

man

gois

Aspi

dopa

ria m

orar

Baril

ius

baril

aBa

riliu

s be

ndel

isis

Baril

ius

shac

raBa

riliu

s va

gra

Botia

alm

orha

eBo

tia lo

hach

ata

Brac

hyda

nio

rerio

Cha

nna

orie

ntal

isC

hann

a pu

ncta

tus

Clu

piso

ma

garu

aC

ross

oche

ilus

latiu

sG

arra

got

yla

Glo

ssog

obiu

s gi

uris

Gly

ptot

hora

x te

lchi

ttaLa

beo

dero

Lepi

doce

phal

us g

unte

aM

asta

cem

belu

s ar

mat

usN

emac

heilu

s co

rica

Neo

lisso

chilu

s he

xago

nole

Psilo

rhyn

chus

pse

udec

hen

Punt

ius

conc

honi

usPu

ntiu

s so

phor

eSc

hist

ura

beav

ani

Schi

stur

a ru

pecu

laSc

hizo

thor

ax ri

char

dson

iiSe

mip

lotu

s se

mip

lotu

sTo

r put

itora

Tor t

or

Fish species

Abu

ndan

ce (C



8 Results

-216-

8.5 Statistical verifications:

There were some differences in fish assemblage and abundance as was evident from broad

and general overlook between upstream and downstream or the reference and disturbed sites

indicating that the fish population dynamics could be a good indicator of the different

disturbance regimes. However, the statistical backing is helpful and necessary to draw any

conclusions regarding the impacts of different kinds of disturbances in rivers and streams.

This study too was involved in an extensive statistical analysis to check which and where

the impacts are significant to help draw the conclusions. Two variables, ‘sum of CPUE

(abundance)’ and the ‘number of species’ were identified as the important variables. All

statistical analysis was done using SPSS and MS EXCEL programs.

The first thing done in the statistical analysis of the data was to create ‘box plots’ of the

data. The box plots not only gives the full dimension of all the data acquired in this work

but also gives a good glimpse of variations of the data in terms of above mentioned

variables to compare the conditions in each rivers studied for all the impacts and that too in

all the seasons. It shows maximum, minimum and median values of the variable as well as

25 –75 percent values which are lodged in the box. In addition it also shows the extreme

values of the variables as out-liers. First, two separate box plots were made one each of all

the impacts in all seasons for sum of CPUE and the total number of species. Latter, they

were splitted to represent the impacts for each season to see which season has the highest

impacts of each disturbance, which were studied. In addition, separate tables were made for

each box plots to describe the data.

The fig.8.5.1 describes the abundance of fish in both upstream and downstream sites for all

the impacts studied in all the seasons (Table 8.5.1). The figure showed that there is a

significant difference between upstream and downstream in industrially disturbed sites in

terms of the abundance of fish. There were some differences in agricultural sites, whereas

very little differences on the impacts of dam and city. Similarly, fig.8.5.2 describes the total

number of fish species in both upstream and downstream sites for all the impacts studied in

all the seasons (Table 8.5.2). This figure also showed some impacts due to industries and

agriculture in the rivers studied, while very little differences were found between upstream

and downstream for the impacts of city and dam.

8 Results

-217-

The fig.8.5.3 describes the abundance of fish in both upstream and downstream sites for the

agricultural impacts in all the seasons studied in this work (Table 8.5.3). The figure showed

a considerable difference in the total abundance and median between upstream and

downstream particularly in autumn and premonsoon season, while in other seasons the

differences were comparatively low. Similarly, fig.8.5.4 describes the total number of fish

species in both upstream and downstream sites for the agricultural impacts in all the seasons

studied in this work (Table 8.5.4). The figure showed a considerable difference in number

of fish species between upstream and downstream in premonsoon and winter seasons.


impacts due to city in all the seasons studied in this work (Table 8.5.5). The figure showed

some differences in median between upstream and downstream in all seasons except in

spring where, though, there was a big difference in the maximum value. Similarly, fig.8.5.6

describes the total number of fish species in both upstream and downstream sites for the

impacts due to city in all the seasons studied in this work (Table 8.5.6). The figure showed a

considerable difference in number of fish species between upstream and downstream in

spring and premonsoon seasons compare to others.


impacts due to dam in all the seasons studied in this work (Table 8.5.7). The figure showed

considerable differences in median between upstream and downstream in premonsoon while

the impacts on other seasons were less. Similarly, fig.8.5.8 describes the total number of

fish species in both upstream and downstream sites for the impacts due to dam in all the

seasons studied in this work (Table 8.5.8). The figure showed some differences in number

of fish species between upstream and downstream in premonsoon and autumn seasons

compared to others.


impacts due to industries in all the seasons studied in this work (Table 8.5.9). The figure

showed considerable differences in median between upstream and downstream in all

seasons indicating that the industries might be a big disturbance to the river ecology.

8 Results

-218-

agriculture city dam industry

cd_impact

0,00

100,00

200,00

300,00

sum

CPU

E

57

58

cd_placeupstreamdownstream

Fig. 8.5.1: Abundance of fish (CPUE) in all impacts in all seasons

agriculture city dam industry

cd_impact

0

5

10

15

20

Num

berf

ishs

peci

es

64


Fig. 8.5.2: Number of species in all impacts in all seasons

8 Results

-219-

spring premonsoon autumn winter

cd_season

0

50

100

150

200

250

300

350

sum

CPU

E

31


impact: agriculture

Fig. 8.5.3: Abundance of fish (CPUE) in agricultural impacts


cd_season

0

2

4

6

8

10

12

14

16

18

20

Num

berf

ishs

peci

es


cd_impact: agriculture

Fig. 8.5.4: Number of species in agricultural impacts

8 Results

-220-


cd_season

0

50

100

150

200

250

300

350

sum

CPU

E

56


impact: city

Fig. 8.5.5: Abundance of fish (CPUE) in impacts of city


cd_season

0

2

4

6

8

10

12

14

16

18

20

Num

berf

ishs

peci

es

61


cd_impact: city

Fig. 8.5.6: Number of species in impacts of city

8 Results

-221-


cd_season

0

50

100

150

200

250

300

350

sum

CPU

E


impact: dam

Fig. 8.5.7: Abundance of fish (CPUE) in impacts of dam


cd_season

0

2

4

6

8

10

12

14

16

18

20

Num

berf

ishs

peci

es


cd_impact: dam

Fig. 8.5.8: Number of species in impacts of dam

8 Results

-222-


cd_season

0

50

100

150

200

250

300

350

sum

CPU

E

174


impact: industry

Fig. 8.5.9: Abundance of fish (CPUE) in impacts of industry


cd_season

0

2

4

6

8

10

12

14

16

18

20

Num

berf

ishs

peci

es


cd_impact: industry

Fig. 8.5.10: Number of species in impacts of industry

8 Results

-223-

Percentiles Impacts N

(valid) N

(missing) median minimum maximum

25% 75% ups 24 0 122.5 26.0 319.44 49.9 234.3 Agriculture down 24 0 82.2 15.0 256.0 42.4 146.9 ups 24 0 72.5 16.5 207.5 39.6 85.4 City down 24 0 51.25 20.0 97.22 38.4 68.4 ups 24 0 51.25 8.64 101.5 28.12 69.7 Dam down 24 0 50.7 2.0 125.0 12.4 80.4 ups 24 0 88.83 27 181 69.87 124.8 Industry down 24 0 41.46 16.67 187 23.5 128.87

Table 8.5.1: Abundance of fish (CPUE) in all impacts in all seasons Percentiles Impacts N

(valid) N


25% 75% ups 24 0 10 4 15 6 12 Agriculture down 24 0 7 3 16 5 11 ups 24 0 8 3 16 6 11.75 City down 24 0 7 4 19 5 10 ups 24 0 6.5 1 10 1.25 8 Dam down 24 0 5.5 1 12 1 9 ups 24 0 12.5 9 18 10.25 14 Industry down 24 0 11 2 17 8 13

Table 8.5.2: Number of species in all impacts in all seasons Percentiles Impacts

AgricultureN

(valid) N

(missing) Median minimum Maximum

25% 75%

ups 6 0 107.02 26 301.33 35.0 297.42 Spring down 6 0 158.1 102.0 247.0 130.0 238.0

ups 6 0 151.5 44.0 257.65 50.5 246.72 Premonsoon down 6 0 44.5 15 124 18.25 104.5

ups 6 0 71 42 319.4 47.25 305.86 Autumn down 6 0 49.25 38.5 105.0 40.0 74.85

ups 6 0 138.75 45.56 208.0 66.2 196.75 Winter down 6 0 100.12 41.67 256.0 43.8 176.1

Table 8.5.3: Abundance of fish (CPUE) in agricultural impacts Percentiles Impacts

AgricultureN

(valid) N


25% 75%

ups 6 0 9 4 15 5.5 12.75 Spring down 6 0 10 6 14 6 13.25

ups 6 0 10 6 13 6.75 11.5 Premonsoon down 6 0 4.5 3 15 3.75 13.5

ups 6 0 9.5 5 12 5.75 11.25 Autumn down 6 0 8 5 16 5 12.25

ups 6 0 11 5 13 5.75 12.25 Winter down 6 0 7 5 11 5.75 8.75

Table 8.5.4: Number of species in agricultural impacts

8 Results

-224-

Percentiles Impacts city

N (valid)

N (missing)

median minimum maximum 25% 75%

ups 6 0 50.16 36.36 207.50 37.78 173.06 Spring down 6 0 53.2 28.24 97.22 38.56 66.1

ups 6 0 79 16.5 83.5 19.87 82.92 Premonsoon down 6 0 54.2 24.5 85.5 43.62 76.13

ups 6 0 82.75 29.5 135.5 42.62 116.0 Autumn down 6 0 46.75 39.5 79.0 41.0 74.13

ups 6 0 60 33 89 41.75 80.4 Winter down 6 0 36.5 20 78 23.75 61.5

Table 8.5.5: Abundance of fish (CPUE) in impacts of city Percentiles Impacts

city N

(valid) N


25% 75%

ups 6 0 10 5 13 6.5 13 Spring down 6 0 6 5 13 5 10.75

ups 6 0 5.5 3 16 4.5 10.75 Premonsoon down 6 0 8.5 4 19 4.75 16.75

ups 6 0 9.5 6 15 6 12.75 Autumn down 6 0 8.5 7 13 7.75 12.25

ups 6 0 7.5 4 11 5.5 9.5 Winter down 6 0 5.5 4 8 4 6.5

Table 8.5.6: Number of species in impacts of city Percentiles Impacts

Dam N

(valid) N


25% 75%

ups 6 0 67.67 23.53 99.4 43.4 86.1 Spring down 6 0 74.76 12.0 100 16.92 85.75

ups 6 0 21.8 8.64 47.5 15.7 47.32 Premonsoon down 6 0 48.95 7.5 125.0 12.0 122.0

ups 6 0 53.0 34.4 63.33 37.86 61.21 Autumn down 6 0 42.0 2.14 58.00 2.41 52.34

ups 6 0 71 28 101.5 28.37 95.87 Winter down 6 0 64.25 2 103.04 8.75 95.89

Table 8.5.7: Abundance of fish (CPUE) in impacts of dam Percentiles Impacts

Dam N

(valid) N


25% 75%

ups 6 0 8 1 10 1 10 Spring down 6 0 8.5 1 12 1 10.5

ups 6 0 5 1 8 1.75 8 Premonsoon down 6 0 2.5 1 11 1 9.5

ups 6 0 8 1 10 1.75 8.5 Autumn down 6 0 5 1 9 1 6.75

ups 6 0 5 1 9 1 7.5 Winter down 6 0 6.5 1 9 1 8.25

Table 8.5.8: Number of species in impacts of dam

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Percentiles Impacts Industry

N (valid)

N (missing)

median minimum maximum 25% 75%

ups 6 0 91.7 36.36 165.0 37.8 143.9 Spring down 6 0 39.9 16.7 66.0 19.2 64.9

ups 6 0 83.11 68.5 96.0 73.75 90.75 Premonsoon down 6 0 118.5 34.67 144.0 35.7 132.8

ups 6 0 97.75 27.0 181.33 62.25 129.50 Autumn down 6 0 32.0 20.67 131.00 20.9 111.5

ups 6 0 111.5 33 162.5 41.75 152.37 Winter down 6 0 88.5 19 187 20.12 176.12

Table 8.5.9: Abundance of fish (CPUE) in impacts of industry Percentiles Impacts

Industry N

(valid) N


25% 75%

ups 6 0 12 10 14 10 14 Spring down 6 0 10 2 14 6.5 14

ups 6 0 12 9 16 10.5 14.5 Premonsoon down 6 0 9.5 5 13 7.25 12.25

ups 6 0 13.5 10 15 11.5 15 Autumn down 6 0 11.5 7 15 8.5 13.5

ups 6 0 12 9 18 9 15.75 Winter down 6 0 11.5 6 17 7.5 15.5

Table 8.5.10: Number of species in impacts of industry

Similarly, fig.8.5.10 describes the total number of fish species in both upstream and

downstream sites for the impacts due to industries in all the seasons studied in this work

(Table 8.5.10). The figure showed more or less consistent differences in number of fish

species between upstream and downstream in all seasons.

The data were then subjected to the test of homogeneity of variance, where the same

variables, the abundance and the number of species, as described before were tested. The

details of the homogeneity test are shown in table 8.5.11. The result of this test showed that

all the data of variables are homogenous and consistent, and thus was fit for further

statistical analysis.

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Test of Homogeneity of Variance

Levene Statistic df1 df2 Sig. Sum of CPUE Based on Mean 2.105 1 188 .149 Based on Median 1.423 1 188 .234 Based on Median and with adjusted df 1.423 1 176.084 .235 Based on trimmed mean 1.487 1 188 .224Number of fish species

Based on Mean .032 1 188 .859

Based on Median .027 1 188 .870 Based on Median and with adjusted df .027 1 187.133 .870 Based on trimmed mean .028 1 188 .868

Table 8.5.11: Test of homogeneity of variance

The next statistical test done was the ‘tests of normality’ where the distribution of the data

of the two variables, sum of CPUE (abundance) and number of fish species, in both

reference and disturbed sites were tested for whether they are normally distributed. Two

methods for tests of normality, Kolmogorov-Smirnov and Shapiro-Wilk were used here and

both of them produced the same result (Table 8.5.12). The data of the sum of CPUE, that is

abundance had no normal distribution whereas, that of number of fish species was found to

possess normal distribution. Therefore, the two variables needed different tests and analysis.

