167

Chenderoh Reservoir, Malaysia:Fish Community and Artisanal Fishery of a

Small Mesotrophic Tropical Reservoir

Kong Kah-Wai and Ahyaudin B. Ali*

Abstract

A study on the fish community and the status of the fishery of Chenderoh Reservoir was carriedout using experimental fishing and creel survey. A total of 27 fish species from 8 families was notedduring the study. Experimental fishing with gill nets indicated the domination of small-sized andnon-economic species such as Cyclocheilichthys apogon, Osteochilus hasselti, Chela anomalura,and Barbodes schwanenfeldii. Although valuable species such as Puntioplites bulu, Thynnichthysthynnoides, Chitala lopis, Oxyeleotris marmoratus, and Mystus nemurus are present, their catchesare not commercially significant. The estimated production was 6.67 kg/ha/year with an annuallanding of 13.74 tonnes. The drop in the yield could be due to both the decline in fish stock or toreduced fishing effort.

CHENDEROH RESERVOIR, located on the Perak River,Peninsular Malaysia (5o01’ 40o56’ N and 100o55’101o00’ E), is the oldest reservoir in Malaysia, beingcommissioned for hydroelectric generation in 1930(Dahlen 1993). Three newer reservoirs, namely theKenering (1984), Bersia (1993) and Temenggor(1974), are located upstream, thus modifying theflow and water level regime of the Chenderoh Reser-voir (Dahlen 1993). The morphometric and limno-logical characteristics of the mesotrophic 67-year-oldreservoir have been described in detail by Ali (1996).Fish communities in the reservoir are subjected tovarying degrees of environmental manipulation anddegradation, such as water level management andfluctuation, riparian land development and home-steading (Ali 1995, 1996). Thus, a change in fishspecies composition has occurred following the con-version from a lotic to a lentic ecosystem, water levelregulation and anthropogenic effects due to develop-ment pressure along the reservoir shoreline (Yap1992a; Ali 1996).

Following impoundment, the artisanal fishery thatonce thrived in the original lotic ecosystem evolvedto adapt to the newly created reservoir fishery. In

Malaysia, this type of artisanal fishery that alsoinvolves variations of aquaculture, such as floatingcage culture and littoral corral culture, is very impor-tant to the economy and well-being of the local com-munities (Yap 1992a; Costa-Pierce 1992; Ali andLee 1996). Therefore, management for sustainableexploitation is very important (Khoo et al. 1987; Yap1988).

Studies by Ali and Lee (1995) showed that in theChenderoh Reservoir artisanal fishery is important tothe local population in providing both protein andsupplementary income. The fishery is multi-speciesand multi-gear in nature with the dominant gearbeing multi-filament gill nets with stretched-mesh of5.7, 10.2 and 11.4 cm (Ali and Lee 1995). At thetime of that study, there was no official fisheryregulation, and community-based management of thefishery was practised by the local people themselves(Ali and Lee 1995; Ali 1996). Subsequently, inlandfishery rules and regulations enacted by the PerakState Government in the late 1980s and was imple-mented State wide in order to protect the fishery(Zakariah and Ali 1996).

The objective of the study was to characterise thepresent status of the Chenderoh Reservoir fishery.The reservoir has been and is being studied exten-sively as part of the monitoring program on thedevelopment and fate of artisanal inland tropical

*School of Biological Sciences, Universiti Sains Malaysia,11800 Minden, Penang, Malaysia

168

fisheries (Lee and Ali 1989; Ali and Lee 1995; Ali1996; Ali and Kadir 1996; Zakariah and Ali 1996).Therefore, this study compares the current status ofChenderoh Reservoir fishery to previous studieswithin the context of conservation and managementof small-scale, multi-gear and multi-species artisanalfisheries.

Materials and Methods

The equatorial location of Chenderoh Reservoir pre-cludes the occurrence of distinct temperature, photo-period or rainfall cycles, thus allowing for fish tospawn all year round (Hails and Abdullah 1982).Since seasonality is absent and to reduce costs,sampling was carried out from July 1994 to January1995. Two sampling sites located about 2 km on theopposite sides of the Perak River were selected(Figure 1). These sites are the main fishing groundsfor the local population. Each site is essentially anembayment and has riparian homestead and thusreceived varying amount of anthropogenic effluents(Ali 1996). Part of Site B (i.e. B2) was studied inten-sively about five years before with respect to itsartisanal fishery (Ali and Lee 1995).

During the study, the sampling techniques usedfollowed closely the practice of the local fishers andwere also used in previous studies (Ali and Lee1995). Experimental fishing was conducted usingpanels of gill nets 208 m long and 3 to 5 m deep anda stretch-mesh of 2.5, 5.1, 7.6, and 10.2 cm respec-tively. The nets were fished (soak time) day andnight at a ratio of 12:12. Nets were set at 1800 h andchecked the next day at 0600 h for the night catchwith a second check conducted subsequently on thenext 1800 h and noted as the day catch. Fishinginterval and gear used is the same to that of the localfishery and thus each day or night catch is con-sidered as a unit of fishing effort and the CPUE isexpressed as kg/fisher/day. All fish caught wereseparated based on mesh sizes, and weighed (g), andmeasured (standard and total length in cm), respec-tively. For each species caught, five specimen were

preserved in 10% formalin to be further identified inthe laboratory using standard taxonomic keys avail-able (Inger and Chin, 1962; Mohsin and Ambak1992; Ng et al. 1992). Creel surveys and Rapid RuralAppraisal (Khon Kaen University 1987) were con-ducted at the two main fish landing sites, i.e. TebokKelantan and Cangkat Duku Village (Figure 1).Species caught and biomass landed were recorded.The number of active fishers and middlemeninvolved in the fishery was noted.

Fish community analysis involved the use ofShannon-Wiener Diversity (Poole 1974), evenness(Poule 1975) and dominant indices (Zar 1984).Non-parametric statistics of Mann-Whitney U-testand Wilcoxon test were used to compare betweensamples because of their independence of normaldistribution (Zar 1984) and small sample sizesobtained (Fowler and Cohen 1990). Water qualityparameters of pH and temperature (Orion ResearchSA250), conductivity (Hanna 18333), dissolvedoxygen (YSI 58), and Secchi Disk visibility weremeasured before 1200 h during sampling and meansof three readings were obtained.

