Progress Report on Fisheries
Development in El Salvador
August 1974 - May 1976
CONTENTS
Page
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . 3
ADMINISTRATION AND FINANCIAL INPUTS............................. 3
RENOVATION AND NEW CONSTRUCTION AT FISHERIES STATIONS.......... 5
National Fisheries Station, Santa Cruz Porrillo.................. 5
Fingerling Production Station, Izalco ......................... 5
FISH CULTURE RESEARCH.............. .......................... 6
Introduction of New Fish Species ........................... 6
All-male Tilapia Hybrids.................................. 6
Nutrition Experiments with Tilapia Using Agricultural By-products .7
Economic Evaluation of Tilapia Stocked at Four Densities........ 9
Tilapia Production in Salt Ponds ............................. 9
Culture of Fish in Cages ...... ;............................. 10
FISH CULTURE EXTENSION.......................................11
Private Ponds...........................................11
Community Ponds....................................... 12
SHORT TERM TECHNICAL ASSISTANCE.............................. 12
FISH MAR KETING SURVEY....................................... 13
INTERNATIONAL TRIPS AND CONFERENCES ATTENDED.................. 13
FISHERIES PUBLICATIONS............................ ......... ... 14
ACKNOWLEDGMENTS ........................................... 16
PUBLISHED 10/7 7 - I M
information contained herein is available to all without regard to race,
color, or national origin.
PROGRESS REPORT ON FISHERIES
DEVELOPMENT IN EL SALVADOR'
August 1974 - May 1976
David G. 
Hughes
2
INTRODUCTION
T HE EL SALVADOR Fishery Resources Service of the
General Directorate of Natural Renewable Resources
(DGRNR), Ministry of Agriculture and Livestock (MAG),
received technical assistance in aquaculture research and
extension and inland fisheries development from 1972 to
1976 through a contract between the Agency for
International Development and Auburn University's Inter-
national Center for Aquaculture. Contract AID/la-688
provided technical assistance funds from January I, 1972, to
December 31, 1973, for Dr. David R. Bayne, Assistant
Professor, Department of Fisheries and Allied Aquacultures,
as full-time resident fisheries advisor. His work focused on the
following areas, as outlined in detail in his 1974 report
3
:
1. Renovation and expansion of research and supporting
facilities at the Santa Cruz Porrillo Fisheries Station.
2. Aquacultural research with emphasis on increased fish
production.
3. Aquacultural extension to disseminate improved
technology to farmers and other user groups.
4. Investigations of the fishery resources of major lakes and
other natural waters of El Salvador.
The work was carried out in conjunction with host-country
technical personnel, U. S. Peace Corps Volunteers, and short-
term technical fisheries staff from Auburn University.
By the end of Bayne's 2-year tour, substantial progress had
been achieved, including the following:
1. Near completion of the renovation and expansion of
research and supporting facilities at the Santa Cruz Porrillo
Fisheries Station.
2. Initiation of a country-wide project to survey lakes and
rivers for fisheries statistics, limnology, and fishery biology
data, and the testing and evaluation of fish gear and capture
techniques.
3. Establishment sof an active aquacultural extension
program.
4. Establishment of an active program of practical
aquacultural research designed to increase production and
profit for the fish farm operator.
5. Initiation of academic training in aquaculture and
fisheries for two host-country staff.
Just prior to Bayne's departure in 1973 an economic
evaluation of the freshwater fisheries of El Salvador was
'The fisheries development program was financially supported by the
Government of El Salvador and the U. S. Agency for International
Development.
'Research Associate, Department of Fisheries and Allied Aquacultures.
aBAYNE, DAVID R. 1974. Progress Report on Fisheries Development in El
Salvador. Res. and Dev. Ser. 7. Auburn Univ. (Ala.) Agr. Exp. Sta. Int.
Center for Aquaculture.
made by Dr. E. W. McCoy, of Auburn University, at the
request of USAID/El Salvador. In a 1974 report
4
, McCoy
described the emerging state of fish culture in El Salvador
and stressed the necessity for continuing applied research to
reach the highest possible level of production and the sub-
sequent melding of research and extension for a successful
field program. He analyzed the macro- and micro-impact of
increased fish production, and the need for providing both
short- and long-run capital for production and processing.
For the period of January 1 to September 9, 1974, the
Fisheries Department had no resident fisheries advisor. Until
March 1974, Sr. Jose E. Cabrero was head of the Fisheries
Service and managed the Fisheries Project. In late March he
enrolled in the Graduate School of Auburn University in a
Ph.D. degree program in the Department of Fisheries and
Allied Aquacultures. From March 1974 until the arrival of
the author in September 1974, the Fisheries Project was
coordinated by Sr. Enrique Castro Butter, a graduate in
biology from the University of El Salvador. Sr. Butter con-
tinued to serve as Acting Fisheries Chief until the return of
Dr. Cabrero in early 1976.
The author was employed as the resident fisheries advisor
of the Fisheries Project, contract No. AID/la-688, beginning
September 9, 1974. Efforts while in-country were focused
principally with the aquacultural research and extension
programs, and to a limited extent in assisting the Fisheries
Service with marine and freshwater fisheries biology, fish
capture programs, and general fisheries administration. This
report limits its discussion to the progress made during the
author's tour of duty.
ADMINISTRATION AND FINANCIAL INPUTS
Upon initiation of the Fisheries Project in 1972, the
Ministry of Agriculture (MAG) changed the status of the
Fisheries Section to that of a full department. A total staff of
eight (six technicians and two supporting) with an operating
budget of 110,0005 characterized the Fisheries Section at
that time. Since then the Fisheries Service (now called Fishery
Resources Service) has experienced substantial growth, par-
ticularly in aquacultural programs, professional and support-
ing staff, and financial support by MAG, table 1.
Aquaculture in 1976 comprised 66.7 percent of the total
Fishery Resources Service budget of o 1,678,952. Amount
budgeted for aquaculture in 1976 was over 900 percent
4
McCoy, E. W. 1974. Economic Analysis of the Inland Fisheries
Project in El Salvador. Res. and Dev. Ser. 6. Auburn Univ. (Ala.) Agr.
Exp. Sta. Int. Center for Aquaculture.
5
U. S. $1.00 = 2.50 colones ().
TABLE 1. FISHERY PERSONNEL AND BUDGETS DEVOTED TO AQUACULTURE
BY THE FISHERY RESOURCE SERVICES, 1972-76
Year Total staff Total colones'
1972 ................... ... 6 
124,000
1973 .................... 7 250,250
1974 ................... 9 352,700
1975 ................... 17 450,000
1976 ................... .39 1,119,032
'U.S. $1.00 = 2.50 colones (e).
greater than the budget in 1972, and 250 percent greater
than in 1975.
Reorganization of the fish culture program in 1976
brought together fish culture research and hatchery produc-
tion of fingerlings with fish culture extension. The new
division (Fish Culture Section) is headed by Sr. Cesar
Abrego Funes, a returned graduate in fisheries from Auburn
University. His wide experience in Salvadorean fish culture
research, extension, and fisheries administration and his
recent participation in an academic program should permit
improved planning and implementation of interrelated ac-
tivities in the rapidly expanding field of aquaculture in El
Salvador. Two areas of aquaculture still remain outside the
dominion of the Fish Culture Section - cage culture of fish
in lakes, which remains under the Inland Waters Section, and
marine shrimp and oyster culture and brackishwater fish
culture, part of the Marine Fisheries Section. The
organization of the Fisheries Resources Service is outlined in
figure 1, with detail on only the Fish Culture Section.
The major portion of aquacultural program money was
allocated to the community pond program. To the
traditional pond construction-fish management team
(engineers, a biologist, and agronomists), four social workers
and one social worker supervisor were added in 1975. Plans
called for doubling the number of social workers for 1976,
the majority to assist the community pond program and the
others to work with communities of artisanal fishermen and
cooperatives. An additional engineer-topographer-draftsman
team was added in 1976, resulting in two complete pond
design-construction engineer teams. A professional geologist
joined the biologist on the site-selection team to evaluate
topographical, soil, water, and geographical characteristics
of proposed community pond sites.
Using USAID funds, Auburn University provided $3,000
(U.S.) worth of equipment for the aquacultural extension
program and for operation of the new fingerling production
station at Izalco, Sonsonate, and $1,000 (U.S.) worth of pub-
lications in the fields of aquaculture, fisheries science, and
aquatic ecology. Over 300 items of scientific literature relat-
ing to aquaculture and fisheries in general were also con-
tributed by the Peace Corps and Auburn University during
the second phase of technical assistance to the project.