Tests of Normality

cd_place Kolmogorov-Smirnov(a) Shapiro-Wilk

Statistic df Sig. Statistic df Sig. Sum of CPUE upstream .188 94 .000 .833 94 .000 downstream .159 96 .000 .877 96 .000Number fishspecies upstream .091 94 .052 .975 94 .070 downstream .080 96 .154 .975 96 .067

a Lilliefors Significance Correction Table 8.5.12: Tests of normality of variables

8.5.1 Nonparametric Kruskal-Wallis Test (for seasonal variations of impacts):

Since the distribution of data of abundance was not found to be normal, nonparametric test,

Kruskal-Wallis Test, was done for this variable. The test was performed for the seasonal

variations of impact for all the seasons in each of the reference and disturbed sites called

here after as upstream and downstream. The Kruskal-Wallis Test for the seasonal variations

in impacts due to agriculture for upstream showed the asymptotic significance as 0.984,

which is greater than 0.05 indicating that the impacts there were not significant (Table

8.5.13). However, the same test for agricultural impact in downstream produced the value

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of 0.010, which is less than 0.05 indicating that the seasonal variations in impacts in

downstream were significant.

Similarly, this nonparametric test for seasonal variations in the impact of city in upstream

produced the value of asymptotic significance as 0.793 and that in downstream as 0.547.

These values indicated that the disturbances due to urban growth did not produce significant

variations both in upstream and downstream in the rivers studied for this purpose. The test

for the impact of dam however produced a mixed result. The value for the upstream was

found to be 0.026 and that for downstream was found to be 0.472. These values revealed

that among the rivers studied, the seasonal variations in CPUE in upstream were statistically

significant whereas in downstream, it was not. Likewise, the same test for the seasonal

changes of industrial impact produced the value of 0.229 and 0.259 in upstream and

downstream respectively. This means the seasonal variations in CPUE for industrial impacts

in rivers were not significant among the cases studied in this work.

Impacts Place Asymp. Significance

Upstream 0.984 Agriculture Downstream 0.010*

Upstream 0.793 City Downstream 0.547

Upstream 0.026* Dam Downstream 0.472

Upstream 0.229 Industry Downstream 0.259

Table 8.5.13: Values of Asymptotic Significance from Kruskal-Wallis Test for sum of CPUE (for seasonal variations of impact) 8.5.2 Parametric One way ANOVA (for seasonal variations of impacts):

As the distribution of data was normal for the second variable, the number of fish species, a

parametric tests were done in this case for all the impacts in each site for seasonal variations

as was done for the sum of CPUE in nonparametric test. The parametric test chosen here

was ‘One way ANOVA’, which is normally done in these cases.

The value of significance for the changes due to the agriculture in all seasons in upstream

was found to be 0.972 and in downstream it was 0.630 indicating that there were not

significant seasonal variations in impacts in terms of number of species in the cases studied

(Table 8.5.14). Similarly, the values of significance in upstream and downstream sites for

the impacts of city were found to be 0.530 and 0.165 respectively. These values too

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indicated that the city had no seasonal changes in impacts in rivers in terms of this second

variable among the rivers studied for this purpose.

The values of significance for the impacts of dam in terms of number of species were found

to be 0.786 and 0.717 in upstream and downstream respectively. This also meant the same

story that there were no significant seasonal variations in impacts if we take the number of

species as a variable among the rivers studied. Finally, for the disturbances due to the

industries the value of significance were found to be 0.448 and 0.716 in upstream and

downstream respectively, pointing towards the same facts as in the other disturbances.

Impacts Place Significance Upstream 0.972 Agriculture

Downstream 0.630 Upstream 0.530 City

Downstream 0.165 Upstream 0.786 Dam

Downstream 0.717 Upstream 0.448 Industry

Downstream 0.716 Table 8.5.14: Values of Significances in one-way ANOVA for number of fish species (for seasonal variations of impact ) 8.5.3 Nonparametric Mann-Whitney Test (for impacts):

After Kruskal-Wallis test another nonparametric, Mann-Whitney test for all the

disturbances were also done to see if the impacts were significantly different between

upstream and downstream in terms of sum of CPUE. Mann-Whitney Test for the

agricultural disturbance in terms of abundance (CPUE) produced the value of 2-tailed

asymptotic significance as 0.135 indicating that there were no significant impacts in the

abundance of fish due to this disturbance among the river studied (Table 8.5.15).

Test results of this test for the impacts of city on the cases studied produced 2-tailed

asymptotic significance as 0.103 also indicating that there were no significant impacts in

terms of abundance of fish. Similarly, the test results of the same test for the impacts of dam

gave the value of 2-tailed asymptotic significance as 0.853. This value also indicated that

there were no significant impacts of dam on the rivers studied. However, Mann-Whitney

Test for the disturbance of industries on the rivers studied produced a different result. The

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2-tailed asymptotic significance in this case was found to be 0.042 indicating that the

impacts from the industries were significant in terms of the abundance of fish.

Impacts Asymptotic Significance (2-tailed) Agriculture 0.135 City 0.103 Dam 0.853 Industry 0.042* Table 8.5.15: Values of 2-tailed Asymptotic Significance from Mann-Whitney Test for sum of CPUE (for impacts) 8.5.4 Parametric One way ANOVA (for impacts):

The second parametric one-way ANOVA test was performed to see the differences due to

the disturbances in upstream and downstream of the rivers in terms of the number of

species. In this second ANOVA, the value of significance for the impacts of agriculture was

found to be 0.343, which means that the impacts were insignificant among the rivers studied

for this purpose in terms of number of fish species (Table 8.5.16). Similarly, the value of

significance for the impacts of city in this method was found to be 0.733, again indicating

that the impacts were not significant among the rivers studied for this disturbance in terms

of number of fish species.

The results of the analysis for the impacts of dam were found to be no different. The value

of significance for the impacts of dam by this method was found to be 0.844 indicating that

the impacts were not significant among the cases studied for this disturbance in terms of the

second variable. However, the results of the analysis for the impacts of industries were

found to be different than others. The value of significance here was found to be 0.011

indicating that the impacts were significant for this disturbance in terms of number of fish

species.

Impacts Significance Agriculture 0.343 City 0.733 Dam 0.844 Industry 0.011* Table 8.5.16: Significances in one-way ANOVA for number of fish species (for impacts)

9 Discussion

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CHAPTER IX: DISCUSSION

9.1 Distribution, abundance and density of fish: Biota at any place is the product of evolutionary and biogeographic process (Karr 1991;

Westra 1995). It means that the resident biota at any site varies according to the geographic

region as well as in evolutionary time. Though biota at any place is a dynamic thing,

biological integrity refers it as a balanced, integrated, adaptive system having its full range

of elements (genes, species, assemblages) and processes (mutation, demography, biotic

interactions, nutrient and energy dynamics, and metapopulation processes) expected in areas

with minimal human influence (Karr 2000).

Management of water resource requires the analysis of physical, chemical and biological

integrity. Monitoring of physical and chemical characteristics of water is quite common, but

biological monitoring based on biological indicator is rare. However, the recently proposed

index of biotic integrity (Karr 1981) that uses the attributes of fish communities to assess

biological integrity to manage water resources is gaining popularity everywhere. The index

of biotic integrity (IBI) uses the comparison of fish species richness and composition, and

abundance as primary criteria for the evaluation of water quality. At present, further

development of IBI has taken place at regional level suggesting that each geographical

region has its own unique set of fish species.

In addition, either to initiate conservation programs or to start commercial production of any

species of fish, a sound knowledge of its distribution, abundance, ecology and biology are

the primary requirements. Although fish base assessment has become a standard and regular

method to evaluate the conditions of the rivers and stocks in North America and Europe, it

is in the premature stage in most of the developing countries including Nepal. Nepal, with a

huge amount of water resources and rich diversity of fish species, has a tremendous

potential for fisheries development as well as enormous opportunity to develop fish base

assessment techniques.

The inland water resource of Nepal includes natural waters such as rivers, lakes and

reservoirs, and also village ponds, marginal swamps and irrigated paddy fields and equals

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818500ha (Khanal 2001). Out of this, the network of rivers and streams, which are more

than 6000 in number alone covers around 395000ha of surface. In total, the length of rivers

and its tributaries in Nepal exceeds well past 45000 km mark. Similarly, a total of 182

species of fish belonging to 93 genera under 31 families and 11 orders has been reported

from Nepal (Shrestha 2001). The high diversity of life forms including fish in Nepal is

mainly attributed to its unique location and spectacular geography.

Some information on ecological and population characteristics of the fish, such as region

and altitude of occurrence, habitat preference, temperature range, maximum length, feeding

habit, life history and a crude status of many of the fish species are available. However, the

information is still not in the state that a scientific fish base assessment such as IBI could be

directly applied. The list of fish species from very large as well as some important rivers

from Nepal has been developed by various authors. Rajbanshi (1982) developed the first list

of fish base work in Nepalese rivers and some of these works carried the species lists.

Talwar and Jhingran (1991) have number of fishes from Nepal mentioned in their work.

Similarly, Shrestha (1990 and 1995) has also listed the fish species from the number of

rivers and streams.

Edds (1993) studied the first spatial and temporal patterns of fish assemblage composition

in Gandaki River and found that the highest numbers of species (33 species) were found in

the lowland site. However, the first descriptive list of the fishes of Nepal in the regional

basis was made by Shrestha (1994), which was also used as one of the key for identification

of fish in this work. In 1995, she worked for the Department of National Parks and Wildlife

Conservation and IUCN, Nepal to enumerate the fishes of Nepal, where a threat category

were tried to assign to each species. She also came up with another list in ‘Coldwater fish

and fisheries in Nepal’ (1999). Similar kind of list with more or less same title was also

worked out by Swar (2001).

The same year Rajbanshi (2001) presented a paper with title ‘Zoogeographical distribution

and the status of cold water fishes of Nepal’. Shrestha (2001) again made the taxonomic

revision of all the fishes of Nepal. Sharma and Shrestha (2001) studied fish diversity and

fishery resources of Tinau, which is an important river in this study. Thus, there are a fair

number of lists of fish from different regions and rivers in Nepal but most of them are not

quantitative. Seasonal variations on the species composition for the rivers and regions are

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hardly mentioned. Many of the list mentioned above is also based on secondary data.

However, the present work is based on primary data collected from the fieldwork mainly in

the rivers of Central and Western Developmental Region of Nepal for one complete

seasonal cycle.

Among the rivers studied in this work, Narayani River, the main channel of the Gandaki

System has been perhaps the most studied river in Nepal. Since the main river has hundreds

of tributaries, it is often confusing on the total number of species found in the river. Even in

this work, out of nine rivers studied six belongs to Gandaki system. The number of species

recorded from Narayani River varies among authors. Shrestha (1999) reported 35 species

from this river, but then they were mentioned as coldwater species. Rajbanshi (2001) has

mentioned around 47 species in this river but there is no discrimination between coldwater

and warm water species. Similarly, Swar (2001) has also mentioned 35 species from this

river as coldwater species. The number of species in this river recorded during this work

was 32 and was the highest among all the rivers. In any case this number is not significantly

less if we consider that due to the size of the river the fishing was possible only in the bank

and that too just in three sampling sites.

East Rapti, one of the tributary of Narayani River recorded 30 species during this study

period. There are some studies regarding fish in the river as it flows through the National

Park, but again the number of species is not consistent. Rajbanshi (2001) has listed 41

species from this river. Once again, the number recorded here though less is not so less

enough as the sampling sites were just two. Similarly Tinau River was found to possess 29

fish species during this work from six sampling sites. The number is very near to the one

mentioned by Sharma and Shrestha (2001) for this river.

Arungkhola had the next highest number of fish species recorded in this work at 27 and

signified that how small rivers like this are important for the fish diversity. No prior records

regarding the fish fauna were available for this river and thus, the number mentioned above

should hold good till the next study. Likewise, Karrakhola was found to consist of 25 fish

species. There might be a few studies of fish in this river especially as a master’s

dissertations, but an authentic record was still missing. Aandhikhola and Seti River both

recorded 18 species each during this study. For Aandhikhola, no list of fish fauna were

found though some of the species were found mentioned in UNDP (1978), while Seti has a

9 Discussion

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several list. According to Rajbanshi (2001) the river consist of only 7 fish species and thus,

the species recorded in this study was significantly high.

Jhikhukhola a small tributary of Koshi System was found to possess 12 species from two

sampling sites. Once again, there were no records of the fish from this river available and

this number should hold good for sometime to come. Bagmati River due to its religious

significance and the location on the other hand is one of the most studied rivers in Nepal.

Several lists and records of fish fauna for this river are available. The latest one by Shrestha

(2001) recorded 21 fish species from this river whereas; during the present study only 3

species were recorded. The high number of fish recorded by various authors may be due to

the extensive sampling sites particularly after the river recovers itself from one of the worst

pollution case and the historical evidences. If any recent list mentions a high number of

species in this river before it enters urban area of Kathmandu then it must be highly inflated.

Seasonal availability of some important fishes in some rivers of Nepal could be found

mentioned in the number of literature, but a detail seasonality of all the fish in specific

rivers are wanting. This could be a new work in this direction where all the fish in the

studied rivers are accounted for their temporal behavior. Some species like N.

hexagonolepis, P. conchonius, P. sophore, B. barila, B. bendelisis, B. vagra, G. gotyla

gotyla, A. botia, S. beavani, S. rupecula, L. guntea, A. mangois, C. punctatus and M.

armatus were found almost in all seasons in the rivers they were recorded, while some

species such as G. chapra, C. reba, P. chola, S. semiplotus, T. tor, N. chelynoides, A. morar,

B. barna, D. dangila, C. latius, P. pseudecheneis, C. garua, G. pectinopterus, G. trilineatus,

P. sulcatus and G. giuris showed some to high degree of seasonality.

The work done regarding the abundance and density of fish species in Nepalese rivers are

very few. Shrestha (1995) while working together with Department of National Parks and

wildlife conservation and IUCN had assigned different threat categories to the fishes of

Nepal. Her work should include some quantitative analysis but is not mentioned. Thus,

there is no concrete basis for assigning threat categories to different species on one hand

and to assess the fisheries potential on the other hand. This study has calculated the

abundance measured in CPUE, that is, number of fish captured in 10 minutes of

electrofishing of all the fish species recorded during this study (Table 8.1.3). Some of the

fishes assigned as common by literatures might not be so as was found in this study.

9 Discussion

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The study also showed that the small rivers could not be ignored for potential of fisheries as

the rivers like Jhikhukhola and Arungkhola were found to possess high abundance of fish.

Relative low abundance of fish found in Narayani river could be due to the fact that the

river could not be waded properly and was restricted to shoreline only. Less abundance of

fish in Bagmati River was probably due to its geographical region as it was at the highest

altitude. Normally, cold and oligotrophic water possess less fish than the warm water

lowland rivers.

Density of fish calculated in this study is just to have an overview and should not be taken

as hard data. The calculation of density requires the measurement of area accurately using

digital devices. The area calculated by taking manual measurement of length and width of

the river would only give a rough estimate. In any case, the exact calculation of the area of

the river is extremely difficult and thus to decrease the margin of error it was calculated in

100 m² instead of general practice in hectare. The density of fish as was shown in table

8.1.4 appeared relatively less but could be explained by that it is the density of fish in

natural conditions and in absence of stockings. Again, the density of fish shown for

Narayani River in the table could be with error but for other rivers it looked fine and

healthy.

