111. AQUACULTURE OF SHRIMP IN MEXICO:SOME ECONOMIC AND SOCIAL CONSIDERATIONS.
Margaret Miller*, Avenida Revolution 1909
5 Piso, Colonia San Angel, Mexico D.F. 01000
Mexico.
This paper evaluates the current situation which exists in Mexico regarding aquaculture production of shrimp and analyzes how development of this industry could affect U.S.-Mexican fishery relations. Analysis concentrates upon the economic feasibility of the industry in different geographic regions within Mexico. It is based on original data obtained through on-site investigations in several states in Mexico:Sinaloa on the North-Pacific Coast and Campeche on the Gulf Coast.
In addition to economic analysis (cost of land, construction, operation, availability of larvae, etc. ...) social factors are also considered. In Mexico, aquaculture production of shrimp is reserved for the social sector or in other words, for cooperative enterprises instead of private enterprises. Further, the majority of suitable coastal lands for shrimp cultivation are held in ejidos, a type of agrarian cooperative enterprise which by law may not rent or sell the land concession it has received from the federal government. The development of shrimp aquaculture in Mexico must therefore include a study of social organizations, not only economic determinants.
The complex social and economic situation surrounding the shrimp aqua-culture industry in Mexico has greatly retarded its development. The result is that Mexico has foregone foreign exchange and job creation opportunities. In the U.S., lack of Mexican aquaculture development has led to a smaller supply of fresh shrimp and therefore, very likely, to higher prices.
Development of shrimp cultivation, however, will require new strategies to encourage private investment and must involve the participation of different social groups. The benefits to both countries from shrimp aquaculture develop-ment in Mexico could be great. This paper analyzes the current situation and suggests strategies for binational cooperation in this important industry.
112. MINIMUM EFFECTIVE DOSE OF LHRH-A FOR THE INDUCED SPAWNING OF MILKFISH, CHANOS CHANOS FORSSKG.
G.T. Miyamoto*, C.S. Lee and C.S. Tamaru
Oceanic Institute, Makapuu Point
Waimanalo, HI 96795 USA.
We investigated the minimum effective dose of LHRH-analogue that will induce milkfish to spawn. In this experiment, the correlation between the dosage of LHRH-a administered to both sexes, the number of fertilized spawns, the number of spawned eggs and spawned egg diameters was also examined.
The milkfish used for spawning had undergone chronic LHRH-a plus 17α-methyltestosterone (17-MT) therapy and ranged between seven and nine years of age. Females possessing average egg diameters of >750/μm were injected with dosages ranging between 1–65 μg/kg body weight. Running ripe males were given dosages between 20 and 65μg/kg body weight. Treated individuals were placed in round, 5,000-liter tanks in a 2:1 male to female sex ratio.
A significantly lower spawning success rate was observed in the 1–5 μg/kg dosage range. There was no correlation between the occurrence of fertilized spawns and the dosages tested on both males and females. No doss-related effect was observed on fertilization rates, fecundity or spawned egg diameters. The interval between hormone injection and spawning ranged widely. The interval between fertilized spawns, however, was significantly shorter than between unfertilized spawns.
Though the females responsed to the LHRH-a therapy, success with males was limited. The necessity for additional stimuli or alternative therapies is the subject of future studies.
113. BIOENCAPSULATION OF THERAPEUTIC QUANTITIES OF THE ANTIBACTERIAL ROMET-30 IN THE NEMATODE PANAGRELLUS REDIVIVUS AND IN NAUPLII OF ARTEMIA SALINA.
Leone L. Mohney and Donald V. Lightner*
Environmental Research Laboratory
University of Arizona, 2601 East Airport Drive
Tucson, AZ 85706.
Nauplii of the brine shrimp, Artemia salina and cultures of the soil nematode, Panagrellus redivivus were fed a suspension of the antibacterial Romet-30 to determine if they could be used as a mechanism for delivery of the water-insoluble drug to larval penaeid shrimp. Two groups of brine shrimp nauplii and nematodes in one liter beakers Romet-30 was added to achieve a suspension concentration of 3 mg of drug per ml of seawater. Animals and antibiotic were kept in suspension by gentle aeration and agitation during the uptake period. After a 4-hour uptake period, samples of nauplii and nematodes were collected with a 100 mesh screen and rinsed with sterile sea-water to remove surface traces of the drug. Predetermined numbers of nauplii and nematodes were placed into stainless steel cylinders on Mueller-Hinton agar plates with 3% salt that had been inoculated with a Romet-sensitive strain of Vibrio alginolyticus. After overnight incubation, the resulting zones of inhibition were compared to that of a standard Kirby-Bauer sensitivity disc containing 25 μg of the drug that was placed on each plate as standard control. Negative controls of equal numbers of nauplii and nematodes that were not exposed to the antibiotic were also included in the tests. Artemia nauplii and nematodes did consume and concentrate the antibiotic from the suspension. They exhibited no signs of toxicity from exposure to the drug, and contained the antibiotic in sufficient quantity to theoretically provide a therapeutic dose of the drug when fed to penaeid larvae.
114. EFFECT OF SALINITY ON GROWTH OF PENAEUS VANNAMEI POSTLARVAE.
J.T. Ogle*, K.A. Beaugez and T.D. McIlwan
Gulf Coast Research Laboratory
703 East Beach Drive, Ocean Springs
MS 39564 USA.
Growth of 22-day-old Penaeus vannamei postlarvae acclimated to four salinities (2, 4, 8 and 16 ppt) was determined after one month. Thirty shrimp were stocked into triplicated 113-liter (30-gallon) aquaria, and fed live Artemia nauplii and freeze-dried calanoid copepods. Although results were variable between studies, best growth occurred at 4 ppt, and highest survival occurred at 8 and 16 ppt.
115. PARALLELS IN THE DEVELOPMENT OF CATFISH AND SHRIMP POND AQUACULTURE.
J.T. Ogle* and T.D. McIlwain
Gulf Coast Research Laboratory
703 East Beach Drive, Ocean Springs
MS 39564 USA.
G.D. Pruder, The Oceanic Institute
Makapuu Point, Waimanalo, HI 96795 USA.
Production of an aquatic animal in pond aquaculture is discussed in relation to catfish and a marine shrimp. Parallels in the development of the two industries are presented. A comparison of tangible differences is discussed in terms of the economic, fixed, and variable costs. A number of intangible differences is presented which may account for the success of the catfish farming and lack of success in shrimp farming. Opportunities for technology transfer are pointed out.
116. CAROTENOID PRODUCTION OF SPIRULINA PLATENSIS (UTEX 1928) GROWN UNDER DIFFERENT LIGHT CONDITIONS.
Miguel Olaizola* and Eirik O. Duerr
The Oceanic Institute, Makapuu Point
Waimanalo, HI 96795 USA.
The effects of variation in quantity and quality of light provided to cultures of Spirulina platensis were investigated in this study. The response in this alga in terms of growth rate and carotenoid production was measured to determine the light regimen which maximizes total carotenoid production. Increasing white light irradiance from 4 to 26 x 1015 quanta cm-2 sec-1 produced an increase in growth rates from 0.8 to 2.8 doublings per day(continuous illumination). Total carotenoid content decreased with increasing irradiance from 2.2 to 0.6% of dry weight over the 4 to 40 × 1015 quanta intensity interval. Growth saturation irradiance levels above 40 × 1015 quanta did cause increasing amounts of carotenoids to be produced. Individual carotenoids showed different response patterns to changes in irradiance levels and light quality. Spirulina exhibited slower growth under blue light, but identical growth under red light when compared to growth in white light at the same total quanta level. Spectral distribution had little effect on carotenoid content and composition.
Maximum carotenoid production based on growth rate and carotenoid content was measured at 26 × 1015 quanta. This point represents the onset of light saturation. Daily carotenoid production at this light level equalled 105 mg for each gram Spirulina starting material. It is concluded from this study that maximizing growth rate is the most important factor in determining carotenoid production by Spirulina platensis.
117. EFFECT OF LIGHT SPECTRUM AND INTENSITY ON GROWTH AND SURVIVAL OF LARVAL PENAEUS VANNAMEI.
Paul G. Olin* and Arlo W. Fast
Hawaii Institute of Marine Biology
P.O. Box 1346, Kaneohe, HI 96744 USA.
Experiments were conducted to determine the effect of light spectrum and intensity on the growth and survival of Penaeus vannamei larvae. Larvae were reared in one liter imhoff cones with 0.2μm filtered seawater at 30 parts per thousand and 27 degrees centigrade. Animals were fed the diatom Chaeto-ceros gracilis and Artemia nauplii. Treatments included white, blue, red and green light along with complete dark. Survival ranged from a high of 69% to a low of 32%, decreasing in the following sequence:green >red> blue > white >dark. These results are discussed in relation to growth, survival and light intensity.
118. EXPERIMENTAL INFECTIONS WITH BACULOVIRUS PENAEI IN PENAEUS VANNAMEI.
Robin M. Overstreet*, William E. Hawkins, Rena A. Krol and Kenneth C. Stuck, Gulf Coast Research Laboratory
Ocean Springs, MS 39564 USA.
The virus Baculovirus penaei causes cytopathological alterations and mortality in a few species of penaeids. including Penaeus vannamei. infections impact production in both hatcheries and ponds. When we experimentally fed infected host tissue, either directly or concentrated as food in rotifers, to protozoeal or mysis stages of P. vannamei, it produced extensive infections in the hepatopancreas and midgut, Typically, all those shrimp acquired infections, with as many as 80% or more of the hepatopancreatic cells affected. Consequently, the system involving larval stage of P. vannamei serves as a valuable model to assess parameters of infectivity. We will use the model to address questions involving a bioassay to detect infection, pathogenesis of infection, longevity of the infective agent, and methods to control infections. Depending on experimental conditions, the characteristic polyhedral occlusion bodies recognizable with light microscopy appeared abundant in infected nuclei of larvae fed as third stage protozoea by the third to fifth day after being fed the virus. Free enveloped nucleocapsids detected by transmission electron microscopy were associated with hypertrophic nuclei and the appearance of virogenic stroma. The proteinaceous bodies with occluded virions discharged into the lumen of the hepatopancreas tubulae or midgut when the host cell ruptured.
The study was conducted in cooperation with the U.S. Department of Agriculture Grant No. 85-CRSR-2-2438.
119. ALGAL ENRICHMENT AT A PENAEID SHRIMP HATCHERY.
Kim F. Page*, Amorient Aquafarm Inc.
P.O. Box. 131, Kahuhu, Hawaii 96731 USA.
Carbon dioxide and additional fluorescent lights were used to increase algae production at Amorient Aquafarm's Kahuku shrimp hatchery. Chaetoceros gracilis cell densities were recorded from 200 liter cylinders with and without CO2 and light additions. Initial cell counts, counts 3 days after inoculation and 6 days after inoculation, averaged 0.3, 2.1 and 2.2 x 10° cells/ml in untreated cylinders and 0.4, 3.8 and 4.4 × 106 cells/ml in treated cylinders, respectively. Cultures were partially harvested and refilled daily after 3 days. Algae cell counts in flasks and carboys with added CO2 also increased. Dense Chaetoceros cultures severely restricted light penetration into cylinders. Injection with CO2 and increased illumination lessened required laboratory space and culture volumes for algae, and allowed greater flexibility in algae production schedules.
