51. WATER QUALITY MODEL FOR SHRIMP POND MANAGEMENT.
Albert Garcia III*, Agricultural Engineering Department
Texas A&M University, College Station, TX 77843-2117.
Jeroen Verheigen, Environmental Engineering Department
Wageningen, The Netherlands.
David E. Brune, Agricultural Engineering Department Clemson University, Clemson, SC 29631.
One of the key factors in aquaculture is water quality management, the creating and maintaining of a high quality environment for the cultured animals. Within this study we developed a general algorithm describing the interrelation-ship between the different parts of the ecosystem and their influence on the water quality by using SLAM II, a Fortran based simulation language. The objec-tives of the algorithm are:1) determine which phenomena dominate the pond water quality dynamics; 2) devise management suggestions which will reliably improve or stabilize the environment quality of the pond at a reasonable cost; 3) indicate which areas require further scientific investigation based on sensitivity analysis.
52. ARGULID PARASITES OF IMPORTANCE TO INDIAN MAJOR CARPS.
Ajoy Kr, Ghost*, Maresh Chandra Dutta1 and Gobind Chandra Laha Central Inland Capture Fisheries Research Institute
Barrackpore-743101, India;
The fish lice (Argulus spp.) are probably of economic importance since heavy infestations of lice may destroy the entire fish populations in confined environment. The problem of parasitism and its attendant degeneration are among the most interesting features in the whole realm of ecology and evolution. The grade of parasitism and the resultant effects in the habits, morphology and biology of the branchiuran parasites are studied. Argulids are the most wide-spread crustacean ectoparasites of both fresh and saltwater fishes of the world. Altogether 540 fish were examined and the degree of infestation (30%) together with numerical abundance of Argulus raychoudhuriin, sp. on its hosts (540) has been highlighted. A range from 14% to 71% of Indian major carps had argulid infestation.. In lieu of host specificity, host preference by this parasite has been discussed. Statistical analysis reveals an association between host species and infestation level. The largest extents of infestation with argulid are shown by Catla catla (31.8%), Labeo rohita (40%) and Cirrhinus mrigala {12.5%). A simple correlation coefficient (r) between the rate of infestation and envi-ronmental parameters in the sampling pond was determined. It reveals that both water temperature and CO2 play positive roles while pH and dissolved oxygen play negative correlation towards increase and decrease of infestation level. To protect the fish from parasitic affliction, the manipulation of the environmental parameters may help so as to avoid the indiscriminate use of pesticides.
1 Fishery and Ecology Research Unit Department of Zoology, Calcutta University.
53. INFLUENCE OF DAILY WATER CHANGE ON MEDIUM QUALITY AND GROWTH OF PENAEUS STYLIROSTRIS IN SEMI-INTENSIVE CULTURE CONDITION IN NEW CALEDONIA.
Denis Goxe*, Station d'Aquaculture de Saint Vincent
France-Aquaculture, BP 2059, Noumea, Nouvelle Caledonie.
Three experiments were conducted to examine the effect of daily water change on the semi-intensive grow-out with P. stylirostris in the Station d'Aquaculture de Saint Vincent (a joined project between Ifremer, France-Aqua-culture and the territory of New Caledonia). Three daily water changes were applied (initially 5, 10 and 20%) in 1,000 m2 earthen ponds, stocked with 12 juveniles/m2 (initial mean weight:1.4 g).
After 129 days, final mean weights were respectively:20.8 g, 21.6 g and 23 g and extrapolated yields:4.9, 5.2 and 5.8 T/ha/year, survival rates ranging from 79 to 81%.
Daily water change has affected environmental parameters as soon as the beginning of the rearing, but growth has only been affected beyond 10 g mean weight 5% water change has induced, when the load reach 100 g/m2 , important risks of mortality (drop of oxygen level-deterioration of the soil) that needed massive water changes.
The most important daily flow (25% in final) has allowed the obtainment of the best growth, a higher yield and an easier rearing control.
54. SHRIMP FARMING IN TEXAS:CAN IT BE DONE?
W.L. Griffin* and J. Richardson, Department of Agricultural Economics, Texas A&M University, College Station, Texas 77843. A.L. Lawrence, Texas Agricultural Experiment Station and Department of Wildlife Fisheries Sciences, P.O. Drawer Q Port Aransas, Texas 78373.
Four different types of shrimp farms utilizing 655 acres of land were evaluated for the mid coast of Texas. Type I stocked postlarvae directly into grow-out ponds and produced one crop of edible shrimp per year. Type II utilized intensive nurseries and produced two crops per year. Types III and IV used large nurseries ponds and produced two and three crops per year, respectively. Investment cost ranged from $2.08 million for Type I to $2.64 million for Types III and IV. Type II farm had the greatest production level followed by Types IV, III and then I. Type IV had the greatest annual cost of production whereas Type I had the least. Types I and II had almost a 25% internal rate of return on investment before income taxes whereas Types III and IV had less than 5%.
55. THE EFFECTIVENESS OF FOUR PRIMER/RESOLVER REGIMENS OF CPH AND LHRH-A ON THE INDUCED SPAWNING OF GREY MULLET, MUGIL CEPHALUS.
P.Y. Ha*, C.S. Lee, CD. Kellye and C.S. Tamaru Oceanice Institute, Makapuu Point, Waimanolo, HI 96795 USA.
Two hormone injections (i.e. a primer and resolver) were used to induce spawning in the grey mullet, Mugil cephalus, during the 1985–1986 spawning season. Four combinations of carp pituitary homogenate (CPH) and LHRH-analogue (CPH/CPH, CPH/LHRH-a, LHRH-a/CPH, LHRL-a/LHRH-a) were tested in 41 spawning attempts. Another four fish received saline injections and served as sham controls. The effectiveness of each hormonal therapy was evaluated in terms of spawning success, fecundity, fertilization rate and the time elapsed from initial and secondary injections to spawning time.
The results demonstrate that a hormonal therapy was required for inducing mullet to spawn. No significant differences existed among the four regimens in terms of spawning success, fecundity, or the time intervals between the infections and the spawns. Multiple contrasts shoved that the CPH/CPH regimen had a signi-ficantly lower rate of fertilization compared to the other regimens being tested.
56. INTENSIVE CULTURE OF UDANG WINDU (PENAEUS MONODON FAB.) IN KARAWANG REGION.
Endjah Hamami and Loedito S. Poerbowasi, Fishery Division of the Manggala Group Company, Jalan Pemuda 720 Jakarta 13220, Indonesia.
Intensive cultures for Udang Windu (Penaeus monodon) have been conducted in the brackishwater pond at Karawang region. The Udang Windu have been cultured in various densities and conditions, to get more information to improvement for culture techniques and grow-out management, especially for Karawang region. Varied production was obtained depending on the season of the year.
57. THE RELATIONSHIP BETWEEN WATER CHEMISTRY AND GROWTH OF TILAPIA NILOTICA IN RWANDAN (CENTRAL AFRICA) FISH PONDS FERTILIZED WITH CHICKEN MANURE.
Boyd -Hanson, Department of Fisheries and Wildlife
Oregon State University, Corvallis, Oregon 97311 USA.
Felicien Rwangano, Valens Ndoreyaho, Eugene Rurangwa and
Marijke Van Sprey-Broeck, Faculty of Agronomy National
University of Rwanda, Butare, Rwanda.
Richard A. Tubb and Wayne Seim, Department of Fisheries and
Wildlife, Oregon State University, Corvallis, Oregon 97311 USA.
Water chemistry and growth of Tilapia nilotica were examined in ponds at the fish culture station of the Universitie National du Rwanda, located at an altitude of 1,700 meters (5,600 feet). Chicken manure was broadcast onto the ponds at one of three levels:125, 250 and 500 kg/ha/wk. Experiments were con-ducted for 150 day repetitions. Minimum water temperatures (surface) in the experimental ponds ranged from 17°C to 22°C during the experiment and maximum pond temperatures (surface) ranged from 25°C to 29°C.
Fish growth and net productivity were significantly higher in both repe-titions in ponds receiving the highest inputs and in those receiving the lowest levels. In the second repetition, growth averaged 0.8 g/day in the highest treatment and 0.4 g/day in the lowest; net productivity averaged 26 kg/are/yr and 12 kg/are/yr, respectively.