The Peace Corps continues to provide key technical input
to the Fishery Resources Service in the training of counter-
parts and in the joint development of specific technical
projects. Since 1974 Peace Corps Volunteers have worked
with their national counterparts in a variety of fishery
projects: one fishery biologist team completed a number of
limnological and fishery studies in the major lakes of the
country; another team studied physical, chemical, and
biological aspects relating to pollution of the country's major
rivers; and another worked in fish culture extension and
training and completed a country-wide fish marketing sur-
vey. Investigations are continuing in the following: feeding,
FIG. 1. Organizational chart of the Fishery Resources Service, showing detail of only the Fish Culture Section.
fertilizing, and stocking densities of tilapia
6 
in pond culture;
pond ecology in dry and wet seasons; ration development for
tilapia utilizing agricultural by-products; fishing gear and
methods development and demonstration; shrimp and
juvenile fish distribution in estuaries; larval oyster biology
and the development of oyster culture technology; and fish
marketing by coastal artisanal fishermen cooperatives.
RENOVATION AND NEW CONSTRUCTION
AT FISHERIES STATIONS
National Fisheries Station, Santa Cruz Porrillo
This station, located in the Department of La Paz, was
renovated starting in 1971. A pond expansion program was
completed in January 1975. Thirty-two 0.05-hectare earthen
and thirty 20-square meter concrete ponds were constructed.
The newly constructed and renovated ponds were fully
utilized in yield trials or fingerling production in 1975 and
1976. Total pond area of the station was 6.10 hectares, of
which 4.03 was used for fingerling production, figure 2. An
'The tilapia species reported herein, although commonly called tilapia,
have been reclassified, Sarotherodon sp.
0.4-hectare community pond was constructed for the benefit
of the station workers, most of whom were skilled in the
techniques of pond culture. This pond will form part of an in-
tegrated farm model of fish-horticulture-small animal
production, to serve as a demonstration for area farmers and
cooperative groups.
Plans have been made to construct 0.5 hectare of addi-
tional ponds for fingerling production and to convert a
large, 1.57-hectare pond into three fingerling ponds. Water
supply and drain lines were redesigned for more effective
operation of the ponds. The conference room was renovated
to function as a combined conference room, study area, and
fisheries library, and this facility was air-conditioned. The
complete regional library of the UN/FAO-CCDP (Central
American Regional Fisheries Development Project) was
transferred from San Salvador to the station after the project
terminated in 1975. A new dormitory and a dining hall were
completed in 1976. Additional feed and fertilizer storage
space was also constructed.
Fingerling Production Station, Izalco
To meet the rapidly increasing demand for fingerlings and
as a first step to decentralize government production of
i 1 i 12 
/ 1
5
?  
18
iBV
SYMBOLS
1-32=500-m
2 
experimental ponds
33-47=various sized production ponds
48= 4,000- m
2 
community pond
A= aquarium, fingerling preparation bldg.
B= deep well
S= water storage tanks (2)
T L
37
36
33
34
LB = biological laboratory
D = dormitory 
48
O=office, library, conference room
C= dining room
LW
= 
wet laboratory
F = feed preparation, storage complex
T=20
-
m
2
concrete tanks
FIG. 2. Schematic plan of the National Fisheries Station at Santa Cruz Porrillo, which had renovation and expansion completed in 1975.
Aerial view of the National Fisheries Station, Santa Crux Porrillo, after
new construction was completed In early 1975. The station now has 30
concrete tanks and 32 earthen ponds for experimentation plus 15
earthen ponds for fingeriing production. Total water area Is 6.1
hectares.
fingerlings, a new station was designed to serve the western
half of the country, at the Centro de Menores, Izalco, Depart-
ment of Sonsonate. This station, scheduled for completion in
late 1976, will have fifteen 400- to 600-square meter pond
1
s
for fingerling production, and two 360 square meter andl two
50-square meter ponds for broodstock isolation. In addmition,
a wet laboratory, storage facilities, office, and dormitory will
be constructed, figure 3. Principal emphasis will be on the
production of the all-male tilapia hybrid, although the station
will have the capability of functioning as a multi-species
nursery and for experiments in fingerling production. An
existing community pond of about 2,000 square meters, lo-
cated adjacent to the fingerling ponds, wvill be utilized for
dlemonstration of fish farming techniques to area farmers and
cooperative groups as well as continue to provide fish for
residents of the Centro.
FISH CULTURE RESEARCH
Tilarpa has continued to be the main culture species in El
Salvaor, principally Sarotherodon aurea, since 1973 when
it was determined to be superior in production to S. mossam-
bica. Until recently S. aurea has been experimented with and
extended to the farmer in monos-pecies culture or in
polyculture with the predator guapote tigre (Cichlasoma
managuentse). Principal emphasis in research has been direct-
ed to increasing production of tilapia or tilapia andl guapote
tigre in earthen ponds through management inputs.
Variations in fertilizer and fertilization rates, feeding of
agricultural by-products, fingerling stocking rates, polycul-
ture species ratios, partial vs. complete harvesting, andi re-
cruitment control by seining have been studied. In addi-
tion, diet testing with S. aurea and the all-male hybrid
tilapia, production trials of the all-male hybrid in earthen
Ta,
ponds, and production trials of S. aurea in salt-producing
ponds and cages have been important activities of
aquacultural research in the past 2 years in El Salvador.
Introduction of New Fish Species
As a part of its efforts to increase the efficiency and quality
of fish culture sy stems, the Fisheries Project in 1974 in-
troduced stocks of Sarotherodon hornoi-um and S. nilotica
from the DNOCS (National Department of Works Against
the Drought) Center for Fisheries Research in Pentecoste,
Ceara, Brazil. Offspring produced from the crossing of the S.
hornorurn male xvith the S. nilotica female are all-male
hybrids with the typically superior growth pattern exhibited
by hybrid animals. The result is the elimination of one of the
most troub~lesome problems encountered in tila pia culture,
that of uncontrolled reproduction which result s in oxvem
crowded fish populations and stunted fish. All-male tilapia
hybrids in yield trials in Brazil consistently produced 8,000
to 10,000 kilograms per hectare per year with individual fish
averaging 400 grams at harvest'.
To counteract reduced fish productions resulting from
heav y groxx th of nloxius aquatic weeds, especially sub-
mergent Hydrilla sp., now prevalent in ponds at the National
Fisheries Station and in a number of private ponds, grass
carp (Ctenopharyngdon idella) were introduced from
Auburn University. Growth has been remarkable, with the
fish stocked in weedy ponds increasing in weight from 50
grams to 3.6 kilograms in 705 days. Attempts at producing
offspring by induced spawning techniques will be made
when the f ish mature sexually.
All-mole Tilaplo Hybrids
Stocks of S. nilotica and S. hornorum for production of
fingerlings arrived in late 1974, and research with the all-
male hybrid tilapia began the following year in El Salvador.
Research, however, has been severely limited principally
because pond facilities at the National Fisheries Station were
inadlequate to properly maintain parent stocks in pure state
and at the same time to produce the number of fingerlings
needed for the testing program. This situation will improve
11Lox 'dN, L. L. 1977. Progress Report on Fisheries Des elopmnent in
Northe~ast Brazil, Juts 1, 1975 -December 31. 1976. Res. and DeN. Ser.
14. Auburn Urns% LAI 1. Agr. Esp. Sta. tnt. Center for Aquacuittire.
13 4
L2= 
20
SYMBOLS
15 fingerling produclion ponds (350-60CM2
LB 19=brood stock isolotion ( 50-M
2
) and production ( 36!-M
2
) ponds
20 - commonity pond (2.000 M)
FIG. 3. Schematic plan of the newly constructed Fingerling Production
Station at the Centro do Monores, Izalco.
sampiing tisn in one oat the 500-square meter experimental ponds at the National Fisheries Station, Santa Cruz Porrillo. Primary emphasis in the
last several years has been on increasing fish production by fertilizing 
and feeding.
by late 1977 with completion of the new Izalco fingerling
production station, which will be used exclusively 
for hybrid
ingerling production. The Santa Cruz Porrillo Station will
continue to produce S. aurea fingerlings for yield trials for
food fishes.