120. EFFECT OF SUBLETHAL CONCENTRATIONS OF TEXTILE DYE EFFLUENT ON FOOD UTILIZATION, GROWTH AND CONVERSION EFFICIENCY OF A FRESHWATER FISH OREOCHROMIS MOSSAMBICUS.
S. Palanichamy*, M. Ramakrishnan and P. Baskaran
P.G. and Research Department of Zoology, A.P.A. College of Arts and Culture, Palani-624602
Tamil Nadu, India.
Oreochromis mossambicus was exposed to different sublethal concentrations of textile dye effluent (0.15 to 0.6%). Mortality, food utilization, growth and conversion efficiency were studied. At a concentration of 0.9%, 100% mortality was observed within 96 h exposure; no mortality occurred at 0.5%; LC50 was 0.75%. Rearing the fish in increasing sublethal concentrations of effluent, it was found that the feeding rate decreased from 33.8 mg g fish-1day-1 (fish reared in effluent free-water) to 10.3 mg g fish-1 day-1 at the highest sublethal concentration (0.6%). Absorption and metabolic rates also decreased with increasing concentrations. Growth rate also decreased from 12.2 mg g-1 d-1. Conversion efficiency decreased with increasing concentrations of effluent.
121. THE EMERGENCE OF CHINA AS A WORLD LEADER IN MARINE SHRIMP PRODUCTION.
Craig L. Paulsen, Paul Liao and John F. Cussigh Kramer,
Chin and Mayo, Inc., 1917 First Avenue
Seattle, Washington 98101 USA.
The People's Republic of China has the potential to become the largest single producer of marine shrimp due to its extensive exploitable coastline, particularly in the Bohai Gulf (200,000–300,000 hectares), and its established, though rudimentary, infrastructure for processing, feed production and product export. KCM International, Inc. is working with a client firm that has secured joint venture agreements to further develop several ongoing marine shrimp farms. The 650 km, mostly flat, coastline of the Bohai Gulf features uniformly shallow near-shore waters that can be readily enclosed by dike construction out to one kilometer or more from shore for significant additional pond culture area. Typical pond production levels in this region for the China, white marine shrimp, Penaeus orientalis. average 105 catties per mu (787 kg per ha), although more intensive shrimp culture practices at the large Tanghai Shrimp Farm near Tangshan resulted in production levels of 440 catties per mu (3.3 MT per ha) in 1986 from approximately 2 to 3 ha ponds. Experimental 5 mu (0.83 acres) ponds at the Nandagang State Shrimp Farm near Cangzhou have reached production levels of 1,070 catties (8 MT per ha). KCMI expects that a production goal of about 2 MT per ha per year is achievable with appropriate inputs of technology and proper designs. Principal limitations to improved levels of shrimp production in the Bohai Gulf are restrictions limiting availability of seedstock supplies, inadequate feed formulations, pond design and general management for improved product quality. These elements are now being supplied through KCMI and projected shrimp production from the Bohai Gulf alone could reach nearly 400,000 MT of shrimp for export annually.
122. MACROBRACHIUM ROSENBERGII AND NOTEMIGONUS CRYSOLEUCAS POLYCULTURE STUDIES IN LOUISIANA.
W. Guthrie Perry, Louisiana Department of Wildlife and Fisheries, Rt. 1, Box 20-B, Grand Chenier
LA 70643 USA.
Johnnie Tarver, Louisiana Department of Wildlife, and Fisheries
P.O. Box 15570, Baton, Rouge
LA 70895 USA.
Polyculture studies were conducted in Southwest Louisiana from 1984 to 1986 with Malaysian prawn, Macrobrachium rosenbergii and Golden shiners, Notemigonus crysoleucas. In 1984, stocking of shiners at 24.7/m2 with prawn at 4.4/m2 resulted in increased average total pond production of 307 kg/ha of the bait fish over the average prawn production of 640 kg/ha. Prawn in monoculture averaged 629 kg/ha. Prawn/shiner polyculture trials in 1985 demonstrated no difference in growth between prawn stocked at 3.7/m2 in polyculture with 32.1/m2 shiners. Prawn growth, survival and yield were not affected by this density of shiners and averaged 533 kg/ha. Shiner survival was decreased by presence of prawn but difference in yield was not significant (P <0.05). A comparison of increased stocking rates of 24.7/nr and 49.4/m2 shiners with 4.9/m2 of prawn in 1986 did not seem to decrease prawn production, averaging 631.6 and 840.5 hg/ha, respectively. Increased shiner stocking density resulted in decreased survival and production of this species; averaged 398.3 and 193.1 when stocked at 24.7/m2 and 49.4/m2, respectively.
These results indicate that it is feasible for bait fish producers in the Southeastern United States to stock prawn in combination with shiners.
123. COMPARATIVE PRODUCTION OF COLOSSOMA MACROPOMUM AND TILAPIA NILOTICA IN PANAMA.
Medardo Peralta, Estacion Experimental de Dulce-Acuicola
Gualaca, Chiriqui, Panama.
David R. Teichert-Coddington*, Department of Fisheries and Allied Aquacultures, Auburn University
AL 36849 USA.
The production of Colossoma macropomum, a relatively little studied fish, was compared with that of Tilapia nilotica. a fish well known for its good production characteristics. Both species were grown simultaneously in a random-ized design that was arranged in 2 x 2 factorial with each species being tested at a density of 1 and 0.25 fish/m2; treatments were replicated three times. Fingerlings were stocked into earthen ponds (870 m2), fed a commercial diet (25% protein), and harvested after 126 days of growth. Mean net production (kg/ha) for tilapia at high and low density was 3,361 and 917, respectively and for colossoma was 3,682 and 977, respectively. The production difference between species was not significant (P>0.05) while the difference between densities was highly significant (P < 0.01). Although net production was not different for the species, colossoma gained significantly more weight per fish than the tilapia gains (g), for the low density of tilapia and colossoma were 379 and 471, respectively. While increasing the stocking density four-fold resulted in an almost four-fold increase in net production for both species, mean weight gains were not significantly affected by density. All other variables being equal, we concluded that the production of a 400 g fish with prepared diets could be achieved equally as efficiently with T. nilotica or C. macropomum. Also, both species should be stocked at a rate of at least 1/m2 for high production without a significant loss of mean fish weight.
124. SHRIMP POND SAMPLING FOR GROWTH AND POPULATION:THEORY AND PRACTICE.
Jeffrey Peterson* and Jairo Llanos
Acuespecies, S.A., Casilla 191-P
Guayaquil, Ecuador.
This paper discusses the development of sampling systems at Acuespecies S.A., a 500 hectare shrimp farm in Guayas Province, Ecuador. A theoretical model of shrimp growth and population dynamics was developed to predict weekly growth and mortality. This model was tested using two techniques. The first were weekly cast-net samples to determine growth and the second were monthly samples using an in-pond grid system and cast net to estimate shrimp population.
Several factors were determined as having a significant effect on the confidence of the sampling results. Pond depth and bottom uniformly affected cast net performance and bi-monthly variations in shrimp activity affected distribution. The latter appear to be related to lunar phase.
125. EFFECT OF DIFFERENT MEDIA ON THE PRODUCTION AND CHEMICAL COMPOSITION OF FREE LIVING NEMATODES PANAGRILUS REDIVIVUS
Ismail Radwin and David B. Rouse*, Department of Fisheries and Allied Aquacultures
Auburn University, Alabama 36849 USA.
Nematodes were cultured in media composed of either wheat flour, oatmeal, or cornmeal. Each growth media was tested with and without yeast as an additive. Total production of nematodes in wheat flour was significantly greater than in oatmeal or cornmeal media. The addition of yeasts prevented fungal contamination of all cultures, but had no effect on nematode yield. Production of nematodes stopped after day 21 in cornmeal, day 35 in oatmeal and day 54 in wheat flour.
A second rearing trial was conducted using media composed of either wheat -flour, cottonseed meal or ground shrimp feed. Wheat flour provided a signifi-cantly greater average daily production and length of production than either cottonseed meal or shrimp feed meal.
Proximate analysis revealed that the chemical composition of the media affected the chemical composition of the nematodes. Protein content of nema-todes cultured in cottonseed meal (64.6%) and shrimp feed meal (57.2%) was significantly higher than protein content of nematodes grown in wheat flour (50.9%). Slight differences in fatty acid profile were also observed in nematodes grown in the different media.
126. LARGE SCALE BREEDING OF INDIAN MAJOR CARPS AND CHINESE CARPS UNDER VARIED HORMONE DOSAGE AND INTERVAL ROUTINES IN BANGLADESH.
M.A. Rahman, Z. Haque, M.S. Shah and D. Deppert Fisheries Research Institute, Mymensingh
2201, Bangladesh.
Varied hormone dosage in different times of breeding season and varied time intervals between the preliminary dose and resolving dose were compared against success in ovulation and fertilization in Indian major and Chinese carps. A total of 962 individual females of Labeo rohita, Catla catla, Cirrhina mrigala, Labeo calbasu and Hypophthalmichthys molitrix were used in the experi-ment. The hormone dosage used was higher at the beginning of the breeding season and lower in the later part of the breeding season. Considering the natural fact the species would give better result in ovulation and fertilization at their optimum breeding season, the varied hormone dosage and time interval between the preliminary dose, and resolving dose appeared to have considerable effect in ovulation and fertilization in all the major carps and Chinese carps.
127. EFFECTS OF DIFFERENT LEVELS OF CRUDE PROTEIN AND FEEDING RATES ON THE GROWTH OF FINGERLINGS OF TILAPIA (OREOCHROMIS AUREA) IN FLOATING CAGES.
Luis F. Garcia Ramos* and Baltazar Cuevas Hernandez
Delegacion Federal de Pesca en el Estado de Nuevo Leon Guadalupe, Nuevo Leon, Mexico, C.P. 67100
Facultad de Ciencias Biologicas, Laboratorio de Alimentos, U.A.N.L., Ciudad Universitaria
C.P. 66451.
Two tests of feeding were carried out to determine the level of crude protein and the feeding rate optimums in the growth of fingerlings of Tilapia (Oreochromis aurea) in floating cages.
In the first test July of 1986, we evaluated the growth and food con-version of four diets that contained the following levels of crude protein:25, 30, 35 and 40%. All diets were isocaloric, with 3,815 Kcal/Kg. A commer-cial diet containing 32% of crude protein was used for control.
For each of the diets three floating cages of 1 m3 were utilized with a density of 100 fishes/cage. A ration equivalent of 4% of the total weight was offered twice daily for 75 days. The diet with 25% crude protein level and 1.7 food conversion gave the best results. Following the diets, 40, 35 and 30% of crude protein gave food conversions of 1.9, 2.1 and 2.4, respectively. The food conversion for control was 2.7. The water temperature changed from 29°C to 26°C.