Total phosphorus, not filterable orthophosphate and total nitrogen levels, as well as pH, and chlorophyll a, were significantly higher in ponds receiving the highest inputs.
58. VITAMIN REQUIREMENTS OF FRESHWATER PRAWNS, MACROBRACHIUM ROSENBERGII.
John M. Heinen, Department of Wildlife and Fisheries
P.O. Drawer LW, Mississippi State, MS 39762.
Postlarval Macrobrachium rosenbergii were reared on purified diets for 12 weeks in individual cages. Deletion of fat-soluble vitamins did not signi-ficantly affect growth rates. Deletion of trace minerals significantly reduced growth rates, but the effect was small. Deletion of water-soluble vitamins caused great mortality. Ten water-soluble vitamins were individually deleted in subsequent experiments and deletion of vitamin C was found to be responsible for the mortality. Other symptoms of vitamin C deficiency were a somewhat higher incidence of small subcuticular black or dark brown lesions, molting of only the abdomen (or only the posterior part of it) for prawns dying while trying to molt, and the presence of subcuticular blotches in the rostrums and in other parts of non-molting animals, these blotches usually being white in living animals and brown in dead ones. Deletion of pyridoxine was found to significantly reduce growth rates. Deletion of riboflavin significantly increased growth rates, indicating that riboflavin was present at a detrimentally high level.
59. GIANT CLAM CULTIVATION IN THE PACIFIC ISLANDS.
Gerald A. Heslinga, Thomas C. Watson and Theofanes Isamu
Micronesian Mariculture Demonstration Center, P.O. Box 359
Koror, Republic of Palau 96940.
Giant tridacnid clams were historically an important seafood in the Pacific Islands, but in many areas natural stocks have been reduced to biolo-gical or economic extinction by subsistence and commercial harvesting. During the past five years the Pacific Fisheries Development Foundation (NMFS/NOAA), the US Department of the Interior, the UN/FAO and other international agencies have funded a giant clam research and development program based at the MMDC laboratory in Palau.
The MMDC has pioneered the development of a low-cost, low-technology system for giant clam spawning larval culture, juvenile culture and grow-out in shallow coral reef waters. Clam growth rates under cultivation have been shown to be relatively rapid, even in the absence of food or fertilizer inputs. Techniques have been developed for control of pests, predators and algal fouling. The use of direct-drive diesel pumps has eliminated dependence on municipal power grids, formerly a serious constraint in Micronesia.
MMDC personnel have raised six of the seven tridacnid species, producing over one million seed clams and some 75,000 pounds of biomass. Several Tridacna derasa cohorts have been raised to full sexual maturity at age five years and production of second-generation cohorts is now practiced routinely, giving inde-pendence from wild broodstock. Techniques have been developed for air-freighting seed clams abroad, and to date more than 45 international shipments have been made. In 1987, revenues from sales of seed clams at the MMDC were invested in reconstruction of the hatchery, doubling its size and production capacity.
Low-technology methods for giant clam hatchery culture and grow-out are now being transferred with demonstrable success, to a number of other countries in the region. Some 12 nations or nation-states in the tropical Pacific have undertaken personnel training and stock enhancement programs using seed clams produced and marketed by the MMDC. Ocean-based cultivation of giant clams is proving to be technically and socially feasible in some very remote Pacific Island settings, where other kinds of marine and terrestrial farming are clearly impractical.
60. SEEDLING PRODUCTION OF PRAWN PENAEUS JAPONICUS FOR RELEASING CONDUCTED BY FISHERMEN'S COOPERATIVE.
Hachiro Hirata*, Faculty of Fisheries, Kagoshima University Shimoarata 4, Kagoshima, 890 Japan.
Seedling production of prawn Penaeus japonicus has been rapidly developed during the last 20 years. Now fishermen's cooperative produce the larvae in their own hatchery and release them to their section of the sea. One of the typical examples of such system is the Yatsushiro Fishermen's Cooperative Asso-ciation located in the Yatsushiro Bay, Kumarooto Prefecture, southern Japan. They have 10 concrete tanks (about 1,000 m3 in total volume) in the hatchery. Annual seedling production is about 7 or 8 million prawn juveniles. All of them have been released for propagating the prawn resources in the natural waters.
In this paper, the seedling techniques in the hatchery and methods of the releasing are introduced. During the last five years, statistic analyses of prawn catching are also discussed.
61. OPTIMAL HARVESTING AGE OF CULTURED MARINE SHRIMP.
Eithan Hochman, The Monaster Center for Economic Research
Ben-Gurion University of the Negev, P.O. Box 653
Beer-Sheva 84105, Israel.
Pingsun Leung, Department of Agricultural and Resource
Economics, University of Hawaii at Manoa
Honolulu, Hawaii, 96822 USA.
Larry Rowland, Applied Analysis, Inc., P.O. Box 7232
Honolulu, Hawaii 96821 USA.
Jim Wyban, Oceanic Institute, Makapuu Point
Waimanalo, Hawaii 96795 USA.
A dynamic decision model is developed to determine the optimal harvesting policy of a shrimp-producing firm. The model incorporates uncertainty in market price and biological growth of shrimp. It also takes into account the effect of seasonality in both price and growth. It provides a set of cut-off prices, weights and revenues as simple managerial decision rules. Results of applying the model using the Oceanic Institute's experimental round pond data and also a commercial shrimp farm in Hawaii will be discussed.
62. ECONOMIC PROGRAMMING MODEL FOR OPTIMAL INTENSIFICATION OF AQUACULTURAL PRODUCTION SYSTEMS.
Douglas G. Holland*, L. Upton Hatch and David R. Bayne
Department of Fisheries and Allied Aquacultures and
Department of Agricultural Economics, Auburn University
Alabama 36849 USA.
Aquacultural farm managers face critical decisions on the appropriate level of intensification. An economic programming model was developed to demonstrate the impact of resource endowments, market situations and biological parameters on intensification decisions. Optimal intensification will vary based on the producer's physical and market environment. By varying critical factors in the “environment”, the model indicates changes in the production system that will result. Penaeid shrimp production is used to demonstrate the models' capabili-ties.
Alternative production intensifications ranged from extensive systems based on natural carrying capacity to intensive pond systems. Use of extensive systems is limited by the availability of unique physical endowments including intertidal land, wild fry and water quality. As these limitations increase, production systems must be based on greater intensification with use of nutrient inputs, higher stocking, and controlled water exchange. Further intensification involves increased rates of input use and the additional inputs of aeration and greater technical skills. The most intensive systems included in this study were restricted to ponds that did not utilize controlled environment aqua-cultural techniques.
Resource endowment effects investigated in the model include land, seed, nutrients and technical skills. Availability of intertidal land, wild or hatchery post-larvae, local feedstuffs, formulated feeds and management expertise are important factors in intensification decisions. Market situation effects investigated are prices of land, seed, feed and shrimp. Results of the model will indicate the operator's appropriate reaction to changes in relative prices among inputs and outputs. Biological parameters investigated include feed conversion and survival. These production coefficients may vary substantially as a result of lack of research data or the individual operator's inability to achieve research production levels.
The model can be expanded to address other effects dependent on the critical factors in the environment faced by the decision maker. Thus, the model will be useful to farm managers and planners who can adjust its para-meters to address their individual circumstances and critical concerns.
63. INDUCED MATURATION OF POND-REARED ABLATED PENAEUS MONODON.
J. Honculada-Primavera*, R. Aviola-Posadas and Rosemarie Caballero, Southeast Asian Fisheries Development Center Aquaculture Department, P.O. Box 256, Iloilo City Philippines.
The effect of tank color and eyestalk tags on reproduction of ablated pond-reared Penaeus monodon in a 12 m3 circular flowthrough tank was tested. In the first experiment, 8-mo-old (9 mo from spawning) females in the black painted tank gave higher nauplii production (6.3 x 106) and hatch rates (54.0%) than in unpainted tanks (1.4 to 3.5 x 106 nauplii, 22.8 to 51.7% hatching). In the second study using 6-mo-old broodstock, the painted tanks gave higher nauplii production but not hatch rates. Average larval production per tank was lower (1.1 to 2.3 x 106 nauplii) compared to the first study. In both experiments, tagging of the (unablated) eyestalk did not appear to affect mating behavior and fertilization rates. Average daily number of spawns, hatch rates, eggs and nauplii produced per tank over a 12-week period are given.