In short, the species richness, composition, abundance and density of fish vary greatly

among seasons and rivers. Thus, assessing the fisheries potential and assigning threat

categories according to the distribution and abundance described above should be started for

conservation and management of the aquatic resources.

9.2 River classification based on biotic and abiotic factors: The use of cluster analysis to classify and group various ecological entities for better

management and conservation is a common process these days in all parts of the world.

There are several examples of these kinds of works in the field of aquatic ecology as well.

Eekhout et al. (1997) classified the rivers in South Africa using this tool. In Japan too, river

system were classified from a landscape ecological aspect using cluster analysis (Nakagoshi

and Inoue 2003). While assessing benthic macroinvertebrates in stream ecosystems, Park et

al. (2004) also used this tool. In India, Singh et al. (2004) also used this tool to see spatial

and temporal variations of water quality in Gomti River.

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This work is the beginning of the use of cluster analysis (CA) as a tool to classify the rivers

and river systems in Nepal. Nepal consists of 4 main drainage basins of Koshi, Gandaki,

Karnali and Mahakali representing different regions of the country. In addition to these,

there is a network of southern rivers and Mahabharat rivers in each regions (Sharma 1997).

The rivers are classified according to origin and geology but hardly with their biological

characteristics. This work to a large extent proves that the species richness and the

abundance could be utilized as variables to classify the Nepalese river system for the

management and conservation purpose. The result as could be seen in the cluster analysis

was amazing as it is exactly the copy of the classification from origin, region and geology.

The six rivers studied in this work belongs to Gandaki system and this analysis showed all

six of them, Aandhikhola, Seti, Arungkhola, East Rapti, Karrakhola and Narayani were

comparatively closer with each other than the other rivers. Even within that it was

interesting to see how Arungkhola, East Rapti and Karrakhola, which originates from lower

Mahabharat and mainly flows through lowlands with similar structure formed a cluster. The

group of six was found to be little different than the independent system Tinau, though the

region was same. They were more different than Bagmati as it another independent system

from another region, and there was the highest difference with Jhikhukhola which is a small

tributary of completely different river system. Thus, this kind of fish base classification was

found to work in the Nepalese situation.

Similarly, the application of Canonical Discrimination Analysis (CDA) is increasing rapidly

in all sectors to classify or group any set of entities. It is especially common when there is a

huge pool of data and high number of variables. Pitkanen (1998) in the work on

classification of biodiversity in managed forest used this analysis to determine the variables

that best describe the classes. Similarly, Lu et al. (2003) used CDA to differentiate

successional stages and to identify the best forest stand parameters to distinguish these

stages.

The CDA was found to be used in classifying the species from different regions too. Silva

A. (2003) in her study in sardine population of two regions used this technique and found

that the two groups of sardine were significantly separated by this method. There are many

application of this analysis in river and stream ecology as well. Legleiter (2003) worked on

stream habitat mapping and used this analysis in conjunction with remotely sensed data.

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Singh et al. (2004) in their work on spatial and temporal variations in water quality of

Gomti River have applied discriminant analysis and found that it showed best results for

data reduction and pattern recognition during both temporal and spatial analysis.

The present work used this analysis to classify different rivers and river system of Nepal in

the basis of morphological and physico-chemical characteristics of rivers and water.

Altogether twelve variables were used from each of the 184 cases spreaded over nine rivers

and four seasons. Thus, it made it a huge pool of data normally useful in CDA. The best

discriminant variables in Nepalese rivers were found to be altitude, substratum such as

boulders, pebbles rock and silt, and other characteristics such as dissolved oxygen (DO) and

conductivity.

The variables discriminated themselves making four distinct groups corresponding to the

classification available for the Nepalese rivers, Bagmati, Gandaki, Koshi and Tinau. 94.6%

correct case for the original group and 93.5% correct case for the cross-validated group

indicated that the classification based on those variables are very near to the reality. This

also suggested that this method could be extended to other rivers and river systems in

different regions once the enough data are collected. In addition, the discrimination analysis

for classification helps in the management and conservation of water resource, fisheries

resource and restoration of the depleted resources.

9.3 The size structure of sucker head, Garra gotyla gotyla (Gray, 1830): A. Length frequency distribution:

The sucker heads (Garra gotyla gotyla) were found to be one of the most common fish

species in Nepal as they were recorded from eight of the nine rivers sampled in this work

and in sufficient number. The species was not found in Bagmati River maybe because of the

altitude of the sites, which is more than 1560 masl described as its altitudinal range

(Shrestha 1995). The species has a much wider distribution below that elevation and is

found in the rivers and lakes on the foothills of the entire Himalayan region (Talwar and

Jhingran 1991). The status of the species was found to be consistent as ‘fairly common’

described by Shrestha (1995).

9 Discussion

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No previous records of length frequency distribution of this species could be traced from the

related literature. However, some authors have mentioned its maximum size. Talwar and

Jhingran (1991), Shrestha (1994) and Shrestha (1995) have recorded the maximum size

140mm, 160mm and 150 mm respectively. This work has found the species measuring up to

180 mm, which is a new record. The range of lengths and the distribution of length

frequencies together with length-weight relationship showed some variations in space and

time suggesting that the habitat conditions, stock size and health, and population

characteristics too might vary in different rivers and seasons.

Among the rivers, judging by the numbers of sucker heads captured and length frequency

distribution, Aandhikhola was found to hold a good and healthy population. The range of

length groups and the highest mean length suggested that the habitat conditions for this

species is the best in this river. However, the absence of 20 mm category suggested that the

main channel might not be most appropriate for the breeding. Arungkhola and Karrakhola

had the similar results indicating the similar conditions for the fish. The presence of 20 mm

category in these streams suggested that the habitat conditions are good for breeding but the

absence of large adults indicated that the conditions are not favorable for the optimum

growth due to natural conditions or some man made disturbances and these adult may

migrate to other bigger channels or may be harvested.

Jhikhukhola, which belongs to Koshi River System, also showed a narrow range of length

groups just up to 120 mm considerably less than Aandhikhola. In addition, absence of 20

mm group indicated that the breeding ground is not suitable. The absence of larger adults

suggested that the conditions were similar to that of Arungkhola and Karrakhola. East Rapti

and Seti showed more or less similar situations. Both of these rivers didn’t have 20 mm

length group indicating harsh condition or disturbances for spawning. The number of the

fish captured in Seti was also very low. The numbers of large adult fish were also less

though the maximum sizes of the sucker heads in these rivers were 140 mm and 130 mm

respectively.

Narayani, one of the biggest rivers in Nepal was found to hold a good population of this

species. The range of the length groups was very high but there was a complete absence of

length groups 20 mm –35 mm indicating that the river is not the site of breeding. However,

presence of very large adults and the mean total length of the population suggested that the

9 Discussion

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habitat conditions here are very good for the optimum growth. Tinau River perhaps was

found to hold the best population of sucker heads both in terms of abundance and

distribution of length frequencies. The substrate, temperature and good sequences of pools

and riffles seemed ideal for this population. It was found to be good for breeding as well as

for larger length groups. There were lots of disturbances in the river but still the population

was found to be healthiest. The absence of very large adults might just indicate that they are

the target of anglers and fishermen.

The temporal variation of the length frequency distribution mainly gave the insight of the

breeding season. Breeding season is normally characterized by the presence of lowest

length group and the low mean length of the population. Presence of the lowest length

group (20 mm) and the lowest mean of the population in premonsoon indicated that the

breeding season starts in this time of the year. However, the record of the lowest length

group in postmonsoon suggested that the breeding period is quite long starting from

premonsoon till the beginning of autumn including the entire monsoon period. Shrestha

(1994) had also mentioned the breeding season of this species as premonsoon, but has not

mentioned how long it lasts. The mean total length of the population in autumn was higher

than in premonsoon.

The winter and the spring seasons completely lacked the lowest length categories and thus,

should not be the time of breeding. More over, the mean total length of the population in

winter increased than that of autumn and was highest in spring indicating that these seasons

are mainly for the growth. Thus, there seemed to be a cycle in the life history of sucker head

where the population has the lowest mean of length in premonsoon, which increases

gradually in autumn, winter and till the spring.

B. Length-weight relationship:

The length-weight relationship was also found to vary in space and time. As in length

frequency distribution, there are no records of length-weight relationship for this species

and hence there were no comparison to be made. Looking at the relationship in different

river systems of Nepal for this species, it was found that Koshi System provided the

optimum growth and the stock there were the healthiest. The Gandaki System, from where

the largest numbers of sucker head collected were found to be with very fluctuating biomass

whereas, Tinau had the intermediate length-weight relationship.

9 Discussion

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The absence of 20 mm category of sucker heads in Jhikhukhola of the Koshi System

indicated that the main channel of this river is not so suitable for the breeding, but presence

of higher length groups suggested that the river might be very suitable for the growing

fishes. As the river flows through highly agricultural area, there could be very high amount

of nutrient in the river due to overflow and hence the optimum growth of the species.

However, there was only one river from Koshi system that had been sampled and that too in

the highly agricultural area, more rivers and streams of Koshi System has to be sampled to

make comparison with Gandaki System, which already has the sample from six different

rivers.

The length-weight relationship of the species from the Gandaki System should be very near

to the normal relationship due to many reasons such as, the high number of sampled rivers,

the high number of the species collected, and the presence of all the length groups. Seasonal

variations in length-weight relationship of the sucker heads here showed interesting

regressions and revealed the aspects of life history as well as the period of stress. Tinau

river, with the largest number of sucker heads recorded during this work and with

intermediate but good length-weight relationship was found to hold good stock and

biomass. The unusually low number of the fish species recorded in premonsoon season due

to massive poisoning, however has decreased the correlation and increased the standard

error (R² = 0.67420788 and Std. Error = 0.0010), suggesting that more sampling has to be

done in the river.

The highest biomass was found to be in premonsoon. The first reason for that is the

optimum growth of gonads as it is the beginning of the breeding season. The other reasons

could be the warm temperature and the high availability of foods and organic matter. The

autumn had the weakest relationship and hence the least biomass except in the Jhikhukhola

of Koshi System. It is simply because it marks the end of breeding season and hence the

gonads are emptied. In addition, the stocks have to face massive floods due to monsoon and

are in great physiological stress.

Winter and spring had an intermediate length-weight relationship. Between autumn to

winter, the sucker heads were found to gain weight rapidly, but between winter to spring

they marginally lose the weight. It may be due to the plunge in temperature and subsequent

coldness that puts them in some kind of physiological stress. However, after spring another

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phase of gaining weight was noticed which peaked in premonsoon season. After spring,

temperature gradually increases and so are the foods and nutrients in water.

Garra gotyla gotyla has a potential to become more than minor fisheries in Nepal as could

be evident from its distribution and abundance. The information regarding its habitat

condition, life history, abundance, health, biomass and other population characteristics are

important to raise it into a major fishery program. The most important parameters to gather

that information are the length frequency distribution and the length-weight relationship.

This study has tried to give some baseline information on the sucker heads regarding these

parameters. Like in any natural fish population, these two parameters were found to vary in

space and time for this species as well. And a careful study of this information should help

to estimate its abundance, growth, health and stock size, which are so important in fisheries

management.

9.4 Assessment of integrity of the river system: As mentioned before (Chapter II), integrity is a difficult and tricky concept, which changes

in time and space. Integrity, normally, means pristine and natural state without human

interference and there are hardly any information regarding fish communities of rivers in

that state anywhere in the world. The characteristics of the rivers and streams, particularly,

fish communities that indicate the integrity today might be very different from the

characteristics in historical times. In the absence of historical data regarding fish

communities from all the rivers studied in this work, it was difficult to make comparisons

and to assess the integrity of the systems. However, it is accepted in this work that

whichever section of the sampling sites showed better fish community structure are better in

integrity.

Another difficulty to assess the integrity of the river systems is related with the spatial

dimension of the integrity. In general practice, two sampling sites, reference or upstream

site and disturbed or downstream sites are sampled in river ecological studies and the

comparisons are made referring reference sites as the one having ecological integrity.

However, depending upon the conditions, there are disturbances, which affects the upstream

more to lose their integrity. In any case, running waters are now seen as 4-phase system

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with horizontal, vertical and lateral interactions together with temporal interactions, and the

integrity is lost if one of them gets disrupted.

Thus, in many cases where the disturbances in river systems are studied, choosing a

reference site is becoming increasingly difficult. In the country like Nepal, it is even more

difficult as even a short distance at many places, mark a big topographical differences,

which is associated with series of other differences in both biotic and abiotic factors. Hence

good comparisons cannot be made between reference and disturbed sites. In addition, if the

reference sites are taken too far away upstream, multitude of other disturbances are added

in its course and the case can no longer be the study of a specific disturbance. For example,

the reference site should not be established at Sundarijal in Bagmati River to study the

impacts of disturbance in the same river when it enters the plain.

This study also fixed upstream and downstream sites for each disturbance in each river. The

upstream or the reference sites were fixed a little distance before the disturbance to avoid

regional differences in fish communities for fair comparison. However, for the study of

agricultural disturbance, the distance between upstream and downstream sites were quite

high as the disturbances come from large fertile areas. Comparisons between upstream and

downstream sites were made to see if there were any differences in some fish population

characteristics. If there are substantial variations between them then it is generally accepted

that the particular disturbance has the potential to alter the integrity of the river system.

There are relatively few literatures regarding the disturbances and specific fish base analysis

of water quality and river conditions of Nepal, except for some EIA reports. Sharma (1996)

and Khanal (2001) worked on water quality and various disturbances on the rivers by taking

biological indicators, but macrozoobenthos. Similarly Ormerod et al. (1997) did river

habitat survey of many rivers in Nepal but used diatoms, bryophytes, invertebrates and

birds. However, some authors have generalized the impacts of various disturbances on fish

communities. A report prepared for UNDP (1978), has discussed the effects of dams on fish

population and had recommended the fish passing facilities in dam constructions. Edds

(1993) while working in Gandaki River concluded that the fish assemblage was influenced

by geography, water quality and stream hydraulics. Shrestha (1994) has mentioned about

erosion, deforestation, industries and dams as major threats to fishes in Nepal.

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Shrestha (1995) has described the effects of various man made disturbances such as dam

construction and pollution on the fish population. Shrestha (1999) has described soil

erosion, dam construction, chemicals, and over exploitation among others as the main cause

of the decline of fishes. Rajbanshi (2001) has mentioned industrial activities, construction of

dams and overfishing as the reasons for the depletion of the indigenous fishes. Swar (2001)

also listed silt, chemical pollution, introduction of exotic species, over and illegal fishing

and hydraulic engineering as the main causes of the decline of natural fish communities.

Meanwhile, Sharma and Shrestha (2001) have studied the impacts of dam in Tinau River

and found that it is affecting the fishes adversely.