A second experiment was carried out in September of 1986. We worked only with 25% crude protein level and changed the feeding rates of 3, A, 5, 6 and 7%. The test had a duration of 60 days. The best results in the feeding rate of 3% were obtained with a food conversion of 1.5, followed by the rates 4, 5, 6 and 7% for a food conversion of 1.7, 2.1 and 2.9, respectively. The water temperature changed from 25°C to 17°C.
In conclusion Oreochromis aurea can be fed in levels of 25% crude protein at feeding rates 3–4%.
128. MARKETING STRATEGIES AND TACTICS FOR AQUACULTURE FIRMS:AN OVERVIEW.
Raymond J. Rhodes*, Division of Marine Resources
S.C. Wildlife and Marine Resources Department
P.O. Box 12559, Charleston, S.C. 29412 USA.
For the aquaculture entrepreneur, the marketing function can be divided into three basic ongoing tasks:(1) market analysis; (2) setting marketing objectives; and (3) deciding on specific strategies to attain the objectives. These tasks may be performed in an intuitive manner and/or be part of a formal written marketing plan. The marketing “tools” for reaching identified target markets are your aquaculture products in various forms, pricing, promotion and distribution strategies and associated tactics. Unfortunately, some aqua-culture entrepreneurs often invest very little time and money into understanding the market situation but prefer to adopt a “trial and error” marketing approach.
Realizing that a small aquaculture firm may lack the resources to cost effectively utilize various marketing tactics, a group of aquaculture firms may have the alternative to pool resources in the form of marketing cooperatives or associations. The cooperative is managed and operated in the interest of its patrons as a jointly owned extension of the members' business compared to a private business concern operated in the interests of the owners as a means of making profits on their capital investment. Historically, agricultural marketing boards or associations in the United States have often concentrated on just generic product promotion for its membership.
129. PRELIMINARY DESIGN SPECIFICATIONS FOR SHRIMP AND OYSTER CO-PRODUCTION.
David Robichaux and Jaw-Kai Wang
Department of Agricultural Engineering
University of Hawaii at Manoa, 3050 Maile Way
Honolulu, Hawaii 96822 USA.
Production of oysters in the effluent of shrimp ponds has the potential to increase the revenues to shrimp farmers by adding a second crop which feeds on unutilized organic detritus and phytoplankton from shrimp ponds.
The metabolic rates of oysters grown in shrimp pond effluent and the effects on the water quality were studied to determine the preliminary design specifications for co-production of shrimp and oysters.
During the course of the experiment it was found that oxygen supply was a limiting factor in growth and feeding of oysters in effluent due to the high level of non-oyster respiration in the system.
Feeding rates of two size classes were determined and growth was measured under two conditions. Suspended solids, turbidity and oxygen were removed from effluent waters passing through an oyster tank, while N03 + N02, P04, NH4 were added in predictable quantities. Effluent from highly productive shrimp ponds may require dilution to reduce particle density and increase dissolved oxygen to maximize oyster production.
130. A COMPUTER DATA ACQUISITION SYSTEM FOR AQUACULTURE POND MANAGEMENT.
Gary L. Rogers*, Charles P. Madenjian and Arlo W. Fast
Hawaii Institute of Marine Biology
P.O. Box 1346, University of Hawaii at Manoa
Kaneohe, Hawaii 96744 USA.
Aquaculture pond monitoring, control and management may be performed by microprocessors. A system has been developed as a research tool for monitoring weather and water quality data at a marine shrimp facility. The unit may be easily adapted to control aeration, circulation, feeders, alarms and other devices as well as function as a data logger. The system has broad application in all areas of fresh or brackishwater aquaculture.
The system uses an Apple IIe microcomputer, Leeds and Northrup dissolved oxygen probe, YSI temperature sensors, wind anemometer, Licor solar sensor, analog to digital conversion board, relay switches, chamber for probes, sub-merged pumps and sample lines. The computer controls relays that turn a sample pump on and cycle to the next pond. Data for each of four ponds is saved to diskette every 10 minutes.
131. FINGERLING PRODUCTION OF TILAPIA NILOTICA AT THE RWASAVE FISH CULTURE STATION OF THE NATIONAL UNIVERSITY OF RWANDA.
Felicien Rwangano, Marijke Van Speybroek and Eugene versite Rurangwa
Faculte d' Agronomie, Universite Nationale du Rwanda
B.P. 117, Butare, Rwanda.
Karen L. Veverica, Department of Fisheries and Allied
Aquacultures, Auburn University, Alabama 36849 USA.
Boyd J. Hanson, OSU/UNR Pond Dynamics CRSP
Department of Fisheries and Wildlife
Oregon State University, Corvallis, Oregon 97331 USA.
Rwanda's climate is cooler than its latitude would indicate (2°S), because elevation of most of the country lies between 1,500 and 2,500 meters. For this reason, the suitability of tilapia culture has been questioned. However, in light of local management constraints, Tilapia nilotica have proven satis-factory when fingerlings were made available.
Production of fingerlings in ponds stocked with T. nilotica brooders has been monitored at the National University of Rwanda's aquaculture research station since 1984, when this species was re-introduced to Rwanda. Finger-ling production is generally very low (usually 10–30 fingerlings per female per month). Age of females at first reproduction was about nine months. Reproduction occurs in every month but is lowest during the dry season (June–August), where minimum air temperatures fall to 4°C to 10°C. Reproduction success has also been attributed to pond design. Brooders stocked in ponds with vertical levees and minimum depths greater than 80 cm did not reproduce. Nesting typically occurs at depths of 20 to 50 cm on gently-sloped sandy substrates.
The low reproductive rate of tilapia in Rwanda may be advantageous and simplify management practices for the rural fish farmers.
132. DETERMINATION OF OPTIMUM STOCKING DENSITY FOR REARING FRY OF ROHU (LABEO ROHITA HAM.) IN NURSERY PONDS.
S.B. Saha*, M.V. Gupta and M. Shahabuddin
Freshwater Aquaculture Research Station
Fisheries Research Institute
Mymensingh-2201, Bangladesh.
Studies were undertaken in ponds of 400 m2 each to determine the optimum stocking density for maximum survival and growth of fry in nursery ponds. The ponds were stocked with 4 days old hatchlings (average length 6 mm) of rohu (Labeo rohita Ham.) . Three stocking densities were tried viz., 6.25, 7.50 and 8.25 million hatchlings per hectare. Each stocking density was replicated in two ponds. All the ponds were fertilized with organic manure (cattle dung) at the rate 10 tons per hectare. The fry were fed daily with a mixture of finely powdered mustard oil cake and rice bran.
The ponds were harvested after 4 weeks rearing and the survival and growth of fry was estimated. The average survival (average of two ponds) was 73.94, 63.40 and 57.41% and the fry reached average lengths of 32.0, 30.2 and 28.2 mm at 6.25, 7.50 and 8.75 million per hectare stocking densities, res-pectively. This has indicated that at the management level (fertilization and feeding) practiced, the stocking densities can not be exceeded. Further work is in progress to study whether stocking densities could be further increased with changes in quality and quantity of fertilizer and feed.
133. EFFECT OF DIFFERENT FERTILIZERS ON THE GROWTH AND SURVIVAL OF SILVER CARP (HYPOPHTHALMICHTHYS MOLITRIX VAL.) FRY.
S.B. Saha*, M.V. Gupta and M. Shahabuddin, Freshwater Aquaculture
Research Station, Fisheries Research Institute
Mymensingh-2201 Bangladesh.
For determining the effect of different fertilizers on the survival and growth of fry in nursery ponds, studies were undertaken in 6 nursery ponds of 400 m2 each. The ponds were stocked with 4 days old hatchlings (average length 8 mm) of silver carp (Hypophthalmichthys molitrix Val.) at a density of 5 million per hectare. Three types of fertilizers were tried viz., organic manure only-cattle dung at the rate of 10 tons per hectare; inorganic fertilizers only-urea and triple superphosphate at the rate of 100 and 75 kg per hectare, respectively; and a mixture of both organic and inorganic fertilizers-cattle dung, urea and triple superphosphate at the rate of 5 tons, 50 kg and 38 kg per hectare, res-pectively. Each fertilizer dose was replicated in two ponds. The fry were fed daily with a mixture of finely powdered mustard oil cake and rice bran (contain-ing about 21% protein). The ponds were harvested after 4 weeks rearing and the survival and growth of fry were estimated.
Ponds fertilized with organic manure only gave the maximum survival of 75.49% (average of two ponds) and the fry attained an average length of 34.36 mm, while the ponds fertilized with inorganic fertilizers only gave the lowest survival of 60.46% and the fry reached an average size of 33.38 mm. Survival of fry was 67.00% in ponds fertilized with a mixture of organic and inorganic fertilizers and the fry reached an average length of 28.83 mm. The study revealed that fertilization of ponds with cattle dung gave not only maximum survival but also optimum growth of fry.
134. STUDIES ON THE COMPARATIVE GROWTH AND SURVIVAL OF SILVER CARP (HYPOPHTHALMICHTHYS MOLITRIX VAL.) IN ONE STAGE AND TWO STAGE NURSING.
S.B. Saha, M.V. Gupta and M. Shahabuddin, Freshwater
Aquaculture Research Station, Fisheries Research Institute
Mymensingh-2201, Bangladesh.
Studies were conducted to evaluate whether one stage nursing or two stage nursing would be appropriate for obtaining maximum production of finger-lings from unit area with optimum growth. In one stage nursing, the ponds were stocked with 4 days old hatchlings (average length 8 mm) or silver carp (Hypophthalmichthys molitrix Val.) at a density of 600,000 per hectare.
At the end of 8 weeks rearing, fry in one stage nursing reached an average length of 41.2 mm to 53.58 mm with a survival range of 69.9 to 84.58%. In two stage nursing, the fry attained a length of 27.46 to 40.30 mm with a survival range of 56.02 to 78.57% in 4 weeks rearing. When the popu-lation was thinned out, they reached a length of 50.01 to 60.00 mm with a survival range of 88.59 to 92.60%, indicating that two-stage nursing is better in terms of higher survival and growth and also in terms of economic return.
135. AN ASSESSMENT OF THE EFFICIENCY OF IODINE DISINFECTANT IN THE TREATMENT OF EGGS OF PENAEUS VANNAMEI.
J.A. Salvador*, R. Tigreros, B. Jaramillo, Z. Romero
H. Lucien-Brun and D. Lee, MACROBIO S.A.:Casilla 562
Guayaquil, Ecuador.
In aquaculture, iodine is used as an egg disinfectant for some fish species, in order to control the propagation of pathogen organisms (bacteria, virus, fungi). This work assesses its effectiveness in Penaeus vannamei eggs.
Results show a reduction in bacteria counts (gram-negative), also a possible positive effect against Baculovirus penaei.
136. A COMPARATIVE ANALYSIS OF SPERM QUALITY BETWEEN WILD CAUGHT MALES AND UNILATERALLY EYESTALK ABLATED REGENERATED MALES IN A COMMERCIAL PENAEUS VANNAMEI MATURATION FACILITY.
J.A. Salvador A*, B. Jaramillo J., Z. Romero M.,
H. Lucien-Brun and D. O'C. Lee, MACROBIO S.A.
P.O. Box 562, Guayaquil, Ecuador.