64. IMPACTS OF INTENSIVE SHRIMP PRODUCTION ON THE CULTURE POND ECOSYSTEM.
J. Stephen Hopkins, May L. Baird, Oscar G. Grados, Philip P. Maier, Paul A. Sandifer and Alvin D. Stokes, Waddell Mariculture Center, P.O. Box 136, Bluffton, South Carolina 29910 USA.
Pacific white shrimp, Penaeus vannamei, were cultured in three replicate 0.25 ha ponds at each of three densities, 20, 40 and 60 shrimp/m2. The ponds were continuously aerated and water was exchanged at a rate which generally increased over the production cycle. Instantaneous aeration and water exchange rates were similar for all ponds. Various aspects of the pond water chemistry and biota were monitored over the course of the production cycle. Comparisons are made between and within density treatments. Spatial differences within ponds were determined for the various parameters. Both long term and diurnal temporal differences within ponds were also determined. The primary parameters measured were temperature, salinity, dissolved oxygen, biochemical oxygen demand, ammonia, nitrite, phosphate, turbidity, hydrogen sulfide, pH, chloro-phyll-a, primary productivity, phytoplankton species composition, zooplankton concentration and species composition, coliform bacteria, benthos density and species composition. In addition, shrimp growth was regularly monitored.
Correlations were noted between shrimp density and the level of dissolved oxygen, nutrients, BOD, chlorophyll-a, primary productivity and various aspects of the biota. Long term temporal differences were noted for these parameters as well. As supplemental aeration was begun, spatial differences within ponds disappeared as a result of the rapid mixing of the water column. Diurnal fluc-tuations were noted in the dissolved oxygen, pH, and chlorophyll-a. Chlorophyll-a levels dropped rapidly at dusk and rose rapidly in the morning while levels were nearly stable through the night and through midday. The benthic population, primarily polychaetes and the aquatic insect population was high early in the production cycle, yet disappeared abruptly after several weeks.
65. THE EFFECT OF SALINITY ON GROWTH OF OREOCHROMIS AUREUS.
Chi-Ming Huang*, Heng-Jeng Cheng, Sulean Chang and I-Chiu Liao
Tungkang Marine Laboratory, Tungkang, Pingtung
Taiwan 92804, R.O.C.
Oreochromis aureus fry, seven days after hatching were reared at salinity levels of 1, 10 and 20 ppt for four weeks. Thirty fingerlings were stocked in circular fiberglass reinforced plastic tanks holding 2,000 1 of water of 1, 10 and 20 ppt. Five replicates were used for 1 and 10 ppt and one for 1 and 20 ppt. Growth tests lasted for twenty weeks for the former and seven months for the latter.
The results showed that initially growth was faster at 1 ppt than at 10 and 20 ppt. Four weeks after stocking, however, body weight and body length of fingerlings were significantly higher at 10 ppt than at 1 ppt and after three months, growth was also significantly faster at 20 ppt than at 1 ppt. There were no injuries to the fish due to frequent measurement and no signifi-cant difference in survival rate, indicating that O. aureus has a good potential for culture in brackishwater.
66. A STATUS REPORT ON SHRIMP FARMING IN INDONESIA.
Hann-Jin Huang*, 26 Tradewinds Drive, Galveston, TX 77554 USA.
Ko-Lun An and Tedjo Wibowo, Jl. Pintu Air
48 Jakarta Pusat 10002, Indonesia.
The data presented in this report were mostly collected from the survey during the author's extensive travels around the country from January to May 1987. Official data were adopted only when it was verifiable.
Indonesia contributed 31,600 tons of shrimp, a total value of 259 million U.S. dollars to the world's seafood market. About half of them, 15,000 tons, were from aquaculture. There are approximately 150,000 hectares of coastal land available and already developed for shrimp culture. Due to insufficient supply of postlarvae, only half of them were utilized for shrimp culture in 1986.
Up to May 1987, there were only 400 hectares in semi-intensive operation and the rest were extensive ponds. Production from extensive ponds was 100–200 kg/ha/crop while it as 2–6 tons/ha/crop from semi-intensive ponds. Two crops can be achieved in each year.
The number of wild-caught postlarvae amounted to 500 million in 1986 and is on the decline while 270 million were produced from hatcheries. Among 130 licensed hatcheries, only about 60 are in operation and less than ten are in consistent production of more than three million of postlarvae per month. Demand for 1987 is estimated to be two billion.
Shrimp culture has caught national attention for its high profitability and short payback term. Net return for extensive ponds can reach as high as US$1,600 per hectare per year. A farm with ten hectares of semi-intensive ponds can gain more than US$500,000 each year. A hatchery which costs US$150,000 to build can produce up to 30 million of postlarvae and is capable of making US$300,000 profit. Payback requires two to three years for a semi-intensive farm without experiencing major problems and one to two years for a well-run hatchery.
67. NATURAL SPAWNING AND LARVAL REARING OF GOLDEN-RABBITFISH, SIGANUS GUTTATUS (BLOCH).
Philip Teguh Imanto, Achmad Basyari and Waspada
Bojonegara Research Station for Coastal Aquaculture
Serang, West Java, Indonesia.
In Indonesia, Golden-Rabbitfish, Siganus guttatus (Bloch) is considered as potential candidate for mariculture because of its fast growth and high price. In order to promote the Golden-Rabbitfish mariculture, especially the seed production, attempts of breeding and larval rearing had been conducted at Bojonegara Research Station for Coastal Aquaculture, Indonesia.
Eight pairs of broodstock were selected and captured in a 10-ton concrete tank. The fish were fed with minced fish or. shrimp mixed with aquatic-plant Ipomoea reptans. Spontaneous spawning occurred every month (3–7 days after new moon) between March and October 1985. The spawning time was between 8 and 10 PM.
The hatching time was varied between 20–24 hours at water temperature of 26–29°C. The hatching rate was 90–95%. Average total length of newly hatched larvae was 1.7 mm. The critical age was at day-3. The larvae metamophosed to be juvenile at day-32 when the average total length reached 26.15 mm.
68. COST OF PENAEID JUVENILES IN INTENSIVE RACEWAY SYSTEM.
Y.S. Juan, Department of Wildlife and Fisheries Sciences
Texas A&M University, College Station, TX 77843.
W.L. Griffin, Department of Agriculture Economics
Texas A&M University, College Station, TX 77843.
A.L. Lawrence, Texas Agricultural Experiment Station and
Department of Wildlife and Fisheries Science
P.O. Drawer Q, Port Aransas, TX 78373.
This analysis compared the use of intensive nursery raceway system with direct stocking of pls into grow-out ponds. The intensive raceway system allows two crops to be produced in Texas whereas only one crop is feasible with direct stocking. Both investment and operational cost are analyzed for three types of greenhouses and three types of raceways where the types vary in price and lengths of life. Three grow-out pond stocking densities and two size farms were evaluated for each combination of greenhouse and raceway type. Investment cost ranged from 142 thousand dollars for the small farm using the least expensive type greenhouse and raceway and utilizing the lowest stocking density to about 2.3 million dollars for the large farm using the most expensive greenhouse and raceway and the highest stocking density per hectare in the grow-out ponds. The operational cost was 7.60 and 9.71 dollars, respectively per 1,000 one gram juveniles produced. Generally, the raceway compared favourably with direct stocking for growth was 1.1 gram per week and survival was less than 35% in the grow-out ponds.
69. COMPARISON OF GENETIC VARIATION IN SIZE-SPECIFIC SELECTION OF TILAPIA HYBRIDS UNDER TWO FEEDING REGIMES.
Wongpathom Kamonrat, Freshwater Division
Department of Fisheries, Bangkhen, Bangkok, 10900 Thailand.
Roger W. Doyle, Department of Biology, Dalhousie University
Halifax, N.S. B3H 4Ji, Canada.