Production trials with the hybrid tilapia were conducted in
500-square meter earthen ponds at the Santa Cruz Porrillo
Station. Two stocking rates and two fertilization rates were
tested during a 91- to 98-day growing season in 1975, table 2.
There were no statistical differences (p>- 0.25) in total fish
production between treatments. Fish at the lower stocking
rate of 10,000 fingerlings per hectare grew at approximately
twice the rate (0.9 gram per day) and were about twice the
size at harvest (106 grams) as those stocked at the higher rate
of 20,000 fingerlings per hectare. Apparently the carrying
capacity of these ponds was reached at about 3,000
kilograms per hectare per year and the increased fertilization
in treatment 3 failed to increase capacity, table 2. Both
treatments at the higher stocking rate failed to produce
adequate numbers of harvestable fish.
Observations of all-male hybrid tilapia production in two
commercial ponds using organic waste materials as a
nutrient supply provided valuable information on yields that
might be expected from this fish in El Salvador. One pond
(2,400 square meters) stocked at 10,000 fish per hectare and
fertilized at 295 kilograms chicken manure per month plus
other organic materials for 150 days had a projected annual
harvest of 7,400 kilograms per hectare. Another pond (1,728
square meters) fertilized with manure of commercially
reared brood sows and partially harvested after the sixth,
seventh, and eighth months and completely harvested after
the ninth growing month had a total projected yield of 7,100
kilograms per hectare per year.
Nutrition Experiments with Tilapla
Using Agricultural By-products
As a means of increasing fish production in farm ponds
above that expected from fertilization alone, and to establish
guidelines for the economical formulation of rations for
tilapia, two experiments were conducted at the National
Fisheries Station using mainly agricultural by-products as
feed sources. Experiments were carried out in 20-square me-
ter concrete tanks located under a roofed, open-sided struc-
ture. Six test diets formulated from locally available agri-
cultural by-products and one complete diet, table 3, were
each tested in triplicate. Only enough water was added to
replace that lost to evaporation.
In the first experiment, S. aurea fingerlings averaging 21
grams in weight were stocked at the rate of 2 per square
meter of water surface. The diets were formulated to
represent a range of low protein-low energy to high protein-
high energy levels, and contained from 14.1 to 36.6 percent
protein and from 2,867 to 3,691 kcals per kilogram gross
energy. The diets were in ground meal form. All fish were fed
once daily, 6 days each week, at rates of 3 percent total fish
weight for the first week, 5 percent for the remainder of the
first 2 months, 4 percent for the third and fourth months, and
3 percent for the fifth and sixth months.
All fish were harvested 156 days after stocking. Production
and cost data are summarized in table 4. The complete
ration, diet 7, produced the highest net gain (5.65 kilograms)
and the best feed conversion efficiency (1 kilogram gain per
3.1 kilograms feed consumed). Test diet 5, the high protein-
high energy formula, produced the best growth and feed
conversion efficiency at the lowest cost. Next was 
diet 6,
which contained shark oil as an energy source. Fish receiving
TABLE 2. RESULTS OF PRODU(CION TRIALS WITH ALL-MALE TILAPIA HYBRID
Fertilization, Average Average
No. of Stocking kg/hamonth Projected total growth Percentage 
Aweight ofTetetfish 
production, grwh marketable wegto
Treatment replicates 
rate/ha Chicken 
0-20-0 khoduction, 
rate, fishmarketable 
fish at
manure 0 0a/year g/day harvest, g
1 3 10,000 1,000 120 2,997 0.90 
96 106
2 3 20,000 1,000 120 3,531 .43 39 
53
3 3 20,000 1,250 150 2,886 .43 31 
50
-9
F!
x
~- 
~' 
I.,
A0*/
diet 1, the low protein-lower energy diet lost weight.
Although cost per kilogram of gain was almost the same for
diets 5 and 6, diet 5 would be favored because it produced
higher weight gain. It was concluded from these preliminary
data that when natural food is unavailable, as encountered 
in
the concrete tanks of this experiment, tilapia require dietary
protein and energy levels similar to those of other cultural
warmwater species for maximum growth rates.
TABLE3. INNGREDII N1 COMPOSI I ION, PIITEIN, \NDG (RoSS 
NE( LE\ ELS,
o)1 SE\ EN TI i DIEis FID o I 5'I IN (IN(RI- II Po N)S
Feedstuff Content 
b diet
I 2 3 4 5 6 7
Pet. Pet. Pet. Pet. Pet. Pct. Pet.
Chicken mlianure ...... 70 30 50 60 
40 50 10
Coffee pulp .......... 30 30 10 ---- 10 ----
Cottonseed meal ...... ---- 10 20 30 
45 20 20
Rice polishings ....... ---- 20 10 
---- 10 10 10
M eat meal ........... ---- ---- 5 
10 5 ---- 20
Corn ................ --.. - 10 5 ---- 5 10
F ish m eal ............ -... .... .... .... .... ....- 
20
So\ bean m eal ........ -- - - --- 
---- -- 10
V ita m in p re m ix . . . . . . - ... .... .... . .... ....- ,
Shark lixer oil ........ ---- -. ---- ---- ---- 5 -
Protein, pet .......... 14.1 13.6 19.8 23.1 26.6 16.7 36.6
Energs, kcals ......... 2.96 2.86 3.11 3.30 3.56 2.88 3.69
Cost/ 100 kg, ........ 2.86 13.64 14.81 16.17 17.78 14.32 55.88
Vitamins per ton: xit. A, 5 million I.U.; Vit. E, 40 g; it. D, 6 million
I.C.U.; ribofla in, 15 g. d - pantothenic acid, 55 g, niacin. 90 g; thiamine
HC1, 20 g; pyridoxine HCI, 5 g; folic acid, 1 g; vit. B
2
, 0.025 g; ascorbic
acid, 500 g; and biotin, 0.4 g.
TABLE 4. NET POIO CTION. FEED CON ERSION AND) FEED COST OF TILAPIA
PRODUCED IN CONCRETE TANKS FROM SFiEN TEs'I DIETFs
Diet no Net gain,' Kg feed/ Cost/kg gain,
kg kg gain C
1 ........... -0.03 ...
2 ........... .77 11.3 1.54
3 ........... .90 8.7 1.29
4 ........... 1.16 10.0 1.6 1
5 ........... 2.00 4.7 .84
6 . .......... 1.29 6.3 .90
7 . .......... 5.65 3.1 1.72
Net gain per 40 fish.
A subsequent feeding experiment was designed to test 
the
growth and economic response of tilapia to four percentages
of protein (20, 25, 30, 35) in isocaloric (1.80 kcal 
per gram)
diets. All-male tilapia produced from the S. hornorum 
male x
S. nilotica female cross, averaging 14.5 grams, were stocked
in the same concrete tanks as used in the previous experiment
at the rate of 1.5 fish per square meter of water surface. Four
diets were formulated basically from agricultural 
by-
Diets formulated from agricultural waste products were 
tested in these
20-square meter concrete tanks at the National Fisheries 
Station, Santa
Cruz Porrillo. Biologist Huezo is feeding pelleted 
feed made from
agricultural waste in the photo at right. Soil placed 
in bottom of tanks is
visible in photo at left.
products to contain 20, 25, 30, and 35 percent 
protein, table
5.
The protein quality of each diet was kept equal by main-
taining a constant ratio of the various protein sources 
in each
diet. Ground corn cobs were used as a filler and beef 
tallow
was used to keep the diets isocaloric. The diets 
were fed in
meal form. A fifth treatment, the control, 
was not given any
supplemental feed. Treatments were 
replicated in four tanks.
The roof over the concrete ponds was 
removed and a 15-
centimeter layer of soil was placed on the 
bottom of each to
more closely approximate natural earthen pond 
conditions
and increase the practical applicability of 
the results. The fish
were fed twice daily at a rate of 3 percent 
of the total fish
weight of each tank, 6 days per week.
Fish were harvested 112 days after stocking. 
No significant
difference (p<0.05) in growth was measured 
among the
various protein levels fed, although the 
fish fed the higher
protein diets grew slightly more, table 6. 
Fish in the control
ponds, which received only natural pond food, 
gained 39 to
42 percent as much weight as the fish that 
were fed, in-
dicating an appreciable food contribution from 
the pond
biota.