Wild caught Penaeus vannamei males were used for insemination and later ablated to compare performances in a commercial maturation facility. The system operates with artificial insemination only, where females artificially mature separately without males.
Males, wild caught and ablated are kept in separate tanks of 4.5 M in diameter at a density of 5.0 to 12.5 animals per M2. Temperature was maintained between 27 and 28.5°C with a water exchange of 90 to 100% per day and the animals were fed with a combination of fresh frozen feeds plus maturation pellets (Nippai). Ablated males received bloodworms as a fatty acid booster in their diets. Wild mature males were received, acclimated and used within 8 to 10 days after arrival. These same animals now without spermatophores were ablated using a ligature method and reused after approximately 10 days when spermatophores showed good development.
The tests involved 1,516 wild caught males (A) for the insemination of 1,128 females, 645 males reused after ablation (B) for 483 females, 212 males reused after a second regeneration (C) for 169 females and 103 males reused after a third generation (D) for 94 females.
Results were analyzed in terms of egg fertilization rates, giving for (A) 25.3%, (B) 25.8%, (C) 27.4% and (D) 17.0%. Additional comparative observations on colour, size and consistency are made. The experiment shows that male eyestalk ablation is a viable way of improving male reuse.
137. INTENSIFICATION OF SHRIMP CULTURE IN EARTHEN PONDS IN SOUTH CAROLINA:PROGRESS AND PROSPECTS.
Paul A. Sandifer*, J. Stephen Hopkins, Alvin D. Stokes and James M. Waddell, Jr., Mariculture Research and Development Center, S.C. Marine Resources Division, P.O. Box
809 Bluffon SC 29910.
Experiments on the intensive cultivation of Pacific white shrimp, Penaeus vannamei, in ponds in South Carolina were initiated in 1985 at the Waddell Mariculture Center. The first study involved two 0.1 ha ponds stocked at approximately 40 postlarvae/m2, with management practices based on those used in Taiwan for intensive pond culture of P. monodon. Harvest yields averaged 6,757 kg/ha for one crop, demonstrating the technical feasibility of such intensive culture of P. vannamei. In 1986, 2.5 ha of ponds at the Waddell Mariculture Center (six ponds totalling 2.0 ha at 40 PL's/m2 and two ponds totalling 0.5 ha at 60 PL's/m2) yielded a total of 13,606 kg (5,442 kg/ha), despite the worst heat wave and drought on record in South Carolina and sub-stantial decreases in aeration and water exchange rates, This serves as a pilot scale, proof-of-concept test. During these studies, no effects of ponds size were noted. Initial implementation of intensification efforts in the embryonic South Carolina shrimp farming industry also occurred during 1986, with approximately 32 ha of private ponds stocked at densities from 10–32 PL's/m2. Harvest biomass increased with stocking density, with maximum yields of 3,575 kg/ha. In 1987, our team is investigating effects of high density (20–100 PL's/m2) in pond culture and impacts of intensification on water quality and pond ecology. Despite disappointing growth rates, yields are expected to be high. Technology transfer efforts have continued, with a 100% increase in private pond area under semi-intensive to intensive management. Two small private ponds have already been harvested yielding 3,600 and 5,100 kg/ha. Prospects for further development in the private sector appear excellent; yields of 10,000 kg/ha/crop are anticipated from private ponds within the next few years. Intensification definitely works in earthen ponds to at least 2 ha in size where the necessary aeration, water exchange, high quality feed and good management are available.
138. THE EFFECT OF FORMULATED FEEDS ON THE PLANKTONIC MICROBIAL POPULATIONS OF SHRIMP POND SYSTEMS IN HAWAII.
Vernon T. Sato*, Warren G. Dominy, Christine M. Solis and Howard Deese, The Oceanic Institute Makapuu Point
Waimanalo HI 96795 USA.
Feeds applied to shrimp pond systems are generally selected to provide for the nutritional requirements of the shrimp. There is a recycling of nutrients via the shrimp and the heterotrophic food web which has a secondary effect of stimulating primary productivity. Various commercial shrimp feeds have been shown to leach specific nutrients at varying rates. In this study, growth responses of the algae and protozoans present in shrimp ponds were evaluated to determine how the specific feeds influenced the microbial biota in the water column.
Four commercial shrimp diets (Nippai, Hanaqua, Purina MR-25 and Waldron) and one experimental formulated diet (0IS861) were incubated in water from a shrimp pond under ambient daytime conditions for 9 .hours. An additional treatment consisting of a standard inorganic nutrient solution was incubated along with a control. The feed.material and pond water were contained in clear plastic tissue culture tubes suspended in the shrimp pond. Changes in the number of microorganisms were noted for each treatment at the end of the incu-bation period. Diatom species responded similarly to all of the treatments (either increased in biomass in all treatments or in none of the treatments). However, the flagellated algal and protozoan species showed growth responses that varied with the feed treatment. It was concluded that the type of feed applied to aquaculture ponds, at least in the short term will influence the microbial composition of those ponds.
139. THE CULTURE OF PENAEUS SEMISULCATUS IN ISRAEL.
Ephraim R. Seidman* and Gilad Issar
Kibbutz Ma'agan Michael, DN Menashe
37805 Israel.
Growth performance data on Penaeus semisulcatus under semi-intensive pond conditions were collected in Israel between 1984 and 1987. Shrimp were grown from PL to a maximum mean size of 11.3 g realizing a production of 2,057 kg/ha in 1984. In 1985, shrimp growth from PL to market size was separated into nursery and grow-out phases. Final grow-out results gave a maximum yield of 3,610 kg/ha and maximum mean size of 21.5 g. Sample shipments to maximize revenues. Any increase in shrimp size at harvest would require new manage-ment practices.
Juvenile shrimp (3.4 to 6.5 g) were held during the winter of 1986 in open ponds and restocked in grow-out ponds in the spring of 1987. Shrimp survivorship during overwintering was low-10 to 15%. However, a maximum shrimp size of 25.6 g and production of 7,450 kg/ha were obtained using this strategy. It is felt that comparable results, but with higher survivorship could be obtained by headstarting shrimp in hothouses. Two major problems that remain to be solved in Israel are the formulation of a local shrimp diet for and year round maturation of P. semisulcatus.
140. ECONOMICS OF COMMERCIAL PRODUCTION OF FRESHWATER PRAWN IN THAILAND.
Yung C. Shang*, Department of Agricultural and Resource Economics, University of Hawaii
Honolulu, Hawaii 96822 USA.
C. Kwei Lin, Division of Agriculture Engineering
Asian Institute of Technology, P.O. Box 2754
Bangkok, Thailand.
A cost and return analysis was conducted for freshwater prawn farming in Thailand for three different scales of farms:small, medium and large. The stocking rate decreases as the farm size increases, while the survival rate increases as the stocking rate decreases. The results of the analysis revealed that freshwater prawn farming in all scales tested in Thailand proved to be profitable but the best results obtained were from farms in the median range.
141. SOCIO-ECONOMIC IMPACTS AND CONSTRAINTS OF AQUACULTURE DEVELOPMENT IN ASIAN COUNTRIES.
Yung C. Shang*, Department of Agricultural and Resource Economics, University of Hawaii
Honolulu, Hawaii 96822 USA.
Aquaculture plays a vital role in Asian countries as a source of animal protein, employment and foreign exchange earnings, as well as a means of impro-ving farm income. However, there are numerous socio-economic constraints that must be addressed by these countries in their development of aquaculture, e.g., inadequate supply and high cost of major inputs (seed, feed, fertilizer, etc.), lack of adequate credit, inefficient marketing infrastructure and socio-cultural problems.
142. THE USE OF DEFATTED AND FULL FAT SOYBEAN MEAL WITH AND WITHOUT EXTRUSION PROCESS AS PARTIAL REPLACEMENT FOR FISHMEAL IN TILAPIA DIET.
Shi-Yen Shiau*, Su-Fun Lin, Su-Lan Yu, Ai-Ly Lin and Chung-Ching Kwok, Department of Marine Food Science
National Taiwan College of Marine Science and Technology
Keelung, Taiwan 20224, Republic of China.
The purpose of the study was to evaluate the nutritional value of differ-ent types of soybean meal with and without extrusion process as replacement for fishmeal in tilapia diet. Two types of commercial soybean meal, defatted and full fat were extruded by twin screw extruder at 80°C and 135°C. Each, diet contained 24% protein and 11% lipid. All diets were isocaloric., Thirty percent of fishmeal protein was replaced by each type of soybean meal with or without extrusion. Fishmeal group was used as control. There were a total of 7 dietary groups; each was fed to 3 aquariums of fish. The experiment was carried out in a closed circulated filtered rearing system for 2 months. Fish received all the soybean meal replacement diets had similar weight gain percentage, feed conversion ratio, protein digestibility, lipid digestibility and dry matter digestibility as compared to that of fish receiving control group fishmeal. Although fish fed the defatted soybean meal, replacement diet had slightly better growth parameters as compared to that of fish fed other replacement groups, the differences were not significant (P>0.05). The body compositions of fish were also identical regardless of which diet was received. These data suggest that fishmeal can be replaced partially by either defatted or full fat soybean meal when the dietary protein level was 24%. Extrusion at either 80°C or 135°C did not enhance the nutritional value of soybean meal as partial replacement for fishmeal in tilapia diet.
143. USE OF MG-L-ASCORBYL-2-PHOSPHATE AS VITAMIN C SOURCE IN SHRIMP DIET.
Kunihiko Shigueno*, Higashimaru Foods, Inc.
2-1-11 Taniyamako, Kagoshima City
891–01 Japan.
Shinobu Itoh, Biochemical Division
Showa Denko K. K. 1-13-9 Shiba Daimon
Minatoku, Tokyo, 105 Japan.
To meet the instability of Vitamin C compounded in formulated shrimp diet, a trial to substitute APM for L-Ascorbic Acid was made. The APM commercial name of Mg-L-Ascorbyl-2-Phosphate introduced by one of the present authors was examined for its stability during processing and staying in sea-water. Also, groups of juvenile Penaeus japonicus, a penaeid shrimp were subjected to a rearing experiment to know if the APM could be utilized by the shrimp. The HPLC analyses indicated that the APM was stable while processing into dried pelleted food. The recovery rate of the APM áfter processing ranged from 77% (1,078 mg APM in 1 kg diet) to 20% (43 mg APM in 1 kg diet). The loss may be attributed to absorption by other ingredients while processing. A couple of experiments to see its chemical stability in seawater detected 97.9% and 99.8% of the initial content after 22 and 26 hours, respectively. The rearing experiment fed with five different diets containing varied amounts of APM laster for 101 days and normal growths were observed, in treatments fed diets with 1,078, 430, 215 mg APM in 1 kg, whereas mass mortality occurred in treatments fed diets with 43 and 0 mg APM per kg. The concentration of accumulated APM and the converted L-Ascorbic Acid in the hepatopancreas in the survived animals indicates the optimum level of the APM to be about 215 mg per kg.
144. HISTOLOGIC RESPONSE OF A PENAEID SHRIMP TO DIETARY VITAMIN C.
R.F. Sis* and D.L. Lewis, Veterinary Anatomy and Veterinary Microbiology, Texas A&M University
College Station, TX 77843 USA.