Genetic parameters of size-specific-growth were estimated in tilapia hybrids (Oreochromis mossambicus/O. hornorum) under two different feeding regimes, namely 'point feeding' and 'broadcast feeding'. The latter reduced within-group competition while the former increased the competition. A scale circulus spacing (CIRC) technique was used as a size-specific-growth estimator. The results showed higher sire-component heritability estimates in the non-competitive than in the competitive treatments. The pattern was reversed for the dam component. The results suggested that maternal effects (i.e., variation in egg size and duration of mouth brooding), which normally the result of genetic parameters estimates, are reduced when growth is measured on size-specific basis.
The higher heritability estimate for size-specific-growth in non-competitive treatment coupled with the very high genetic correlation among sequential estimates suggested that selection for size-specific-growth in non-competitive environments is a promising technique for selective stock improvement in aquaculture.
70. MATURATION PRODUCTION FROM BACULO VIRUS PENAEI (BVP) SHEDDING VERSUS NON-SHEDDING PENAEUS VANNAMEI.
David K. Kawahigashi*, Nick P. Carpenter and Julian Calderon
Pesquera Acuesemillas S.A., Av. de las Americas
Ed. Mecanos Sto. Piso, Ofs. 503–504, P.O. Box 191-P
Guayaquil, Ecuador.
The virus, Baculovirus penaei (BVP) exists in feral populations of Penaeus vannamei along the coast of Ecuador. At Acusemillas S. A., microscopic fecal examinations for the presence of polyhedral inclusion bodies were conducted on P. vannamei broodstock to determine the reproductive performance from BVP shedding versus non-shedding spawners.
Two thousand three hundred naturally mated spawners were monitored for BVP over a four month period. Comparison in fecundity and nauplii production between 1,100 BVP positive and 1,200 BVP negative spawners resulted in no significant, differences.
The data demonstrate that Baculovirus penaei infection in a P. vannamei maturation system does not have a negative effect on maturation production.
71. PROPERTIES OF EXTRUSION COOKED SHRIMP FEEDS CONTAINING VARIOUS COMMERCIAL BINDERS.
Joseph P. Kearns*, Wenger International, Inc., One Crown Center, Suite 510, 2400 Pershing Road, Kansas City,
MO 64108 USA. Gordon R. Huber, Wenger Manufacturing,
714 Main Street, Sabetha, KS 66534 USA. Warren G. Dominy,
The Oceanic Institute, Makapuu Point, Waimanalo, HI 96795 USA.
Donald W. Freeman, USDA-ARS Tropical Aquaculture Research Unit, The Oceanic Institute, Makapuu Point, Waimanalo, HI 96795 USA.
Shrimp feeds were prepared by extrusion cooking using various commercial binders to check improvement of product stability. Three test diets were utilized in conjunction with the inclusion of low levels of binders. The three diets were based on various formulation strategies:1) diets containing high levels of marine protein; 2) diets containing low levels of marine protein; and 3) an Oceanic Institute standard test diet.
The extruded shrimp feeds were evaluated for water stability at six inter-vals over a 24-hour period by measuring the physical integrity of the feeds. The testing system was designed to closely approximate actual feeding trial studies. Results showed that a variance in water stability occurred with the use of dif-ferent binders in the same formulation. A variance in the pellet water stability was also seen when using various formulations containing the same binders. Con-clusions are drawn with regard to binders used in the different formulation strategies .
72. THE ANNUAL REPRODUCTIVE CYCLE OF CAPTIVE MILKFISH, (CHANOS CHANOS) IN HAWAII.
C.D. Kelley*, C.S. Tamaru and C.S. Lee
Oceanic Institute, Makapuu Point
Waïmanalo, HI 96795 USA.
Three parameters (percent of fish maturing, state of maturity and steroid profiles) were used to study the annual reproductive cycle of captive milkfish in Hawaii. The percentage of fish undergoing maturation and the state of gonadal maturation (oocyte diameter in females and milt volume in males) were obtained monthly between April and November 1985 and again between March 1986 and September 1987. Serum steroid levels (testosterone, 11-ketotestosterone and estradiol) was obtained via monthly blood sampling between April 1986 and March 1987. All three parameters were consistent and indicated that gonadal maturation takes place between the months of April and October. This contrasts with the most restricted spawning season described for wild milkfish. Naturally occurring milkfish larvae have reportedly been found in Hawaiian waters only between the months of June through August.
Data obtained in 1987 on sexually segregated groups suggest that gonadal maturation takes place in segregated males, but is inhibited in segregated females. The sex ratio in maturation tanks can therefore be of potential importance to milkfish culture.
73. THE CORRELATION OF SERUM TESTOSTERONE, 11-KETOTESTOSTERONE, AND ESTRADIOL LEVELS WITH THE ANNUAL REPRODUCTIVE SEASON IN THE MILKFISH, CHANOS CHANOS FORSSKAL.
CD. Kelly, C.S. Tamaru and C.S. Lee, Oceanic Institute
Makapuu Point, Waimanalo, Hawaii 96795 USA.
In this study, the annual reproductive activity of milkfish, Chanos chanos, was investigated in captive fish held at the Oceanic Institute, Hawaii, USA. Nine female and 11 male milkfish, each over seven years of age, were maintained in two 30,000-liter tanks. From the beginning of March 1986 to the beginning of March 1987, the fish were captured and anesthetized on a monthly basis. Ovaries were biopsied via intraovarian cannulation. Males were subjected to abdominal pressure and the quantity of extruded milt was rated between 0 and 3. Three ml of blood was obtained from half of the fish for radioimmunoassay (RIA) of serum 11-ketotestosterone (males only), testosterone (T), and 17-estradiol (females only), There was a significant increase in the percentage of maturing males and females in April 1986. This number remained high through August. The number of females starting maturation dropped off in September, while the number of males continued through October and dropped off sharply in November. From November through February, the number of maturing fish of both sexes remained low. In March 1987, the number of maturing males began to rise again. Serum steroid levels mirrored these results showing the greatest activity between April and September. Of particular interest is the relatively early rise of 11-ketotestosterone as compared to testosterone in males. This steroid is suspected of playing a role in spermatogenesis in fishes. Its appearance in March, prior to an increase in testosterone may be related to the development of the gonad from its immature off-season state. Although naturally occurring milkfish larvae can only be found between June and August, gonadal maturation may be starting several months earlier.
74. COMPARATIVE SURVIVAL BETWEEN DIPLOID AND TRIPLOID GRASS CARP LARVAE REARED IN PONDS.a Cooperative
J. Howard Kerby*, North Carolin
Fishery Research Unit, Box 7617
North Carolina State University, Raleigh, NC 27695–7617.
T. Michael Freeze, Keo Fish Farm, Arkansas Aquatics, Inc.
Highway 165 North, Keo, AR 72083.
Concerns have been expressed by producers of grass carp (Ctenopharyn-godon idella) that triploids are not as competitive as diploids and that survival of triploid fry is reduced in mixed populations. We used a new batch sampling technique (developed by the North Carolina Cooperative Fishery Research Unit) that estimates the percentage of triploidy in larval fish samples to compare relative survival between triploid and diploid larvae reared to finger-lings and/or subadults.
Female grass carp were induced to ovulate using human chorionic gonado-tropin and carp pituitary. Triploidy was induced by employing temperature or hydrostatic shock treatments to ova at two to four minute intervals after fertilization. Batch samples of 100 four-day-old larvae were examined using flow cytometry and percent triploidy was estimated for each treatment. Larvae from each treatment were stocked in separate ponds. At harvest, individual blood samples from 120 fingerlings (50–75 mm long) from each pond were examined using a coulter counter to determine percent triploidy. Ponds were restocked and later blood samples from 120 subadults (200–275 mm) were again tested using the coulter counter. In almost all tests, percentages of triploid fingerlings and/or sub-adults were very similar to initial estimates of percentages of larval triploids provided by the batch analysis technique. These results indicate that there were no significant differences in relative survival between diploids and triploids to either the fingerling or subadult stage.
75. BIOMASS EVALUATION OF MACROBRACHIUM ROSENBERGII PONDS IN ACONTINUOUS STOCKING SYSTEM, ON A 27-HA FARM IN FRENCH GUIANA.
P.Y. Kersuzan*, L. de Parceval and J.C. Falguiere
c/o SAOR, B.P. 170, 97300 Cayenne, French Guiana.
