UNIVERSITI PUTRA MALAYSIA

ECONOMICS OF TECHNOLOGY ADOPTION: THE CASE OF BRACKISHWATER AQUACULTURE

IN BULACAN, PHILIPPINES

Jose Erezo Padilla

FEP 1985 3

It is hereby certified that we have read this thesis entitled Economics of Technology Adoption: The Case of Brackishwater Aquaculture in Bulacan, Philippines by Jose Erezo Padilla, and in our opinion it �s satisfactory in terms of scope, quality and presentation as partial fulfilment of the requirements for the degree of Master of Science

A ZAINUDDIN, PhD. Assoc. Professor/Dean of Graduate Studies

Univcrsiti Pertanian Malaysia (Chairman Board of Examiners)

KEE CHAr CHONG, PhD. Research Specialist

Fisheries/Aquaculture Economics Center for Agro Economics Research

Winrock International (External Examiner)

('

ABDUL RAHMAN, PhD. Lecturer

rtment of Economics Faculty of Reso ce Economics and Agribusiness

Universiti Pertanian Malaysia (Internal Examiner)

, M.S.

Department of Agr"cultural Economics Faculty of Resource Economics and Agribusiness

Universiti Pertanian Malaysia (Supervisor)

This thesis was submitted to the Senate of Universiti Pertanian Malaysia and was accepted as partial fulfilment of the requirements for the degree of Master of Science.

Date: A • ZAINUDDIN, Ph.D. A ate Professor/ Dean of Graduate Studies

ECONOMICS OF TECHNOLOGY ADOPTION:

THE CASE OF BRACKISHWATER AQUACULTURE

IN BULACAN, PHILIPPINES

by

Jose Erezo Padilla

A thesis s ubmitted in partial fulfilment of the requirements

for the degree of Master of Science in the Faculty of Resource Economics and Agribusiness,

Universiti Pertanian Malaysia

December 1985

ACKNOWLEDGENENT

The author wishes to express profound appreciation and

gratitude to the following persons and institutions who have

contributed to the completion of his stud y . Hr. Abu Hasan Md.

Isa, thesis supervisor, for guidance and invaluable comments in

the preparation of this thesis. The suggestions of Dr. Brian

Lockwood and Dr. Ian Smith of the International Centre for Living

Aquatic Resources Management (TCLARM) dur ing the initial stages

of this research were educational and encouraging. It was from

them that the interest in undertaking a research in aquaculture

economics arose.

This thesis relied heavily on data provided by the 60

obliging fishfarmers from Bulacan, without them, this study could

n o t h a ve been u n d e r t aken.

appreciated.

Th eir c o o p e r a tion i s h i gh ly

The Agricultural Development Council, Inc. was very generous

in providing the graduate fellowship. The people behind the

A/ D /C, Mr. Ge rard Rixhon and Dr. Gerald Nelson were very

responsive to the problems met by the author in the course of his

graduate program. Partial research funding by ICLARM was also a

tremendous he 1 p.

The Dean and staff of the Faculty of Resource Economics and

Agribusiness, UPM, were very supportive. The Dean, Dr. Mohd.

Ariff Hussein facilitated access to MARDI Computer Centre. The

ii

comments of Dr. Rosl a n bin A. Ghaffar on the econometric aspects

of this s t udy were usefu l . Mr. Siow Kiat Foo was p artic ularl y

helpful in the use of the microcomputers.

The logistical arrangements extended by Emma Escover, Otis

Salon and Emil Bal l esteros are deeply appreciated. The company

a nd a s si s ta n ce of f r iends from t h e T e c h nic a l Boa r d for

Agricul tural Credit: Vic Tan, Ginny Jamon, E l l en, FIery, Payday

a nd Rosalie; friends in UPLB and I R RI: Adem, Liza and Susan

M a g h a ri; all colleagues in UPM pa rtic ularl y the gre garious

Filipino group, Luz Yater and Ex Danlag for the company through

t hick and thin; they all de s erve more than gratitud e . Special

thanks are due to Pau l , Eny a and family for all their kindness.

Finally , the encouragement of my fami l y: parents, brother,

siste rs and niec es who hav e bee n the moti v ating for c e in

undertaking a graduate program.