A comparison of feed costs per kilogram of 
weight gain in-
dicates that, under conditions such as those 
where tilapia
received a significant amount of food from 
the pond, there
was no economic advantage in increasing 
protein levels over
20 percent. It is tentatively recommended 
that supplemental
TABLE 5. PERCENTA(ES OF INGtEDIEN I COMPOSITION, PROTE IN AND ENE'F
LEV ELS. AND COST S OF FOi I RSOCAOHIC DIE s OI V ARIOE s PROTEIN LE ELS
FF "io TIIAPIA IN CONC RETE PONDos
Feedstuff 
Content, by diet
1 2 3 4
Fish nimeal .................. 5.0 4.3 3.6 2.9
Soybean oil meal............ 15.3 13.2 11.0 8.8
Rice polishings ............. 32.7 28.1 23.5 18.8
Coffee pulp ............... . 7.0 6.0 5.0 4.0
Cottonseed oil meal ......... 40.0 34.4 28.8 23.0
Beef tallo w ... ............ ---- 6.2 12.4 18.8
Corn cobs ................. ---- 7.8 15.7 23.7
Protein, pet ................ 35 30 25 20
Energy, kcl/kg .............. 1,800 1.800 1,800 1,800
Cost/ 100 kg, ' .
. . . . . . . . . . . .  
34.97 30.09 25.15 20.13
Excludles costs of beel tallow and corn cobs.
TABLE 6. PROTEIN CONTENT, NET PRODUCTION, FISH GROWTH,
FEED CONVERSION EFFICIENCIES, AND COST PER KILOGRAM
OF FISH PRODUCED, WITH FOUR ISOCALORIC DIETS
OF VARIOUS PROTEIN LEVELS
Diet
Protein Net production, 
Kg feed! Cost/kg
Number percentage kg kg gain gain, o
1 35 3.20 1.9 0.23
2 30 3.22 1.8 .16
3 25 3.12 1.9 .12
4 20 2.95 2.1 .09
Control not fed 1.26
diets (composed of feedstuffs with sufficient nonprotein
energy and diversified to provide good protein quality) for
feeding to fish in ponds 
of moderate primary 
productivity
and densities up to about 3.8 kilograms per square meter
should contain approximately 20 percent protein for
economical growth. For more intensive culture systems, such
as raceways and cages, protein requirements would probably
be near 30 percent of the diet.
Economic Evaluation of Tilapia Stocked at Four Densities
Economic evaluation was made of Sarotherodon aurea
with fertilization alone or fertilization with feed production
in earthen ponds at four stocking densities. Seven treatments
were studied, six replicated four times and one replicated
three times. Guapote tigre was stocked with the tilapia at the
ratio of 1 guapote to 4 tilapia. Four densities of tilapias were
tested, 1, 2, 3, and 4 per square meter. Inorganic (0-20-0) and
organic fertilizer (dry chicken manure) were applied at rates
of 122 and 1,050 kilograms per hectare per month, respec-
tively. Beginning on day 29 of the experiment, feed
equivalent to 3 percent of the calculated tilapia biomass was
applied 6 days per week. The formulation used was based on
information gained from testing diets with S. aurea in con-
crete tanks in previous experiments at the Santa Cruz Porrillo
Fisheries Station, table 7. After 140 days the experiment was
terminated due to the beginning of aerial cotton spraying in
the area, which in previous years resulted in fish deaths of
varying magnitude.
Fish production was relatively low in the fertilized-only
treatments, and not significantly different (p>0.05) for the
three lower stocking rates-956, 1,173, and 1,189 kilograms
per hectare. The per square meter stocking did not include an
unfertilized treatment, table 8. The factor most likely affec-
ting production was excessive turbidity during the rainy
season due to erosion of pond banks. Growth rates of the
three unfertilized treatments were 0.42, 0.29, and 0.21 gram
per fish per day for the three respective stocking rates.
At all stocking densities in the fed treatments, growth and
TABLE 7. INGREDIENT COMPOSITION, PROTEIN, ENERGY, FIBER, AND COST
OF SUPPLEMENTARY ATFEED USED IN THE ECONOMIC EVALUATION OF TILAPIA
STOCKED AT FOUR DENSITIES IN 1976
Feed ingredients
C offee pulp .....................................
Corn.........................................
Cottonseed m eal................................
Chicken litter ...................................
Rice polishings ..................................
M eal m eal .... .................................
Shark liver oil ..............................
Protein, pct . ... ................................
Fiber, pct . ......................................
Energy, kcals/kg .................................
Cost, e/100 kg ...................................
Unpelleted ................................
Pel eted, delivered to station .................
Content, pct.
5.0
2.5
32.5
45.0
10.0
2.5
2.5
23
26
1166
17.00
26.00
TABLE 8. BIOLOGICAL AND ECONOMICAL RESULTS FOR A 168-DAY GROWING
SEASON WITH TILAPIA AT FOUR DIFFERENT DENSITIES IN 1976
1,
1,
2,
2,
3, 1
3,
4,
Treatment, Growth,
fish/m
2  
g/fish/
day
not fed....... 0.42
fed........... .68
not fed....... . 29
fed........... .67
not fed ....... . 21
fed .......... .48
fed .......... .41
Feed
conver-
sion, 'S'
1.42
1.55
1.53
1.70
Total Total
produc- income,
tion, kg/ha ?
1,080 1,198
1,710 2,463
1,280 1,445
2,670 3,960
1,210 1,316
2,980 4,172
3,600 4,858
Total
cost,
?
2,178
2,872
2,372
3,575
2,557
3,839
4.292
Net
income
?
-980
-409
-925
385
-1,241
333
566
production were substantially improved over fertilizer alone.
Tilapia stocked at 1 per square meter grew 0.68 gram per
day, about 0.3 gram per day faster than fish stocked at the
same rate with fertilizer only. Growth rates for the fed treat-
ments stocked at 2, 3, and 4 tilapia per square meter were
0.67, 0.48, and 0.41 gram per fish per day, respectively. No
significant difference (p>0.05) was found among "S" feed
conversion values among the fed treatments, the values rang-
ing from 1.42 to 1.70. The highest total fish biomass pres-
ent at harvest was 2,860 kilograms per hectare for ponds
fed ad stocked at 4 tilapia per square meter. In the fertilized-
only treatments the carrying capacity was approached with
1,200 kilograms per hectare. In the 3 tilapia per square meter
treatment this level was reached in 4 months; in the 2 tilapia
per square meter treatment it was calculated for about 7
months. There was no indication of declining growth rate in
any of the fed treatments during the last part of the experi-
ment.
An economic analysis, following procedures described by
Greenfield
8
, was made to determine the point of maximum
net returns for each treatment for a 6-month period. A
payment schedule was calculated for a total of 168 days (two
14-day periods after the total experiment time of 140 days).
None of the fertilized-only treatments had net profits at the
end of 140 days or for the projected 168-day growing period.
Feeding increased tilapia growth rates and costs. At 1 tilapia
per square meter, a loss was calculated for both the 140- and
168-day periods. The next three stocking rates resulted in
profits at the 140-day period, o265, o412, and o 160 for 2, 3,
and 4 tilapia per square meter, respectively. The 2 tilapia per
square meter treatment reached maximum profits at 154
days (o420 net profit), while the 3 tilapia per square meter
treatment declined to 366 at 154 days and to 333 at 168
days. The 4 tilapia per square meter treatment profits contin-
ued to increase, reaching 0524 at 154 days and o566 at
168 days.
Although the 4 tilapia per square meter treatment resulted
in higher net profits, the 2 tilapia per square meter fed treat-
ment is recommended for field testing. The testing should be
with farmers who can maintain reliable records and have a
history of successful pond management. Ponds should meet
the basic conditions of having no weeds, stable banks, and be
harvestable. The 4 tilapia per square meter fed treatment
should be tested further under strict experimental conditions,
due to the large variation found between fed ponds, before
adoption as a field recommendation for qualified farmers.
Tilapia Production in Salt Ponds
The first controlled stocking of Sarotherodon aurea in salt-
producing ponds was conducted in El Salvador in 1975,
8
GREENFIELD, J. E. 1974. Economic Evaluation of the Tilapia Hybrid
Culture in Northeast Brazil. Paper presented at FAO/CARPAS Sym-
posium on Aquaculture in Latin America. Montevideo, Uruguay.
November 26-December 2, 1974.
)
- -- --
p, JTt Ialt-drying ponds neaI J;quilisco Bay are used to produce salt only during the dry season. With slight modification, however, the
500-hectare pond complex could substantially increase aquacultural production in El Salvador.
using ponds from a private firm located adjacent to Jiquilisco
Bay. Fish were stocked and harvested in the wet season when
the ponds are normally inactive in the production of salt.