Stock data are a key point for pond and financial management. The proposed biomass evaluation method is integrated into normal fishing activities; it is based on the knowledge of three notions:
the fishing efficiency (F.E.) calculable through two ,successive fishings across the complete surface of the pond:
the net selectivity which is an estimation of the size classes totally and partially caught by the net.
the pond population structure by size classes (histogram). The effi ciency of the successive fishings and the harvested amount enabled us to calculate the fraction of the pond population reached according to the net selectivity; the relation of this fraction in the population histogram gives the pond biomass.
Reliability is based on a similar fishing efficiency in the two seinings. In fact for more accuracy it is better to use a slightly smaller mesh net than the one used for commercial fishing; three or four biomass evaluations per year can be carried out in a pond. Comparison helps to test an eventual lack of precision. Various calculations are possible and comparable through a computer program. The few draindowns that have had to be done confirmed the reliability of this method.
76. CAGE CULTURE EVALUATION OF TILAPIA HYBRIDS.
J.B. Kingsley*, L.L. Behrends and M.J. Bulls
Tennessee Valley Authority, National Fertilizer Developmente
Center, Agricultural Resarch Branch
Muscle Shoals, AL 35660.
Two cage culture studies were conducted simultaneously from June 3 to August 26, 1987. Study I compared the growth and yield of two hybrid tilapia strains while Study II compared 32 percent (AT32) and 36 percent (AT36) crude-protein floating feeds as cage rations. The studies were conducted in replicate 0.5 m3 floating cages stocked with equal numbers of red- and normal-colored phenotypes at 300/m3. The two strains, similar genetically to Oreochromis aureus (AT) or O. niloticus (NT), were developed via hybridization and five generations of backcrossing. Weight and specific growth (SG) were measured every 15 days.
In Study I, red- and normal-colored AT fingerlings were 45.6 and 53.0 g, respectively, and NT fingerlings were 45,6 and 45.8 g, respectively, at stocking. After 86 days, AT hybrids averaged 193.5 g (SG = 1.68) and 189.5 g (SG = 1.48) and NT hybrids averaged 224.5 g (SG = 1.85) and 215.7 g (SG = 1.80) for red- and normal-colored phenotypes, respectively.
In Study II, red- and normal-colored AT32 and AT36 fingerlings were stocked at 39.5 and 38.4 g and 45.6 and 53.0 g, respectively. After 86 days, red- and normal-colored AT32 tilapia averaged 193.5 g (SG = 1.68) and 189.5 g (SG = 1.48), respectively, while AT36 tilapia averaged 175.0 g (SG = 1.73) and 154.6 g (SG = 1.61) for red- and normal-colored phenotypes, respectively.
77. NITRATE AND AMMONIA DEPLETION IN INDONESIAN AQUACULTURE PONDS FERTILIZED WITH CHICKEN MANURE.
C.F. Knud-Hansen* and T.R. Batterson, Department of Fisheries and Wildlife, Michigan State University East Lansing, MI 48823 USA. I.S. Harahat, Institut Pertanian Bogor, Fakultas Perikanan Jalan Raya Pajajaran Bogor, West Java, Indonesia.
Twelve 0.2 ha aquaculture ponds for Nile tilapia production in West Java were fertilized weekly with 4 levels of chicken manure:12.5, 25, 50, and 100 g m-2. During a 150 day grow out period, weekly ammonia-N and nitrate-N concentrations often exceeded 0.05 mg L-1 in the ponds fertilized with 12.5 and 25 g m-2 wk-1, but were usually less than 0.05 mg L-1 in ponds fertilized with 50 and 100 g m-2 wk-1. These differences between treatments in dissolved inorganic nitrogen (DIN), and apparent nitrogen limitation of algal productivity at higher loading rates, were examined through daily and diurnal measurements of ammonia-N and nitrate-N. Data suggest that algal production was limited by a shortage of CO2 at lower fertilization rates and by a shortage of DIN at higher fertilization rates. At higher fertilization rates, CO2 for algae was additionally supplied through microbial respiration of organic carbon in chicken manure. Laboratory experiments measuring the release of ammpnia-N and nitrate-N from chicken manure and urea were conducted to evaluate nitrogen transfer rates from these materials. An economic analysis is presented which relates appropriate application rates to fish yields and the cost of fertilizers in West Java.
78. THE EFFECTS OF VARIOUS BINDERS ON THE GROWTH AND SURVIVAL OF LARVAL KURUMA SHRIMP, PENAEUS JAPONICUS. FED MICRO-PARTICULATE DIETS BASED ON CRAB PROTEIN.
Shunsuke Koshio*, Shin-Ichi Teshima, John D. Castell and Akio Kanazawa, Faculty of Fisheries, Kagoshima University 4-50-20, Shimoarata, Kagoshima 890 Japan.
Nutritional values of crab protein as a dietary protein source have been recognized suitable for juvenile crustaceans. However, those for larvae are not fully understoodr Therefore, the availability of crab protein for micro-particulate diets to larval Penaeus japonicus was examined in this study.
Six binders such as carrageenan, glutens (Gluten M and activated gluten), zein, gelatin, CMC were mixed with microparticulate diet. None of the groups showed good growth and survival compared with the groups fed control diets, indicating the leaching of nutrients due to poor bindings and/or insufficient nutritional values of crab protein for larval shrimps. The next experiment was, therefore, conducted to examine the effect of casein supplement to crab protein and leaching by employing the microcoated diets.
The good performance was obtained from the diet which has 20 and 40% supplement of casein, and there was no effect of coating in those groups. We can conclude that although crab protein is not a superior single protein source for larval P. japonicus, it will be better when other protein source such as casein is supplemented. In such a case, carrageenan is one of the best binders for microparticulate diet.
79. HATCHERY CULTURE OF MAHIMAHI, CORYPHAENA HIPPURUS; NUTRITION AND DISEASE FACTORS.
Syd Kraul, Alan Nelson*, Karen Brittain and Carl Arume
Waikiki Aquarium, 2777 Kalakaua Avenue, Honolulu
Hawaii 96815 USA.
Successful mass production of mahimahi fingerlings requires large quantities of living plankton. As larvae grow, their diet for optimum survival changes from rotifers to copepods and progressively larger plankton species. Artemia salina is not an adequate diet for successful mahimahi culture. Although mortality correlates with diet, significant mortality occurs at all hatchery stages, regard-less Of diet. Larval mortality patterns are variable, but symptomatic of disease.
High densities of marine bacteria, including Vibrios and other classically pathogenic bacterial species, are not necessarily lethal to mahimahi larvae. Antibiotic treatment of plankton can adversely affect larval survival. Detection and avoidance of lethal bacteria species are described.
80. PENAEUS MONODON NAUPLIUS TO JUVENILE ON THE SAME ARTIFICIAL DIET.
K. Kurmaly, S. Amjad and D.A. Jones, School of Ocean Sciences
University College of North Wales, Menai Bridge
Gwynedd LL 59 5EY, U.K.
Penaeus monodon larvae have been successfully reared using microencapsu-lated diets (Frippak Feeds) from late nauplius stage VI to early juvenile stages with an average survival of 60%. Development and growth were dependent on capsule size and feed concentration.
81. PRELIMINARY CALCULATIONS ON THE ENERGETIC REQUIREMENTS OF PENAEUS MONODON LARVAE USING ENCAPSULATED DIETS.
K. Kurmaly*, A. Yule and D.A. Jones, University College of North Wales, School of Ocean Sciences, Marine Science Laboratories, Menai Bridge, Gwynedd LL59 5EY United Kingdom.
Ingestion rates for Penaeus monodon larval stages have been measured using algae, Artemia and microencapsulated diets. Respiration rates have also been measured for different larval stages over a range of temperatures. These data have been used together with assimilation and growth rates to calculate preliminary energetic requirements for the larvae.
82. FRESHWATER PRAWN MACROBRACHIUM ROSENBERGII (DE MAN) REARING IN FRENCH GUIANA:MEAN OF PRODUCTION CONTROL IN THE CONTINUOUS GROW-OUT SYSTEM.