Abov e a l l , to the Almighty who has made ev erything possible ,

for giv ing meanin g a n d chall enge to my life, this work is the

least I could offer.

iii

TABLE OF CONTENTS

ACKNOWLEDGEt1ENT

LIST OF TABLES

LIST OF FIGURES

ABSTRACT

ABSTRAK

CHAPTER I INTRODUCTION

1.1 Background 1.2 Ti1apia farming in the Philippines 1.3 Statement of the problem 1.4 Objectives 1.5 Hypotheses 1.6 Organisation of the thesis

CHAPTER IT CONCEPTUAL FRAMEWORK AND REVIEW OF RELATED STUDIES

2.1 Rationale and classification of technological innovations

2.2 The innovation-decision process 2.2.1 Knowledge function

2.2.2 Persuasion function 2.2.3 Decision function 2.2.4 Confirmation function

2.3 Review of related studies on technology adoption

2.3.1 Education

2.3.2 Farm size 2.3.3 Labour availability 2.3.4 Risk and uncertainty

CHAPTER III ANALYTICAL FRfu�WORK

ii

v

vii

viii

xi

1

4

8

11

11

12

13

15

17

18

24

25

26

27

28

28

29

3.1 Costs and returns analysis 30

3.2 Distribution of observed dependent variables 31

3.3 Problems of using ordinary least squares in

strictly dichotomous studies 34

3.4 The logit model 40

iii

CHAPTER IV THE STUDY AREA AND PRELIMINARY RESULTS

4.1 The study area 4.2 Na ture and sources o f data 4.3 Specification and measurement of variables 4.4 General charac teristics of the sample

CHAPTER V

5.1

5.2

respondents

RESULTS AND DISCUSSIONS

Cos ts 5.1. 1

5.1. 2

Choice 5.2.1 5.2.2

and returns analysis Comparative costs and returns of milkfish monoculture Comparative costs and returns of milkfish monoculture and milkfish­t Llapia culture

of technology model The explanatory variables Conditional probability, partial effec ts and elasticities

5.3 Intensity of adoption model 5.3.1 The expalanatory variables 5.3.2 Demand for new technology

5.4 Impact of selec ted activi t ies geared t oward the diffusion of tilapia c ulture in brackish­water ponds

CHAPTER VI SUMMARY AND CONCLUSIONS

BIBLIOGRAPHY

APPENDICES

iv

45 49 51

55

68

69

75

85 89

94

98 101 102

102

107

114

112

Table

1.1

1.2

1.3

4.1

4.2

4.3

4.4

4.5

4.6

5.1

5.2

5.3

5.4

LIST OF TABLES

Yearly average retail prices of rnilkfish (pesos/kg) in Metro Manila, Phtlippines, 1974-1983

Tilapia introduction in the Philippines (1950 - 1982)

Estimates of tilapia production from Philippine waters, 1 981

Brackishwater fishponds in operation and number of opera to r s by municipality: Bulacan, Philippines, 1983

Distribution of sample-respondents, by educational attainment

Distribution of sample-respondents, by size of operation

Frequency of use of material inputs, by group of respondents

Problems encountered in milkfLsh farming, 1983-84 crop year

Problems encountered in tilapia culture, 1983-84 crop year

Costs and returns of milkfish monoculture, per hectare per cropping: 1979 and 1983-84 crop years

Summary of income and expenses of milkfish monoculture, per hectare per cropping: 1979 and 1983-84 crop years

Costs and returns of milkfish monoculture (old technology) and milkfish-tilapia culture (new technology), per hectare per cropping: 1983-84 crop year

Summary of income and expenses of milkfish monoculture (old technology) and milkfish­tilapia culture (new technology), per hectare per year: 1983-84 crop year

v

Page

3

5

7

48

57

60

62

64

66

70

71

77

78

5.S

5.6

5.7

5. 8

5.9

5.10

5.11

Costs and returns of milkfish and tilapia crops of adopters, per hectare per cropping: 1983-84 crop year

Summary of income and expenses of milkfish and tilapia crops of adopters, per hectare per year: 1983-84 crop year

Means of continuous variables and frequencies of dichotomous variables, by group of farmers

Choice of technology model: maximum likeli­hood estimates for 60 fishfarms, Bulacan, Philippines: 1983-84 crop year