However, there are so many works regarding the field from elsewhere of the world.

Assessment of river quality through fish assemblage, though started earlier was established

by Karr (1981) in the form of Index of Biotic Integrity (IBI). Angermeier et al. (1986 and

1994) mainly improved the methods of sampling and interpreting the results. Fausch et al.

(1984) modified the application of IBI on regional basis with the main hypothesis that as

human society degrades watersheds, the aquatic communities they support are modified to

varying degrees. Latter he studied the general environmental degradation by taking fish

communities as indicators (Fausch et al.1990).

Hughes and Gammon (1987) in their study found that a modified IBI appeared to reflect

changes in fish assemblage patterns and habitat quality better than the other indexes. Miller

and Leonard (1988) studied the regional application of IBI and found that it holds promise

for direct biological monitoring because of its strong ecological foundation and flexibility.

Similarly, Oberdorff and Hughes (1992) modified IBI to use in France and found that it

would offer a reliable means of assessing spatial patterns and temporal trends in water body

improvement or degradation in France. Lenat and Crawford (1994) studied the effects of

various disturbances on water quality and aquatic biota and found that the abundance of

some fish species and average size increase at the agricultural site whereas, urban site was

characterized by low species richness, low biomass and the absence of intolerant species.

As mentioned before (Chapter VI), four types of disturbances – agriculture, city, dam and

industry in rivers were studied in this work. All disturbances had three examples making 12

cases, and each case was studied for four seasons, thus, making it 48 cases in total. The

results are discussed below according to the disturbances.

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9.4.1 Disturbances due to the Agriculture:

Study of the of the agricultural disturbance on the integrity of the river system or simply the

effects and impacts in the running water by taking fish as an indicator is widespread in the

world, particularly in the developed countries. In fact, the first application of index of biotic

integrity (IBI) was to assess the integrity of the river flowing through highly fertile

agricultural land (Karr 1981). Since then, a number of fish base studies on agricultural

impacts has been done. Foy and Kirk (1996) studied the relationship of water quality

measured on a fisheries ecosystem scale with the stocking rate of grazing animals and found

that the manure produced significantly increased biological oxygen demand (BOD). Thus, it

is not only the chemicals such as pesticides and fertilizers coming from agricultural areas

but also organic wastes from livestock have impacts on the rivers and streams.

McCarthy et al. (1997) studied the bioaccumulation of various chemical compounds in fish

tissues coming from agriculture and industries in Slave River of the Northwest Territories in

Canada. Mensing et al. (1998) found that the fish diversity and richness generally decrease

with increasing cultivation in the landscape. In one of the study in Honduras, Kammerbauer

and Moncada (1998) found that in river water samples, more pesticides residues at higher

concentrations were associated with areas of more intensive agricultural production. In

Nepal too the similar situation is found in the areas of intensive agriculture but more studies

are needed in this direction.

In Mexico, Soto-Galera et al. (1998) found that 50% of the sites in Rio Lerma Basin were

no longer capable of supporting fish and one of the reasons behind was agricultural

development. In one of the study towards the management of wastewater due to industries

and agriculture, Liang et al. (1999) studied the accumulation of varieties of chemicals in

fish flesh and viscera and found that the viscera played an important role in storing

chemicals. Berg (2001) studied fish farms in Mekong delta, analyzed the use of pesticides

and found that the farmers growing fish in their rice field used less pesticide than farmers

growing only rice. This kind of approach could be very beneficial to Nepal in lowering the

intensive use of pesticide, as the paddy is also the main crop in the country.

Bohn and Kershner (2002) in their study regarding aquatic restoration found that non-point

source pollutants including runoff from agriculture and livestock grazing accounted for

more than half of the United States water quality impairments. In Nepal, the story may not

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be so but the impairments of water quality are high in the areas of intensive cultivation. This

study has investigated three such areas with fish as an indicator and the results showed the

effects of agriculture were present in those areas. In many African countries, the economy,

mainly, depends upon the agriculture and as such pesticides constitute the major

contaminants in the river water. In their study about tilapia exposed to organochlorine

pesticides Okoumassoun et al. (2002) found significant amounts of Vitellogenin in fish

from contaminated sites.

Similarly, Balogh et al. (2003) studied methylmercury (MeHg) in rivers draining cultivated

watersheds and found that the land use in these rivers was over 90% row-crop agriculture,

and extensive artificial drainage systems deliver runoff and associated solids quickly to

local streams and rivers. They also urged for further studies regarding mercury uptake

mechanisms in resident fish populations. In a similar study in Brazil, De Oliveira-Filho et

al. (2004) studied the susceptibility of fresh water species to copper-based pesticides and

fertilizers as they were widely used in agriculture and compared the toxicity to different

fresh water species including B. rerio, a fish, which is also found in Nepal.

The literatures cited above represent the state of art regarding the study of agricultural

pollution in rivers and streams and their effects on fish population. It is also established

from above that the use of chemical fertilizers and pesticides are a global problem and due

to their runoffs to the rivers, aquatic species are suffering. Chandroo et al. (2004) even

studied whether fish can sense pain, fear and stress and found that they do experience these

factors in similar ways as in tetrapods. Thus, it is now well established that the fish

population through their various characteristics indicates the degree and extent of impacts

due to various disturbances including agriculture.

The significance of agriculture in Nepal’s economy has already been described in earlier

chapters. It is a backbone of country’s economy and utilizes large amount of fertilizers,

pesticides and organic manures. Thus, it is one of the factors of river pollution, especially,

in the areas of intensive cultivation. Three different such cases, Jhikhukhola in Kavre

district, East Rapti in Makawanpur and Chitwan districts and Tinau in Palpa district were

studied in this work. Some differences in the abundance of fish (CPUE) and total number of

species were seen between upstream and downstream sites (Fig.8.5.1 and 8.5.2), but the

differences were not decisive. The value of nonparametric Mann-Whitney test for the

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impact of agriculture in terms of abundance of fish in all rivers also showed no significance

(P > 0.05). In the same way, parametric one-way ANOVA for the impact of agriculture in

terms of number of species too showed no significance (P > 0.05)

However, the impacts should not be generalized as there were visible differences between

upstream and downstream in some rivers and in some seasons and these differences were

also backed by statistical tests. For example, though one-way ANOVA for seasonal

variations between the sites in terms of number of species showed no significance (P >

0.05), the nonparametric Kruskal-Wallis test for the same in terms of abundance showed

significant seasonal differences in downstream (P < 0.05). This indicated that downstream

site exhibits seasonal differences of the impacts of agriculture. The median value of

abundance was highest in spring and lowest in premonsoon (Fig.8.5.3) indicating that due to

the lowest flow of water the concentration of the pollutants was highest and thus less

abundance. This was further proved by the second variable, number of species, which was

lowest in premonsoon in downstream. Nevertheless, the individual cases were found to be

different.

For the individual cases, Jhikhukhola downstream consistently showed significantly higher

abundance of fish indicating higher productivity probably due to the nutrient input from the

agricultural field (Fig.8.4.93 and 8.4.94). The downstream in this river also showed a few

more species than the reference sites. Species such as B. vagra, B. rerio, H. fossilis and N.

corica were missing from the upstream sites suggesting that they are more suitable to the

mesotrophic habitat. However, the high abundance of fish and their richness do not

necessarily denotes a better condition as it is well known fact that a cool oligotrophic water

supports less number and varieties of fish than the warm mesotrophic water. With this

theory, it can be concluded that the upstream sites were better in terms of integrity, though,

the productivity was higher in the downstream.

Further, the seasonal variations in abundance also showed interesting picture. The

abundance of fish in the reference site was consistent throughout all the seasons of the year,

but downstream showed a fluctuating trend. It was highest in winter and lowest in autumn

indicating the role of agricultural season and the monsoon. During monsoon due to high

current and discharge, the fishes are either drifted away further downstream or the nutrients

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were washed away. Thus, there was a more or less visible impact of agriculture in this river

and downstream was found to be a disturbed site.

The second case of agricultural disturbance was that of East Rapti River in the fertile valley

and plains of Makawanpur and Chitwan. The impacts of the agriculture were probably least

visible in this river compared to other rivers and it may be due to relatively larger discharge

of water. The yearly data showed marginally higher abundance and the lower number of

fish species in the reference site compared to disturbed site (Fig.8.4.95 and 8.4.96).

However, the seasonal pattern in abundance and the species number showed more

inclination towards the seasonal climate than the impacts of agriculture.

In the reference site in this river, the abundance was least in autumn just after the monsoon

season indicating the flushing of fish population by very high current, while the highest was

in the spring when the water is less and cool. The downstream site showed the consistent

abundance of fish in all seasons except also in spring when it is exceptionally high.

Relatively larger number of species in disturbed sites may be due to various reasons such as

the geographical and substrate, downstream connectivity with large river as this river drains

in Narayani River some kilometers downstream, and the location as it is in the sensitive area

of the National Park. The same thing could also be the reasons for the differences of species

composition between two sites. The downstream site showed more of the lowland warm

water species.

The third case of agricultural disturbance was that of Tinau River in Palpa district. The

impact of agriculture was visible in this river too, but in a different way. Unlike

Jhikhukhola, the yearly data (Fig.8.4.97 and 8.4.98) of this river showed very high

abundance of fish in upstream compare to downstream, though the numbers of species on

both the sites were more or less the same. This fact suggested that it is not only the nutrient

content in water is important but also the substrate and other physical factors. The upstream

site was a small channel with smaller substrate and the large abundance was mainly due to

the small fish P. sophore, which dominated the number. Though, structurally downstream

site was better with boulders, rocks and cobbles dominating, it might be due to the

chemicals that the downstream site had less number of fish. However, the bigger fish

species such as T. putitora and N. hexagonolepis and some catfishes, which prefer the

structured habitat, were never present in the reference site.

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Seasonal abundance was consistent in the upstream site suggesting the least impact of the

chemicals coming from cultivated areas, whereas, the fluctuation of abundance in

downstream corresponded with the general agricultural practice of the people and hence

suggesting its impact. Both the abundance and the number of species in downstream were

lowest in premonsoon season, indicating the high concentration of toxic chemicals in water

due to low flow. The number of species recorded in this season was merely 5, which in

favorable time was recorded as high as 16. The best assemblage of fish both in terms of

abundance and the species richness were recorded in spring, which follows the winter

normally marked by the least agricultural activities. Least agricultural activities mean the

least application of chemical fertilizers and pesticides in the field. Marginally better species

richness in the downstream, however, could be linked as mentioned before to the better

structure of the river.

In short, the study of the impacts of agricultural disturbances produced mixed results

indicating that the impacts could not be generalized and the cases must be assessed

individually. Nevertheless, the study also pointed that this particular disturbance has the

potential to alter the water quality of the rivers and streams, and thereby affecting the

integrity of the system.

9.4.2 Disturbances due to urbanization (City):

Like the agriculture disturbances, disturbances due to urbanization on the integrity of the

river system by focusing on fish too are important and popular studies all over the world,

especially, in the developed countries. There are numerous studies in this field, but the

studies from Nepalese cities are clearly lacking. Weaver and Garman (1994) studied

urbanization and long term changes in a stream fish assemblage, and found that the

observed changes were consistent. Even a high-tech ecological assessment using GIS to

assess river watershed had included fish health as one of the indicator (Zandbergen 1998). It

must be because fish based characteristics are good indicators of water quality and

conditions. The disturbances due to urbanization, particularly, sewage inputs in the rivers

and its impact was one of the main areas studied by Penczak and Kruk (1999). They found a

high correlation between them.

Wichert (1995) found that better waste water treatment and management allowed sensitive

species to colonize. In one of the studies by Miltner et al. (2004), they found that the

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biological health of lotic communities was negatively correlated with the amount of urban

land use in the surrounding watershed. This highlights the rational of including the study of

the impacts of city by taking fish as an indicator in Nepalese rivers. Bohn and Kershner

(2002) also found that one of the major non-point source pollutants comes from runoff from

municipalities and is the cause of water quality impairment. This also supports why there

was a need to investigate the effects of cities in the rivers in Nepal.

Nepal is still a predominantly rural society, but there has been a tremendous growth of

urbanization, especially, in past few decades. The numbers and sizes of the urban centers in

Nepal have already been discussed in earlier chapters. However, one point to stress is that

the cities in Nepal are, generally, growing haphazardly without many facilities like sewage

and sanitations, sufficient water supply and efficient waste management. The lack of these

basic municipal facilities puts enormous burden on nearby rivers and streams as they are

seen as the remedies for all. This is why the study of impacts of cities on the rivers was

included in this work.

Three different cases, Narayanghat, Butwal and Pokhara were studied to see their impacts

on rivers Narayani, Tinau and Seti respectively. There were not substantial differences

observed between upstream and downstream both in terms of the abundance and species

richness (Fig. 8.5.1 and 8.5.2) in the first glance except that both of these variables were,

marginally, less in downstream sites. The nonparametric Mann-Whitney test for the impact

of cities in terms of abundance of fish in all rivers too showed no significance (P > 0.05).

Similarly, parametric one-way ANOVA for the same impact in terms of number of species

also showed no significance (P > 0.05). This indicated that, overall, the cities studied here

have not impaired the water conditions in the respective rivers.

The seasonal variations of the impacts too were proved not significant in terms of

abundance of fish by nonparametric Kruskal-Wallis test (P > 0.05). In the same way, one-

way ANOVA for the seasonal variations of the impacts in terms of number of species was

no different (P>0.05). Thus, all the statistical hypothesis tests uniformly showed that there

were no substantial differences between upstream and downstream sites for this impact and

thus, these cities have not impaired the integrity or the conditions of corresponding rivers.

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When seen individually, there were marginal differences between upstream and

downstream in Narayani Rivers in yearly data in terms of both the variables (Fig.8.4.99 and

8.4.100). This proved that though, slightly, the upstream site still had a better condition.

This was further proved by the presence of the species like S. richardsonii and T. tor, which

normally prefer cool and less contaminated water in the upstream site. Further, the seasonal

variations in two sites showed the abundance of fish always higher in the reference site

compared to disturbed site except in spring season when it was lower. This could be

because the downstream site had a little warmer temperature than the upstream site.

The second example of the impact of urbanization studied was that of Pokhara city on Seti

River. In fact, the yearly data of impacts in upstream and downstream in this river showed a

little bit reverse trend. Though the differences between upstream and downstream, in terms

of both the variables, were not so substantial, it was, slightly, in favor of downstream

(Fig.8.4.101 and 8.4.102). Again, the same law, that the fish assemblage all the time does

not, necessarily, show the better conditions might be applied here. The upstream site with

cool oligotrophic water directly coming from the Himalayas were expected to support less

fish than a more warm and nutrient enhanced water in downstream.