Four ponds, 6,340 to 9,510 square meters in size, were
stocked with fingerling tilapia of 5-15 grams weight. Ponds
were filled by gravity flow during high tide, with water
passing through two metal screen filters, first a coarse grade,
then a fine grade screen. In several ponds, however, the
screens became clogged and broke, allowing entry of other
aquatic organisms, including various predators. All ponds
were fertilized with 80 kilograms per hectare of 20-20-0
inorganic fertilizer applied bi-monthlv. Two ponds were
stocked with 2 fish per square meter and two with 1 fish per
square meter. Salinity at the initiation of the experiment was
2?5/oo, increasing to 310o by experiment end. Harvesting
revealed numerous brackishwater fish and shrimp other than
the stocked tilapia. Although production was lower than in
freshwater, ranging from 917 to 1,392 kilograms per hectare
per year, adequate filtration of intake water can be expected
to reduce tilapia predators and competitors to the point that
management of the ponds exclusively for fish or tilapia-
shrimp polyculture would be economically attractive. The
500 hectares of such ponds along the coast of El Salvador,
producing the minimum expected yield of 1,000 kilograms
per hectare per 6 months, would produce during the wet
season more than 500 metric tons of high quality, high value
fisher\ products.
Culture of Fish in Cages
Enthused by the positive results from preliminary produc-
tion trials of Sarotherodon aurea in cages on Lake Ilopango
in 1974, both the Fisheries Service and the private sector em-
barked on more conclusive tests of its economic feasibility in
1975. Ten large cages, measuring from 20 to 40 square
meters in surface area and with a depth of 1.5 meters, were
placed in Lake Ilopango by the Fisheries Service and a
private individual. Results were mixed. There was good
growth during the latter half of the dry season when heavy
phytoplankton blooms in the upper several meters of the lake
furnished abundant natural food for the fish. Poor growth
and feed conversion efficiencies during the rest of the year
resulted from inadequately formulated or processed feed, loss
of fish due to poaching, wave damage to cages during storms,
and harvesting difficulties. Nonetheless, production data
were attractive enough to stimulate an expansion of effort by
the GOES in cage culture research and development. The
GOES's plan for 1976 was to test the interaction of stocking
- a
a
to
A private entrepeneur at Lake llopango, near San Salvador, uses these
floating cages for rearing tllapla. Made of steel framing and covered
with netting, the cages measure 4 X 8 X 1 meter.
f7
0 ,
111111IN-_
k, 
4
density, feed type (based on rations containing mainly
agricultural 
by-products), 
daily feeding 
rates, and cage 
shape
(square vs. cylindrical) on the production of S. aurea. Results
of these studies will go far toward determining the economic
feasibility of cage culture. A plan was also established to in-
troduce the culture of tilapia in large commercial sized cages
(up to 40 cubic meters) as a supplementary and alternative
source of income for members of~ fishermen cooperatives of
Lake lopango and Laguna Metapan. Encouraged partly by
the relativelv high sale price of tilapia (c2.00-2.75 per
kilogram liveweight) in markets in nearby San Salvador, at
least two new cage culture operations were initiated in 1976.
FISH CULTURE EXTENSION
In early 1974 the entire effort in fish culture extension was
carried out by two Salvadorean agronomists and one Peace
Corps Volunteer biologist. Due to change in policy within the
Ministry of Agriculture, the fish culture extension program
was suspended for the major part of 1974. The three exten-
sion staff in the meantime worked on other productive tasks,
one in the successful eradication of the water hyacinth
(Eichhornia crassipes) from Laguna de Chalchuapa, the
other two in a nationwide survey of fish marketing. In late
1974, shortly after the arrival of this advisor, fish culture ex-
tension was formally resumed under the direction of the
Fisheries Service. During 1975 two additional biologists were
hired and one biologist with past experience in extension was
transferred to the extension division, thus increasing the field
extension staff to five with each assigned a particular
geographical zone.
A full-time supervisor was assigned to manage both the
private and community pond activ ities. Twxo engineering
teams, each consisting of a civil engineer, topographer, and
assistants, with a draftsman to serve both teams, designed
and supervised construction of new community ponds. In-
creased demand on trained staff for the expanding com-
munitv pond program required the reassignment of one ex-
tension worker to survey sites for new community pond
projects, thus reducing the number of zones to four. Exten-
sion staff had the responsibility of providing technical
assistance to both private and community ponds. Fish culture
supervisors and extension specialists prepared and presented
short courses and lectures for students at the National
Agricultural School, the Navigation and Fisheries School,
area agricultural vocational high schools, and to extension
staff of FOCCO, the Agricultural Development Bank (BFA),
and the Agricultural Extension Service (CENTA). They also
prepared exhibits on aquaculture activities in El Salvador for
display at regional agricultural fairs. In response to the need
for seines by private and community pond owners, extension
workers assisted traditional net-makers by introducing basic
techniques of seine manufacturing. Production of seines now
is a regular economic activity for several persons that were
previously underemployed.
Private Ponds
A 197 1-72 survey revealed that 500 fish ponds existed in
the country with a total area of about 53 hectares. The ponds
ranged from 20 square meters to more than 1 hectare, with
an average size of 0. 11 hectare. Production in farm ponds for
1972 was 6.8 metric tons, with an average productivity of
136 kilograms per hectare per year. With technical assistance
provided by the Fisheries Service, 22 farmers produced an
average of 4,879 kilograms per hectare per year in 1973.
Upon reestablishment of pond extension services in late 1974,
4
li
Harvestable size river shrimp, Macrobrachiumn tnstum, after several
months of growth with tilapla and guapote tigre In a private pond that
used Irrigation water as its water source.
major effort was begun to increase production in existing
ponds. Pond owners were contacted to determine the status of
their ponds and to establish the level of interest by the owner.
Owners who showed interest in managing ponds for fish
production were assisted in renovating -their ponds and im-
plementing sound fish production programs. Advice was also
given to private individuals on site selection and construc-
tion of new ponds. As a result of these extension efforts, 97
ponds with a surface area of 26 hectares, on 48 different
farms, were totally rehabilitated by late 1975. Another 85
ponds on 47 farms, with 12.7 hectares of water surface, were
in the process of being rehabilitated. As a direct result of the
extension efforts in placing new or renovated ponds in pro-
duction, fingerling distribution reached the record level of
456,925 in 1975, up from 96,033 in 1974 and 30,000
in 1972.
Fish production from private ponds reached 39.8 metric
tons by the end of 1975, compared to 6.8 metric tons in
1972. Annual fish production should be at least 3,000
kilograms per hectare under average management and 5,000
kilograms per hectare when ponds are well managed. For the
38.7 hectares of ponds rehabilitated or in the process of
rehabilitation in 1975, harvest potential ranged from 116
metric tons under average management inputs to as much as
193 metric tons under well-managed conditions.
For the first time in El Salvador, formal guidelines and
specific funds were established to extend loans to prospective
fish farmers. This was accomplished through a cooperative
effort between the Fisheries Service and the Agricultural
Development Bank. Prospective creditors were given
assistance by the Fisheries Service in preparation of a cost-
benefit analysis for their proposed fish farming plans. The
farmers also were advised in the execution of these plans.
Several large commercial projects were initiated during 1975
and 1976 through this and other sources of credit. The
largest, located near Acajutla, consisted of 16 newly con-
structed ponds covering over 5 hectares of water. Ponds
stocked with Sarotherodon aurea and gua pote tigre, as well
as juvenile freshwater shrimp, Mvacrobrachbiumn spp., collect-
ed from rivers, were fertilized with 20-20-0 fertilizer and
chicken manure, or received supplementary rations con-
sisting of agricultural by-products.
Community Ponds
In 1974 the GOES implemented a program for dexelop
ment of community ponds. This program is funded through
FOCCO (Communal Development and Cooperation through
Self Drive and Mutual Help), a separate governmental in-
stitution whose objectiv e is to assist in community develol
ment. The community ponds program is aimed at developing
wsithin selected communities various resources and
management skills to enable numbers of the communities to
achieve a better standard of living. Rural cooperatives,
agrarian reform settlements, and members of government
facilities are ty pically the participants in this program. Nor-
mallv land to construct a pond is given to an organized
community group by the government, local mnunicipalit-x
agrarian reform settlement, or a priv ate dlonor. The coin-
munity provides labor during the land preparation andl pond
construction phases, and once fish are stocked, community
labor maintains the ponds and feeds and harvests the fish.