Estimates of partial effects and elasticities

Intensity of adoption model: ordinary least squares estimates for 30 fishfarms, Bulacan, Philippines: 1983-84 crop year

Effects of various activities geared toward the diffusion of tilapia culture in brackish­water ponds, Bulacan, Philippines

vi

81

82

87

88

97

100

105

Figure

2. 1

2.2

'3.1

3.2

3.'3

4.1

4.2

LIST OF FIGURES

The innovation-decision process

Isoquant map showing neutral and non­neutral technological changes

Distribution of lim i ted dependent variables

Comparison of linear and cumulat i ve distribution functions

Comparison of logit and problt distribution functions

Map showing the s t udy area and its vicinity

A t y pical milkfish pond lay-o u t showing n ursery, t ransition, and nursery ponds

vii

Page

16

21

33

38

39

47

59

An a b s t ract o f t he thesis p r e s e n t e d t o the Sena t e o f Unive r s i t i Pe r ta nian Malaysia in partia l f u l f i l me n t o f the requirements for the Degree of Master o f Science .

ECONOMICS OF TECHNOLOGY ADOPTION:

THE CASE OF BRACKISHWATER AQUACULTURE

IN BULACAN. PHILIPPINES

by

Jose Erezo Pad i lla

December 1985

Super v isor Mr. Abu Hassan Md . Isa

Faculty Resource Economics and Agribusiness

Brac k i s hwa ter fi s h p o n d s a r e t r a d i t i on a 11 y d e v o t e d t o

m i l kf i sh c u l t u r e . Howe v e r , f o r the p a s t thr e e t o f o u r y ea r s ,

brackishwater mi l kfish o p e r a t o r s i n Bu l a c an , Phi l i p p i n e s ha v e

been c u l tur i n g t i l a p i a i n a d d i t i o n t o t h e i r m i l k f i sh c r o p s .

Owi ng t o t h e d e a r t h o f p r i ma r y d a t a o n t hi s a s p ec t , r e a s o n s

a d v a nced b y r e sea rche r s on the eme rg e n c e o f such p ract i c e w e r e

based o n secondary information .

The purpose of this study was to pro v ide i nformation on

the c ircumstances surroundi ng the phenomenon of cul turi ng t i l apia

in traditiona l mi lkfish systems. The under l ying reasons for the

shifting to t i la pia cul ture were i n v estigated. Another objective

was to i de n t if y and mea s u r e f a c t o r s wh i c h t e n d to e n c o ur a g e o r

viii

restrain t he adoption and extent of adoption of s u c h p rac t ice.

The analytical t ools include d costs and returns analysis i n

addition to models sp ec ified in the context of innovation

adoption. Inf ormatioll for the study was obtained from a sample

survey of fishfarmers in Bulac an, Philippines. The survey

covered 1983-84 crop year. Additional data from a previous

survey in the study area reporting 1979 crop year were also

included in the study.

Betweon 1979 and 1983-84 crop years, milkfi sh producers

w (� r e c aug h t il \ ,1 C () S t- P r i r: I? S q Ll e e z e ;1 sin put cos t s r 0 s e m 0 r e

rapidly than Ollt put prices. As a result, mi1kfish culture

profitabi liLy occlirwo considerably and some milkfish farmers

s!\irt"t! to ollwr SPf'Clf'S particularly, t i l apia . These farmers

(iJ(ioptl'fS) w('rf' rOIIlld io he th(' :ILlr:�jr1nl [lnd less effi.cient

mLlkfish growers aDo the culture u[ Lilapia provided higher

rdurlls than lhe old prncticc. NeL return accruing from tilapia

culture amounted to 1,125 p esos per cropping per hectare which

was three times more than profit real ize d i n milkfish culture.

This was due t o the fact that tilapia required less materi al

inputs than milkfish.

Using logistic regression technique, seven technical and

socioeconomic vilrinbles were hypothesized to explain the decision

to adopt the new practice. Significant variables were perception

on profi ta hi 1 ily Rnd capital reqllirements of the innovation,

extension c on tae t, mi 1 kf ish cuI ture experience and market

ix

accessibility. The intensity or extent of adoption model was

speci f ied i n semi-logarithmic form wIth essentially the same set

of explanatory var i a b les as i n the adopt i on model. Four

variables were si gnificant, namely: tilap ia culture experience,

dist anc e of pond from coastline, and the perception variables on

the innovation (profitability and capital requirement ).