Results

Generally, there were no differences in water qualityparameters between the two sites (Table 1). Meansurface temperature at Site A and B were 27.4 + 0.4and 28.1 + 0.6oC, respectively. The mean pH anddissolved oxygen were 6.44 + 0.19 and 6.66 + 0.58,and 5.01 + 0.50 and 5.05 + 0.69 mg/L for sites A andB, respectively. The conductivity for the two siteswere 38.15 + 10.53 and 40.00 + 10.00 uS/cmwhereas the Secchi Disk visibility readings werewithin the mesotrophic range of 0.8 + 0.4 and 1.1 +0.2 m, respectively.

Forty two species from 13 families were observed(Table 2) in contrast to 63 species observed sevenyears earlier (Lee 1989; Ali 1996). Only 27 speciesfrom 8 families, however, were caught in experi-mental fishing. A total of 18 species were sampled insite A in contrast to site B which yielded 21 species

Table 1. Water quality parameters at the two study sites of Chenderoh Reservoir, Perak, Malaysia.

Sites Temperature(oC)

pH Conductivity(uS/cm)

D.O.(mg/L)

Secchi Disk(m)

A ±0.4(26.8 – 27.9)

±0.19(6.81 – 6.14)

±10.53(24.20 – 54.70)

±0.50(3.91 – 6.72)

±0.4(0.6 – 1.7)

B ±0.6(27.2 – 29.4)

±0.58(5.98 – 6.85)

±10.00(27.00 – 66.20)

±0.69(3.91 – 6.20)

±0.2(0.6 – 1.7)

169

Figure 1. Map of Chenderoh Reservoir showing location of the study sites.

Site B

Site A

DURIAN PIPIT

KUAK

Kg Corokuh

Tebuk Kelantan

Kg Sardan

Kg Beng

Sg

Beng

Sg Durau

Sg Jetan

Kg Raban

Cangkat Duku0 1 km

12

N

INDONESIA

MALAYSIA

SINGAPORE

KEDAH

PERAK

PAHANG

MELAKA

NEGERISEMBILAN

KELANTAN

Chenderoh Reservoir

Straitsof M

alacca

SouthChinaSea

TERENGGANU

JOHOR

SELANGOR

THAILAND

170

and the family Cyprinidae (50%) has the mostnumber of species (Figure 2). The Shannon-Wienerdiversity index showed very little difference betweenthe two sampling sites. The diversity index for site Awas 3.3192 whereas for site B it was 3.2057. Theevenness indices for the two sites were also fairlyclose, with site A having an index of 0.7960 and siteB 0.7289.

A total of 1247 individual fish with a biomass of55.5 kg was caught with gill nets during experi-mental fishing (Figure 3). Eighty percent of thosecaught were sampled with the 2.5 cm mesh nets and

‘r’ species (Ali 1996) such as Barbodes schwanen-feldii (24%), Cyclocheilichthys apogon (22%), Oste-ochilus hasselti (14%), and Rasbora sumatrana(12%) were the most common. In the 5.1 and 7.6 cmmesh, however, the commercially important ‘K’species of Puntioplites bulu and Thynnichthysthynnoides were dominant (Figure 3). The species P.bulu remained dominant in the largest mesh net(10.2 cm) followed by other ‘K’ species of Osphro-nemus goramy and Osteochilus melanopleurus. Interms of catch per set, 69% of the fish caught couldbe considered as ‘mixed fish’ which are small in sizewith little commercial value and consisting ofspecies such as Barbodes schwanenfeldii,Osteochilus hasselti, Chela anomalura, Cyclocheili-chthys apogon, Pristolepis fasciatus and Labio-barbus sp. (Figure 4). The length frequencyhistograms for six most numerous species are shownin Figure 5. Although presently there are no changesin length structures of non-commercial species ofCyclocheilichthys apogon, Rasbora sumatrana, andOxygaster (Chela) anomalura, when compared toprevious studies of Ali and Lee (1995), there is areduction in size of the commercially importantPuntius bulu.

Figure 2. The percentage composition of the major fishfamilies caught.

The number of full time fishers has declined to 15from the high of 60 in early 1980s (Ajan 1983) and30 in mid-2980s (Ali and Lee 1995). Results of theRRA indicated that most remaining fishers are intheir late forties and fifties. The major portion of the

Table 2. List of species observed in the ChenderohReservoir during the study.

Species Present

CyprinidaeOxygaster anomalura (Chela anomalura) +Cyclocheilichthys apogon +Cyclocheilichthys heteronema +Cyclocheilichthys spp. +Hampala macrolepidota +Labiobarbus lineatus +Osteochilus hasselti +Osteochilus melanopleurus +Osteochilus vittatus +Puntioplites bulu +Puntius daruphani +Barbodes gonionotus +Barbodes schwanenfeldii +Rasbora cf sumatrana +Thynnichthys thynnoides +Aristichthys nobilis +Ctenopharyngodon idellus +Hypopthalmichthys molitrix +Labiobarbus sumatrana +Leptobarbus hoeveni +Puntius partipentazona +

BelontiidaeBetta pugnax +Trichogaster pectoralis +Osphronemus goramy +HelostomidaeHelostoma temminckii +MastacembelidaeMastacembelus armatus +PristolepidaePristolepis fasciatus +PangasiidaePangasius micronemus +Pangasius sutchi +TetraodontidaeTetraodon leiurus +

Cyprinidae59.0%

Pristolepidae4.6%

Tetraodontidae4.6%

Osphronemidae4.6%

Eleotridae4.6%

Channidae4.6%

Notopteridae9.0%

Bagridae9.0%

171

commercial landings consisted of mixed fish(33.4%) (Figure 6). Among the commercial speciesthe highest catch was for P. bulu (14.1%), Mystus sp.(10.0%), T. Thynnoides (8.8%) and the snakeheads(5.7%). The average daily CPUE of both commercialand experimental catches is strongly related (Figure7). The values for both catches range between 1.2 to3.6 and 1.7 to 2.9, respectively; however, both thesevalues are lower but more stable than the highlyfluctuating values obtained in 1988/1989 studies (Aliand Lee 1995).

1 (column %/row %)

1 (column %/row %)t – < 1%

Table 3. Number and percentages (in parentheses)1 of fish caught and percentages of empty catches during experimentalfishing with different mesh-size gill nets at Chenderoh Reservoir, Malaysia.