A.L. Lawrence and F.L. Castille, Texas Agricultural Experiment Station,
Texas A&M University System
P.O. Drawer Q, Port Aransas, TX 78373 USA.
This is a report of a study utilizing a purified diet in evaluating Vitamin C effects on histopathology of tissues of postlarval shrimp (Penaeus vannamei). The study was conducted utilizing 20 liter circular tanks in a recirculating system, over a period of four weeks. Vitamin C levels of .071 to 11.31 g/kg were used and the tissue response was evaluated among eight shrimp from each treatment. The animals were fixed in Davidson's solution and evaluated at the light microscopy level. The dietary effects of Vitamin C levels were evaluated in terms of pathologic changes observed in the shrimp tissues. The histology and histopathology of the tissues will be described.
145. THE IMPORTANCE OF FATTY ACIDS IN A DRY FEED USED AS A COMPLETE REPLACEMENT FOR ARTEMIA.
Linda L. Smith* and Addison L. Lawrence
Shrimp Mariculture Project, Texas Agricultural Experiment Station,
Texas A&M University System
P.O. Drawer Q, Port Aransas, Texas 78373 USA.
Two semi-purified experimental feeds were formulated to include 100% menhaden or 100% corn oil as the primary lipid source. Growth of Penaeus vannamei larvae fed each of the dry formulations plus algae was compared to that of larvae fed Artemia plus algae or only algae. All feeding regimes included 100,000 cells/ml Chaetoceros gracilis and 30,000 cells/ml Tetraselmis chuii. Dry feeds were presented in four equal allotments/day at six hour intervals beginning from the third protozoeal substage until termination of the fifth postlarval substage. Artemia was presented in a single feeding/day.
The addition of dry feed to an algae regime significantly improved growth and survival of Penaeus vannamei over that obtained on an algae-only regime. Larvae fed the dry feed containing menhaden oil were larger than those fed the feed containing corn oil; however, the difference was not significant at alpha = .01. Growth of larvae fed either formulated feed was inferior to that of larvae fed Artemia.
146. PROTEIN REQUIREMENT OF LARVAL PENAEUS VANNAMEI
Linda L. Smith* and Addison L. Lawrence
Shrimp Mariculture Project, Texas Agricultural Experiment Station,
Texas A&M University System
P.O. Drawer Q, Port Aransas, Texas 78373 USA.
A semi-purified feed was used to examine the protein requirement of Penaeus vannamei. Protein levels examined were:37.6, 44.6, 51.6 and 58.6%. Lipid was constant at 12.4%. Energy varied between 4,763 and 5,078 KCal/kg. Feeds were presented in four equal allotments/day at six hour intervals from the third protozeal substage until termination at the fifth postlarval substage. Algae (100,000 cells/ml Chaetoceros gracilis and 30,000 cells/ml £. chuii) was added to all dry feed regimes and to the two control regimes (algae-only and algae plus Artemia).
There was no significant difference in survival, rate of metamorphosis or final weight/PL-5 of larvae fed feeds containing any level of protein, suggesting that within this series of formulated feeds, a protein level of 37.6% is sufficient. Final weight of Artemia-fed larvae was equal to that of larvae fed dry feeds.
147. BELIZE'S FIRST COMMERCIAL SHRIMP FARM SET UP.
John R. Snell, Linda Cardelli* and M. Ahmed
General Shrimp, Ltd., Independence, Belize, C.A.
Our hatchery and farm are constructed near the mouth of the Sennis River by the sea in southern Belize. The hatchery facility includes maturation, larviculture, algae production, artemia culture, spawning and labwork.
The maturation room consists of 8–12' diameter swimming pools plus spawning tanks with partial artificial lighting. Clear seawater from a large reservoir flows by gravity to the hatchery. Maturation water passes through rapid sand filters and larviculture water through diatomaceous earth filters. The larviculture area consists of 20,000 L rectangular epoxi-coated tanks with four bottom designs. Larvae are stocked at 50 animals per liter and fed on algae and artemia plus artificial diets. The hatchery will produce approximately 6 million PL's per month for stocking 330 plus acres of ponds.
The algae area produces Chaetoceros gracilis and Tetraselmis chuii. Test tube, flask and carboy cultures are raised in a 21°C air conditioned room. The mass production consists of 10 250 L, 10 1,000 L and 8 8,000 L algae tanks covered by a transparent plastic roof.
Penaeus vannamei and P. stylirostris have been raised on site with some work on P. schmitti (local species) .
Stage one, 3 feet deep ponds average 25 acres. The electrical driven 25 cfs vertical 12 foot lift propeller pumps lift double-screened, clear sea-water into a supply canal. Outlet canals discharge water 1.5 miles distant. Harvesting by nets in 12 foot shared concrete discharge silos simplifies operations.
The unique features, advantages and problems of working this site are discussed thoroughly.
148. INTENSIVE PENAEUS MONODON CULTURE ON THE ISLAND OF NEGROS, PHILIPPINES:A COMPARATIVE ANALYSIS OF PRODUCTION ECONOMICS AND CULTURE TECHNIQUES.
B. Alan Stockwell* and David B.C. Williams
Agrodev Canada, Inc., 600–222 Somerset Street
West Ottawa, Ontario K2P 2G3, Canada.
In the Philippines, the cultivation of the tiger prawn, Penaeus monodon, is generally carried out in brackishwater ponds either in monoculture or in polyculture with milkfish. Traditional and extensive culture practices, involving low pond stocking densities, no supplemental feeding and limited water management, have and continue to be the most widely used methods of prawn production in the country. In recent years however, wide spread expansion of the prawn farming industry in the ASEAN region has led to the introduction of semi-intensive and intensive culture practices on a limited number of farms in the Philippines. Although other areas are involved to a limited extent, the highest concentration of semi-intensive and intensive operations is on the island of Negros in the Western Visayas.
This study first examines present day culture practices and the production economics of the prawn farming industry on Negros. Management criteria and production parameters are defined. The economics and technical aspects of prawn farming on Negros are then compared to those commonly associated with the industry in other parts of the Philippines. Data used in this study were collected over the period 1986–87 during two independent studies carried out in the Philippines, one having national scope and the other focusing specifically on the Negros prawn farming sector.
149. FURTHER STUDIES OF DENSITY EFFECTS IN INTENSIVE POND CULTURE OF PERAEUS VANNAMEI.
Alvin D. Strokes*, Paul A. Sandifer, J. Stephen Hopkins and Robert A. Smiley, Waddell Mariculture Research and Development Center, P.O. Box 809, Bluffton, South Carolina 29910.
Pond grow-out studies have been conducted to examine the intensive culture potential of Penaeus vannamei in South Carolina since 1985. In May 1987, an experiment was initiated to evaluate the effect of density on the growth and survival of P. vannamei reared in intensive grow-out ponds.
Hatchery reared postlarvae were stocked in nine .25 ha ponds at three densities:20, 40 and 60 shrimp/m2. Each pond was equipped with two paddle-wheel aerators (8 hp/ha) and water was exchanged at an average rate of 9%/pond/day. The shrimp were fed a 40%' protein diet twice each day during the study and water quality parameters were monitored daily. Estimates of growth were made by seine samples, which were conducted at 14 day intervals. By grow-out day 154, the shrimp stocked at 20, 40 and 60/m2 had reached mean weights of 12.8, 12.3 and 11.2 grams, respectively. At that time, there appeared to be no significant effect on density on the growth rate of the shrimp.
150. COMPARISON OF LIVE AND ARTIFICIAL DIETS FOR REARING THE LARVAE OF PENAEUS VANNAMEI IN A SMALL-SCALE EXPERIMENTAL SYSTEM.
Kenneth C. Stuck*, John T. Ogle and Adeline A. Barrett
Gulf Coast Research Laboratory, Ocean Springs
MS 39564 USA.
A series of larval diet studies was conducted with a small-scale rearing system utilizing 1-liter Imhoff settling cones. Each cone was initially stocked with 100 stage I protozoeae of Penaeus vannamei and maintained for 11 days. Upon termination of each experiment, growth parameters such as dry weights, survival and stage of development were determined for larvae reared on each diet. Larvae were reared using 10 combinations of live foods including nematodes, rotifers, brine shrimp and diatoms. There were significant differences in growth between larvae reared on the various diets. It was found that larvae of P. vannamei can be reared from protozoea I through postlarva solely on nematodes and rotifers; however, these larvae had lower survival, lower weight gains and retarded development compared to larvae reared on diets including diatoms and brine shrimp. Best growth was always obtained with diets which included brine shrimp. The greatest weight gains were obtained with a diet which included a combination of diatoms, nematodes and brine shrimp. The highest survival was obtained with a diet consisting only of diatoms and brine shrimp. Larvae reared on live diets were also compared with larvae reared on three commercially available artificial feeds. Although these artificial diets can be used as a partial or total replacement for diatoms, the supplemental use of brine shrimp is required to obtain good growth.
151. FEEDING REGIMES FOR ENHANCED PENAEUS VANNAMEI PRODUCTION IN INTENSIVE NURSERY RACEWAYS.
Leslie N. Stunner* and Addison A. Lawrence
Shrimp Mariculture Project, Texas Agricultural Experiment Station,
Texas A&M University System
4301 Waldron Road, Corpus Christi, Texas 78418.
The potential of enclosed nursery systems for “headstarting” penaeid postlarvae in temperate climates has been demonstrated in 65 m2 raceways. Several feeding experiments were conducted in 1987 to further evaluate these intensive systems and to enhance Penaeus vannamei juvenile production. The effects of continuous feeding, accomplished by six automatic feeders per raceway, versus interval feeding on shrimp growth and survival were compared at stocking densities of 3,000 and 6,000/m2 for 45 and 30 days, respectively. Supplementation of the dry diet (50% crude protein) with Artemia nauplii was also tested in replicated raceways at the lower stocking density for 30 days.
Shrimp growth and survival were not significantly influenced by the continuous or interval feeding regimes at either density. A 0.85 g juvenile (overall mean harvest weight) was produced at a harvest density of 1,668/m2, whereas a 0.59 g juvenile was produced at a harvest density of 3,324/m2. Corresponding harvest yields were 1,418 and 1,960 g/m2 for the low and high densities, respectively. Artemia supplementation also did not affect P. vannamei production. Overall mean harvest weight and survival were 0.71 g and 70%, respectively for the 30-day nursery period.
These results coupled with low feed conversion ratios (0.9 to 1.2:1) obtained in each feeding experiment, implied utilization of the high natural productivity associated with artificial habitats installed in the raceways (240 m2 of substrate area per raceway). The contribution of these “fouling” communities to P. vannamei production, determined by stable carbon isotope analysis is discussed.