From the foregoing r esu l ts, it was conc l u d e d tha t the

shift by milkfish farmers to other species, particularly tilapia

was profi t-motivated. Farmers' perceptions of the innovation

were related to adoption behavi our actuall y taken. M oreo v e r,

management 3bi 1 ity was an i m p or t ant determinant in innovation

adopt ion and ill the quanU ty of innovRtion to secure. At the

same time, consi4eratIon of physical factors such as salinity of

pond water was imperative i n the frequency of tilapia cropping.

Extension contact and access to printed materials on aquaculture

sign ificantly influenced adoption decision.

x

Abs trak tesis yang dikemukakan kepada Senat Uni versiti Pertanian Malaysia sebagai memenuhi dari keperluan untuk Ijazah Master Sains

EKONom PENERIMAAN TEKNOLOGI:

KES AKUAKULTURA AIR PAYAU

DI BULACAN, FILIPfNA

oleh

Jose Erezo Padilla

Disember 1985

PenyeIia: Encik Abu Hassan Md. Isa

FakuIti: Ekonomi Sumber dan Perniagaantani

M�ngiklll lr<ldisi, ko l am air pnynu lebih banyak ditumpukan

kepada kul tur "mil kfL sh". Wal au bagaimanapun selama tiga empat

tahun terakhir ini, pengll s aha "mi lkfi sh" air pay a u di Bulaean,

Filipina telah mengkultur tilapia sebagai tambahan kepada hasil

"milkfish" mereka. Oleh kerana amalan ini bermula baru-baru ini,

tidak ada data primer yang wujud mengenai a spek inL Oleh itu,

alasan-alasan yang dikemukakan oleh penyelidik-penyelidik

mengenai kemunculan amalan sedimikian adalah berasaskan maklumat

s ekunder.

Tujuan kajian ini ialah memberi maklumat mengenai situasi di

s ek itar fenomena mengkul tur tilapia dalam sistem "milkfish".

Alasan-a1asan yang menjadi dasar peralihan kepada kultur tilapia

xi

tel ah dis iasat. Di samping itu kajian ini cuba mengena l past i dan

mengukur fak t o r - f ak t or yang bo l eh mengga l ak a t a u mengha l an g

p e n e r imaan ama l a n d i a t a s d a n s e takat manakah ama l an berkenaan

d i t e r ima . Di an tara kae d ah-kaedah a na l i sis kos-p u l a n g a n d i

s a m p i n g m o d e l -m o d e l k h u s u s y a n g d i g u nakan d a l am k o n t ek s

p e n e r imaan i n o v a si. Mak l ukma t u n t uk ka j ia n t e l ah d i p e ro l ehi

d a ripa d a satu tinjauan sampel ke atas 60 p en t e r na k ikan d i

B u l a c a n , Fi l i pina , y a n g me l i p u t i t ahun ha s il 1 983-84. D a t a

tambahan daripada sa tu tinjauan sebe1umnya da1am kawasan kaj ia n

tersebut yang me lapurkan tahun has i l 1 979 te l ah juga d imasukan

dalam kaj ian .

Di an tara tahun hasil 1979 dan 1 983-84 , penghasi l-penghasi l

"mil kfish" terperangkap da l am tekanan harga kos dengan kos input

m e nen g k a t 1ebih c e p a t d a r i p a d a h a r ga o u t p u t . Ak i b a t n y a ,

k e b e r u n t un gan ku l t u r "mi l k f i sh" banyak merosot dan s e t e n gah­

s e t e n g a h p e n t e r n a k " m i l k f i s h " b e r a l ih k e p a d a j e n i s l a i n ,

khususnya t i l apia. Ada l ah didapati petani-petani yang menerima

peral ihan merupukan penternak-penternak "mi l kfish" yang margina l

dan kurang cekap , dan kul tur t i l ap ia t e l ah memberikan p e langa n

ya ng l ebih tinggi dibandingkan dengan amalan lama. Pula n g a n

b e r s i h y a n g d id a p a t i d a r i pada k u l t u r t i l a p i a a d a l ah s e b a n y a k

1 , 125 peso sehektar semusim merupakan tiga kal i ganda daripada

keuntungan yang didapati daripada kul tur "mi lkfish". Ini ada l ah

kerana t i l apia memer l ukan bahan-bahan input yang kurang daripada

"milkf ish" •

Dengan menggunakan teknik regresi l ogistik , tujuh p embol ehu-

xii

bah sosioekonomi telah dihipotesiskan untuk menerangkan keputusan

untuk menerima amalan yang baru inL Pembolehubah-pembolehubah

yang bererti adalah seperti persepsi mengenai keberuntungan dan

keperluan modal bagi inovasi berkenaan, hubungan pengembangan,

pengalaman mengku 1 tur "mi lkfish" dan kebolehdapatan pasaran.