2.5 cm mesh 5.2 cm mesh 7.6 cm mesh 10.2 cm mesh Total fish caught

Mixed catch 802 (81/93) 55 (29/ 6) 5 (13/ 1) 0 ( 0/ 0) 862 (100)Commercial catch 194 (19/50) 135 (71/35) 34 (87/ 9) 22 (100/ 6) 385 (100)

Total fish caught 996 (80) 190 (15) 39 ( 3) 22 ( 2) 1247Empty catch (11) (16) (30) (43)

Table 4. Number and percentages (in parentheses)1 of different species of fish caught during experimental fishing withdifferent mesh-size gill nets at Chenderoh Reservoir, Malaysia.

Species 2.5 cm mesh 5.1 cm mesh 7.6 cm mesh 10.2 cm mesh Total fish caught

Barbodes gonionotus – – – 1 (5/100) 1Barbodes schwanenfeldii 236 (24/93) 17 (9/7) 1 (3/t) – 254Channa micropeltis 4 ( t/100) – – – 4Chela anomalura 113 (11/100) – – – 113Chitala lopis – – – 2 (9/100) 2Cyclocheilichthys apogon 216 (2/100) – – – 216Cyclocheilichthys heteronema 44 (4/100) – – – 44Hampala macrolepidota 20 (2/71) 7 (4/25) 1 (3/4) – 28Labiobarbus lineatus 27 (3/77) 7 (4/20) 1 (3/3) – 35Mystus negriceps 18 (2/100) – – – 18Mystus nemurus 1 (t/50) – – 1 (5/50) 2Notopterus notopterus – 2 ( 1/100) – – 2Oshphronemus goramy 2 (t/40) – – 3 (14/60) 5Osteochilus hasselti 139 (14/83) 27(14/16) 1 (3/t) – 167Osteochilus melanopleurus – 1 (t/11) 2 (5/22) 6 (27/67) 9Osteochilus vittatus 6

t/100)– – – 6

Oxyeleotris marmoratus 7 (t/54) 6 (3/46) – – 13Pristolepis fasciatus 4 (t/50) 2 (1/25) 2 (5/25) – 8Puntioplites bulu 36 (4/23) 87 (46/57) 22 (56/14) 9 (41/6) 154Rasbora sumatrana 121 (12/100) – – – 121Tetraodon leiurus 1 (t/100) – – – 1Thynnichthys thynnoides 1 (t/2) 34 (18/77) 9 (23/21) – 44

Total 996 190 39 22 1247

Table 5. Comparison in yearly production and catch perha between the present studies and previous studies onChenderoh Reservoir, Malaysia.

Studies No. of activefishers

Yearlyproduction(tonnes/yr)

Catchper ha

(kg/ha/yr)

1983 (Ajan 1983) 60 166.62 66.601989 (Ali and Lee 1995) 30 25.71 10.281995 (This study) 15 13.85 6.76

172

DiscussionAlthough Chenderoh Reservoir can still be classifiedas early mesotrophic, there exist a clear trendtowards the reservoir becoming eutrophic due toincreasing human settlement especially around theembayment areas (Ali 1996). Larger reservoirs suchas the Kenyir tend to be oligotrophic (Secchi Disk,2.55 to 5.35 cm) with low productivity (Yusoff et al.1995). Because of shallowness, there was less tem-perature variation in Chenderoh as compared toKenyir which ranged from 20.8 to 32.0oC (Yusoff et

al. 1995). Chenderoh Reservoir also has narrower pHvalues and higher D.O. concentrations when com-pared to Kenyir which exhibited a range of valuesbetween 5.96 to 7.90 mg/L and 0.00 to 8.75 mg/L,respectively (Yusoff et al. 1995). The permanenttemperature stratification which created an anoxicbottom layer associated with larger and deepertropical reservoirs such the Temenggor (Zakaria-Ismail and Sabariah 1995) and Kenyir (Yusoff et al.1995) does not occur at Chenderoh Reservoir due toits shallowness and short retention time (Ali 1996).

Figure 3. The percentage composition of abundance of different fish species caught in gill nets of different mesh sizesduring experimental fishing.

Cycl. heteronema4.0%

Barb schwanenfeldii24.0%

Chela anomalura11.0%

Puntioplites bulu4.0%

Others9.0%

Rasbora sumatrana12.0%

Osteo. hasselti14.0%

Cycl. apogon22.0%

2.5 cm 5.1 cm

Puntioplites bulu46.0%

Others2.0%

Osteo. hasselti14.0%

Oxy. marmoratus3.0%

Labio. lineatus4.0%

Thyn. thynnoides18.0%

Hampalamacrolepidota

4.0%

Barb.schwanenfeldii

4.0%

Thyn. thynnoides23.0%

Osteo. melanopleurus5.0%

Others12.0%

Pristolepis fasciatus5.0%

Puntioplites bulu55.0%

Osteo. melanopleurus27.0%

Osph. goramy14.0% Mystus nemurus

5.0%

Chitala lopis9.0%

Barb. gonionotus5.0%

Puntioplites bulu40.0%

10.2 cm7.6 cm

173

Figure 4. Percentage of abundance of different fish species caught by experim

ental fishing and the composition of m

ixedand com

mercially valuable catches obtained.

Barbodes gonionotus

Barb. schwanenfeldii

Channa micropeltis

Chela anomalura

Chitala lopis

Cyclocheilichthys apogon

Cyclo. heteronema

Hampala macrolepidota

Labiobarbus lineatus

Mystus negriceps

Mys. nemurus

Notopterus notopterus

Osphronemus goramy

Osteochilus hasselti

Osteo. melanopleurus

Osteo. vittatus

Oxyeleotris marmoratus

Pristolepis fasciatus

Puntioplites bulu

Rasbora sumatrana

Tetraodon leiurus

Thynnichthys thynnoides

2520151050

Percentage caught

10.2 cm

Mesh size

7.6 cm5.2 cm2.5 cm

Mixed catch Commercial catch100

80

60

40

20

0

Percentagelanded

174

Figure 5. L

ength-frequency histogram of selected fish species obtained by experim

ental fishing.