152. SALINITY EFFECTS ON PENAEUS VANNAMEI PRODUCTION IN NURSERY AND GROW-OUT PONDS.
Leslie N. Stunner* and Addison A. Lawrence
Shrimp Mariculture Project, Texas Agricultural Experiment Station,
Texas A&M University
4301 Waldron Road, Corpus Christi, Texas 78418.
The effects of two salinity levels, ambient (35–40 ppt) versus a differential of 12–15 ppt maintained by freshwater dilution, were evaluated on Penaeus vannamei production in both nursery and grow-out phases. Four trials were conducted in 1987 to test these treatments in replicated, 0.1-ha earthen ponds:1) postlarvae nursed for 32 days in spring at a stocking density of 250/m2; 2) a 26-day nursery period in mid-summer stocked at 225 PL/m2; 3) juveniles (mean weight = 0.6 g) stocked at 10/m2 for 63 days in the summer; and 4) a 70-day grow-out period in fall stocked at 12.5 juveniles/m2.
Neither survival rates nor harvest weights were significantly influenced by salinity levels in Trial 1, with respective means (overall) of 60% and 0.74 g obtained. During Trial 2, a significant difference (P<0.05) in sur-vival suggested a possible temperature interaction as mean water temperatures increased from 27°C in the first nursery period to 30°C in the second. Differ-ences in growth (overall harvest weight mean = 0.67 g) were not detected. These trends were repeated in the grow-out trials, indicating that the combination of high salinity and high temperature was not favorable for P. vannamei production.
Differences in other water quality parameters (particularly dissolved oxygen levels), primary productivity (measured by chlorophyll a, b and c concentrations) , and secondary productivity (polychaete populations), which may have further influenced these results are discussed.
153. UNEXPECTED RAPID DESTRUCTION OF SPERM IN CAPTIVE PENAEID SHRIMP.
P. Talbot, D. Howard, T. Lee, W.- Li and H. Ro
Department of Biology, University of California
Riverside, CA.
J. Trujillo and A. Lawrence, Texas A&M University
Corpus Christi, TX 78418.
Male penaeids typically become infertile in captivity. Experiments were conducted to examine the condition of the penaeid reproductive tract as a function of time in captivity. Penaeus setiferus sourced off Corpus Christi were introduced on day 1 into laboratory tanks. At 35 and 48 days after capture, the reproductive tracts of 5 males were compared microscopically to those of day 1 males. The ampoules at both 35 and 48 days lacked turgidity were slightly brown and in general contained little secretory product. Experimental spermatophores exhibited darkening and progressive loss of the wing. The sperm cap which forms a hemicylinder around the sperm mass of the day 1 spermatophore was partially resorbed by day 35 and missing by day 48. The sperm mass of the spermatophore contained numerous bacteria by day 48. Only the glutinous mass of the spermatophore appeared normal at both experimental time points. The vas deferens in most males at 35 and 48 days appeared normal with the dissecting microscope. However, when examined with phase contrast microscopy, the sperm from segment 2B of 48 day males were grossly distorted and the sperm mass contained numerous bacteria. These observations establish that bacteria proliferate in the sperm mass of captive male shrimp and that destruction of penaeid sperm is occurring in regions of the vas deferens that appear normal with the dissecting microscope. Thus, captive males become infertile prior to what would be expected based on external morphology of the vas deferens.
154. THE EFFECT OF VARIOUS COMMERCIAL ARTIFICIAL SEASALTS ON THE GROWTH OF PENAEUS VANNAMEI.
Scott E. Talley*, Linda L. Smith and Addison L. Lawrence
Shrimp Mariculture Project, Texas Agricultural Experiment Station,
Texas A&M University System,
P.O. Drawer Q Port Aransas, Texas 78373.
Eight brands of artificial seasalt mixtures were evaluated with Hawaiian Marine, the standard artificial seawater used in the rearing of penaeid larvae in the experimental Imhoff cone system. Twenty-four hours prior to use, the nine artificial seasalt mixtures were mixed using deionized water and 1 ppm EDTA to a salinity of 30 ppt. Penaeus vannamei larvae were acclimatized as nauplii to the nine mixtures and stocked into the cone system during the first protozoeal substage. All treatments were fed algae (100,000 cells/ml Chaetoceros gracilis and 30,000 cells/ml Tetraselmis chuii) from the nauplius substage; Artemia was added from the third protozoeal substage. The experiment was terminated when at least 90% of the larvae in the Hawaiin Marine control metamorphosed into the PL1 substage. Percent survival, percent metamorphosis and dry weight/PLl were determined.
Mean survival among the nine brands ranged from 85% to 93%, Metamorphosis (62–95%) and dry weight/PLl (99.6–134.6μg/PLl) varied significantly among the nine brands. Tropic Marin, Sera and Ocean 50 can be used as replacements for Hawaiian Marine without deleterious effects upon survival, metamorphosis and growth to the PL1 substage. The other brands (particularly Marine Environment, Forty Fathoms and Instant Ocean), either due to technical problems such as incomplete dissolution of salt components or poor larval response in comparison to Hawaiian Marine were found to be less suited for penaeid larviculture research.
155. STEROID PROFILES OF NATURAL AND ACCELERATED MATURATION IN FEMALE MULLET (MUGIL CEPHALUS).
C.S. Tamaru*, C.D. Kelley and C.S. Lee
Oceanic Institute, Makapuu Point
Waimanalo, HI 96795 USA.
K. Aida and I. Hanyu
Laboratory of Fish Physiology, Faculty of Agriculture
University of Tokyo, Bunkyo, Tokyo, Japan.
Ten females were subjected to chronic LHRH-a plus testosterone treatment. Therapy was initiated (Nov. 1986) at the onset of vitellogenesis as scored by ovarian biopsy. Average egg diameters, serum estradiol-178 and testosterone were monitored until March 1987. Twenty control individuals were monitored in the same way from September 1986 through March 1987.
When therapy was initiated females possessed eggs that averaged 220 ± 42 μm. The treated individuals exhibited an acceleration in the rate of egg growth. After 22 days of therapy, average egg diameters of 490 ± 122μm were obtained in the treated group versus 304 ± 52 μm in the placebo group.
Steroid profiles of treated females also reflect the acceleration of ovarian maturation. Peaks in serum E2 and testosterone were observed a month prior to the control group's peak. The E2 levels found in treated fish are significantly lower than the control fish when compared at the same stage of maturation. No difference can be observed in testosterone values.
Three of the treated fish were induced to spawn in December. They then rematured and were spawned a second time by March 1987. This is a significant achievement because this species is considered an annual spawner.
156. USE OF DRIED TETRASELMIS CHUII AS BOTH A COMPLETE AND PARTIAL REPLACEMENT FOR LIVE ALGAE IN THE FEEDING REGIME OF LARVAL PENAEUS VANNAMEI.
Tamara K. Thomsen*, Linda L. Smith, James M. Biedendach and Addison L. Lawrence, Shrimp Mariculture Project
Texas Agricultural Experiment, Texas A&M University System
P.O. Drawer Q, Port Aransas, TX 78373.
Spray dried Tetraselmis chuii was examined as both a complete (100%) and a partial (33% and 67%) replacement for live algae fed to Penaeus vannamei larvae (N5 to PL). The two live algae regimes were 130,000 cells/ml Tetraselmis chuii and a combination of 100,000 cells/ml Chaetoceros gracilis + 30,000 cells/ml T. chuii. The live algae was grown under unialgal (non-axenic) batch conditions in natural seawater enriched with Guillard's f/2 strength nutrients. Experimentation was conducted in the Imhoff cone system at a stocking density of 100 larvae/liter.
Final survival and dry weight of larvae fed 100% dried T. chuii was equal to that of larvae fed either of the two live algae regimes. Rate of metamorphosis of larvae fed the dried algae was significantly slower than that of larvae fed the live algae, but only by a matter of hours.
Replacing 33% of the live C. gracilis + T. chuii regime (on a cell number basis) with dried T. chuii increased the metamorphic rate of Penaeus vannamei but did not significantly improve growth. A 67% replacement significantly improved both growth and metamorphic rates over that of the 100% live combination regime and equalled that obtained with the 100% live T. chuii regime.
The use of dried algae in the larval feeding regime offers several practical advantages over that of live algae. This particular dried algal product has excellent potential for use in penaeid larviculture.
157. SEX-REVERSAL OF OREOCHROMIS AUREAUS WITH MIBOLERONE, A NEW SYNTHETIC STEROID, USING BOTH IMMERSION AND FEED TREATMENTS.
Les Torrans*, Department of Agriculture
University of Arkansas at Pine Bluff
Pine Bluff, AR 71600 USA.
Frank Meriwether, Water Center
Tennessee Tech University
Cookeville, TN 38505 USA.
Fran Lowell, L.W. Baruch Institute for Marine Biology and
Coastal Research, University of South Carolina
Columbia, SC 29208 USA.
Bill Wyatt, Department of Chemistry
Arkansas State University
State University, AR 72467 USA.
Mibolerone (MI), a new synthetic steroid was used to sex-reserve undifferentiated Oreochromis aureus fry. Fry were exposed to 0.0 ppm, 0.3 ppm, 0.6 ppm or 1.0 ppm MI in static-water solutions for five weeks (immersion treatments), or were fed a diet containing 1.0 ppm MI for four weeks in a flow-through system. After hormonal treatments, the fish were grown to 60 mm minimum total length prior to sex determination using gonadal squash examination of 50 fish per treatment replication. Data were also collected on the MI concentrations in immersion-treated fish and on the loss of MI from static-water systems.
Fish exposed to 1.0 ppm, 0.6 ppm or 0.3 ppm MI had average tissue MI concentrations of 14.3 ppm, 5.6 ppm and 3.3 ppm, respectively over the five weeks immersion treatment. Exposure to 1.0 ppm or 0.6 ppm MI for five weeks resulted in an average of 82% males and 18% ovo-testicular fish (non-functional females), with no functional females being produced. Exposure to 0.3 ppm resulted in 78.7% males, 20.7% ovo-testicular fish, and 0.7% females. Control treatments approximated a 50:50 male:female sex ratio. Fry growth and survival was reduced in all MI immersion treatments. Feeding a diet containing 1.0 ppm MI resulted in 85% males, 11% ovo-testicular fish and 4% females.
The MI concentration in aerated static-water without fish present was reduced by 42% after seven days, while the MI concentration in aerated static-water of aquaria stocked with fish was reduced by 67% over the same time period. These results indicate that substantial bio-degradation of MI occurred, since the amount of MI loss from the water was approximately five times greater than was previously found as residue in fish tissues in the immersion treatment study after a comparable exposure.
Exposing tilapia fry to static-water solutions of 0.6 ppm MI for five weeks appears to be a feasible method of eliminating the production of functional females. Immersion solutions should be changed weekly to maintain an effective hormone concentration.