Mode l keamatan atau setakat manakah penerimaan inovasi telah

ditentukan dalam bent uk semi-logarit m a dengan pembolehbubah­

pembolehubah yang sama seperti yang terdapat dalam penerimaan di

alns. Empat pembolehllhah adalah didapati. hererti, iaitu pengala­

m,lI1 mengkultur tilapi'l, jarak kolam daripada garispantai dan

pembolehubah persepsl t erhadap inovasi (keuntungan dan keperluan

modal).

Daripada keputllsan yang A.wa} ltll, telah disLrnpulkan bahawa

peralihnn ol('h pptdnl "milkfish" kepnda mC'ngku1tur iknn jenLs­

jcnis lain, khusllsnya ti lapia adalah bermoti vasikan keuntungan.

Persepsi petani terhadap inovasi adalah berkaitan dengan tingkah­

laku penerirnaan yang sebenarn ya dibuat. Lagipun, kebolehan

mengurus adalah pcnentu yang penting dalam penerimaan inavasi dan

dalam kuantit i inovasi yang hendak diperolehi. Pada masa yang

sama pertimbangan faktor-faktor fizikal seperti kemasinan air

kolam adalah penting dalarn kearnatan penghasilan tilapia.

Hubungan pengembangan dan kedapatan bahan-bahan bercetak atau

risaiah-r i s a l a h m e n g en a i akllaku ltlira banyak mempengaruhi

keputusan penerimaan.

xiii

CHAPTER 1

INTRODUCTIO>l

1.1 Background

Since ,lquilculturp was f i rst practised in the Phjlippines in

1020, brack i shw;ltl'r ponds hdve be£'n devoted l'1ostly to the culture

of Chanos chanos (mj 1 kfish). In 1981, total fish production from

176,000 hectares of these ponds reached 170,000 metric tons

(lWAR, 198 2). Of this, 8n eslim!1ted 90 percent was milkfish

(Smith and Chong, 1981). In their assessment of the economic

status Clnd ful\lre prospects of the Southeast Asian milkf ish

indtlstry, Sm i t h illld Chong (198'3) lloted that, while milkfish

pr oducti on in the Ph ilippin e s c ontinued to grow, its share to

tota 1 fish production was level ing off. Using price data, they

dttrbbuted lhis apparent trend to decl i nin g profitability of

milkfish monocul ture. Producers were being caught in a cost­

price squeeze as input costs rose more ra pidly than milkfish

retail prices. Comparing costs and returns in 1974 and 1978 crop

years, nominal receipts increased 108 percent while expenses were

up 133 percent (Librero et aI, 1977; Chong et aI, 1982).

Several factors con t r i bu ted to the decline in profits of

brackishwater milkfish producers . First, there was an increased

supply of lower-priced milkfish and other substitute species from

freshwa ter pens and Ci'lges of Laguna de Bay. This resul ted in a

decline in milkfish retail prices (in real terms) in Metro

1

2

Manila with spillover effects on outlying provinces which

originaUy supplied pRrt of the metropolis' requirement. In

fact, yearly average retai 1 prices of milkfish in Metro Manila

markets went down by 21 per cent in real terms for the period

1 974-1 983, although in nominal te rms, these was an increase of 90

percent in thp same period (Table 1.1). As corresponding farm

gate or fish landing site prices arc not available, the extent by

which fishfarmers were affected by the declining prices is not

knowll.

The second factor was related to consumers' buying power and

preferen ces. Declining real Wilgcs and inflRtion reduced per

capita fish consumption from 38 kilograms (kg) to slightly over

20 kg in 1 980 (NEDA, 1982). As demand for fjsh is more elastic

;11 lower inCOlllf"; (Smith :l11d Chong, 19W3), cont-inllous fall in rea]

per capita income brought about by the present ec on o m i c crisis

has led to an even greater diminution in the demand for fish.