Frequency of occurrence (%)

Rasbora sumatrana

35

30

25

20

15

10

5

0

9.5–10.1

10.2–10.8

10.9–11.5

11.6–12.2

12.3–12.9

13.0–13.6

13.7–14.3

14.4–15.0

cm-group

Frequency of occurrence (%)

Cyclocheilichthys apogon

50

40

30

20

10

0

7.0–7.6

7.7–8.3

8.4–9.0

9.1–9.7

9.8–10.4

10.5–11.1

11.2–11.8

11.9–12.5

cm-group

Frequency of occurrence (%)

Chela anomalura

60

50

40

30

20

10

0

8.6–9.7

9.8–10.9

11.0–12.1

12.2–13.3

13.4–14.5

14.6–15.7

15.8–16.9

17.0–18.1

cm-group

Frequency of occurrence (%)

Osteochilus hasselti

50

40

30

20

10

0

7.0–8.4

8.5–9.9

10.0–11.4

11.5–12.9

13.0–14.4

14.5–15.9

16.0–17.4

17.5–18.9

cm-group

Frequency of occurrence (%)

Puntioplites bulu

60

50

40

30

20

10

0

7.6–10.5

10.6–13.5

13.6–16.5

16.6–19.5

19.6–22.5

22.6–25.5

25.6–28.5

28.6–31.5

cm-group

Frequency of occurrence (%)

Barbodes schwanenfeldii

50

40

30

20

10

0

6.1–7.2

7.3–8.4

8.5–9.6

9.7–10.8

10.9–12.0

12.1–13.2

13.3–14.4

14.5–15.6

cm-group

15.7–16.8

175

On the other hand, the highly irregular shoreline withnumerous embayments tend to trap nutrients such asorthophosphate (0.02 to 0.775 mg/L) and nitrate(0.944 to 3.982 mg/L), resulting in fairly high totalchlorophyll concentrations (1.7 to 154.03 µgL) (Ali1996).

The species diversity for Chenderoh Reservoir, asis indicated by the Shanon-Wiener index, is almostthe same as that of the Tasik Merah Reservoir(3.32/3.21 vs 3.12) (Yap 1982). However, whencompared to previous studies, the declining trend inspecies diversity in Chenderoh Reservoir was noted.A total of 63 species was observed in 1988/1989studies (Lee 1989) as compared to only 42 speciespresently. Overfishing and anthropogenically relatedenvironmental perturbations most probably accountfor the decline (Ali 1996; Zakariah and Ali 1996).

In previous studies, Ali and Lee (1995) found thatthe mainstream section of the reservoir is the mostproductive with respect to fish catch. Subsequently,this and other studies (Ali 1996) showed that embay-ments have become more productive due to shallow-ness and a more extensive littoral zone, slow flowingwater and higher cultural eutrophication by the sur-rounding human settlements. In fact, almost 70 to80% of the embayments in the reservoir are affectedby human-related activities such as homesteading,

rubber plantations and fruit orchards. Ground verifi-cation of the 1981 map (Director of MappingMalaysia 1981) has indicated changes to the marginand littoral zone of the reservoir due to shorelinesedimentation and growth of littoral aquatic macro-phytes such as Hydrilla verticillata, Ceratophyllumdemersum, Nymphae sp., Phragmites australis andPandanus sp.

The dominance of cyprinids in tropical reservoirshas been observed in Sri Lankan reservoirs, wherethe family formed over 50% of the species presence(Amarasinghe 1992). Elsewhere in Malaysia, thesame observation was also made in Subang (42%),Bukit Merah (29%) (Yap 1992a), Temenggor (57%)(Zakaria-Ismail and Lim 1995), and Kenyir Reser-voir (57%) (Yusoff et al. 1995). As noted by Ali(1996), most of these cyprinids were primarily ‘r’strategists consisting of Barbodes schwanenfeldii,Cyclocheilichthys apogon, Osteochilus hasselti,Rasbora sumatrana and Oxygaster (Chela) anoma-lura (Table 2). These species were caught essentiallyin the embayments with O. anomalura andR. sumatrana being more commonly found feedingon the surface of the littoral zone of the reservoir.Yap (1992a) and Zakariah and Ali (1996) noted thatthese river cyprinids have been able to adapt from

Figure 6. Percentage composition of biomass of different fish species landed by fishers during the study.

Mixed catch

Channa spp

Mystus spp.

Chitala lopis

Puntius bulu

Rasbora sumatrana

Thynnicthys thynnoides

Hampala macrolepidota

Leptobarbus hoeveni

Mastacembelus sp.

Notopterus notopterus

Osphronemus goramy

Osteochilus melanopleurus

Oxyeleotris marmoratus

Pangasius micronemus

Puntius daruphani

Barbodes gonionotus

Oreochromis sp.

0 10 20 30 40

Percentage landed

176

the original palustrine condition of the riverineecosystem to the lacustrine ecosystem.

In comparing the species list to previous studies,we noted the rarity of Barbodes gonionotus and Oreo-chromis sp. both in our samplings and in the fishery.These two species have been stocked and restockedat various times reaching up to 14 to 27% of the totalhatchery production by the Fishery Department intovarious rivers and reservoirs including ChenderohReservoir (Yap 1992a; 1992b). The species are alsobeing cultured in floating cages and littoral corrals ofthe reservoir, but the low number of the species in thecatch probably reflects the inability of these twospecies to adapt to the reservoir.

In the Kenyir Reservoir, Yusoff et al. (1995) foundthat Barbodes schwanenfeldii (biomass 24.3 to54.1%) and the predator Hampala macrolepidota(biomass 15.2 to 42.6%) were the most dominantspecies in their experimental gill nets. The moststriking observation in the fish population of theChenderoh Reservoir is the lack of dominantpredatory species such as Channa spp., Hampalamacrolepidota and Chitala lopis. The predator-preyrelationship for the reservoir is only 2.7 as compared

to the value of 32.2 for Kenyir Reservoir (Yusoff etal. 1995). This poor representation of predatoryspecies probably accounts for the dominant of several‘r’ prey species in the population (Figure 3).

With the reduction in landings especially forT. thynnoides (8.8% of total commercial landingsas compared to 19.4% in 1988/1989 (Ali and Lee1995), other previously unimportant species ofOsteochilus hasselti and Barbodes schwanenfeldiibegan to be caught and utilised by the local fishersespecially as ‘pekasam’ or fermented fish whichfetches good market values and thus their lengthstructure began to decline to between 7 to 10 and 8to 9 cm as compared to 5 to 25 and 5 to 15 cm,respectively in the mid-1980s (Ali and Lee 1995).