The Fisheries Service, through the FOCCO funds, provided
assistance in selection of the po~nd site, p~ondl design, construc-
tion of the pond (tractor and driver), fish to stock the 
pond,
and assistance in pondl management. Until 1976 social
workers under the direction of FOCCO collaborated in each
comumunity pond project. In 1976, with the arrival of several
social workers, the Fisheries Serv ice assumed the entire
responsibility of the community pond dev elopment program
and of providing social assistance to the projects. Four teams
of one fish culture extension specialist and one social worker,
with the back-up assistance of two pond design-construction
enginer teams, were formed to provide technical assistance
that is more comprehensiv e and responsiv e to community
needs.
At the end of 1975 there were 57 conmonitN ponds func-
tioning, while others were in the process of dlesign or con-
struction. The goal in 1976 was to complete 100 additional
ponds comprising about 20 hectares in surface area. Benefit
to the community has generally been in the form of fresh fish,
usually a percentage of the harvested fish based on a worker's
share in total labor provided by the community members.
Community ponds in general have not reached the level of
prodluction achieved in experimental or priv ate ponds.
Nonetheless, some of the best production in rural ponds has
been recorded from communits ponds, the most salient
example being the pond at the Izalco Livestock Experiment
Station where over 7,400 kilograms of fish per year were
produced.
SHORT TERM TECHNICAL ASSISTANCE
On two occasions Auburn University fishery personnel
visited the Inland Fisheries Development Project to provide
general review and evaluation of progress. Dr. Donovan D.
Moss, Assistant Director of the International Center for
TOP: Harvesting the uniformly sized all-male hybrid tilapia at the
community pond project in the Livestock Center, Izalco. BOTTOM:
Members of the Izolco community pond project and social worker
agents and fish culture extension agents chart production of the all-
male tilapia hybrid, which surpassed 7,000 kilograms per hectare per 0
year with pig manure used.
Aquaculture, visited in January 1975. He reviewed the site
and plans for the new fingerling production station at Izalco
and the recently completed new construction at the National
Fisheries Station, studied the problem of aerial pesticide con-
tamination at the same station, and lectured to the general
public and the staff of Natural Renewable Resources on the
topic of intensive aquaculture around the world.
Dr. Bryan Duncan, a coordinator of international training
programs at the International Center for Aquaculture, visited
the Project in March 1976. He concentrated mainly on a
review of the organization of the community pond and exten-
sion program and fingerling production system. He presented
a lecture on the principles of fish culture extension to the fish
culture extension division, and discussed milkfish culture in
the Philippines before the fish culture research staff.
FISH MARKETING SURVEY
To determine the factors which influence the marketing of
fish in El Salvador and their implications in the development
of aquaculture, a countrywide survey on fish marketing was
conducted by two Fisheries Service staff. The survey covered
an entire year, from August 1, 1973, to July 31, 1974,
and placed emphasis on marketing in the rural area where
incomes are lowest, diets are inadequate, and 60 percent of
the nation's population resides. The publications resulting
from this study, considered by many to be the most impor-
tant contribution to fish marketing in Central America, have
been in heavy demand (Parkman and Salgado 1975, Park-
man and McCoy 1976, 1977). The conclusions reached by
the authors included the following:
1. Most of the fish consumed in El Salvador comes from
marine sources, although the freshwater artisanal fisheries
contribute substantially to the total supply.
2. Fish compared favorably in price with other animal
protein products, both on a cost per kilogram and cost per
unit edible protein basis. Second-class marine fish, sold at the
retail price of o 1.43 per kilogram and containing 132 grams
protein per kilogram fish, costs o10.82 per kilogram of
rotein. Loin beef, on the other hand, costs o29.22 per
ilogram protein, pork loin e20.24, poultry 020.28, eggs
S19.43, and milk o 12.94 per kilogram of protein.
3. Major cities served as centers of fish distribution for
surrounding areas. The per capita consumption of all types of
fish was greater in the major cities than in the rural towns,
due to the low incomes of most rural inhabitants and the
dependency of rural markets on the major cities for fish sup-
plies. In fact, the large cities absorb the majority of already
inadequate fish supply reaching the city distribution centers,
thus limiting the amount available to the more distant rural
towns.
4. Consumers preferred the flavor of freshwater fish over
most marine species. Among the freshwater fishes, the
cichlids (mojarras, guapotes, and tilapias) brought premium
prices while the catfishes, characins, and topwater minnows
were sold at prices comparable to those paid for second-class
marine fish.
5. As a result of a moderately expanding per capita income
and population increases, projected demand for fish will
grow in all locations. Domestic production has not increased
significantly in recent years. By 1985 the projected urban
demand will be 4,354 metric tons and the rural demand will
be 1,077 metric tons. To benefit low income consumers, large
increases in production of inexpensive fish are needed in all
sectors.
6. Pond-raised fish is seen as an important source of future
supplies in El Salvador. In addition to being preferred over
many other types, pond-raised fish can be economically
produced at competitive prices and can be raised near areas
of consumption, thus reducing transportation costs and in-
creasing quality. In addition, fish production in ponds will
reduce the dependency of rural areas on the cities for already
inadequate fish supplies.
INTERNATIONAL TRIPS AND CONFERENCES ATTENDED
The Acting Fisheries Chief, Lic. Enrique Castro Butter,
and the advisor attended the first UN-FAO Regional Sym-
posium on Aquaculture in Latin America, at Montevideo,
Uruguay, from November 26 to December 2, 1974. The
meeting was designed to bring together aquaculture leaders
from the region to share their experiences in aquaculture,
define the present level of aquaculture technology, and to
establish priorities for future research and development in
aquaculture. On return to El Salvador from the conference,
the author routed through Fortaleza, Ceara, Brazil, to visit
the DNOCS/USAID/Auburn University Fish Culture Devel-
opment Project. The Chief of Party, Dr. Leonard Lovshin,
and John Jensen, fish culture extension advisor, both of
Auburn University, toured the author through the research
facilities at the Center for Ichthyological Research in For-
taleza, the extensive pond research facilities located at two
sites in Pentecoste, area DNOCS fingerling production
stations, and several private farms employing the all-male
tilapia hybrid culture technology. The author carried back to
El Salvador stock of the species S. hornorum and S. nilotica
for production of all-male fingerlings.
The Acting Fisheries Advisor, the Marine Resources Unit
Head, Lic. Ricardo Hernandez Rivas, and the author attend-
ed the Central America Seminar Workshop on Artisanal
Fisheries Development and Coastal Aquaculture at San Jose,
Costa Rica, January 13-17, 1975. Objectives of this meeting
were for the representatives to present the state of develop-
ment in artisanal fisheries and aquaculture in their countries,
to develop a methodology to define problem areas, and to
define some of the priority action areas.
The Acting Fisheries Chief attended the UN/WHO-
sponsored Inter-American Meeting in Guatemala, April 16-
19, 1975, where he presented a paper on the intensive culture
of fish for improving human nutrition in the Central
American countries. The paper was part of a series given in
the section dedicated to the use of small animal species for the
production of food in the Americas.
A 3-day trip to-Guatemala was made by the heads of the
Inland Fisheries Unit and Aquaculture Unit and the author
during March 1976 to obtain information on past ex-
periences with fish culture in the higher, cooler altitudes of
Guatemala. The information was gathered for application to
El Salvador's plan to determine the feasibility of extending
pond aquaculture to the highland areas.
The author and two members of the Marine Resources Unit
attended a 2-day short course on environmental pollution,
sponsored jointly by ICAITI (Central American Institute for
Industrial Research and Technology) and ROCAP (AID
Regional Offices for Central America and Panama) at San
Salvador in early 1976.
Two fish culture extension staff of the Inland Fisheries Unit
attended a 2-week course in San Salvador on "Communi-
cation and Agricultural Extension," July 1-12, 1975, spon-
sored by IICA (Inter-American Institute of Agricultural
Sciences). One fish culture extension specialist of the Inland
Fisheries Unit participated in a 2-month practical training
course in intensive aquaculture in various parts of Israel,
sponsored by the government of Israel, in late 1976.