Another reason for the fish assemblage to be higher in downstream was also because of the

connectivity of this river with other major rivers, while the upstream is completely cutoff

due to a weir just before the city. The species missed in reference site such as A. botia, B.

rerio, C. orientalis, D. dangila and H. fossilis also indicated that the downstream had more

nutrients. However, in any case, the differences were not so big and this meant,

surprisingly, that the city of Pokhara has little impact on the integrity of this river.

The seasonal differences in the abundance of fish in upstream and downstream site showed

interesting picture corresponding with hydrological regime and temperature rather than the

impacts of the city. The abundance of fish was found to be, comparably, higher in upstream

in premonsoon season while it was reverse in autumn, when downstream had more fishes.

Premonsoon, normally marked by high temperature and low flow showed water shortage in

the downstream, especially, due to the diversion by a weir some distance after the upstream

site. Thus, there were more fish in upstream due to more water and warm temperature. In

autumn, the season just after monsoon, the water flow was not a constraint in downstream

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and hence showed the larger abundance of fish. Also, by autumn, the temperature declines

and some of the species have to find warmer water.

Another example of the impacts of urbanization studied was that of Butwal in the bank of

Tinau River. There were clear differences between upstream and downstream in this river

both in terms of abundance of fish the number of species (Fig.8.4.103 and 8.4.104). The fish

based indicators showed a clear picture of impacts in this case. The yearly data showed a

huge dip in the abundance of fish in downstream indicating that the conditions there were

not good. Similarly, the number of species too was considerably low highlighting the

serious impacts of the city. In addition, the missing species such as B. rerio, C. latius, G.

pectinopterus, G. telchitta, L. dero, N. corica, N. hexagonolepis, P. sulcatus and T. putitora

indicated the poor water quality. The reference site, in this case, clearly had the better water

quality and structure.

Seasonal differences in the abundance and species richness between reference and disturbed

site were also big and consistent in all seasons except premonsoon. This further confirms

the serious impacts of Butwal city in this river. If, the impacts were not so grave, the

abundance and number of species surely would have fluctuated according to water regime

and fish life history. However, premonsoon was an exceptional case that year because a

massive poisoning of the river to collect big volume of fish was reported just about a week

before the sampling in this season. In fact the abundance of fish in disturbed site was higher

in this season indicating that tolerant species survive more in such incidents.

In short, the study of the impacts of city on the river also produced mixed results indicating

that the impacts could not be generalized for all the cities. The cases must be assessed

individually as was shown by this study. Though hypothetical tests showed no significant

impacts in both the sites in any seasons, the case of Butwal city showed that some visual

judgments could produce better result than the statistics. There were no visible impacts of

city in Narayani River because of the couple of reasons. First, the river is one of the largest

rivers of the country and has a great carrying capacity. Second, the city has grown across

the river and not along the river, which limits the interaction of the city and the river to a

very small area.

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Some impacts of Pokhara city on Seti River were very much expected as it flows through

the heart of the city. But surprisingly, here too no substantial impacts were detected. The

reasons behind this must be the source of water, which is clean and directly coming from

the mountains with high carrying capacity, and connectivity of downstream with other

rivers. However, Butwal city gives a clear account of the impacts of city on the river. It was

such a remarkable difference within a very short distance. The upstream site was just a

kilometer before the main city in the river and downstream always had been the point from

where the river gets underground and disappear. In fact the river is seen braded into a

number of channels and all get terminated midway through the city. This area was also

marked by open toilets, haphazard slums and massive gravel extractions. Thus, the impacts

seen on the river was fully expected.

9.4.3 Disturbances due to dams:

Another important disturbance having potential to influence the integrity of the river system

is the construction of dams and weirs. Judging by the researches done on the impacts of

dams on the river world wide, their significance in changing the ecology of aquatic systems

is well established. Thus, it could not be ignored in Nepal as well since the biggest resource

of the country is water. In his study regarding the conservation of native fresh water fishes

Moyle (1995) has described that the construction of dams and reservoirs in every major

stream in California is the main reason for depleting fish resources. In Nepal, the result

might be the same but the studies are required.

Brain and Kinsolving (1993), in their study have found that the longitudinal pattern of

species occurrence and fish abundance was consistent in the free flow river, while

inconsistent in the river with dams. In their study, Rinne and Stefferud (1999) have also

acknowledged the marked alteration of historic hydrology by dams and diversions. When

hydrological regime is altered, then the entire aquatic ecosystem too is changed. Jager et al.

(2000), in their description of population viability analysis of riverine fishes have

mentioned about the conflicts between cost-efficient hydropower and the protection of

riverine fishes. This also indicates that the construction of dams inevitably affects the fish

population and thus, the fish population studies reveal the degree of severity.

Hagglund and Sjoberg (1999) likewise have studied the effects of beaver dams in forest

streams but unlike others, they have concluded that these dams might enhance fish species

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diversity. This indicates the natural soft barrier, sometimes, increases the types of habitat

and so increases the diversity. However, once the size and material of the dam changes, the

adverse effects to fish population get started. This could be seen from the work of Howard

and Layzer (2002) in large regulated river, where they observed that significant differences

occurred temporally and spatially. They also concluded that downstream sites were more

diverse and supported higher abundance indicating that the upstream is affected more by the

construction of dams in terms of fish population.

Jackson and Marmulla (2001) have also pointed the mixed nature of impacts of dams in

their work. In one hand, they say that there are negative impacts of dams on the native

fishes, but on the other hand argues that the reservoir created could be utilized well with

exotic commercial species. However, Larinier (2001) concludes that the construction of

dams on rivers block or delay upstream migration and thus contribute to the decline and

even the extinction of species that depend on longitudinal movements along the stream

continuum. Further, he lists, habitat loss or alteration, discharge modifications, changes in

water quality and temperature, increased predation pressure as well as delays in migration

as significant issues, all affecting the fish resource.

Fish base evaluations for the disturbances such as dams are very useful as was found by

Penczak and Kruk (1999). In fact, they have concluded that the abundance/biomass

comparison method is applicable for detecting all human impacts on fish population. Thus,

the fish based analysis done in this work is a standard method to detect the impacts. The

literature cited above illustrates different aspects of fish base studies of the impacts of dams

in different parts of the world. However, this study could be the first of this kind from

Nepal.

The importance of dams for power and irrigation in Nepal has already been discussed in

earlier chapters. In fact, the future of the country largely depends on the utilization of water

resource and for that the construction of dams will continue for sometime until the

alternatives are explored. Three different cases of dams for their impacts by taking some of

the fish base characteristics were studied in this work. The dams in Aandhikhola River at

Galyang, Syangja, in Bagmati River at Sundarijal, Kathmandu and in Tinau River, Palpa are

the three cases. Some similarities of these dams are that all of them are not a massive

construction and also not new.

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There were not visible differences in terms of both the abundance and the number of species

between upstream and downstream sites of the dams as seen through box plots (Fig.8.5.1

and 8.5.2). Similarly, nonparametric Mann-Whitney test showed no significant impacts due

to the dam in terms of the abundance of fish (P > 0.5). The parametric one-way ANOVA

test in terms of the number of species too showed no significance. This indicated that if all

the cases are seen together, no significant impacts due to dams were apparent. However, as

already mentioned before, individual cases should be analyzed in both spatial and temporal

(seasonal) basis to see the clear picture of the impacts.

Accordingly, significant seasonal variations in impacts were shown by nonparametric

Kruskal-Wallis test in the reference sites in terms of abundance (P < 0.05). This meant that

the conditions in upstream sites were not stable temporarily, which further indicated that the

fish and fisheries were highly affected in upstream. Amazingly, the upstream of the dam

was only the second instance of significant impacts shown by this hypothesis test after

agriculture downstream in this study and hence must be very important. Though, the one-

way ANOVA test for seasonal variations of impacts of dams in terms of the number of

species did not show any significance in either of the sites.

Most importantly, the individual cases normally showed some kind of better conditions in

downstream rather than upstream in terms of both variables. The yearly pictures of fish

attributes in upstream and downstream of dam in Aandhikhola showed more abundance as

well as richness in downstream indicating that the dam has restricted the upstream

migration of the fish (Fig.8.4.105 and 8.4.106). It also seems that the fish ladder built at the

side of dam is not working, but this needed to be verified. The good abundance and

richness of fish in downstream could be because the river is connected with one of the

largest river of Nepal, Kali Gandaki further down. However, the situation in upstream was

not so bad as was expected in terms of these variables and this could be because the river

could maintain a fine structure of its banks and substrate.

The seasonal variation of abundance and number of species between upstream and

downstream in Aandhikhola was interesting to note. There was a big difference of

abundance in premonsoon season in favor of downstream indicating that the fish from Kali

Gandaki were migrating in Aandhikhola, though water flow was minimum in this season,

probably for spawning. In other seasons, there was not substantial variation in the

9 Discussion

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abundance. In terms of number of species, upstream was rather consistent in all seasons but

in downstream in autumn it was too low. This consistency of species richness in upstream

meant that the fishes are either resident or they are restricted from traveling due to the dam.

On the other hand fluctuations in downstream indicated that there were to and fro

movement of fish species between Kali Gandaki and Aandhikhola.

The second case of disturbances due to dam studied in this work was that of Bagmati River

at Sundarijal. There lies one of the oldest dams of the country. The result of this dam was

just opposite of the first case, which means, highly in favor of the upstream if we take the

fish attributes as indicators. The yearly data of the study in this river showed that the

abundance of fish was significantly higher in upstream site compared to downstream

indicating that the upstream has better conditions than the disturbed site (Fig.8.4.107 and

8.4.108). However, the number of species in both the sites was too low with just 3 and 2

species respectively. This value of species richness is too low to talk about even though the

cool water in high altitudes supports less number of fish. Good news for fish communities

in these sites is that they lie inside Shivapuri National Park.

Too less abundance in downstream of the dam in this case was probably because of the low

flow due to diversion and lack of connectivity with other tributaries further down. The river

once it reaches Kathmandu Valley, gets so polluted that it is virtually impossible to trace

any fish communities, thus, further disrupting the longitudinal corridor within the same

channel by the pollutants. In any case, it is even difficult for fishes to reach the base of the

dam, naturally, also due to steep gradient and in low flow the river at some places appear as

a water fall.

The seasonal differences of fish attributes between upstream and downstream were found to

be consistently in favor of upstream. The biggest difference between two sites was in winter

season and the least (almost equal) in premonsoon. This could be because in winter the

fishes come as near to dam as possible to counter the temperature and pre monsoon, most

likely, marks the beginning of the spawning time and thus, the fishes move further upstream

for that. In any case, there were visible differences between upstream and downstream of

the dam in Bagmati River and judging by the fish assemblages, the upstream of dam was in

better condition.

9 Discussion

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The third case study of the impacts of dam studied in this work was in Tinau River in Palpa

district. This dam too is small and fairly old. The yearly data of fish assemblage showed

little difference between upstream and downstream, marginally better situation in

downstream (Fig.8.4.109 and 8.4.110). However, there were some differences between the

two sites in terms of species composition. Upstream site was found to possess T. putitora

and T. tor, the presence of which generally marks the better quality of water, while

downstream site showed up some tolerant lowland species.

The seasonal variation of the impacts in terms of the abundance and the number of species

in upstream and downstream of this dam was also interesting to note. The spring season

showed no differences of impacts in two sites with nearly the similar abundance of fish and

the same number of the species. The impacts were least visible in this season. The

premonsoon season on the other hand showed big but mixed differences of impacts between

the two sites. The abundance of fish in upstream was too low though the species richness

was higher than the downstream site. However, too less abundance in upstream could be

because of a massive poisoning in the river just before the sampling. Little higher

abundance with less number of species in downstream also suggested that it might be due to

high numbers of a few tolerant species, which could withstand the poisoning. In any case

the variations here looked more because of this reason than the dam.

The autumn season marked the good recovery of abundance and the species richness in both

of the sites indicating that the monsoon that appears between premonsoon and autumn

flushed all the residues of the poison and the health of the river was vastly increased. Thus,

in this season too there were no visible differences of impacts of dam in the two sides. But

in winter, the impacts of dam were most visible. Very less abundance and the number of

species in upstream site compared to the downstream site could not be simply related with

the event of poisoning and seasonal variations in water regime, but to the effects of dam.

And though, in winter the river disappears underground after some kilometers downstream

of dams, it highlighted the importance of longitudinal connectivity the floods in monsoon

bring about. The very one connectivity was found to be enough to sustain the fish

communities in downstream till the dam. The dam however completely blocks the

movement of fish upstream and hence was found to put some impacts on the integrity of the

river.

9 Discussion

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In short, the results showed that the impacts of dams on the integrity of the rivers and river

system too were of mixed nature, depending upon so many factors and as in the case of

other disturbances could not be generalized. The statistical backing for the impacts of dams

in upstream was found to be very strong in terms of the abundance of species, which were

illustrated by the case study of Aandhikhola and Tinau. However, the case study of Bagmati

River was found to be just opposite in the fact that there were visible impacts of the dam in

downstream site. Downstream large river connectivity, seasonal fluctuations in water

regime and the externalities such as poisoning are some of the factors found to modify or

determine the impacts of dams. Nevertheless, one thing is surely established by this

research, that the dams play a big role in changing the conditions of the rivers and thus

affecting the integrity of the systems.

9.4.4 Disturbances due to the industries:

The impact of industries in the local water bodies is well established all over the world. In

Nepal too, how the industries are related with water pollution was already discussed in

earlier chapters. Relatively, more studies on the effects of industries to water quality

compared to the other disturbances are reported from Nepal. However, most of the studies

focused on physico-chemical and pathogenic aspects of the pollution. Thus, study of the

impacts of industrial disturbances on the integrity of the river system is included in this

work. As in the study of other disturbances in this work, the fish base analysis of the

impacts of industries is also a new field of study in Nepal.

There are so many researches done on the effects of industrial pollutions on fish and fish

base analysis of industrial impacts, again particularly, in developed countries. Grant (1997)

has mentioned about applying ecosystem principles to all of the industrial activities such as

site and building design, landscape planning and site management policies where they have

also described the effects of water pollution on fish communities and how to overcome it.

McCarthy et al. (1997), studied the fish tissue to find contaminants, mainly the chemicals

coming from variety of sources including industries. Similarly, Liang et al. (1999) studied

the bioaccumulation of trace metals in fish, which normally comes out from effluents of

some of the industries. Zann (2000) has also mentioned that one of the main reason due to

which fisheries are declining is the industrial pollution. Kim et al. (2004) studied the

accumulation of cadmium in fish, while Nikl and Farrell (1993) studied the toxicity of the

9 Discussion

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wood preservative agent and found the reduced swimming performances due to this agent.

Gomaa et al. (1995), studied the distribution pattern of some heavy metals in Egyptian fish

organs, highlighting the effects of industrial effluents on fish. Since, fish are the important

food resource for human beings, there are numerous such studies where the industrial

pollution, particularly, affects fish primarily and to other organisms through the food chain.

However, these kinds of studies are yet to get momentum in Nepal.