Consumers turned to lower-priced substitutes and demand for milk­

fish has been most affected. Horeover, changing preferences of

consumers toward other species, particularly tilapia had further

aggravated the situation for milkfish producers.

Entrepreneurs adjust to economic conditions. Thus, in res­

ponse to the declining profitability of milkfish culture, produ­

cers have made short-run adjustments in their farms: adopting new

technologies through complete or periodic shifting to the culture

of other species or poly culture with the milkfish crop. These

phenomena have been reported not only in brackishwater ponds but

TABLE 1. 1

YEARLY AVERAGE RETAIL PRICES OF MIL1:FISH (PESOS/KG) IN METRO ;'1A�ILA, PHILIPPINES, 1 974- 1 983

3

=================�=============================�=�=================================================

Percent change

1974 1 975 1976 1 977 1978 1979 1 980 1 98 1 1 982 1983 1 974-1983

Current Pesos 6.45 7. 1 4 7.2 6 8.97 8.84 1 1 . 46 1 1.98 12.90 1 2.92 12.2 5 +90

Constant pesos 6.45 6.60 6.32 7.24 6 . 68 7.2 3 6. 42 6 . 39 5.58 5. 09 -2 1

Consumer retail price index 152.2 164.6 174. 8 188.6 202.9 24 1 . 1 284. 1 335.2 352.2 366.2 (1972 = 100)

=============================================�===================================================�=

1

2

3

Constant peso price = current peso price deflated by the consumer price index (see row 3) for all items n(1972 = 100).

January - June only.

Average for first 6 months of the year.

Source: 1974-1977: 1978-1983:

Bureau of Agricultural Economics Philippine Fish Marketing Authority

Note: Table was lifted from Smith and Chong (1983).

4

also in freshwater pens. However, the most significant shifting

has been occurlng in brackishwater systems. These have given

rise to a significant development in a quaculture. A sort of

multiple cropping has evolved comparable to those existing in

rice-based farms . The shi fL ing from one species to another at

certain times of the year, or the culture of two or more species

sjmultaneously in different compartments or in the same pond, has

created a distinctive cropping pattern. Among the species which

has caught the interest of fishfarmers is tilapia.

1.2 Tilaria culture in the Philippines

Tllapia was first cultured 1n the country in 1950 with the

introduction of the MOLambique tilapia, (Oreochromis mossambicus) from Thailand. The growing of O. mossambicus in those years did

not fluorish because of improper management. The fish bred in an

early age that ponds were filled with tiny, almost useless fish.

This outcome hindered commercial tilapia f arming. Worse, the

fish invaded brackishwater ponds and became a scourge to milkfish

farmers for sometime as it competed WIth the main crop for food

and space. The introduction of Nile tilapia, 0 niloticus, in

1972, however, r enewed interest jn tilapia culture. The new

species was better accepted by farmers and consumers alike

because of its faster growth and lighter colour. Several species

were subsequently introduced (Table 1.2),

Tilapias are considered euryhaline species; they can sur­

vive, grow and some species, O. mossambicus, O. aureus, and

TABLE 1.2

TILAPIA INTRODUCTION IN THE PHILIPPINES (1950-1982)

5

=============:==�===:=============�=======�====:================

Species

Oreochromis mossambicus

O. hornorum X O. mossambicus

O. niloticus (Uganda)

O. niloticus (Egypt

Tilapia zill i i

O. aurellS

O. niloticus (Ghana)

O. niloticllS (Ghana)

O. aurellS (Israel)

O. au reus (Israel)

O. niloticus (Ghana)

Red tilapia (hybrid)

Red tilapia

O. aureus (Israel)

O. niloticus (Ghana)

Red tilapia

Year Origin

1950 Thailand

1971 Singapore

1972 Israel

1972 Thailand

n.3. n.a,

1977 U.S.A.

1977 Israel

1977 Singapore

1977 Singapore

1978 Singapore

1978 Singapore

1979 Taiwan

1981 Taiwan

1982 Israel

1982 Israel

1982 Taiwan

====================�======================�============�=======

n. a. = not ascertained

Source: Guererro (1983)

6

Tilapia zillii, can even reproduce in sea water of up to 40 parts

per thousand (ppt) salinity (Chervinski, 1982). The most common

habitat of tilapia, however, is freshwater. Since commercial

tilapia fry is produced in freshwater hatcheries, proper acclima­

tion must be done if these are to be cuI tured in brackishw ater

ponds to achieve higher survi val rates . It has been observed

that Nile tilapia fry is adversely affected by salinities higher

than 15 ppt ; however, with proper acclimation, growth and survi­

val of tilapia fry are not affected (Guerrero, 1983).