D. Lacroix*, J.M. Griessinger, Th. Pollet, Ph. Gondouin and M. Costero, IFREMER - France Aquaculture B.P. 477, 97331
Cayenne Cedex, French Guiana, Tel:(594) 31.77.30
Telex:910358 FG.
The application of freshwater prawn continuous grow-out system follows a theoretical model based upon a steady progression of different size classes formed by periodic stockings of post-larvae. This progression is kept in motion by culling permanently large market-sized animals. The theoretical model species stocking sequence (number of PL and frequence) and harvesting characteristics (retained size and fishing frequence) in order to get a yield of homogeneous size prawns ranging from 2.5 to 3 metric tons/ha/year.
In practice, several factors can interfere with this steady advance leading to a significant lowering of production. A technical assistance team set up in the early 80's as part of development plans in French Guiana, systematically analyses size histograms to diagnose low production ponds. Most of the time, an over representation of sub-harvestable size classes due to a slowing down of their growth, is responsible for a general blockade of the production system. The origin of this slow growth is seeked into environmental conditions or in population management, especially harvesting.
Over a long period of time, control of a population reared with the conti-nuous grow-out system is effective.
83. ESTIMATION OF ESSENTIAL AMINO ACID REQUIREMENTS FOR PENAEUS VANNAMEI.
Addison L. Lawrence* and Frank C. Castille
Shrimp Mariculture Project, Texas Agricultural
Experiment Station, Texas A&M University System
P.O. Drawer Q, Port Aransas, Texas 78373.
The essential amino acid requirements for Penaeus vannamei were estimated by two experimental methods. One, they were estimated by determining the dietary requirement of one essential amino acid using a purified diet and extrapolating the dietary requirements for the remaining essential amino acids using the essential amino acid profile of tail muscle. The second method used to estimate the essential amino acid requirements will allow increase use for cheaper feedstuffs in the shrimp feeds. The resulting cheaper feeds would signi-ficantly reduce the cost for producing marketable size shrimp in ponds.
84. THE NUTRITIONAL RESPONSE OF POSTLARVAL PENAEUS VANNAMEI TO MEAT AND BONE MEAL.
Addison L. Lawrence* and Frank C. Castille
Shrimp Mariculture Project
Texas Agricultural Experiment Station
Texas A&M University System, P.O. Drawer Q
Port Aransas, Texas 78373.
Nutritional response of postlarval Penaeus vannamei to meat and bone meal was evaluated. There was no significant reduction in survival for the four week test period for shrimp fed diets containing 27.6% and 40% protein (dry weight basis) as percent meat and bone meal in the diets was increased from 0% to 20% and 0% to 40%, respectively. Regression of growth in terms of percent weight gain per animal onto percentage of meat and bone meal indicated that growth is decreased as percentage of meat and bone meal in the diet is increased from 0% to 20% and 0% to 40% in 27.6% and 40% protein diets, respectively. Percent reduction of growth for 27.6% protein diets containing 10% and 20% meat and bone meal versus 0% was 8.8% and 42,9%, respectively. The 8.8% decrease in growth was not but the 42.9% was significantly less than growth of shrimp fed diets not containing meat and bone meal as determined by Student-Newman-Kuels test. Percent reduction of growth for 40% protein diets containing 10%, 20%, 30% and 40% meat and bone meal versus 0% was 6.4%, 14.8%, 34.0% and 56.7%, respectively. The 6.4% and 14.8% were not but the 34.0% and 56.7% decreases in growth were significantly less than growth of shrimp fed diets not containing meat and bone meal. Data indicate that meat and bone meal could be cost-effectively used in diets for Penaeus vannamei depending upon the relative costs of meat and bone meal versus the more expensive marine animal meals.
85. SHRIMP FEEDING RESPONSES TO FOOD WEB MANIPULATIONS IN EXPERIMENTAL GROWOUT PONDS.
Kenneth M. Leber*, Warren G. Dominy and Gary D. Pruder
The Oceanic Institute, Nakapuu Point, Waimanalo
HI 96795 USA.
Although penaeid shrimp have long been considered opportunistic omni-vores, data from field studies indicate that these shrimp are primarily carnivores. In their natural habitats, penaeids typically prey upon copepods, amphipods, small shrimp and crabs, and polychaete worms. The foraging habits of Penaeus vannamei marine shrimp were examined in eight 200 m2 earthen ponds during a manipulative field experiment designed to examine shrimp growth under simple detrital-based and phytoplankton-based food webs. Results from unmani-pulated control ponds were compared to those from ponds receiving organic and inorganic inputs designed to stimulate primary and secondary productivity. Although prey groups normally consumed by penaeids in their natural habitats were rare, shrimp growth in these experimental ponds rivaled growth rates in nature and those in semi-intensive growout ponds receiving applied commercial feeds. These experiments document extreme flexibility in prey-size requirements and trophic level position for Penaeus vannamei. Penaeid growth rates in semi-intensive growout ponds appear to be greatly affected by natural prey availability.
86. USING EXPERIMENTAL MICROCOSMS IN SHRIMP RESEARCH:THE GROWTH-ENHANCING EFFECT OF SHRIMP POND WATER.
Kenneth M. Leber* and Gary D. Pruder
Oceanic Institute, Makapuu Point
Waimanalo, HI 96795 USA.
Progress in agricultural research is accelerating at a rapid pace and great strides have already been made in the past 30 years. The influence of ecological theory upon this progress is clear; from the impact of population ecology upon integrated pest management to the effects of ecosystem dynamics upon optimized harvesting, ecological principles have provided major advances. In contrast, progress in aquaculture has only recently begun to accelerate, and the impact of ecological principles is just beginning to emerge. Research on shrimp culture has recently begun to focus upon the impact of natural food webs as a direct food source for shrimp, the influence of shrimp feeding behavior on their uptake of applied feeds, primary productivity and its role in oxygen balance and nutrient cycling and effects of microbial interactions upon oxidation-reduction processes in sediments. Research in these areas involves expensive, labor-intensive field experiments in experimental ponds or small-scale farm ponds. We believe that microcosm laboratories can be appropriate arenas for testing hyphotheses concerning pond environmental effects upon feed conversion rates, growth, yields and survival. In pond microcosms, shrimp can be subjected to physical, chemical and biological conditions that in many ways approximate growout-pond conditions. These conditions appear to have tremendous effects upon growth potential. Recent microcosm experiments reveal that, even under intensive growout conditions, shrimp-pond water alone can sustain growth and survival for at least six weeks. Research is now under-way in microcosm laboratories to determine the mechanisms behind the growth-enhancing effect of pond water.
87. AN ANALYSIS OF THE INFLUENCE OF DIETARY AND OTHER REARING CONDITION VARIABLES ON GROWTH AND SURVIVAL RATES OF LARVAL PENAEUS VANNAMEI IN A COMMERCIAL HATCHERY.
Daniel O'C. Lee1*, R. Illescas1, L. Miranda1, F. Escobar1, J.A. Salvador1 and H. Lucien-Brun1,2
Growth rates, survival rates and data on feeding levels for larval Penaeus vannamei were recorded in 62 independent larval rearings. A total of 76.0 million nauplii were stocked over a period of 4 months and reared for an average of 21 days to reach a 10 day-old postlarvae (P10). Overall survival was 60.9% with mean growth of 0.239 mm/day to reach an average body length of 5.29 mm at harvest. The temperature was 28.2°C ± 1°C and the salinity 35%.
The following factors were analyzed to reveal relationships with growth and/or survival rates; concentrations of algal feeds during the protozoea and early mysis larval substages; total number of live Artemia nauplii fed; total weight of microencapsulated artificial diet “Frippak” fed as an algae and/or an artemia supplement; shrimp nauplii stocking density and postlarval harvest density.
Regression analysis revealed a significant positive correlation between the two variables growth and survival. The value of these two factors as measures of quality is discussed.
1MACROBIO S.A, Casilla 562, Guayaquil, Ecuador.
2EPHE, Station Marine d'Endoume, 7 rue de Batterie aux Lions, 13007 Marseille, France.
88. SALINITY TOLERANCE OF FERTILIZED EGGS AND YOLK-SAC LARVAE IN MILKFISH (CHANOS CHANOS FORSSKAL).
J. Lee, South China Sea Fisheries Research Institute
Kwangchow, PROC.