Unlike in the mid-1980s, the current landingreduction could not be attributed to poor catch butprobably to lower fishing effort rather than low pro-ductivity. The yearly production and catch per ha for1983, 1989 and the current studies are 166.62, 25.71and 13.85 t/year, and 66.60, 10.28 and 6.76 kg/ha/year, respectively (Ajan 1983; Ali and Lee 1995).Studies on reservoir fisheries in Malaysia indicatedthat shallow reservoirs tend to be more productive

Figure 7. Comparison of catch-per-unit of effort (CPUE) between experimental fishing and commercial landings of thepresent study with the 1988/1989 study. (modified from Ali and Lee 1996).

14

12

10

8

6

4

2

0

CPUE (kg/fisher-day)

1 2 3 4 5 6 7

Sampling period

1988/89 Exp. fishing Comm. landings

177

than the larger deeper reservoirs. Subang Reservoirand Bukit Merah Reservoir produced 90 and 37 kgof fish/ha/year (Yap and Furtado 1983; Yap 1983)whereas in the larger and deeper Kenyir Reservoirestimates ranged from 2.0 to 20.0 kg/ha (DoF, 1994;Yusoff et al. 1995). Thus, Chenderoh Reservoir,being shallower like the Subang and Bukit MerahReservoir, has the potential to produce at least60 kg/ha of fish if properly managed.

The state of Perak where Chenderoh Reservoir islocated is one of the few states in Peninsula Malaysiawhich has enacted Inland Fishery Regulations con-trolling the types of gears to be used in the fishery(Ismail 1992). The enactment has controlled the useof destructive fishing techniques such as poisoning,electro-fishing and small mesh gill nets. With thereduction in fishing effort and proper managementstrategies, we expect the reservoir to recover its fishproduction. Considering the appropriate limnologicaland morphometric conditions of the reservoir (Ali1996), we feel that the reservoir could be made asproductive as in the early 1980s. Increased fish pro-duction has been obtained through introductions andrestockings in other Asian reservoirs (Amarasinghe1992; Hardjamulia and Wardoyo 1992; Pawaputanon1992). In fact, inland fisheries of Sri Lanka onlydeveloped as recently as 1952 with the successfulintroduction of O. mossambicus (Amarasinghe1992). However, the caveat to any exotic speciesintroduction is the negative impacts it would have onenvironment and native fish species and whether thespecies is acceptable to the local populace (Ali1998). Other factors negatively affecting reservoirfisheries should also be tackled in order to improvefish production. These factors, such as increasedfishing pressure, open access and unregulatedfisheries, and biologically incompatible reservoirwater level management, are commonly associatedwith reservoir fisheries in the Indo-Pacific region(Petr 1995). Others such as sustainable riparian landuse, protection of riversbanks and littoral zones, andmanagement of watershed area are also important inconserving the biodiversity and production of thefishery.

Acknowledgments

This study was funded by the Malaysian Govern-ment R&D-IRPA grant. We thank Md. Yaakob Md.Yusof, Abdullah Nayan, Meor Ahmad Fauzi andWan Abdul Aziz for their help during the study. Wealso thank Tok Lang and her family and the kindpeople of Chenderoh Reservoir for their help andhospitality.

References

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Growth Rates of Transplanted Large Icefish (Protosalanx hyalocranius) in Daoguanhe Reservoir, China

Hongjuan Wu1 and Musheng Xu2

Abstract

Protosalanx hyalocranius was first transplanted in January 1995 into Daoguanhe Reservoir(400 ha), Hubei Province. Breeding populations of P. hyalocranius were established two yearsafter transplantation, and currently the species contributes about 12 kg/ha/yr to the fishery yield ofthe reservoir. Information on growth and other related indices on P. hyalocranius in DaoguanheReservoir were estimated and presented. This paper describes in detail the growth characters oftransplanted P. hyalocranius, when four stages in growth can be recognised, and the results arecompared with those from other reservoirs in China. It is concluded that P. hyalocranius influencesthe ecology of the reservoir and also results in increased production in the waters of HubeiProvince.

LARGE ice fish (Protosalanx hyalocranius),Salmioninae, Salangidae can be found in the littoralof East Sea, Huang Sea and the waters of ChangjiangRiver, middle-down reach of Huai River. Recently, ithas become regarded as a valuable fish and has beensuccessfully transplanted to many reservoirs in Chinabecause of its fast growth, short life-cycle and highnutritional value and economic importance. The aimof this study was to explore whether large ice fishcould grow in reservoirs in central China.

Daoguanhe Reservoir (DGH) lies south of DabieMountain, east of Wuhan, with 1.09 × 109m3 of totalstorage, a catchment area of 108.84 km2, an averagedepth of 18.5 m, and 4000 ha surface area.

Materials and Methods

The materials were large ice fish caught in DGHReservoir by lamp, trawl-net or gill-net, and pre-served in 8–10% formalin. The body length (L) andthe body weight (W) were measured monthly. Thebody length composition, the growth index and bodycondition were calculated using standard formulae.

Results

Growth in body length

Three hundred and thirty-six specimens werecollected and measured from April 1995 to January1996 (Table 1). The growth rate was different atvarious phases. The fastest growth period was at3–4 months of age (from May to July) with an averagemonthly increase of 27.6 mm. There was only10–20 mm increase in other months. There were twopeak values of growth index in the life of large icefish: the first occurred in June and July with 21.4–22.1of growth index, the second in October, with 18.1.

Growth in body weight and the index of condition

The body weight of large ice fish (Protosalanxhyalocranius) was simultaneously measured with thebody length (Table 2). There were three periods withmarked increases in body weight: the first period inJune and July with 1.81 g of average increase, thesecond in September with 4.20 g of average increase,the third in November and December, in the sexualmaturation phase, with 9.8 g of average monthlyincrease in females and 6.67 g in males. After that,there was a decline in body weight, possibly due tospawning.

Based on analysis on the index of condition, thelowest was 0.16 in its earlier phases (2–3 months ofage in April and May). Then the index of condition

1Institute of Reservoir Fisheries, Ministry of WaterResources and CAS, PR China, 4300792Wuhan Water Conservancy Bureau, PR China, 430015

180

went up until in November and December reached amaximum, 0.36 in females and 0.34 in males. Finally,the index of condition decreased to 0.29 in femalesand 0.27 in males in January of the next year.