In their study in the Rio Lerma Basin, Soto-Galera et al. (1998) used fish as indicators of

environmental quality, which is mainly degraded by industrial development. Violette et al.

(1998) in their study of indicators of biotic integrity in Quebec Rivers, they have illustrated

that how industrial pollution affects aquatic communities, especially the fish communities.

Schulz and Martins-Junior (2001) used a fish species, Astyanax fasciatus as bioindicator of

water pollutions mainly coming from industries. Karels and Niemi (2002) studied fish

community responses to pulp and paper mill effluents and found that different species have

different sensitivity towards this pollution. One of the case studies of industrial impacts

included in this work is also regarding the same industry.

Mrakovcic et al. (1995), in their study discussed the status of freshwater fish in Croatian

river systems, which are, generally, marked by industrial pollutions. Similarly, Balik (1995)

also studied the status of freshwater fish in Turkey and found that industrial pollution was

the main reason of their decline. Detail effects of the various pollutants, especially from the

industries on fish and fish populations are well described by Lloyd (1992) in his book titled

‘Pollution and freshwater fish’.

As mentioned earlier, there are very few literatures regarding industrial pollution and its

effects on fish community in Nepal, though there are some on the other aspects of the

pollutions. There is one study by Pradhananga et al. (1998) that compares the effluent of

two paper mills in the country on their effects on local biotic communities. Kharel and

Thapa (2003) studied effluent impact of Bhrikuti Pulp and Paper Mill on water quality of

Narayani River mainly in terms of physico-chemical parameters. There also exists series of

reports on the tolerance limits for industrial effluents discharge into inland surface waters

by Ministry of Industry.

9 Discussion

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Though, not an industrial nation, the studies of industrial pollution are important in Nepal

mainly because of two reasons. Firstly, the process of industrialization will continue for the

development of the country, and secondly, most of the established industries are related

with water pollution. Thus, this work has included the impacts of industrial disturbances on

the river system of Nepal. The analysis of the health and integrity of the rivers in Nepal with

the help of fish communities marks the field of new research and this work is just a starting

point. Three different cases of industrial pollution, Shree Distillery on Arungkhola, Hetauda

Industrial District (HID) on Karrakhola and Bhrikuti Pulp and Paper Mill on Narayani River

were selected in this work for the study.

Differences in the median value of abundance of fish and total number of species were

found between upstream and downstream sites for this disturbance when seen from broader

look (Fig.8.5.1 and 8.5.2). In terms of both the variables, it was found that the downstream

site was more impaired, as is normally found for this disturbance. The impacts from the

industries were the only impact studied in this work showing significance by nonparametric

Mann-Whitney test (P < 0.05). This meant that there were significant impacts by this

disturbance in terms of the abundance of fish. In addition to that, this disturbance was also

the only case where parametric one-way ANOVA showed significant impacts (P< 0.05)

indicating that the impacts in terms of the number of species too were significant.

However, nonparametric Kruskal-Wallis test for the seasonal variations of impacts in terms

of the abundance of fish in upstream and downstream sites showed no significance (P >

0.05) indicating that the impacts were rather uniform and did not fluctuate much according

to the seasons. Similarly, one-way ANOVA for the seasonal variations of impacts in terms

of the number of fish species in upstream and downstream sites too did not vary much. The

generalization that could be made from these tests is that there were significant impacts of

industries on the rivers studied and the impacts were uniform all through the year. These

facts were also illustrated by the box plots (Fig.8.5.9 and 8.5.10) on the impacts of

industries in terms of two variables where except during the premonsoon season for the

abundance, all the differences between upstream and downstream are more or less

consistent and in favor of the upstream. However, it still looked useful to see the individual

cases.

9 Discussion

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Arungkhola, which receives the effluents from the distillery, showed much less impacts

than expected as could be seen from the yearly data (Fig.8.4.111 and 8.4.112). The

differences of abundance of fish between upstream and downstream sites were negligible

and in terms of the number of species there were minor differences. Through this data, it

appeared that the upstream site was only marginally better than the downstream and that too

if we consider the species composition. The species, such as B. shacra, D. aequipinnatus,

M. pancalus, M. blythii and S. semiplotus, which were never present in downstream site but

in upstream site indicated that it was still in healthier conditions with good water quality.

The seasonal variations of the variables were interesting to note. The abundance of fish was

always higher in upstream site compared to downstream except in the winter season when

even the number of species there greatly improved. This suggested that in winter due to

warmer water and nutrient availability, many fishes move downstream and colonize the

area. Another thing to note here is that the abundance of fish in upstream was not less

either. In premonsoon season the case was just found to be reverse. The abundance of fish

downstream was too low in comparison with the other seasons and with the upstream. This

indicated that due to low flow of water the effluent concentrations in that site increased. The

condition must increase the toxicity of chemicals or the Biological Oxygen Demand (BOD)

and in either case the abundance of fish declines.

Thus, the case of Arungkhola illustrated the impacts of the industry though the impacts

were very less. The impacts of the industry appeared within the carrying capacity of the

river. However, the analysis was able to discriminate between upstream and downstream

sites and the health or the integrity of upstream site was found to be in better condition.

Karrakhola, which receives the effluents from the entire industrial district of Hetauda, was

taken as the second case study in this work. Unlike from the previous case, the effluents

received by this river are of mixed nature, which come from variety of industries inside the

industrial district as described in the earlier chapters. However, the yearly picture showed

little differences in terms of the abundance and the number of species between upstream and

downstream sites (Fig.8.4.113 and 8.4.114) indicating either the industrial impact is not

significant in this case or the presence of other factors that compensate the impacts.

9 Discussion

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The composition of the species gave some trends of the impacts as some tolerant species

such as N. corica and P. conchonius were only present in the disturbed site and the species

such as B. barna, E. danricus and P. sulcatus, which were found relatively sensitive only in

the reference site. It’s a small trend, which was mainly compensated by the downstream

confluence of this river with a larger order river East Rapti, a little distance after the

downstream site. The fish from this larger river get access to Karrakhola making it rich in

terms of species diversity.

Seasonal variations of the abundance showed some glimpses of the industrial impacts,

though it was never very low in both the sites in all seasons. The abundance of fish in

upstream site was found to be higher in all the seasons except premonsoon. There could be,

mainly, two reasons for this. The water flow in this season was found to be very low in this

season and the fishes tend to move downstream towards the confluence with East Rapti.

This could be one reason for more abundance in downstream site. The other reason could be

the nutrients coming from the effluents of industries. In premonsoon, the concentration of

the nutrient increase due to low flow and the fishes seem to feed there. The advantage, they

have is if the effluents are not desirable, the fishes can quickly escape to another river as the

confluence is very near from the downstream site.

Thus, the case study of Karrakhola for the study of the impacts of industries did not

produced an alarming situation as was pointed out by the statistical case. Most of the time

the statistical tests of the impacts proved it less significant than the general overlook of the

case, but the case of Karrakhola was quite opposite as there were powerful statistical

evidence whereas very moderate situations of the impacts. Nevertheless, the case showed

some mild glimpses of the impacts.

The third case of industrial disturbance studied in this work was of the Narayani River,

which receives the effluents from Bhrikuti Pulp and Paper Mill. Some information

regarding this industry and its effluents were already described in the earlier chapters. The

yearly picture of the abundance of fish in upstream and downstream of this river showed a

big impact matching with the statistical tests (Fig.8.4.15 and 8.4.16). The impacts in terms

of the number of species were a little less, though it was a big difference between upstream

and downstream in terms of species composition. The downstream site or the disturbed site

was found to have a significant impact of this industry. Moreover, the absence of the

9 Discussion

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species such as B. bendelisis, B. shacra, C. latius, G. gotyla gotyla, G. telchitta, L. dero, P.

pseudecheneis, S. semiplotus, T. putitora and T. tor, some of them even considered as

lowland and relatively tolerant species indicated that the integrity of the river at this point

was highly threatened.

The downstream site was found to possess highly tolerant species such as C. orientalis, C.

punctatus and P. conchonius. The only exception was G. giuris, which was found to be rare

in number in this study, was present in this site. The overall yearly picture, in any case,

showed a grave situation in this site and it could be a matter of further study to find if the

river recovers this impairment further downstream.

Seasonal differences of impacts in terms of the abundance and the number of species

consistently showed better conditions in the upstream and impaired conditions in the

downstream. The premonsoon season showed a comparatively better situation in

downstream site and there could be some reasons for that. It was not sure if the production

activities of the industry was very less in this season and hence less effluents coming in or

the fishes might find more nutrients in this site in this season. The fish assemblage showed a

large number of juveniles in this season indicating that it could be an easy feeding and

growing ground because of the nutrients and absence of predators.

In short, the study of the impacts of industrial disturbances produced results that indicated a

strong relationship of the industries and the water quality and integrity of the rivers.

However, once again the analysis showed that the cases could not be generalized.

Sometimes, even the statistical analysis could be insensitive or more sensitive than the

actual situations. It was thus, found that the cases should be analyzed individually and the

specific changes or trends due to the impacts should be identified before applying any

corrective measures to restore the integrity of the rivers.

10 Conclusions and recommendations

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CHAPTER X: CONCLUSIONS AND RECOMMENDATIONS

The main aim of this work was to study the fish population dynamics and to see whether

these traits show differences in contrasting disturbance regime so as to develop a tool that

could assess the integrity of the river system. Since so many valuable information regarding

the both, fish and water, resources were collected from the field for this purpose, the present

work has tried hard not to lose the information for the good by utilizing them in the

analysis.

The total number of fish recorded during this study was 47, which, by any standard, is not

less if we consider that only nine rivers and 23 sites were covered. Yet, it is acknowledged

that if River Narayani, one of the rivers studied in this work could be sampled by boat

mounted fishing gear, the species diversity could have gone much higher. Still, this river

was found to possess the highest number of species among the rivers studied. The lowest

number of the species was recorded from River Bagmati, but then the sampling site in this

river also had the highest altitude. The national record of 182 fish species is actually

spreaded over thousands of rivers, lakes and ponds in different ecoregions of the country.

Among the species, B. barila, B. bendelisis, B. vagra, G. gotyla gotyla, S. beavani, and S.

rupecula were found to be most widely distributed species as they were found in all or eight

out of nine rivers, which were sampled. This implied that these species are not threatened

now and there abundance could be developed into metrics to assess the river conditions.

Similarly, G. chapra, C. reba, T. tor, N. chelynoides, A. morar, B. barna, D. dangila, S.

progastus, P. pseudecheneis, B. almorhae, C. garua, M. blythii, G. pectinopterus, G. giuris

and M. pancalus were found to have very limited distribution and thus could be vulnerable.

Some of these species are listed as common by IUCN, and thus require further evaluations.

In the meantime, this second group of species too could form a metrics for the evaluation of

water and habitat quality of the rivers.

Further, new altitudinal ranges for G. chapra, C. reba, P. chola, S. semiplotus, D. dangila,

P. pseudecheneis, M. blythii and S. beavani were recorded in this study than previously

recorded indicating that more primary information is required to find out exact distribution

ranges of many species. Similarly, the new records of size were also established for the


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following fish species, L. dero, P. conchonius, B. barila, B. rerio, D. dangila, G.

annandalei, G. gotyla gotyla, S. beavani, B. almorhae, B. lohachata, L. guntea, G. telchitta,

H. fossilis, C. orientalis and M. armatus.

The abundance of all the species in each river was also calculated to see clear picture of

their status. The abundance of fish was found to be highest in East Rapti River where as it

was lowest in Bagmati River. However, it should be noted that East Rapti is lowland warm

water river, which naturally supports more fish and the sampling sites in Bagmati were in

considerably high altitude with coldwater. The low abundance of fish in Narayani could be,

as mentioned before, the inadequacy of sampling technique in the large river. The other

rivers, which were studied in this work, had a fairly good abundance indicating good water

and habitat conditions in general.

Among the species, S. beavani, G. gotyla gotyla, S. rupecula and B. barila were found to

have good abundance among the rivers sampled. Whereas, B. barna, C. reba, D. dangila, G.

giuris, G. pectinopterus, G. chapra, M. pancalus, N. chelynoides, P. pseudecheneis, P.

chola, S. semiplotus and Tor tor were found to have very low abundance among the species

recorded. By comparing the limit of distribution and the abundance, a fairly clear status of

the species could be worked out. This information not only help in the conservation of

threatened species, but also give the information about the species which could be harvested

sustainably. In the meanwhile, metrics based on rare or intolerant species to assess the river

conditions could also be developed in the future.

Besides, the density of all the species in each river was also deducted, though it should be

taken as rough minimum estimates. Minimum is, because, it is not possible to capture all the

fishes of the area using any gear, even electrofishing. And rough is, because, the calculation

of the area in rivers is very difficult and tricky. The best way to calculate the area is by

digital map and that was not available for this study. Here the density was calculated as the

number of individuals/100 m² of area. The density of fish species in each river would

advance the picture of the status on one hand, and on the other hand the information would

be very handy on estimating the biomass and standing crop if the information of size

structures for each species is available.


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To help calculate the biomass, an example of size structure analysis was also worked out in

this work. The length frequency distribution and length-weight relationship of the fish

species have various applications. Not only these analysis help in calculating the

productivity of the rivers but also allowed to see some life-history and ecological traits of

fishes such as breeding seasons, migrations and period of stress. Thus, the size structure

analysis of each fish species in the country is highly recommended.

The fish community parameters and the morphological and physico-chemical parameters

were also applied to classify the rivers and river systems that were studied. The results were

found to be very impressive as it classified the rivers into natural regional groups. This

indicated that the fish population variables and the abiotic factors are efficient to

discriminate each other to form natural groups. The application of this kind of classification

is tremendous especially in management and monitoring of fish and water resources and is

hence highly recommended.

The assessment of the impacts of various disturbances on the integrity of the rivers

produced highly encouraging and unbiased results. The results indicated that the prevalent

agricultural practices in the country have potential to change the integrity of the rivers as the

chemical fertilizers and pesticides, ultimately, finds its way into the rivers. Though the

species richness and the abundance of fishes were more in disturbed sites due to the nutrient

input, the integrity of the river, which might be defined as the natural state, was found to be

degraded. This is a classical example where the high productivity does not always means

the high integrity.

Besides, the impacts of agriculture were found to be influenced by morphology and the

hydrological regime indicating that the generalization of the impacts was not possible. The

impacts were found to be high and low depending upon the substrate as well as the seasons.

Thus, river and region specific assessment of this impact is necessary to derive any

conclusion and that too should be in all the seasons.

The impacts of urbanization or the cities were found to be the weakest among the cases

studied in this work. Among these, the highest impacts were seen in Tinau River that of

Butwal city. It might be because in all of the seasons except monsoon the river terminates

right in the middle of the city and at this point river was found to be highly polluted. This


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polluted section was still found to possess some highly tolerant species. The downstream of

Seti River was found to harbor, marginally, more varieties and abundance of fish and could

be attributed to the mild pollution inducted by Pokhara city. This is another example of the

fact that the diversity and abundance of fish rather increases in small pollution and that they

decrease only when the pollution level is substantial.