While there urc no statistics available, it is strongly felt

by some researchers that the volume of tilapia produced in inland

waters is quite substantial. In 1981, est i rna t e s 0 f an n u a 1

production in the coulltry were placecl at a bout 50,000 metric tons

Crable l.J)(Guerrero, 1983; Smith and Pullin, 1984).

Nile tilapia is the most common species raised in freshwater

ponds and cages/pens. The culture of these species contributed

to higher productivity in these systems. On the other hand, low

production in brackishwater ponds can be traced to the fact that

tilapia is just a fortuitous harvest, particularly O. mossambicus

which invades ponds during water flashing activities, survives

pest eradication by farmers and is eventually harvested together

with the main crop.

Periodic and total shifting to tilapia in brackishwater

ponds have been practised in Bulacan and Pampanga for the last 2

or 3 years. Tilapia production practices are in many ways

similar to milkfish farming, but tilapia culture requires proper

TABLE 1 . 3

ESTTMATES OF TTLAPIA PRODUCTION FROM

PHILIPPINE WATERS, 198 1

7

=====================================�====z=====================

Production system

Aquaculture

Brackishwater ponds

Freshwa ter ponds

Cages/pens

Open-water f ishing

Lakes and reservoi rs

Area Yield Annual harvest (ha ) (kg/ha/yr ) ( metric tons )

1 76 , OOO.,� 1 00 1 7 , 600

1 2 , 000 1, 000 1 2 , 000

1 , 000 1 0 , 000 1 0 , 000

200 , 000 50 1 0 , 000

Total 49 , 600

================================================:=============== *

This was changed from 1 82 , 000 to 1 7 6 , 000 to conform with BFAR data .

Source : Guererro (1983)

8

schedul ing of the produc t ion process to a v oid highl y-sa l ine water

i n t rus i on whi ch causes shock and s t r e s s to the g r o w i n g f i sh.

Gradua l l y , producers are ] earning the proper cul ture of ti lap ia

and the practice is gaining momentum on a wider sca le .

Severa l factors con tr ibuted to the growth o f ti lapia indus­

t r y (Gue r r e r o , 1983; Sm i t h and Pul l i n , 1 9 8 4 ) . One s i gn i f i c a n t

factor was the energy crisis in the ear l y se venties that shif ted

empha s i s f r om mari ne f i sh i n g to aquacu l tur e . Techno l o g i c a l

breakthroughs by researchers for the impro v ed management of t i l a­

p i a encouraged f i sh f a r m o p e r a t o r s t o take a second l ook a t the

f i sh. A l so , i nc r e a s ed acc e p t a b i l i t y o f the f i sh b y c o n sume r s

favoured widespread enthusiasm for ti lapia production and a sub­

s equent boom i n p r o d uc t i o n . The i n i t ia t i v e o f the Fi l i p i n o

fishf armer f o r v e ntur i n g i n t o i ng e n i ous c u I ture t e chni que s i n

t i l a p ia cu I ture ( c a g e , p e n a n d pond c u I tur e ) wa s a l so a m a j o r

contri butor .

Ti1 apia can be mass-produced from eggs or intensi v e l y farmed

in "batteries" un l ike mi lkfish fry which has to be caught in the

wild . Tilapia can al s o co n v er t p l an t p roduc t s i n t o a n i m a l

p r o t e i n a t a v e r y e f f i c i e n t a n d econom i c a l two-to-o n e r ati o

( Mac l ean , 198 4 ) . Thus , i t p r oduc e s che a p a n i ma l p r o t e i n i n

backyards or high-technol ogy enterprises.

1 .3 Statement of the problem

I n some r e s p ec t s , the shi f t t o the cul ture o f t i 1 a p i a i n