C.S. Lee and J.E. Banno*, Oceanic Institute
Makapuu Point, Waimanalo, HI 96795 USA.
The tolerance of milkfish embryos and larvae to direct salinity change was investigated. Embryos (blastomere and gastrulae) and one- and two-day-old larvae were obtained from milkfish hormonally induced to mature and spawn in captivity. Specimens were transferred directly from 32% to 5, 10, 15, 20, 25, 30, 35 and 40%. Larval hatching and survival rates up to six days were determined.
Hatching was observed in all salinities tested regardless of the stage at which transfer occurred. Normal larvae hatched from eggs transferred at blastomere and gastrula stages between 10–40 and 15–40%, respectively. Highest values of normal or viable hatch were found between 20–40%.
One-day-old larvae could not tolerate direct transfer into 5%. Two-day-old larvae survived direct transfer to all test salinities. On Day 6, higher larval survival rates were found between 15 and 30% for larvae transferred at one-day-old between 5 and 25% for larvae transferred at two-day-old.
This study clearly demonstrated the euryhaline capability of milkfish and their ability to tolerate salinity fluxes very early in life.
89. AN ECONOMIC COMPARISON OF EXTENSIVE, SEMI-INTENSIVE AND INTENSIVE SHRIMP CULTURE TECHNOLOGIES IN HAWAII AND GUAM.
Kendrick Lee, Robert Cantre11*, Ping Sun Leung, Yung C. Shang and Jaw-Kai Wang, Department of Agricultural and Resource Economics Gilmore Hall 112, University of Hawaii-Manoa Hawaii 96822, USA.
Although Hawaii and Guam are considered favourable areas to culture marine shrimp, the optimal farm system has not been identified. A previously developed spreadsheet model was modified for this research. Three technologies will be examined for transferability to Hawaii and Guam:extensive, semi-intensive and intensive. Insufficient data from existing commercial farms (in Hawaii and Guam) was lacking, so data from literature and other shrimp farming regions and assumptions were used to provide a reasonable data range for analysis.
90. THE ECONOMICS OF TECHNOLOGICAL INNOVATION IN TAIWANESE AQUACULTURE DEVELOPMENT, 1953–1985.
Kendrick K.F. Lee, 107 I Kalikimaka Street
Honolulu, Hawaii 96817–1224 USA.
Taiwanese aquaculture development was analyzed from an agricultural deve-lopment economics perspective focusing on the role of technology. The temporal patterns of area, output per area and real prices, for six species groups:milkfish, carp, oyster, tilapia, eel and shrimp; were analyzed, utilizing the theory of an “innovation cycle”, providing evidence that technology was related to aquaculture development. In an “innovation cycle”, new technology (either new species or new culture techniques) will first be reflected in an increase in output per area (learning effect), followed by a decline in real prices (market effect) . Examination of general economic and social conditions over time helps identify the conditions which should exist to make successful aquaculture development possible. Implications for future of the Taiwanese aqua-culture sector and the transferability of aquacultuce as a development tool for other third world countries were derived from this research.
91. THE EFFECT OF ASCORBIC ACID ON SPERM AND SPERMATOPHORE QUALITY IN PENAEUS VANNAMEI MALES FED PREPARED DIETS.
Joanna R. Leung-Trujillo* and Addison L. Lawrence
Texas A&M University Shrimp Mariculture Project
4301 Waldron Road, Corpus Christi, Texas 78418 USA.
The effect of ascorbid acid (AsA) on sperm and spermatophore quality was studied in Penaeus vannamei. Adult P. vannamei were stocked at a 1:1 male:female ratio in indoor 3.7 m diameter fiberglass tanks and maintained on a recirculating seawater system. Mean weights ± SD were 50.99±9.2 and 40.46 ± 5.2 g for females and males, respectively. Three 3-tank replicates were fed the following experimental diets:1) Diet A-60% prepared dry diets supplemented with 10 g/kg of encapsulated Vitamin C, 40% marine polychaetes; 2) Diet B-60% prepared dry diet without Vitamin C supplement, 40% marine polychaetes; and 3) Control-40% squid, 20% shrimp, 20% marine polychaetes and 20% adult brine shrimp.
Reproductive response of the males were evaluated by comparing mating rate among treatments and by evaluating overall morphology of the reproductive tract (testes, vas deferens, terminal ampoules). Sperm quality parameters were also determined through spermatophore morphology, sperm counts, trypan blue dye exclusion and sperm cell morphology.
92. THE APPLICATION OF ARTIFICIAL PLANKTON B.P. IN PENAEUS MONODON LARVAL PRODUCTION.
I-Chiu Liao*, Tungkang Marine Laboratory
Tungkang, Pingtung, Tawain 92804, R.O.C.
Fumio Kumeno, Zenzo Iida and Tadashi Kobayashi
Nippai Shrimp Feed, Inc., 3–9, Moriya-Cho
Kanagawa-Ku, Yokohama, Japan.
Penaeus monodon is the major culture species in Southeast Asia. Conven-tional larval rearing methods rely heavily on live foods, primarily Skeletonema, rotifers and Artemia. for the various stages of growth. However, the culture of live foods is subject to such unpredictable factors as weather. Furthermore, Artemia is not indigenous everywhere. Therefore, an ideal food substitute for the future is artificial feed. This study explores the applications of artifi-cial plankton B.P. in P. monodon larval rearing.
Half ton fiberglass reinforced plastic tanks containing 450 1 of water and constantly aerated were used to culture P. monodon from nauplius to PL 1. Water temperature and salinity were maintained at 30 ± 1°C and 31 ± 3 ppt, respectively and pH ranged from 8.0 to 8.4; the tanks were covered with black orchid net and the larvae were fed every 6 hours. The optimal larval density and combinations of B.P. and live food were studied. Results of this study show that the initial stocking density of 80 to 100 nauplii/1, and 1.0 to 1.5 g B.P./450 I/feeding combined with 2,000 cells/ml of Skeletonema given once a day, produced the best result. Although Skeletonema was found:to be still essential, results are encouraging.
93. FEASIBILITY STUDY FOR ALTERNATIVE CULTURE SPECIES IN TAIWAN-PENAEUS PENICILLATUS.
I-Chiu Liao, Tungkang Marine Laboratory
Tungkang Pingtung, Taiwan 92804, R.O.C.
Penaeus monodon is almpst synonymous with aquaculture in Taiwan indicating the level of success the culture of this species has attained over the past two decades. However, other species are being considered for future culture to diversify an industry heavily dependent on one product as well as provide the market with an alternative commodity. This paper explores the feasibility of P. penicillatus as an alternative culture species in Taiwan.
Penaeus penicillatus has five major merits considered ideal for aqua-culture:
Induced maturation of spawners in captivity is possible even without eyestalk ablation.
Larval rearing is comparatively easy.
Penaeus penicillatus is relatively disease resistant and may be cultured in grow-out ponds at high densities (1–1.2 million/ha).
This species still grows at low temperatures (about 20°C) and can be fed a low-protein diet (as low as 22%).
The “white shrimp”, P. penicillatus is readily acceptable in the international market.
This paper also discusses some difficulties in the culture of this prawn.
94. PRODUCTION AND CONSUMPTION OF FRESHWATER PRAWNS - THE THAI WAY.
C. Kwei Lin, Agricultural & Food Engineering Division Asian Institute of Technology, Bangkok, Thailand.
Production of farmed freshwater prawns (Maerobrachium rosenbergii de Man) in Thailand has increased exponentially during the recent 10 years. The present production, involving more than 2,000 farms over about 4,000 ha of pond area, reaches 4,000 tons annually. Most production farms practice intensive mono-culture, applying appropriate technology developed locally. Vertically integ-rated management style is adopted by medium and large size farmers, who produce their own post larvae, manufacture supplemental feed, manage ponds, harvest and wholesale the products. Year-round favorable temperature, abundant surface water, relatively inexpensive feed and labor force, and innovative local tech-nology have been main factors contributing to profitable and thriving prawn farming in Thailand. The domestic consumption has been the major market for farmed prawns. As prawns being native to Thai waters many traditional Thai ways of preparing prawn dishes were developed. Undoubtedly, the success of prawn farming enterprise, has been associated with the anthropological back-ground unique to Thailand.