The least impact of Narayanghat city on its river is another good example of the ratio of the

contact areas of the river and the cities. The city is oriented perpendicularly to the river, thus

decreasing the area of contact. Thus, the impacts on the integrity of the river by this

disturbance was found to be least among the cases, nevertheless, the fish base metrics were

able to show the trends of influences. Thus, the impacts of city could be generalized in the

sense that it affects downstream, the degree again depends upon so many externalities.

The study of the impacts of dams also indicated its potential to alter the health and integrity

of the rivers, and this time, the effects were found to be more serious upstream. It was found

that if there are any permanent or momentary connectivity to other rivers downstream, the

impacts of dam were found to be more in the upstream. However, if there is no connectivity

downstream, then the impacts are more in downstream like in River Bagmati. In addition,

the impacts could be much higher in the beginning of the construction of dams, which could

not be seen, as all the cases in the study were quite old. In any case, the longitudinal

corridor for the fish migration should be maintained through fish ladders and fish passes.

The impacts of industries were found to be the most serious among the disturbances that

were studied. In all the cases there were more or less clear picture of alterations on the fish

base characteristics between reference and disturbed sites indicating the influence of

industry. However, the degree of impairments was again found to be fluctuating depending

upon so many factors. In some cases such as the disturbed site of Arungkhola, the fish

community even appears to benefit from the effluents in some seasons. But the main aim of

the integrity assessment is to see the deviation from natural and normal conditions, and

sudden rise of abundance of fish, sometimes, should also be taken as an indicator of

impairments.

The table 10.1 illustrates the summary of the impacts of various disturbances in the rivers

studied throughout the year.


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Seasonal impacts Total impact

Disturbances Rivers Site

Spring Summer/ premonsoon

Autumn/ postmonsoon

Winter

Upstream East Rapti Downstream *

Upstream Jhikhu Downstream * * ** ** Upstream * * * *

Agriculture Tinau

Downstream *

* #

J T Upstream * Narayani Downstream Upstream Seti Downstream Upstream

Urbanization/ City

Tinau Downstream * * *

T

Upstream ** Aandhi Downstream * Upstream Bagmati Downstream * * * ** Upstream * *

Dams and weirs

Tinau Downstream

* A B

Upstream Arung Downstream * * Upstream * Karra Downstream Upstream

Industries

Narayani Downstream ** ** ** **

**# N

A - Aandhikhola

B - Bagmati River

J - Jhikhukhola

N - Narayani River

T - Tinau River

* - Visible impact

# - Visible yearly impact

*- Impacts having statistical significance

Table 10.1: Summary of the impacts in different rivers

Visible yearly impacts


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Based on the above conclusions the following recommendations are made:

• The fish base data of Nepal is still not sufficient as could be seen from several new

findings on the distribution of the species. Thus, the studies and research on fish

ecology should be highly encouraged.

• There is also an urgent need to develop national data bank of fish species specific

and river/region specific information, which should be easily made available to

anyone who wants to use it. Department of Fisheries could be the right institution to

do this.

• There are various applications of fish ecological information as was shown in this

study. To determine the status of the species, to calculate biomass and productivity

of the rivers, to classify the rivers and river systems of the country and to assess the

water quality and integrity of the rivers are just a few examples. More applications

of this information should be explored.

• Fish base assessment and monitoring river habitat and water quality are standard

practice in developed countries due to various reasons. This should be encouraged in

Nepal but also the other methods using macrozoobenthos, bacteria and physico-

chemical parameters should supplement it.

• The rivers in Nepal face numbers of disturbances as was described in this work, but

the generalization could not be made. Thus, the case specific assessment should be

practiced to draw conclusions rather than blaming the larger sector.

• The disturbances to the rivers, particularly coming from the agriculture, construction

of dams and weirs, and the industries were found to affect the integrity with

certainty and thus, more careful approaches to lower and limit the adverse impacts

of these must be encouraged to practice.

• There is an intimate relationship between fisheries and water resources. Any

developmental or other activities involving water resources should deal fisheries as


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another important resource of the country, which cannot be overlooked. The best

way is to integrate them.

• The studies and the research, which has the direct relation with local communities

and local economy, should be made national priority rather than the works just of

academic interest.

• Finally, it is just a repetition, as is mentioned in all other fields to call for education,

awareness and training, which are important in this field too.

11 Executive summary

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XI: EXECUTIVE SUMMARY

The present work titled, “FISH ECOLOGICAL STUDIES AND ITS APPLICATION

IN ASSESSING ECOLOGICAL INTEGRITY OF RIVERS IN NEPAL” was started

with the hypothesis that the fish fauna are able to reflect the differences influenced by

variety of disturbances in river conditions and quality through the change in their population

and community measures such as composition, diversity and abundance. The main aim of

the study was to assess the integrity of different rivers in Nepal with the help of fish

community metrics. However, the fish base information collected during the study was

applied in much wider perspectives.

The main objectives of the study was thus widened into the study of distribution, abundance

and density of the fish species, the size structure analysis, the methods of using variables in

the classification of the rivers and river systems, and finally assessing the impacts of

different disturbances so as to see if there were any impairments on the water quality and

the integrity of the rivers.

The method used was the evaluation of fish population characteristics in contrasting

disturbance regimes and comparing them. The four important disturbances on the rivers in

Nepal were identified as agriculture, urbanization, dams and weirs, and the industries. Nine

rivers, Aandhikhola, Arungkhola, Bagmati, Jhikhukhola, Karrakhola, Narayani, East Rapti,

Seti and Tinau were selected for the study as these rivers were facing one or more of these

disturbances.

Among them, Jhikhukhola, East Rapti and Tinau rivers were studied for the impacts of

agriculture while Narayani Tinau and Seti were studied for the impacts of city or

urbanization. Similarly, Aandhikhola, Bagmati and Tinau were studied for the impacts of

dams while Arungkhola, Karrakhola and Narayani were chosen for the study of the impacts

of industries. Two sampling sites each for the each case study were setup before the actual

sampling representing the reference and disturbed sites. Thus, there were 23 sampling sites

altogether for 12 cases and it is one short because the reference site in River Narayani was

taken as the reference for both the disturbance, city and the industry.


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Sampling period lasted from third week of February, 2003 to the January, 2004 during

which four replicates of sampling corresponding to each major season of the country were

done. Fish sampling was done by standard wading method with the backpack electrofishing

gear. Sampling was done in two runs and the sum of which were never less than 30 mins in

any of the sampling. All safety measures for the proper use of the gear were given topmost

priority. The shocked fishes after capture were transferred into the bucket with fresh river

water to note down the measurements and other information before they were released back

to the river. Most of the identification of the fish species were done in the sampling site

itself while unidentified specimens were preserved and latter verified with the experts.

Total length (TL) and the representative weights of every fish specimens captured were

noted down in a simple but standard protocol. Basic physico-chemical parameters, geo-

morphological features and exact coordinates of the sites were also recorded in a suitable

protocal. For the information regarding water discharge of the river the data from

Department of Hydrology and Meteorology (DHM) were utilized. Altogether 27588 fishes

were captured during the entire sampling period lasting around one complete year. The

captured fish represented 5 orders, 12 families, 33 genus and 47 species. A good spatial

and temporal variation was seen in their distribution.

Among the rivers, Narayani was found to be richest in fish diversity while Bagmati had the

least diversity. Arungkhola, Karrakhola, East Rapti and Tinau were found to hold a good

diversity of fish fauna while Aandhikhola, Jhikhukhola and Seti were found to possess a

moderate diversity of fishes. The abundance of the fish which was calculated as CPUE

(catch per unit effort: no. of individuals/10 minutes of electrofishing) gave a different

picture with East Rapti having the highest abundance and Bagmati again the least. Narayani

was found to have considerably less abundance of fish, but a different method of sampling

than the wading method should be applied in such a deep and large river for precision. The

other rivers were found to have moderate to good abundance. The total average abundance

of fish in all these rivers were found to be good at 79.23.

The density (no. of individuals/100 m²) of each species in each river was also worked out

and to avoid the large margin of error it was calculated per 100 m² rather than per hectare.

Narayani river was found to have the lowest density of the fish and it could be natural also

as it is a big river. But as mentioned before more efficient method of sampling must be


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applied in this river. Jhikhukhola and Tinau river was found to have the highest density.

Though, the values of density in the table may look little less, it should be noted that these

are natural population and no stockings were recorded in these sections of the rivers as well

as it is a crude but minimum density.

The classification of rivers and river systems was tried next by two methods, one using the

fish base variables and the other the values of abiotic factors. It was remarkable to see that

the cluster analysis by Ward method using biotic variables and the canonical discrimination

analysis using abiotic factors produced almost the same results. Both the methods showed

that the six rivers, Aandhikhola, Arungkhola, Karrakhola, Narayani, East Rapti and Seti

formed one group where as the others formed their independent group. The classification

was found to be absolutely matching with the reality and the age-old classification of

Nepalese rivers. Thus, this kind of classification and grouping would be very helpful in

managing water and fisheries resources on the larger scale.

The size structure analysis was also done to show how the result of this gives the insight of

the fish biology and ecology on one hand and on the other hand the water quality and river

conditions. The length frequency distribution and the length-weight relationship of the

sucker head, Garra gotyla gotyla was worked out and studied. The length frequency

distribution was studied of each river and each season. It was found that the frequency

varied between rivers and seasons indicating that the habitat conditions in each river are

different as well as seasons of breeding, stress and growth.

Finally, the main analysis was the assessment of water quality and integrity of the rivers

using fish base characteristics. Two important variables, the number of species and their

abundance were applied to see if there are different pictures corresponding to different

disturbance regime. The two variables were compared between the reference and disturbed

sites of each disturbance and the conclusions were drawn only after the significance tests.

Whenever, relevant composition of the assemblage was also discussed.

The agricultural disturbance was found to exert significant impacts on the river which has a

potential to degrade the water quality and integrity of the river. This could be easily

observed through the comparison of bar charts of the reference and disturbed sites of each

case study. The hypothesis test too backed the conclusion that this is an important


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disturbance on the river ecosystem. However, the general view of the figure suggested that

all the cases were not same because they were influenced by several factors and most

important among them was river morphology. It was also interesting to note that in general

the species richness and abundance of fish rather increased in disturbed site possibly due to

the high nutrient flow. Thus, high diversity and abundance may not always indicate higher

integrity.

The impact of the city or the urbanization was found to have the least impacts on the rivers

among the cases studied. The significance tests also showed no threats to the river integrity.

However, some trends of impacts were visible when comparing the bar charts of reference

and disturbed sites. This implied that though the impacts of cities on their respective rivers

studied in this work had no immediate threats to the integrity of the river, the story could be

different if further expansion of cities take place without increasing basic facilities.

The impacts of the dam on the river was also found to be an important threat to the river

integrity, particularly, in the reference or the upstream sites. This conclusion was also

backed by the hypothesis test. However, there was at least one case where more

impairments were visible in the downstream of the dam. This suggested that there are other

factors, too, that influence the impacts of the dams on the rivers. One of the most important

factor identified in this case was the downstream large river connectivity, which often

maintain fish communities downstream of the dam but the upstream or the reference

section are deprived of that.

The impact of the industry on the integrity of the river was found to be the most serious

among all the disturbances. Its seriousness was also highlighted by the statistical test. It was

seen that the downstream sites were more affected by this disturbance than the upstream.

However, here too, the evaluation of the impacts should be done carefully. In some seasons

and in the disturbed sites of some industries, the abundance of fishes could be more and

thus, might give the false impression of better conditions. The effluents of not all the

industries are toxic and chemical intensive. In these cases more fishes colonize the affected

area because of the warmer water or plentiful nutrients.

In chemical intensive industries such as paper mill, it was found that the disturbed site was

consistently showing impairment of the integrity of the river. It was observed that the


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generalization of the impacts of the industries could be made but not the evaluation criteria.

If only a single metrics such as the abundance of fish is taken, the impacts of the industries

might not be explained. Hence, multi-metrics evaluation criteria must be developed to

assess the exact situation not only for the industrial disturbance but also for anyone of them.

Numerous applications of fish population and fish ecological information has been shown in

this work. So far, many of the information regarding fish species in Nepal were limited to

the academic discussions only. The people and the country are not able to take direct benefit

from this important resource. This work has shown how the most important resource of the

country, the water resource could be managed and monitored by assessing its integrity

through fish community parameters.

Thus, this work has tried to illustrate the relationship of two crucial resources of the

country. If the management and monitoring of one resource help the same for the other then

considerable costs and time would be saved. This kind of strategy is more suitable for the

country like Nepal. The two resources should be integrated for studies or any developmental

work concerning these resources. If that happens, not only it helps in conservation and

management of these resources but also the restoration of already depleted and polluted

resource. The benefits of these surely transcends to the larger population of the country.

12 References

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13 Appendix

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Appendix I : Working time table

KU - Kathmandu University, Dhulikhel, Nepal . BOKU - Universität für Bodenkultur, Vienna, Austria.

YEAR 2002 ACTIVITIES AT KU/ BOKU

FEBRUARY

OÄD Scholarship has been accepted for a three years sandwich program between BOKU, Austria and KU, Nepal, leading to a PhD degree in the field of river ecology. Registration made at KU with Prof. Dr. Herwig Waidbacher (BOKU) and Dr. Subodh K. Sharma (KU) as the supervisors. YEAR 2002 ACTIVITIES AT BOKU

MARCH APRIL MAY JUNE JULY AUGUST

Course works, practical, fieldworks, literature reviews and consultations with the supervisor at BOKU in Austria. Finalization of detail proposal and protocols.

YEAR 2002/2003 ACTIVITIES AT KU

SEPTEMBER OCTOBER NOVEMBER DECEMBER JANUARY (2003) FEBRUARY MARCH APRIL MAY JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DECEMBER

Arrangements for extensive field work, sampling data collection literature and information. Sampling mainly includes electric fishing at number of sites on both regulated and unregulated rivers. In addition, other physico-chemical parameters like temperature, velocity, depth, discharge, substrate, conductivity, pH and dissolved Oxygen are also taken into account.

YEAR 2004 ACTIVITIES AT BOKU

JANUARY FEBRUARY MARCH APRIL MAY JUNE JULY AUGUST SEPTEMBER AUGUST NOVEMBR DECEMBER

Data processing and analysis, Statistics, literature review and writing a comprehensive thesis for a PhD degree.

YEAR 2005 ACTIVITIES AT KU

JANUARY / FEBRUARY Defense of the thesis in front of expert panel and public set up by the exam and research committee.