158. ORGAN CULTURE ASSAY OF THE EFFECTS OF PUTATIVE REPRODUCTIVE HORMONES ON IMMATURE PENAEUS VANNAMEI OVARIES.
Brian Tsukimura and Fred I. Kamemoto
University of Hawaii at Manoa
Department of Zoology, Edmondson Hall
2538 The Mall, Honolulu, Hawaii 96822 USA.
The vertebrate-type steroid hormones, progesterone, 17a-hydroxyprogesterone (17-OHP) and estradiol-17b (E2) and insect juvenile hormone III (JHIII) were assayed to determine the effects on oocyte growth of Penaeus vannamei. Immature ovarian pieces (2–4 mm) were cultured in 600 μl Medium 199, with salt concentrations adjusted to Homarus saline, plus 100 μl hormone solution. The steroids and terpenoid were dissolved in 100% EtOH to produce 7.0 mM solution, which was then serially diluted with saline to produce concentrations of 700 nM, 70 nM, 7 nM, 700 pM, 70 pM and 7 pM hormone solutions. Controls received 100 μl saline. Samples assaying EtOH in saline (1:10,000) showed no significant difference from controls. Tissues were fixed in Kahle's solution, dehydrated in an EtOH/butanol mixture, embedded in paraplast-plus and stained with hematoxylin and eosin. Twenty oocytes were measured for each animal at each concentration for each 24 hour period. When compared to controls, 17-OHP and JHIII caused highly significant increases in oocyte diameter after 24 hours of culture. Progesterone and E2 did not produce any significant effects on cell diameter.
159. SELECTION IN THAI OREOCHROMIS NILOTICUS; CORRELATED RESPONSE BETWEEN AGE AND SIZE AT MATURATION AND JUVENILE GROWTH.
Supattra Uraiwan1 and Roger W. Doyle2 1
1National Inland Fisheries Institute, Kasetsart
University Campus, Bangkhen, Bangkok 10900, Thailand.
2Department of Biology, Dalhousie University
Halifax, Nova Scotia B3H 4J1, Canada.
Two generations of divergent selection for age at maturity of Oreochromis niloticus were studied at the National Inland Fisheries Institute (NIFI) and Bangsai, Thailand. The study indirectly resulted in a genetic growth gain. The early-maturity selected line was significantly larger and grew faster than the late-maturity selected line (size 19–26% larger and growth 5–9% faster). Phenotypic correlation coefficients between age and size at maturity range between 0.5 to 0.9. Juvenile growth rates of the selected and unselected lines were also compared. There were no differences in pre-maturity growth rates between the selected and unselected lines.
160. EFFECTS OF VARYING STOCKING DENSITIES OF MACROBRACHIUM ROSENBERGII IN A POLYCULTURE SYSTEM WITH TILAPIA NILOTICA
Joseph C. Emmer Valentin,
P.O. Box 1218
Sabana Grande, P.R. 00747.
Dallas Alston*, Ph.D., Universidad de P.R.-RUM
Department of Marine Sciences, Mayaguez, P.R. 00708.
Tilapia nilotica were stocked at a rate of 6 000/ha with three different densities of Macrobrachium rosenbergii nursed post-larvae (15, 30, 45 thousand/ha). A seven day feeding regime was used for a grow-out period of 180 days. The prawns were not fed intentionally during the course of the study and the fish were fed with 32% protein sinking pellets at a rate adjusted to the average weight of the fish and divided into two equal portions per day. Tilapia fingerlings averaged 34 g at stocking and 524 g at harvest. Postlarvae averaged 0.03 g at stocking and 26.4 g at harvest. Fish yield averaged 2 612 kg/ha and 86% survival. Prawn yield averaged 587 kg/ha and 84% survival. Results showed that the growth and survival of fish were independent of prawn stocking densities (P<0.05). Prawns were influenced by their own stocking rate. Individual prawn growth weights and stocking densities are negative correlated while yield is positively correlated (P<0.05) with stocking densities. Survival of the prawns was different (P0.05) with the three treatments used in this experiment. Survival was 91% at the low stocking rate and 74% at the higher stocking rate. Fish attained an average weight of 450 g around day 155; a higher stocking density for the fish could have been employed.
161. STUDIES OF OFF-FLAVOR IN AQUACULTURE:GEOSMIN PRODUCTION BY BLUE-GREEN ALGAE.
Martine van der Ploeg* and Claude E. Boyd
Department of Fisheries and Allied Aquacultures
Swingle Hall, Auburn University, AL 36849.
Geosmin concentration and phytoplankton were monitored in 43 ponds that received either feed or fertilizer. Ponds were located at the Auburn University Research Unit and sampled from April to October in 1986 and 1987. Six ponds were sampled over a period of 4 to 8 weeks to describe geosmin production dynamics. In all ponds geosmin could be detected; concentrations ranged from less than 0.05 μg/l to lO.O μg/1. Twenty ponds were dominated by Microcystis blooms and had geosmin concentrations lower than 0.05 μg/l, except for one pond with 0.8 μg/l. The ponds containing Soirulina had 2.5 μg/l geosmin. From five ponds with Aphanizomenon blooms only one pond had a geosmin concentration higher than 0.2 μg/1, i.c. 9.8 μg/l. Geosmin concentrations were high (2.9 to 10.0 μg/l) in ponds where Anabaena variabilis was abundant, but lower (less than 0.05 μg/l to 0.3 μg/l) in ponds with other Anabaena species.
Comparison of geosmin concentrations of raw and cell free water showed that 90 to 99% of the geosmin is contained in the algal cells. When the geosmin producing algae are abundant, the geosmin concentration is correlated with the chlorophyll a content of the water.
162. TEMPERATURE AND SALINITY EFFECTS ON METAMORPHOSIS AND SURVIVAL OF PENAEUS STYLIROSTRIS NAUPLII.
Daniel F. Villamar*, Addison L. Lawrence and William Neill
Shrimp Mariculture Project, Texas Agricultural Experiment Station, Texas A&M University System, P.O. Drawer Q Port Aransas, TX 78373.
Effects of temperature, salinity and temperature-salinity interactions on Penaeus stylirostris naupliar survival and metamorphosis were evaluated. Newly hatched nauplii from three different maternal shrimp were exposed to three temperature and five salinity levels, 23°C, 28°C, 33°C and 23 ppt, 28 ppt, 33 ppt, 38 ppt, 43 ppt, respectively. Survival and metamorphic rates of nauplii to protozoea were determined by microscopic examination of each individual larva at 24 h, 48 h, 72 h and 96 h. Results were analyzed by ANOVA.
Differences in mean percent survival and metamorphosis among temperature and. salinity levels were highly significant (P = .0001). Metamorphosis was a more sensitive measure of temperature and salinity preference than survival. Greatest percent metamorphosis was 96% at 28°C and 33 ppt with 100% survival. Salinities below and above 33 ppt at 28°C yielded lower rates of survival and metamorphosis. Temperature and salinity interactions with respect to larviculture production and pelagic larval ecology are discussed.
163. CONSTRAINTS ON THE USE OF AQUACULTURE FEEDS IN DEVELOPING COUNTRIES WITH SPECIAL REFERENCE TO AFRICA.
Michael M.J. Vincke and Michael B. New
Aquaculture Development and Coordination Programme Fisheries Department, FAO, 00100 Rome, Italy.
After providing background information on the current and potential scale of aquaculture in the developing world and the production techniques utilized there, constraints on the use of feed are examined. Examples of results from the use of simple feeding strategies in Africa are provided and the needs for applied research and development in the manufacture and use of supplemental feeds are identified.
164. SHRIMP FORAGING EFFECTS UPON MICROBIAL COMMUNITIES IN EXPERIMENTAL MICROCOSMS.
Pieter, T. Visscher, Kenneth M. Leber and Shaun Moss The Oceanic Institute, Makapuu Point
Waimanalo, HI 96795 USA.
Foraging effects of Penaeus vannamei were experimentally examined in 30-gallon round flow-through microcosm tanks containing grow-out pond water, well water and sediments. Shrimp were stocked at a density level of 50 animals/m2. We manipulated:1) feed availability (presence or absence of a Taiwanese feed), 2) feeding frequency, 3) water source, and 4) grazing pressure from P. vannamei. Natural prey densities and prey colonization rates in sediments and in the water column were then monitored. Effects of shrimp predation on microbes and meiofauna were intense. Availability of commercial feed greatly affected rates of shrimp predation on microbial and meiofaunal prey. These experiments suggest that even under intensive grow-out conditions, natural productivity in pond water has tremendous impact on p. vannamei growth rates.
165. PROCESS AUTOMATIZATION IN AQUACULTURE:REALITY OR UTOPIA?
J. Volkel and J. Wens*
Aquatek, Biotechnical Engineering Department
Schlúterstr. 39, D-1000 Berlin 12, West Germany.
In order to remain economically feasible aquaculture in tropical countries has usually had to minimize on technology out of pure necessity. The need for pure and heated waters in great quantities for special aquaculture systems such hatcheries, recirculated water systems or intensive rearing units in moderate regions, where water is very precious, often leads to the question of whether process technology in aquaculture may be a practical undertaking.
When our project began in 1983, we had to cope with an inadequate measurement technology, notably lacking in “on-line” electrodes for oxygen monitoring' (probably the most important parameter for determining water quality). There were also no appropriate electrodes for detecting nitrogen containing substances, such as ammoniac, ammonia, nitrate and nitrite. At that time, measurement technology and the relatively high prices for computers hindered the introduction of process automatization in aquaculture outside our laboratory. Nevertheless, we were still able to monitor most of the essential water quality parameters accurately and to use them for process regulation. Since specialized manpower can be well economized and insurance fees kept substantially low, the introduction of automatic measurement and control systems became a possibility even in the days of low technology aquaculture facilities.
We developed a computerized modular monitor and regulation system in our department designed to meet the needs of the aquaculture industry. The process controller registers data from various sources and offers appropriate alarms capable of monitoring water quality, external environment, equipment control, feeding schemes and production planning. In the event of operational problems in aquaculture facilities, it is possible to pinpoint errors and introduce appropriate corrective measures to effectively counteract these irregularities .
In particular we could monitor retrospectively in order to systematically analyze the chain of events and thereby enable correct future adjustments. Changes in the input parameters can be simulated and transferred to the process.
The development promotes a scheme with which critical levels of various water parameters may be avoided, employing automated adaption of the feeding regime and of the overall management procedures.
166. TROPHIC STATUS OF POND AQUACULTURE SYSTEMS:MASS BALANCE EVIDENCED FOR NET ORGANIC MATTER PRODUCTION IN SITU.
Richard S. Weisburd*, Edward A. Laws and Stephen V. Smith Department of Oceanography, University of Hawaii at Manoa 1000 Pope Road, Honolulu, HI 96822 USA.
Aquaculture ponds which receive large allochthonous organic inputs (feed) might be expected to be net consumers of organic matter. This hypothesis has been tested in a semi-extensive Macrobrachium rosenbergii pond for eight days and in four semi-intensive Penaeus vannamei ponds for two months. Mass balances for carbon have been constructed in order to quantify the trophic status of these systems. The ponds were sampled hourly with data loggers for pH and water temperature. Alkalinity and salinity were sampled at least weekly. The concentration and distribution of dissolved inorganic carbon (DIC) species was calculated with carbonate equilibrium equations for every hour during the deployments. CO2 partial pressures and climatic data were used to estimate CO2 transfer between the ponds and the atmosphere. DIC fluxes due to water inflow and seepage were calculated. Mass balances indicated that some of the sampled ponds were net consumers of CO2 during the investigation. Since the concentration of DIC in the water did not increase substantially during the study periods, inputs of inorganic carbon to these systems must be accounted for by autotfophic carbon fixation.