Relationship of L and W

It was calculated that the relation of L and W was

W = 1.2120 × 10−6 L3.1820

Growth equation

Based on Von Bertalanffy growth equation

L1 = L∝[1 − e-k(t − t0

)], Wt = W∝[1 − e-k(t − t0

)] .

WhereLt: the body length when t month old, Wt: the body weight when t month old,L∝: the maximum body length, W∝: the maximum body weight,t0: the age when theoretical length was zero,k: average curvature of the growth curve.

It was calculated that

L∝ = 193.03mm, W∝ = 22.70g, k = 0.3050, andt0 = 0.3328mm.1

3---

*Relative growth rate [length increase ÷ (initial length × time)]

Index of condition: (weight × length3)100

Table 1. Large ice fish (Protosalanx hyalocranius) growth in body length in Daoguanhe Reservoir.

Date No. Body length (mm) Growth index

Relative growth rate

Range Mean±SD SR

17 April 30 19–34 26.5±0.94 17 May 24 38–74 44.6±4.0 3.555 13.7 1.120017 Jun 21 69–92 72.2±8.0 1.725 21.4 1.930515 Jul 19 90–108 98.0±6.5 1.545 22.1 0.357316 Aug 31 95–121 111.4±5.50 1.336 12.6 0.136723 Sept 40 114–138 122.8±6.60 1.287 10.8 0.102319 Oct 39 139–161 142.4±5.6 1.591 18.1 0.203621 Nov 27Γ 125–178 148.9±17.0 5.95 6.35 0.0070

12Ε 155–160 157.5±3.20 2.361 8.36 0.065620 Dec 33Γ 145–186 164.3±12.4 3.307 6.66 0.0431

18Ε 155–190 169.8±13.9 4.582 5.41 0.033418 Jan 14Γ 143–174 161.5±9.1 2.515 –8.51 –0.0489 28Ε 161–184 80.5±4.20 1.020 17.96 0.1176

Total 336

Table 2. Large ice fish growth in body weight in Daoguanhe Reservoir.

Date No. Weight Monthlyincrease

(g)

Average indexof condition

Range Mean±SD SE

17 April 30 0.01–0.05 0.03±0.11 0.1350 0.16 17 May 24 0.36–1.16 0.98±0.32 0.1778 0.10 0.11 17 Jun 21 0.78–1.25 0.98±0.23 0.3302 0.55 0.26 15 Jul 19 1.60–3.90 2.77±1.12 0.2643 1.81 0.30 16 Aug 31 3.50–4.70 4.20±0.35 0.0843 1.23 0.30 23 Sept 40 4.30–5.60 4.96±0.35 0.0676 0.76 0.27 19 Oct 39 8.20–13.80 9.16±1.56 0.4499 4.20 0.32 21 Nov 27Γ 3.90–8.90 8.31±5.10 1.7850 –0.85 0.25 12Ε 7.50–9.30 8.40±1.22 0.5205 –0.76 0.22 20 Dec 33Γ 9.80–21.00 14.98±3.49 0.4851 6.67 0.34 18Ε 7.80–29.00 17.58±6.24 2.0347 9.18 0.36 18 Jan 14Γ 8.00–15.00 11.45±2.03 0.5620 –3.53 0.27 28Ε 8.12–25.00 17.2±7.01 2.8200 –0.38 0.29

Total 336

181

Figure 1. The relationship of length and weight of large ice fish (Protosalanx hyalocranius). H2 — Haizi Reservoir,TH — Taihu Lake, TJ — Tianjing Reservoir, DGH — Daoguanhe Reservoir.

Figure 2. The growth curve of large ice fish (Protosalanx hyalocranius) in Daoguanhe Reservoir and Lake Taihu.

HZ

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body length (mm)1 2 3 4 5 6 7 8 9 10 11

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g)

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t (month old)

1 2 3 4 5 6 7 8 9 10 11 12

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TH

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TH

200

150

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50

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body

leng

th (

mm

)

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182

Discussion

Growth characters

The life of large ice fish in DGH Reservoir could bedivided into four phases: the first phase was (about1–3 months of age) from April to May when its foodchanged from yolk to zooplankton. Low condition,slow growth, small size and higher related growthrate were characteristics in this period. The secondphase was June to October (4–8 months) when it fedon small fish but with less growth and condition. Thethird phase was in the sexual maturation period(8–10 months) with little increase in body length andmuch increase in body weight and maximum con-dition, especially in females. Decreased body weightcharacterised the last phase (10–12 months).

Comparison with the growth of large ice fish in other reservoirs

As Figure 1 shows, the relationship curve of thelength (L) and the weight (W) of large ice fish inDGH Reservoir basically coincides with that in HaiziReservoir (Zhu 1985), close to that in Lake Taihu(Wang and Jiang 1992; Seng 1995). It shows that thegrowth of large ice fish in its earlier life stage wasfaster.

In addition, the time at which the body weight oflarge ice fish greatly increased in DGH, HaiziReservoir and Taiu Lake was later than in TianjingReservoir (TJ).

Conclusion

The growth characteristics of large ice fish wereobserved to be the same as in other reservoirs inChina. They showed that the fish is widely adaptiveto environment and can grow in most reservoirs inthe north catchment areas of Changjiang River andthe north of China.

Acknowledgment

Wuhan Science Committee, China supported thisstudy.

References

Seng Qizhang 1995. The study report of transplanting largeice fish (Protosalanx hyalocranius) to Haizi Reservoirin Beijing, China. Reservoir Fisheries, (1): 27–28 (inChinese).

Wang Yufen and Jiang Quanwen. 1992. The studies on thegrowth characters of large ice fish (Protosalanx hyalo-cranius) in Lake Tai, China. Lake Science, 4(1): 56–62(in Chinese).

Wang Yupei et al. 1992. The technique of protecting andpropagation of large ice fish (Protosalanx hyalocranius)resources in Tianjing, China. Reservoir Fisheries, (6):25–28 (in Chinese).

Zhu Chende, 1985. Primary study on the growth and foodof large ice fish (Protosalanx hyalocranius) in Lake Tai,China. Acta Aquaculture, 9(3): 275–287 (in Chinese).