13 Appendix

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Appendix II: Field protocol GENERAL Name of the water body

Locality Date Time Weather

River order

River length Stretch code Stretch length Width

Depth

Latitude Longitude Altitude Impact

Season

PHYSICO-CHEMICAL Temperature

Dissolved Oxygen Ph Conductivity Velocity

Discharge

MORPHOLOGY

1. SUBSTRATE Rock

Boulder

Cobbles

Pebbles

Gravels

Sand

Silt

2. RIVER BANK RIGHT LEFT Natural

Artificial Eroded Planted

Natural Artificial Eroded Planted

Bare Overhanging branches

Woody Debris

Bare Overhanging branches

Woody Debris

3. Channel Type: 4. Geological Feature

Other Descriptions Sketch Map

13 Appendix

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Appendix III: Field protocol (Fish base) 1.Place: 2. Run: 3. Fishing time: 4. Fished distance

No

Species Length Weight Sex/dev

No Species Length Weight Sex/dev

1

26

2

27

3

28

4

29

5

30

6

31

7

32

8

33

9

34

10

35

11

36

12

37

13

38

14

39

15

40

16

41

17

42

18

43

19

44

20

45

21

46

22

47

23

48

24

49

25

50

13 Appendix

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Appendix IV: Checklist of fishes of Nepal (Source: Shrestha 2001)

NO ORDER FAMILY GENUS SPECIES THIS STUDY

1 Clupeiformes Clupeidae Gudusia Gudusia chapra (Hamilton-Buchanan)

*

2 Engraulididae Setipinna Setipinna phasa (Hamilton-Buchanan)

3 Osteoglossiformes Notopteridae Notopterus Notopterus notopterus Pallas 1767

4 Chitala Chitala chitala Hamilton 1822

5 Cypriniformes Cyprinidae Neolissochilus Neolissochilus hexagonolepis McClelland 1839

*

6 Carassius Carassius carassius Linnaeus 1758

7 Catla Catla catla Hamilton-Buchanan 1822

8 Chagunius Chagunius chagunio Hamilton-Buchanan 1822

9 Cirrhinus Cirrhinus mrigala Hamilton-Buchanan 1822

10 Cirrhinus Cirrhinus reba Hamilton-Buchanan 1822

*

11 Labeo Labeo angra Hamilton-Buchanan 1822

12 Labeo Labeo bata Hamilton-Buchanan 1822

13 Labeo Labeo boga Hamilton-Buchanan 1822

14 Labeo Labeo calbasu Hamilton-Buchanan 1822

15 Labeo Labeo caeruleus Day 1877

16 Labeo Labeo dero Hamilton-Buchanan 1822

*

17 Labeo Labeo dyocheilus McClelland 1839

18 Labeo Labeo fimbriatus Bloch 1795

19 Labeo Labeo gonius Hamilton-Buchanan 1822

20 Labeo Labeo pangusia Hamilton-Buchanan 1822

21 Labeo Labeo rohita Hamilton-Buchanan 1822

22 Oreichthys Oreichthys cosuatis Hamilton-Buchanan 1822

23 Osteobrama Osteobrama cotio Hamilton-Buchanan 1822

24 Schismatorhyncthios Schismatorhynchos nukta Sykes 1839

25

Puntius Puntius apogon Cuvier and Valenciennes 1844

26 Puntius Puntius chola Hamilton-Buchanan 1822

*

27 Puntius Puntius clavatus McClelland 1839

28 Puntius Puntius conchonius Hamilton-Buchanan 1822

*

29

Puntius Puntius gelius Hamilton-Buchanan 1822

30 Puntius Puntius guganio Hamilton-Buchanan 1822

31 Puntius Puntius phutunio Hamilton-Buchanan 1822

32 Puntius Puntius sarana Hamilton-Buchanan 1822

33 Puntius Puntius sophore Hamilton-Buchanan 1822

*

13 Appendix

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34 Puntius Puntius ticto Hamilton-Buchanan 1822

*

35 Semiplotus Semiplotus semiplotus McClelland 1839

*

36 Tor Tor mosal Hamilton-Buchanan 1822

37 Tor Tor putitora Hamilton-Buchanan 1822

*

38 Tor Tor tor Hamilton-Buchanan 1822

*

39 Naziritor Naziritor chelynoides McClelland 1839

*

40 Amblypharyngodon Amblypharyngodon mola Hamilton-Buchanan 1822

41 Aspidoparia Aspidoparia jaya Hamilton-Buchanan 1822

42 Aspidoparia Aspidoparia morar Hamilton-Buchanan 1822

*

43 Barilius Barilius bola Hamilton-Buchanan 1822

44 Barilius Barilius guttatus Day 1869

45 Barilius Barilius barila Hamilton-Buchanan 1822

*

46 Barilius Barilius barna Hamilton-Buchanan 1822

*

47 Barilius Barilius bendelisis Hamilton-Buchanan 1822

*

48 Barilius Barilius radiolatus Günther 1868

49 Barilius Barilius shacra Hamilton-Buchanan 1822

*

50 Barilius Barilius tileo Hamilton-Buchanan 1822

51 Barilius Barilius vagra Hamilton-Buchanan 1822

*

52 Brachydanio Brachydanio rerio Hamilton-Buchanan 1822

*

53 Danio Danio aequipinnatus McClelland 1839

*

54 Danio Danio dangila Hamilton-Buchanan 1822

*

55 Danio Danio devario Hamilton-Buchanan 1822

56 Esomus Esomus danricus Hamilton-Buchanan 1822

*

57 Bengala Bengala elanga Hamilton-Buchanan 1822

58 Rasbora Rasbora daniconius Hamilton-Buchanan 1822

59 Chela Chela cachius Hamilton-Buchanan 1822

60 Chela Chela laubuca Hamilton-Buchanan 1822

61

Salmostoma Salmostoma acinaces Valenciennes 1842

62 Salmostoma Salmostoma bacaila Hamilton-Buchanan 1822

63 Salmostoma Salmostoma phulo Hamilton-Buchanan 1822

64 Securicula Securicula gora Hamilton-Buchanan 1822

65 Crossocheilus Crossocheilus latius Hamilton-Buchanan 1822

*

67 Garra Garra gotyla Gray 1830

*

68 Garra Garra lamta Hamilton-Buchanan 1822

70 Garra Garra nasuta McClelland 1839

13 Appendix

-292-


71 Garra Garra rupecula McClelland 1839

72 Schizothorax Schizothorax richardsonii Gray 1832

*

73 Schizothorax Schizothorax sinuatus Heckel 1838

74 Schizothoraichthys Schizothoraichthys esocinus Heckel 1838

75 Schizothoraichthys Schizothoraichthys labiatus McClelland 1839

76 Schizothoraichthys Schizothoraichthys macrophthalmus Terashima 1984

77 Schizothoraichthys Schizothoraichthys nepalensis Terashima 1984

78 Schizothoraichthys Schizothoraichthys niger Heckel 1838

79 Schizothoraichthys Schizothoraichthys curvifrons Heckel 1838

80 Schizothoraichthys Schizothoraichthys progastus McClelland 1839

*

81 Schizothoraichthys Schizothoraichthys raraensis Terashima 1984

82 Psilorhynchidae Psilorhynchus Psilorhynchus balitora Hamilton-Buchanan 1822

83 Psilorhynchus Psilorhynchus sucatio Hamilton-Buchanan 1822

84 Psilorhynchus Psilorhynchus homaloptera Hora and Mukerji 1935

85 Psilorhynchus Psilorhynchus pseudecheneis Menon and Datta 1961

*

86 Balitoridae Balitora Balitora brucei Gray 1832

87 Nemacheilus Nemacheilus corica Hamilton-Buchanan 1822

*

88 Acanthocobitis Acanthocobitis botia Hamilton-Buchanan 1822

*

89 Schistura Schistura beavani Günther 1868

*

90 Schistura Schistura devdevi Hora 1935

91 Schistura Schistura multifasciatus Day 1878

92 Schistura Schistura rupecula McClelland 1839

*

93 Schistura Schistura scaturigina McClelland 1839

94 Schistura Schistura savona Hamilton-Buchanan 1822

95 Cobitidae Botia Botia almorhae Gray 1831

*

96 Botia Botia dario Hamilton-Buchanan 1822

97 Botia Botia histrionica Blyth 1861

98 Botia Botia lohachata Chaudhuri 1912

*

99 Acantophthalmus Acantophthalmus pangia Hamilton-Buchanan 1822

100 Lepidocephalus Lepidocephalus guntea Hamilton-Buchanan 1822

*

101 Somileptus Somileptus gongota Hamilton-Buchanan 1822

102 Anguilliformes Anguillidae Anguilla Anguilla bengalensis Gray 1831

103 Siluriformes Amblycipitidae Amblyceps Amblyceps mangois Hamilton-Buchanan 1822

*

104 Bagridae Batasio Batasio batasio Hamilton-Buchanan 1822

105 Mystus Mystus bleekeri Day 1878

13 Appendix

-293-


106 Mystus Mystus cavasius Hamilton-Buchanan 1822

107 Mystus Mystus menoda Hamilton-Buchanan 1822

108 Mystus Mystus tengara Hamilton-Buchanan 1822

109 Mystus Mystus vittatus Bloch 1794

110 Aorichthys Aorichthys aor Hamilton-Buchanan 1822

111 Aorichthys Aorichthys seenghala Sykes 1839

112 Rita Rita rita Hamilton-Buchanan 1822

113 Siluridae Ompok Ompok bimaculatus Bloch 1797

114 Ompok Ompok pabda Hamilton-Buchanan 1822

115 Ompok Ompok pabo Hamilton-Buchanan 1822

116 Wallago Wallago attu Schneider 1801

117 Schilbeidae Ailia Ailia coila Hamilton-Buchanan 1822

118 Clupisoma Clupisoma garua Hamilton-Buchanan 1822

*

119 Clupisoma Clupisoma montana Hora 1937

120 Eutropiichthys Eutropiichthys vacha Hamilton-Buchanan 1822

121 Pseudeutropius Pseudeutropius atherinoides Bloch 1794

122 Pseudeutropius Pseudeutropius murius batarensis Shrestha 1978

123 Silonia Silonia silondia Hamilton-Buchanan 1822

124 Sisoridae Bagarius Bagarius yarrelli Sykes 1839

125 Erethistes Erethistes elongatus Day 1878

126 Erethistes Erethistes pusillus Müller & Troschel 1849

127 Erethistoides Erethistoides montana montana Hora 1950

128 Euchiloglanis Euchiloglanis hodgarti Hora 1923

129 Gagata Gagata cenia Hamilton-Buchanan 1822

130 Gagata Gagata sexualis Tilak 1970

131 Coraglanis Coraglanis kishinouyei Kimura 1934

132 Myersglanis Myersglanis blythii Day 1870

*

133 Glyptosternon Glyptosternon reticulatum McClelland 1842

134 Glyptosternon Glyptosternon maculatum Regan 1905

135 Glyptothorax Glyptothorax annandalei Hora 1923

136 Glyptothorax Glyptothorax cavia Hamilton-Buchanan 1822

137

Glyptothorax Glyptothorax conirostre Steindachner 1867

138 Glyptothorax Glyptothorax indicus Talwar 1991

139 Glyptothorax Glyptothorax kashmirensis Hora 1923

13 Appendix

-294-


140 Glyptothorax Glyptothorax pectinopterus McClelland 1842

*

141 Glyptothorax Glyptothorax gracile Günther 1864

142 Glyptothorax Glyptothorax telchitta Hamilton-Buchanan 1822

*

143 Glyptothorax Glyptothorax trilineatus Blyth 1860

*

144 Hara Hara hara Hamilton-Buchanan 1822

145 Hara Hara jerdoni Day 1870

146 Laguvia Laguvia ribeiroi Hora 1921

147 Nangra Nangra nangra Hamilton-Buchanan 1822

148 Nangra Nangra viridescens Hamilton-Buchanan 1822

149 Pseudecheneis Pseudecheneis sulcatus McClelland 1842

*

150 Sisor Sisor rabdophorus Hamilton-Buchanan 1822

151 Olyridae Olyra Olyra longicaudata McClelland 1842

152 Chacidae Chaca Chaca chaca Hamilton-Buchanan 1822

153 Heteropneustidae Heteropneustes Heteropneustes fossilis Bloch 1794

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154 Claridae Clarias Clarias batrachus Linnaeus 1758

155 Beloniformes Belonidae Xenentodon Xenentodon cancila Hamilton-Buchanan 1822

156 Cyprinodontoformes Poecilidae Gambusia Gambusia affinis Baird & Girard 1853

157 Aplocheilidae Aplocheilus Aplocheilus panchax Hamilton-Buchanan 1822

158 Perciformes Channidae Channa Channa barca Hamilton-Buchanan 1822

159 Channa Channa orientalis Bloch & Schneider 1801

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160 Channa Channa marulius Hamilton-Buchanan 1822

161 Channa Channa punctatus Bloch 1793

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162 Channa Channa stewartii Playfair 1867

163 Channa Channa striatus Bloch 1793

164 Ambassidae Chanda Chanda nama Hamilton-Buchanan 1822

165 Parambassis Parambassis baculis Hamilton-Buchanan 1822

166 Parambassis Parambassis ranga Hamilton-Buchanan 1822

167 Sciaenidae Johnius Johnius coitor Hamilton-Buchanan 1822

168 Nandidae Badis Badis badis Hamilton-Buchanan 1822

169 Nandus Nandus nandus Hamilton-Buchanan 1822

170 Anabantidae Anabas Anabas testudineus Bloch 1792

171 Belontidae Colisa Colisa fasciatus Schneider 1801

172

Colisa Colisa lalia Hamilton-Buchanan 1822

173 Colisa Colisa sota Hamilton-Buchanan 1822

174 Ctenops Ctenops nobilis McClelland 1845

13 Appendix

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175 Gobiidae Glossogobius Glossogobius giuris Hamilton-Buchanan 1822

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176 Synbranchiformes Synbranchidae Monopterus Monopterus cuchia Hamilton-Buchanan 1822

177 Mastacembelidae Macrognathus Macrognathus aral Bloch & Schneider 1801

178 Macrognathus Macrognathus pancalus Hamilton-Buchanan 1822

*

179 Mastacembelus Mastacembelus armatus Lacepede 1800

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180 Mugiliformes Mugilidae Sicamugil Sicamugil cascasia Hamilton-Buchanan 1822

181 Rhinomugil Rhinomugil corsula Hamilton-Buchanan 1822

182 Tetraodontiformes Tetraodontidae Tetraodon Tetraodon cutcutia Hamilton-Buchanan 1822

13 Appendix

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Appendix V: Letter from Defense Ministry for safety during sampling

13 Appendix

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Appendix VI: Letter from the University for cooperation during sampling

13 Appendix

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Appendix VII: Permission letter from DNPWC for sampling in RCNP

13 Appendix

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Appendix VIII: Permission letter from DNPWC for sampling in SNP

13 Appendix

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Appendix IX: Permission letter from SNP for sampling

13 Appendix

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Appendix X: Permission letter from NEA for sampling

FISH ECOLOGICAL STUDIES AND ITS APPLICATION IN...

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