167. INFLUENCE OF BIOLOGICAL AND ENVIRONMENTAL FACTORS ON SHRIMP FOND PRODUCTION AS PREDICTED BY STOCHASTIC MODEL.
John Whitson*1, Addison Lawrence1 and William Grant2 1Shrimp Mariculture Project, Texas Agricultural Experiment Station, Texas A&M University System P.O. Drawer Q, Port Aransas, TX 78373.
2Department of Wildlife and Fisheries Sciences
Texas A&M University, College Station
TX 77843.
A stochastic model of shrimp pond production is constructed based on new findings about shrimp dietary habits and present understandings of shrimp pond and other marine environments.
A baseline run of the model is discussed and a series of variations of stocking densities, feeding rates and stocking dates are examined. Attention is drawn to implications of over- and underfeeding and the effects on the planktonic and benthic ecosystems of the shrimp pond.
The behavior of the model is compared to existing data from the ponds at the Texas Agricultural Experiment Station Shrimp Mariculture Project, and its usefulness as a management tool is evaluated.
168. INDUCED SPAWNING, LARVAL CULTURE AND JUVENILE GROWTH OF PAPHLA UNDULATA (MOLLUSCA:VENERIDAE) IN THE LABORATORY.
T.M. Wong, Shamsuddin Salleh and T.G, Lim
School of Biological Sciences, Universiti Sains
Malaysia, 11800 Penang, Malaysia.
Induced spawning of Paphia undulata was studied using various techniques developed for bivalve molluscs. Injection of 0.5 ml of 2 mM/L serotonin into the food consistently induced spawning between 0.5 to 2 hours after the injection.
Mature eggs measured 61 μm in diameter. Mobile early trochophore larvae were seen after 4 hours and the straight-hinged stage reached 10–14 hours later (Shell length = 65 μm). Reared on a diet of Isochrysis sp., 2-day old D-stage veligers measured 95.0 μm in shell length. Early umbo larvae were seen by the 6th day (S.L. - 120 μm). The pediveliger appeared by the 12th day (S.L. = 232 μm). Settlement was completed by the 15th day. Mean shell length of settled spats measured 324 μm.
Juvenile growth was rapid when cultured in an upwelling system and mean shell length of 17.9 mm was reached 104 days after spawning.
The implications of these findings in the commercial culture of P. undulata are discussed.
169. SHRIMP YIELDS AND ECONOMIC POTENTIAL OF INTENSIVE ROUND POND SYSTEMS.
James A. Wyban*, J.N. Sweeney, R.A. Karma and E.S. McSweeny
Oceanic Institute, Makapuu Point
Waimanalo, HI 96795 USA.
A 337 m2 round pond system for intensive shrimp culture was designed and built in 1985. In 1986, three grow-out trials at shrimp densities of 45 shrimp/m2 were completed in the pond (Wyban and Sweeney, 1987). In 1987, two grow-out trials at shrimp densities of 100 shrimp/m2 were completed. In 1987, a commercial prototype, 2,000 m2 round ponds was designed and constructed. One grow-out trial at shrimp densities of 75/m2 was completed in the prototype. This paper summarizes the results of these six grow-out trials. Pond design and management of feeding, water quality and sedimentation are discussed. Shrimp growth rates, survival, feed conversion ratio, shrimp production and crop value are reported. Financial projections based on pond construction costs, operating costs and crop value are reviewed.
170. INDUCED OVARIAN MATURATION AND SPAWNING OF PENAEUS VANNAMEI.
Isao Yano*, Department of Medical Zoology
School of Medicine, Mie University
Tsu, Mei 514 Japan.
James A. Wyban, The Oceanic Institute
Makapuu Point, Waimanalo, HI 96795 USA.
The effect of implantation of American lobster's ganglion on ovarian maturation and spawning was investigated in Penaeus vannamei. Females with undeveloped ovaries were used for the present study. Females implanted with ganglion and males were housed in a 10 m3 tank with flowing, filtered seawater. Water temperature was 24–26°C and photoperiod was 14L:10D. Salinity ranged from 35–36%. More advanced ovarian development stages were observed in the females implanted with ganglion. Many eggs were spawned by the ganglion implanted females. These results indicate that implantation of lobster's ganglion is effective in inducing ovarian maturation and spawning in P. vannamei.
171. THE ECONOMICS OF ENGINEERING ASPECTS OF POND AQUACULTURE IN TEXAS.
M.E. Yates* and W.L. Griffin
Department of Agricultural Economics
Texas A&M University, College Station
Texas 77843 USA.
The items of capital cost involved in aquaculture pond grow-out facilities were grouped into nine categories. These are:surveying, engineering design, earthwork, road construction, piping, channels, outlet structures, pumps and aerators. The quantitative relationship of each category to the scale of the operation was calculated, based upon their intrinsic relationship. Three models were built for a 100, 200 and 1 000 acre farm, respectively, reflecting these relationships. The costs of different materials and methods of construction were introduced into the models and that which was optimal was chosen in each size category.
Comparisons were made between the capital cost per acre of the three models. Sensitivity analyses were run, showing the response of the total capital costs to changes in the component inputs. The capital cost models were integrated into an existing overall budgetary model for Texas shrimp farms. The sensitivity of the total cost of each sized unit to changes in the capital cost components was thereby ascertained.
172. ROBOT AQUA-FEEDER.
Kao Yi-Tung*, Fang Min-Ting and Hu Shun-Chih
Nan Rong Fishing Machinery Co., Ltd.
75–10, I-Chou Li, Yiang Hsuei Cheng
Tainen Hsiang, Taiwan, Republic of China.
This totally brand-new feeder has been designed and made to perform the long sought-after job of self-guiding, auto-moving, spray feed work inside the pond. It leaves the positioned 'harbor' according to scheduled timetable, cruises the entire pond 4 meters away from the edge while spray-feeding. After a cycle it enters the harbor for re-charging.
This robot feeder is now put on field test, with satisfactory results so far.
173. EFFECTS OF TEMPERATURE AND FEED RATE ON GROWTH IN
THE CHINESE CATFISH, CLARIAS FUSCUS.
Michael J.A. Young* and Arlo W. Fast
Hawaii Institute of Marine Biology
Kaneohe, HI 96744 USA.
Growth of Chinese catfish was evaluated under four temperature regimes:20, 25, 30 and 35°C. Within each temperature treatment, three feed rates:2, 4 and 6% body weight per day were tested. Fish were stocked into each temperature-feed treatment at 2 months old; approximately 1–4 grams in weight. Stocking density for each treatment was 100 fish/m2. Growth and survival was monitored biweekly for one year.
Growth was significantly depressed at 20 and 35°C, and survival poor, 54 and 0%, respectively. Maximal growth and survival was obtained at 30°C for animals between 1 and 119 grams in weight, and at 25°C for animals above 120 grams. Best overall feed conversion was obtained at the 2% feeding level at all temperatures.
PUBLICATIONS AND DOCUMENTS OF THE
ASEAN/UNDP/FAO REGIONAL SMALL-SCALE COASTAL FISHERIES DEVELOPMENT PROJECT
(RAS/84/016)
Working Papers
ASEAN/SF/86/WP/1 Rabanal, H. R. Seafarming as alternative to small-scale fishing in ASEAN region. Manila ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 1986. 55p.
ASEAN/SF/86/WP/2 Soeyanto, T. The status of Bali Strait fisheries with special reference to Muncar, Kedonganan and Jimbaran coastal villages. Manila, ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 1986. 36p.
ASEAN/SF/86/WP/3 Boongerd, S. and S. Chitrapong. Small-scale fishing for squids and related species in Thailand. Manila, ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 1986. 44p.
Workshop Reports/Other General Reports
ASEAN/SF/86/GEN/1 Report of national consultative meeting on aquaculture engineering held in Tigbauan Research Station, SEAFDEC Aquaculture Department, Iloilo City, Philippines, 2–5 October 1985. Manila, ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 1986. 186p.
ASEAN/SF/86/GEN/2 Zabala, P. T. (Comp.) Preliminary annotated bibliography on small-scale fisheries in the ASEAN Region. Manila, ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 1986. 41p.
ASEAN/SF/87/GEN/3 Report on the training course on shrimp culture held in Jepara, Indonesia, 2–22 December 1987. Manila, ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 1987. (In preparation).
ASEAN Fisheries Manuals
ASEAN/SF/86/Manual No. 1 Suprayitno, H. Manual of running water fish culture. Manila, ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 1986. 34p.
ASEAN/SF/88/Manual No. 2 Godardo L. Juanich. Manual on seaweed farming:1. Eucheuma spp. Manila, ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 1988. 25p.
Periodic Progress Reports
ASEAN/SF/86/PR-1 Soesanto, V. Project progress report of the ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 5 October 1985–5 April 1986. Manila, ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 1986. 9p.
ASEAN/SF/86/PR-2 Soesanto, V. Project progress report of the ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 6 April–6 October 1986. Manila, ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 1986. 11p.
Technical Reports Contributed to Symposia/Meetings, etc.
ASEAN/SF/85/Tech. 1 Rabanal, H. R. and V. Soesanto. The world fishery and culture of Macrobrachium and related prawn species. Contributed to the National Conference on Prawn Technology, sponsored by the Philippine Fishfarmer's Technical Assistance Foundation, Inc., Manila, Philippines, 27–28 November 1985. 16p.
ASEAN/SF/86/Tech. 2 Rabanal, H. R. and V. Soesanto. Commercial species of shrimps and prawns, their sources and export markets. Contributed to the Seminar on Quality Control in the Production, Processing and Marketing of Frozen Shrimps for Export, sponsored by Food Research Department, Food Terminal Incorporated, Taguig, Metro Manila, Philippines, 29–31 July 1986. 64p.
ASEAN/SF/86/Tech. 3 Rabanal, H.R. Status and prospects of shrimp farming in the Philippines. Contributed to the Monthly Seminar Series on Timely and Related Fisheries Issues, sponsored by the Philippine Council for Agriculture and Resources Research and Development, (PCARRD), Los Baños, Laguna, Philippines, 5 November 1986. 24p.
ASEAN/SF/87/Tech. 4 Delmendo, M, N. Fishery administration and policy in the Philippines:Past and present. Contributed to the National Conference on Fisheries Policy and Planning, Baguio City, Philippines, 16–20 March 1987. 35p.
ASEAN/SF/86/Tech. 5 Delmendo, M. N. Milkfish culture in pens:An assessment of its contribution to overall fishery production of Laguna de Bay. Paper read in the Seminar on the occasion of the Fish Conservation Week, BFAR, October 1987. 17p.
ASEAN/SF/87/Tech. 6 Delmendo, M. N. and B. H. Delmendo. Small-scale aquaculture operations in the ASEAN countries. Manila, ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 1987. 49p.
ASEAN/SF/88/Tech. 7 Rabanal, H. R. History of aquaculture. Manila, ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 1988. 13p.
ASEAN/SF/88/Tech. 8 Rabanal, H. R. and M. N. Delmendo. Organization of the aquaculture industry. Manila, ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 1988. lOp.
ASEAN/SF/88/Tech. 9 Rabanal, H. R. Report on the World Aquaculture Society, 19th Annual Conference and Exposition, Honolulu, Hawaii, U.S.A., 4–10 January 1988. Manila,, ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project, 1988. 99p.