183

Estimation of the New Icefish Neolsalanx taihuensis Yield in Zhanghe Reservoir, China

Jiashou Liu1, Jianhua Peng1, Fuhu Yu1, Jie Jiang1, Xianquin Yao2

and Yuanhong Yi1

Abstract

Zhanghe Reservoir covers 7000 ha and is important in the flood control of the middle and lowerreaches of the Yangtze River. The new icefish Neosalanx taihuensis was introduced into thereservoir and has become the only fish of economic value. A study was carried out in ZhangheReservoir from June to November 1997 and from June to September 1998. The new icefish weresampled monthly with a trawlnet driven by two boats in three sampling stations, which werelocated in the upper, middle and lower parts of the reservoir. Zooplankton was also sampled at thesame time. The distribution depth of the fish at dawn and dusk in the reservoir was about 5 m. Itwas estimated that the maximum yearly sustainable yield of the icefish in the reservoir was 150 tand the rational capture yield was 120 t.

ICEFISH (Salangidae) are a group of small-sized,transparent or translucent fish characterised by earlyonset of sexual maturity, short life span, a highreproductive potential (Chen 1956), delicious meatand a high market price (Dou and Chen 1994). Morethan 20 species of icefish have been found in China(Dou and Chen 1994), among which the large icefishProtosalanx hyalocranius and the new icefish Neos-alanx taihuensis are the most valuable and widelytranslocated species (Hu et al. 1998). The large ice-fish feed mainly on small-sized fish and shrimp (Zhu1985) and the new icefish mainly on zooplankton(Chen 1956).

The large icefish is mainly introduced intoreservoirs in northern China, especially in Shandong,Liaoning, Tianjing provinces and Inner Mongolia,whereas the new icefish is mainly introduced intoreservoirs in Central and Southern China, especiallyin Yunnan, Hubei, Zhejiang, Jiangsu, Guangdongand Guangxi (Hu et al. 1998). The introduction oficefish into reservoirs has brought good economicreturns, especially in Shandong and Yunnanprovinces. In some reservoirs, they have become

the dominant species. The icefish in reservoirs arenormally captured 2 to 4 years after translocation(Hu et al. 1998). However, the shared problem forthe two species is that the capture yield is not oftensustainable.

The new icefish was first introduced into DianchiLake, Yunnan Province, in 1979 and the highest pro-duction reached 3500 t in 1985. But currently, theproduction is lower than 50 t. Heavy water pollutionwas thought to be the main reason for the rapiddecrease of the new icefish yield in Dianchi Lake(Peng 1997). The other reason may be over fishing.

The new icefish was first introduced into GeheyanReservoir, Hubei Province in 1996 and the highestproduction was over 300 t in 1998, but it was only1 t in 1999 because of over fishing. Therefore,precise estimation of the new icefish production inreservoirs is important to determine sustainableproduction levels.

Estimation of the maximum sustainable yield canbe achieved by the application of models, e.g. theBevertor-Holt Model, the Ricker Model and theChapman-Roson Model (Zhan 1997). However, allof these models have been developed for fish with along life span, which may not be strictly applicableto new icefish, because the lifespan of the new ice-fish is only one year (Hu et al. 1998).

Zhanghe Reservoir, located in the centre of HubeiProvince, was impounded in 1966, with a surface

1Institute of Reservoir Fisheries, the Chinese Ministry ofWater Resources and the Chinese Academy of Sciences,Zhuo Dao Quan, Wuhan 430079, P.R. China2Administration Bureau of Zanghe Reservoir, Jingmen,Hubei 448156, P.R. China

184

area of 7000 ha, a storage of 2.035 × 1010m3, a meanwater depth of 29 m and a catchment area of2212 km2. Its main functions are flood control andirrigation. The fertilised eggs and broodstocks of thenew icefish were introduced in 1992, and the yieldwas 126 t in 1996. The purpose of the study was todetermine the fish production and sustainable yieldof the new icefish in the reservoir.

Materials and Methods

The study was carried out in Zhange Reservoir fromJune to November 1997 and from June to September1998. The new icefish were sampled at dawn anddusk with a trawlnet driven monthly by two boats inthree sampling stations, which were located in theupper, middle and lower parts of the reservoir, respec-tively (Figure 1), since dawn and dusk are the timefor the icefish to be active in the water surface (ITSG1995). Zooplankton was also sampled at the sametime. Each boat was driven by two engines of 30 hp.The trawlnet was 18.2 m wide, 2.0 m deep and 20 mlong. The trawl speed was 0.56 m/s. The samplingtime was 20 to 30 minutes each time. The catch fromeach sampling station was measured (to the nearest0.1 g) and 20 g of fish was randomly collected fromthe catch and counted, and the total length (to thenearest 0.1 mm) and body weight (to the nearest0.01 g) of individual fish were determined. The vonBertalanffy equation (von Bertalanffy 1936) was usedto describe the growth characteristics of the fish.

Zooplankton biomass was calculated using themethods of Zhang and Huang (1989).

The standing crop of the new icefish in the reser-voir was calculated using the following equation:

P = S × H × R

where P is the standing crop of the new icefish in thereservoir (t); S is the surface area of the reservoir(ha); H is the valid water depth in which the new ice-fish normally distribute at dawn and dusk (m) and Ris the mean catch per cubic m (g/m3). H was deter-mined by trawling the new icefish at nine differentwater depths at dawn and dusk at Station III inSeptember of 1988. Each depth was trawled threetimes and each time was kept for 30 minutes. Thecatch per m3 at each sampling station (R,g/m3) wascalculated with the following equation:

R = W/V

where W is the catch at each sampling station (g);V is the volume of water filtered (m3). V was calcu-lated with the following equation:

V = v × t × L × h

where v is the trawling speed (m/s); t is the trawlingtime at each sampling station (s); and L is the mouthwidth of trawlnet (m); and h is the height of thetrawlnet.

All the statistical calculations were done withSTATISTICA 5.0 (StatSoft 1994).

Figure 1. Distribution of sampling stations in Zhanghe Reservoir.

The Main Dam

The Wangjiawan Dam

The Side Dam

N

185

Results

Growth of the new icefish

A total of 8619 new icefish from Zhanghe Reservoirwas used for growth measurements, among which5400 were collected in 1997 and 3219 in 1998. Table1 lists the monthly mean total length and bodyweight of the new icefish. The mean body weightand mean length of icefish caught in August toOctober were significantly (P<0.05) higher than inthe other months (Table 1). In the remaining months,these parameters did not differ significantly.