13
FISHERIES PUBLICATIONS
The number of fisheries publications in the field of inland
fisheries and aquaculture has dramatically increased since
Bayne in 1974 reported publications completed at the end of
the first phase of the Inland Fisheries Project. Works not
reported at that time and completed, or in press, since then
are listed below:
ABREGO F., CE~SAR, JOSE~ MAXIMILIANO HERNA(NDEZ, RENE" SALGADO, ROBER-
To REYNOLDS Y GARY JENSEN. 1975. Inventario y evaluacic'n de estanques
pisci'Colas en El Salvador 1970-1972. Servicio de Recursos Pesqueros,
DGRNR, MAC, El Salvador. 48 p. (mimeo).
BAYNE, D. R. 1974. Progress Report of Fisheries Development in El
Salvador, Project AID/la-688. Auburn Univ. (Ala.) Agr. Exp.. Sta. Int.
Center for Aquaculture, Auburn, Ala. 11I p.
y E. CASTRO BUTTER. 1974. MWOdo para el control quimr'ico
del jacinto de agua Eichhornia crassipes (Mart.) en El Salvador. Simposio
FAG/CARPAS Sobre Acuicultura en America Latina, 26 noviembre-
2 diciembre 1974, Montevideo, Uraguay. 5 p.
_________DAVID DUNSETH, AND CECILIo GARCIA R. 1976. Supplemen-
tal Feeds Containing Coffee Pulp for Rearing Tilapia in Central America.
Aquaculture 7 (1976): 133-146.
BOWMAN, DAVID. 1972. Historia de investigacio~n piscicola en El
Salvador y la biologia* de Tilapia aurea (Steindachner). Departamento
Pisci'cola. DCRNR. MAC, El Salvador. 15 p. (mimeo).'
____ .__ 1974. Comparacidn entre Tilapia aurea Steindachner y
Tilapia mossambica Peters en estanques de El Salvador. Simposio
FAG/CARPAS Sobre Acuicultura en America Latina, 26 noviembre - 2
diciembre 1974, Montevideo, Uruguay. 13 p.
BROMLEY, D. W. AND S. Y. LIN. 1975. The Role of Fisheries Aquaculture
in Latin America. Report of USAID Trip to Brazil, Panama, El Salvador
and Guatemala, September - October 1974. 20 p. (mimeo).
CAMPOS, Josi! HUMBERTO. 1974. Estudio hidrolhfgico para embalses de
usos mu tiples en Zona Oriental. Servicio Hidrol6gico, DGRNR, MAC, El
Salvador. 33 p. (mimeo).
CASTRO ARAGON. RICARDO A. 1975. Reproduccio~n de Cichlasoma
managuense (guapote tigre) en estanques de arcilla. Informe tdcnico 3
(7):3 1 p. Servicio de Recursos Pesqueros, DGRNR, MAC, El Salvador.
_________ 1975. Estudio bioldgico del cangrejo de rio
Pseudoteiphusa magna. Informe tecnico 2 (8): 17 p. Servicio de Recursos
Pesqueros, DGRNR, El Salvador.
._____ 1976. Estudio bioho'gico de la Rana pipiens (Rana leopar-
do). Informe te'cnico 3( l):22 p. Servicio de Recursos Pesqueros, DGRNR,
MAC, El Salvador.
._____ 1976 Purificacidn de Tilapia aurea y Tilapia mossambica
en estanques de arcilla y concreto. Informe tecnico 3(3): 10 p. Servicin de
Recursos Pesqueros, DGRNR, MAC, El Salvador.
__________1976. Manejo de estanques de arcilla con cosechas par-
ciales, 30,000 peces/ha usando gallinaza, fertilizante inorganico y los
efectos del insecticida. Informe te'nico 3(8): 12. Servicio de Recursos
Pesqueros, DGRNR, MAC, El Salvador.
_________ 176. Estudlio relimi;n~nar bolgiopequr _dli
DEGEORGES, P. A. 1975. Behavioral Notes on the Fishes of Lago
Coatepeque. 1973. Informe tecnico 2(6): 15 p. Servicio de Recursos
Pesqueros, DGRNR, MAG, El Salvador.
DUNSETH, D. R.- 1974. Cultivo de Tilapia aurea en corrales de 100 
M
2
,
probando diferentes tasas de alimentacidn (2%, 4%, 6% y testigo) usando
alimento en forma de pildoras conteniendo 30% de pulpa de cafe.
Servicio de Recursos Pesqueros, DGRNR, MAG, El Salvador. (mimeo).
._____ 1974. Manejo de poblaciones de Tilapia aurea con
cosechas parciales. Servicio de Recursos Pesqueros, DGRNR, MAG, El
Salvador. (mimeo).
_______ 1974. Evaluacid'n de pulpa de cafe* como sustituto para
afrecho de trigo y maiz molido en raciones dada a Tilapia aurea en jaulas.
Servicio de Recursos Pesqueros, DGRNR, MAG, El Salvador. 5 p.
(mimeo).
I .1975. Production of Tilapia aurea (Steindachner) in Corn-
bina tion with the Predator Cichiasoma managuense (Gunther) at Dif-
ferent Stocking Rates and Ratios. M. S. Thesis. Auburn Univ., Auburn,
Ala. 63 p.
.1975. Impact of Fishculture for Small Commercial Farms
and for the Region in El Salvador. Report for Aquaculture Economics
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__________R. SALGADO FLORES y R. W. PARKMAN. 1973. Inventario y
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__________________1975. Estudio biolo'gico-pesquero del Rio
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2 
en lagos de El Salvador. Servicio de Recursos Pesqueros,
DGRNR, MAG, El Salvador. (In print).
14
S1972. Evaluacio'n de la
laguna El Jocotol, septiembre de 1972. Departamento Piscicola, DGRNR,
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S1972. Evaluacion de la
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y ANDRE DEGEORGES. 1975. ontribucion al conocimiento
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. 1975. Reconocimiento limnolgico
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HUGHES, D. G. y R. SALGADO FLORES. 1976. Maximizaci6n de produccidn
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tribucidn al conocimiento limnoldgico comparativo del lago de Guija en
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-. 1971. The Fishery of Apastepeque Lagoon, El Salvador,
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. 1972. A Preliminary Study of the Fishery in the Reservoir
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AND ANTONIA ARGUMEDO. 1971. The Fishery of Lake
Coatepeque, El Salvador. A Preliminary Report. Departamento Pisciiola,
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.1971. La pesca del lago Ilopango.
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(mimeo).
LEDGERWOOD, R. D., D. G. HUGHES y M. VARGAS ORTIZ. Wet and Dry
Season Comparison of Tilapia aurea Production in El Salvador in New
Fertilized and Unfertilized Earthen Ponds. Proc. World Mariculture
Soc. 7 (1976). (In print).
y M. VARGAS ORTIz. Una evaluacid'n econo'mica de Tilapia
aurea producida con cuatro densidades de siembra en estanques reciblen-
do fertilizante o fertilizante con alimentacio'n. Servicio de Recursos
Pesqueros, DGRNR, MAG, El Salvador. (in print).
MACHON COREA, M. R. 1975. Produccion pesquera de las principales
especies comerciales de El Salvador en 1974. Servicio de Recursos
Pesqueros, DGRNR, MAG, El Salvador. 46 p. (mimeo).
. 1976. Anuario Pesquero de El Salvador. 1975. Servicios
de Informacion y Recursos Pesqueros, DGRNR, MAG, El Salvador. 56 p.
MARCHANT, ANDRES. 1975. La situacion pesquera en El Salvador. Informe
presentado para el Seminario Centroamericano sobre Desarrollo de Pesca
Artesanal y Acuicultura Costera, 13-17 enero 1975, San Jose
, 
Costa Rica.
5 p.
NEWMAN, M. W. Cost, Formulation, Nutrition and Growth of Four Diets
Used in Commercial Tilapia Farming Conditions in El Salvador. Servicio
de Recursos Pesqueros, DGRNR, MAG, El Salvador. (In print).
IR. D. LEDGERWOOD y D. G. HUGHES. Produccion del
hfbrido macho (Tilapia hornorum macho x Tilapia nilotica hembra) en la
estacid'n lluviosa tropical con dos tasas de siembra y fertilizacion. Servicio
de Recursos Pesqueros, DGRNR, MAG, El Salvador. (In print).
y D. G. HUGHES. Crecimiento de Tilapia alimentadas con
siete dietas pra'cticas de varios niveles de energia y proteina formuladas
de subproductos agriolas. Servicio de Recursos Pesqueros, DGRNR,
MAG, El Salvador. (In print).
y H. E. HUEZO. La respuesta de machos hfbridos de tilapia
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proteina cruda en dietas isocalricas. Servicio de Recursos Pesqueros,
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(mimeo).