Catches of the new icefish at different water depths in Zhanghe Reservoir

Table 2 shows the results of the catches of the newicefish collected in 30 minute hauls at dawn anddusk from different water depths at Station I.Analysis of variance showed no significant differ-ences in the catch among water depths from 0–2, 1–3to 2–4 metres (P>0.05) (Table 2). However, thecatch significantly decreased with further increase indepth (P<0.05) (Table 2).

1 Values with the same superscript are not significantlydifferent from each other (P>0.05).

The standing crop and exploitable yield of the new icefish in Zhanghe Reservoir

Based on the trawl catches, the standing crop of newicefish in the reservoir was estimated. Accordingly,in 1997, the standing crop of the new icefish inZhanghe Reservoir increased from 35.7 t in June to

103.2 t in September, and then decreased to 28.7 t inNovember (Table 3). In 1998, the tendency of thestanding crop of the fish in the reservoir was com-parable to that at the same time in 1997 (Table 3).

1 R is the mean catch of the new icefish per cubic metreswithin the valid depth.2 P is the standing crop (t) of the new icefish in the reservoir.

The commercial fishery for icefish in the reser-voir is very seasonal and occurs only for a fewmonths in the year. In 1997, it commenced on22 September and ended on 15 November. In 1997,the yield was 68.5 t until 19 October, and 123.6 tuntil 15 November. In 1998, capture for the newice-fish started on 23 September and ended on13 November. The yield was 59.5 t until 19 October,103.2 t until 13 November.

Growth rate of the new icefish in Zhanghe Reservoir

The size of the new icefish in Zhanghe Reservoir ismuch smaller than that in other water bodies. Forexample, the mean length and weight were 51.9 mmin total length and 0.29 g in Zhanghe Reservoir inOctober (Table 1). However, at a comparable time,the mean length and weight were 70.0 mm and1.171 g in Fushui Reservoir, Hubei Province (Gonget al. 1977), 68.9 mm and 1.21 g in Taihu Lake,Jiangsu Province (ITSG 1995), 66.0 mm and 1.7 g inDianchi Lake, Yunan Province (Gao and Zhuang1989), respectively.

Table 2. The catches of the new icefish from differentwater depths collected at dawn and dusk.

Water depth (m) Mean catch (kg) ± s.e.1

02 3.714 ± 1.212a

13 3.953 ± 1.089a

24 3.021 ± 0.678ab

35 2.845 ± 0.154b

46 2.122 ± 0.169c

57 1.021 ± 0.078d

68 0.367 ± 0.025c

79 0.212 ± 0.012f

810 0.041 ± 0.009g

Table 3. The standing crop of the new icefish in ZhangheReservoir in 1997 and 1998.

Sampling time R (g/m3)1 P (t)2

22 June 1997 0.102 35.7021 July 1997 0.156 54.7521 August 1997 0.191 66.7721 September 1997 0.295 103.1820 October 1997 0.146 51.2020 November 1997 0.082 28.7020 June 1998 0.098 34.3720 July 1998 0.161 56.3520 August 1998 0.178 62.3020 September 1998 0.281 98.35

Table 1. The mean total length and body weight of the new icefish in Zhanghe Reservoir.

Sampling time 1997 1998

June July Aug Sept Oct Nov June July Aug Sept

Total length (mm) 38.79 41.70 44.27 46.82 51.93 56.53 38.21 41.30 46.27 50.81Body weight (g) 0.149 0.197 0.226 0.247 0.287 0.477 0.141 0.200 0.276 0.350

186

The new icefish is a zooplankton feeder (Chen1956). Its growth rate is dependent on the trophiclevel of water bodies. Zhanghe Reservoir is oligo-trophic, but Fushui Reservoir, Taihu Lake andDianchi Lake are eutrophic. The zooplankton biomasswas only 0.02–0.13 mg/L in Zhanghe Reservoir fromJune to November of 1977, showing a decreasingtendency with increasing fish size (Figure 2), perhapsindicative of food limitation in the latter part of theyear. Transplantation of the new icefish is notrecommended into water bodies with a zooplanktonbiomass less than 2.8 mg/L (Rong and Zhang 1997).The practice in Zhanghe Reservoir indicated that size-able populations of the fish could still occur in oligo-trophic water bodies, though it has much lowergrowth rate.

Zhanghe Reservoir recorded the heaviest floodingin 1998. Heavy rains brought plenty of nutrients intothe reservoir and improved its trophic conditions.

The zooplankton biomass was 0.09–0.22 mg/L inZhanghe Reservoir from June to September (Figure3) which was higher than that in the same time of1997. Consequently, the size of the new icefish inAugust and September in 1998 was significantlybigger than that in the same time of 1997 (P<0.05)(Table 1), indicating again that the growth of the newicefish was dependent on food availability. If thezooplankton availability could be improvedartificially, the size of the new icefish in ZhangheReservoir may be improved.

Valid water depth of distribution at dawn and dusk of the new icefish in Zhanghe Reservoir

The new icefish is strongly phototaxic. They moveupwards to the water surface at dawn, dusk and onmoonlit nights (ITSG 1995), a behavioural traitexploited by fishers. In some reservoirs, e.g. Xinan-jiang Reservoir, Zhejiang Province, people around

Figure 2. Biomass of zooplankton at three sampling stations in Zhanghe Reservoir in 1997.

Figure 3. Biomass of zooplankton at three sampling stations in Zhanghe Reservoir in 1998.

0.3

0.2

0.1

0

Bio

mas

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g/L

)

Jun Jul Aug Sept Oct Sept

I

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Jun Jul Aug Sept

187

the reservoir catch the fish by luring the fish withartificial lights (ITSG 1995). We captured the fish atdifferent water depths and found no significant dif-ferences in the catch at depths of 0–2, 1–3 and 2–4 m(Table 2).

Acknowledgments

We would like to thank Dr S.S. De Silva at theDeakin University for checking the manuscript andmaking valuable proposals. Thanks also to ProfessorChuanlin Hu and Mr Daoming Huang at the Instituteof Reservoir Fisheries, the Chinese Ministry ofWater Resources and the Chinese Academy ofSciences for providing some useful information. Thestudy was jointly founded by the Chinese Ministry ofScience and Technology (originally the ChineseCommission of Science and Technology) (ProjectNo. 96-008-02-04) and the Water Resources Bureauof Hubei Province.

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