S1974. Aspectos de la comercializacidn
de pescado en El Salvador con fines de desarrollar la piscicultura. Ser-
vicio Piscifola, DGRNR, MAG, El Salvador. 72 p.(mimeo).
. 1976. An Overview of Fish Marketing in El Salvador. M.
S. Thesis, Auburn Univ., Auburn, Ala. 109 p.
AND E. W. McCoY. 1977. Fish Marketing in El Salvador.
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Aquaculture, Auburn, Ala. 19 p.
S1977. Marketing as a Factor in Fish-
culture Development in El Salvador. Res. and Dev. Ser. 13. Auburn Univ.
(Ala.) Agr. Exp. Sta., Int. Center for Aquaculture, Auburn, Ala. 8 p.
RAMIREZ HIDALGO, M. y K. L. JOHNSON. 1972. Evaluacidn del embalse "5
de Noviembre", enero-febrero 1972. Departamento Piscicola, DGRNR,
MAG, El Salvador. 16 p. (mimeo).
S1973. The fishery of Lake
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MAG, El Salvador. 39 p. (mimeo).
. 1975. Analisis de las redes
agalleras de malla pequelta, atarraya y sus efectos hacia la pesca de
sardina en laguna de Olomega. Informe Tecnico. Servicio Piscitola,
DGRNR, MAG, El Salvador.
_ MAXIMILIANO HERNA(NDEZ y K. L. JOHNSON. 1976. Estudio
sobre selectividad de artes de pesca, distribucidon por especie y su compor-
tamiento en el lago de Ilopango. Informe te'cnico 3(5):19 p. Servicio de
Recursos Pesqueros, DGRNR, MAG, El Salvador. Reynolds, Roberto.
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(mimeo).
SALGADO FLORES, R. 1975. Estudio te4nico-piscicola inicial. Servicio 
de
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y R. W. PARKMAN. 1973. Inventario y. evaluacidn
preliminar de la flora y fauna acultica de la zona costera del rio Jiboa.
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y G. L. JENSEN. 1974. Informe del primer ensayo de
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p. (mimeo).
SANCHEZ, CARLOS. 1972. Informe sobre el primer ensayo con filin (Rhan-
dia guatemalensis). Departamento Piscicola, DGRNR, MAG, El Salvador.
4 p. (mimeo).
1972. Embriologii del camaron del rio Macrobrachium
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(mimeo).
15
_________*1973. Ensayo sobre policultivo de guapote pando
(Cichiasoma fredrichtalii) con Tilapia aurea. 
Servicio Pisci6ola, DGRNR,
MAG, El Salvador. 7 p. (mimeo).
__________*1973. Proyecto de cultivo de mojarra negra (Cichiasoma
guija) para repoblacid'n de rios del pai's. Servicio Piscifcola, DGRNR,
MAG, El Salvador. 7 p. (mimeo).
_________*1973. Ensayo comparativo de 
mojarra negra (Cichiasoma
guija), su reproduccio1i y crecimiento. Servicio 
Piscilcola, DGRNR, MAG,
El Salvador. 7 p. (mimeo).
_________1973. Ensayo con falsa anguila (Symbranchus 
mar-
moratus) y plateada (Astyanax fasciatus) para ver su reproduccio~n 
en un
cuerpo de agua controlado y en buenas condiciones ambientales. Servicio
Piscifola, DGRNR, MAG, 1973. El Salvador. (mimeo).
__________1973. Estudio de un intento de desove artificial 
con
tepemechin (Agnostumus monticola) sometidos al estilnulo de la apoidina
(gonadotropina corionica). Servicio Piscifola, DGRNR, MAG, 
El
Salvador. (mnimeo).
__________1974. Cultivo mono-sexual (machos)' de Tilapia aurea
40,090 peces/ha usando pfldoras con 30% de pulpa de cafe Serviejo
Piscicola, DGRNR, MAG, El Salvador. 6 p. (mimeo).
__________1974. Ensayo de 3 replicas con cosechas parciales 
de
20,000 peces/ha. manejo y producciodh. Servicio Piscitola, DGRNR,
MAG, El Salvador. (mimeo).
_______ 1974. Cultivo de Tilapia aurea (Steindachner) en corrales
de 100 in
2
, probando diferentes tasas de alimentacid'n usando alimento a
base. de cafd'. Servicio de Recursos Pesqueros, DGRNR, MAG, 
El
Salvador. 8 p. (mimeo).
__________1974. Proyecto de cultivo de bagre (Arius guatemalensis).
Servicio Piscitola, DGRNR, MAG, El Salvador. (mimeo).
__________1975. Desarrollo de juveniles del camaron 
de rio,
Macro brachium tenellum (Smith) en estanques de 
arcilla y concreto. In-
forme te*'cnico 2(2): 15 p. Servicio de Recursos Pesqueros, 
DGRNR, MAG,
El Salvador.
__________1976. Desarrollo larval de Macrobrachium 
tenellum.
FAG Technical Conference on Aquaculture, Kyoto, 
Japan, May 26,
1976, FAG-FIR: AQ/CGNF/76/E.57, 6 p.
-______ 1976. Tdcnica de produccid'n 
de alevinos de Cichlasoma
managuense (Gunther), guapote tigre. Servicio de Recursos 
Pesqueros,
DGRNR, MAG, El Salvador. (In print).
._____ 1976. Reproduccidn de Tilapia aurea (Steindachner) 
bajo
control manual. Servicio de Recursos Pesqueros, DCRNR, 
MAC, El
Salvador. (In print).
1976. Desarrollo de lisa Mugil 
cephalus en estanques de
agua dulce. Informe te'ocnico 
3(4):8 p. Servicio de Recursos 
Pesqueros,
DGRNR', MAC, El Salvador.
SERvIcIo DE RECURSOS PESQUEROS. 
1975. Consideraciones t
4
nicas para el
establecimniento de cultivo 
de pescado en aguas contineintales. 
DCRNR,
MAC, El Salvador. 5 p. (mimeo).
__________________1975 . Seleccionando 
el lugar para la cons-
truccifn de estanques. DGRNR, MAC, 
El Salvarlor. (mnimeo).
1975. La piscicultura es rentable. 
DCRNR,
MAC, EL Salvador. 2 p. (mimeo).
.1975. Costos y ganancias 
de la produccidn
de tilapia. DCRNR, MAC, El 
Salvador. 4 p. (mimeo).
1976. Informaciin general 
sobre algunos
aspectos importantes para. 
la piscicultura salvadore~a. 
(Revised).
DCRNR, MAC, El Salvador. 
14 p. (mimeo).
1976. Manual de piscicultura. 
(1973 edition
revised), DCRNR, MAC, El 
Salvador. 34 p.
VALENTI, WARREN. 1976. La factibilidad 
de cultivar ostras suspendidas en
El Salvador. Un reporte preliminar. 
Servicio de Recursos Pesqueros.
DCRNR, MAC, El Salvador. (In print).
--1976. Distribucidn estacional de larvas 
de
ostra (Ostrea iridescens) en el Colfo 
de Fonseca, El Salvador. Servicio de
Recursos Pesqueros, DCRNR, MAC, 
El Salvador. (In print).
VAR'GAS ORTIZ, MAR&'A 1974. Sucesi1li 
de comnunidades en estanques de
arcilla fertilizado y no fertilizado. Servicio 
Pisciiola, DCRNR, MAC, El
Salvador. l Op. (mimeo).
1976. Estudio de las influencias 
de fertili-
zante orga'nico e inorga'hico en 
el cultivo de Tilapia aurea en 
planicie
costera. Tesis de grado, Facultad 
de Ciencias y Humnanidades, Universi-
dad de El Salvador. (In print).
ACKNOWLEDGMENTS
The author acknowledges the contributions made 
by the
Fisheries Service biologists, extension workers, 
engineers, and
social workers to the fish culture research and 
extension pro-
grams, and other members of the General Directorate 
of
Natural Renewable Resources who were particularly 
helpful
and friendly to me, Appreciation also 
is expressed to the
Peace Corps Volunteers and staff of the USAID 
Office of
Rural Development for their support and cooperation 
during
the Project.
16