95. NUTRITION STUDY ON CHINESE PRAWN (PENAEUS ORIENTALIS) I:PROTEIN.
H.W. Liu and B.S. Wu, Shandong Mariculture Institute
Qingdao, China.
Fifteen Penaeus orientalis juveniles (average weight = 1.5 ± 0.3 g) were kept in each of the fifteen 150-L glass aquaria supplied with seawater (33 ppt) through a sand-gravel filter. Five diets were prepared containing 23–60% protein and fed at 10% of body weight/day for the first two weeks and 8% for the succeeding two weeks.
Prawns fed the 40% protein diet produced the best growth, food conversion ratio (FCR) and survival rate. Growth depressions occurred among the prawns fed 47% and 60% protein.
96. COMPARISON OF PHYTOPLANKTON COUNTS AND GROWTH OF PENAEUS VANNAMEI IN PONDS UNDER DIFFERENT ENVIRONMENTAL CONDITIONS.
Jairo Llanos, Diana Marin and Jeffrey Peterson
Acuespecies, S.A., Guayaquil, Ecuador.
Data were analyzed from 40 10.9 hectare shrimp production ponds at Acuespecies S.A., a 500 hectare shrimp farm in Guayas Province, Ecuador.
Comparison were made between average monthly shrimp growth rates (grams/month) versus average monthly phytoplankton counts (cells/ml). The study was conducted over a 12-month period during which climatic conditions varied widely.
The Guayas basin, where the ponds are located is characterized by wide variations in salinity due to seasonal rainfall. Salinities during the study period ranged between 0.0 and 24.0 parts per thousand. Temperatures varied between 24.0 and 30.0°C.
Results correlate higher growth rates with higher phytoplankton populations.
97. AUTOMATED WATER QUALITY DATA ACQUISITION IN AQUACULTURE . SYSTEMS.
Thomas M. Losordo, Raul H. Piedrahita and James M. Ebeling,
Department of Agricultural Engineering
University of California, Davis, CA 95616.
An automated water quality data acquisition system has been developed by the Aquacultural Engineering program at the University of California at Davis (UCD). The self-contained computer based system consists of a Campbell Scien-tific “micrologger”, a weather station and a unique water sampling raft. The system can monitor and record the following information on a routine basis:, a) weather data including solar irradiance, photosynthetically active radia-tion, wind speed, wind direction, air temperature, relative humidity and rainfall; b) pond environmental data taken at 20 cm intervals (to a maximum depth of 175 cm) including dissolved oxygen, temperature, pH and photosynthe-tically active radiation.
This poster describes the data acquisition system, its uses in aqua-culture research, and possible modifications for use in commercial aquaculture system monitoring.
98. AN ANALYSIS OF THE SURVIVAL AND THE GROWTH IN PONDS OF HATCHERY REARED PENAEUS VANNAMEI LARVAE.
Herve Lucien-Brun*,1,2 A. Aguilar,1 J.A. Salvador1 and D.O'C. Lee,1
The survival and the growth of Penaeus vannamei juveniles originating from the same hatchery are analyzed in several Ecuadorian shrimp farms. The object of this paper is to establish an eventual relationship between farm results and the hatchery techniques employed with special attention to:
nauplii origin, wild caught gravid females versus artificially matured and inseminated females;
preventive antibiotic usage;
use of supplementary artificial microencapsulated feeds; and
age of postlarvae at the time of stocking in ponds.
The analysis deals with the two types of grow-out technology most used in Ecuador. In the first system postlarvae are stocked in a separate nursery ponds prior to on-growing. In the second, the postlarvae are stocked directly into the grow-out ponds. In the first instance, the analysis considers only the nursery stage.
1MACROBIO S.A., Casilla 562, Guayaquil, Ecuador.
2EPHE, Station Marine d'Endoume, 7 rue de la Batterie aux Lions, 13007 Marseille, France.
99. STOCKING DENSITY AND FEED LEVEL EFFECTS ON GROWTH AND SURVIVAL OF JUVENILE PENAEUS VANNAMEI AND P. STYLIROSTRIS IN POND CAGES.
Jack R. Luszcynski*, Frank L. Castille and Addison L. Lawrence, Shrimp Mariculture Project, Texas Agricultural Experiment Station, Texas A&M University System
P.O. Drawer Q, Port Aransas, TX 78373 USA.
A formulated shrimp feed containing 30% protein was tested on juvenile Penaeus vannamei and P. stylirostris held in bottomless cages. Desired feed levels ranging from 0 to 15% wet body weight per day were used for stocking densities of 10, 20 and 40 per m2. Further experiments used desired feed levels ranging from 0 to 5% wet body weight per day with stocking densities of 20, 40 and 60 per m2.
Growth of P. vannamei and P. stylirostris was inversely related to stocking density. In addition, growth of shrimp fed the 30% protein feed was better than that of unfed shrimp. No significant differences in growth of P. vannamei occurred between desired feed levels ranging from 5 to 15% or between desired feed levels ranging from 1.25 to 5%. Growth of P. stylirostris was better at desired feed levels of 2.5% when compared to 1.25% and did not differ from that of shrimp fed at 5%. The results suggest (1) that in ponds, low feed levels can increase the growth of 1 to 5 g shrimp; (2) that feed rates above 2.5% do not give any additional benefit; and (3) that supplemental feeding may be more important to p. stylirostris than to P. vannamei.
100. POLYUNSATURATED FATTY ACIDS IN THE DIET OF PENAEUS VANNAMEI
Julia S. Lytle*, Thomas F. Lytle and John T. Ogle
Gulf Coast Research Laboratory, 703 East Beach
Ocean Springs, MS 39564 USA.
Studies have suggested that bloodworms provide nutritional components in diets of tank-reared shrimp that are essential for maturation and cannot be provided by conventional diets. Omega-3 fatty acids have been implicated as target compounds needed to trigger maturation. Because the link between fatty acids and shrimp maturation has not been firmly established, an investigation was undertaken to characterize fatty acids in bloodworms and contrast levels and distributions with those in other food materials used in shrimp rearing. Included were pellet foods, live foods such as squid, oysters, algae and brine shrimp; live foods enriched with the PUFA boosters, MarilaT or SelcoT; and two species of bloodworms, one from the Maine coast and one from Panama. Because bloodworms are usually purchased from a limited supply, other worms which might be grown locally have also been analyzed for fatty acids. Wide variations in fatty acids were observed among tested foods. Variables derived from this fatty acid data provide information for future investigations of dietary factors essential to shrimp maturation. Several food materials proved to equal or exceeded bloodworms in absolute quantities of PUFAs and may offer an alternative to the bloodworm diet.
Bloodworms typically are frozen for prolonged use. Fatty acid analyses made of worms stored for one year indicated little degradation in fatty acids as long as food remained frozen at 4°C until use. Seasonal variations in fatty acid content for bloodworms purchased in January and in August have also been assessed.
101. SEMI-INTENSIFICATION OF EXTENSIVE MARINE SHRIMP CULTURE IN ECUADOR:PLANNING AND IMPLEMENTATION.
Spencer Malecha*,1 Elizabeth MacMichael,1 Tom Desmond,1 Gil Kohnke2 and Jonathan Roberts2
Historically, most of the marine shrimp, Penaeus vannamei pond culture in Ecuador has been extensive with production averaging 300–500 kg/ha/yr. In the last few years natural seed supply has been unpredictable, and the once inexpensive coastal land areas are no longer available. On the surface, this situation mandates an intensification of production using hatchery reared stock, feeding, water management, etc. In theory, intensification should bring greater net profits. However, there are many problems in intensifying an existing operation. Our company has been attempting to intensify in a joint venture with the Ecuadorian hatchery and grow-out firms, Ecualarvae S.A. and Prexamar C.A. Although designing, building and starting up the hatchery, de novo pre-sented many challenges. The greatest problem involved “retrofitting” the 200 hectare grow-out farm from an extensive operation to a semi-extensive one. Our strategy, which gives a potentially economic favorable return is to only slightly intensify (500–1,000 kg/ha/yr) the grow-out operation for the first two years. This paper discusses our overall strategic planning, most prominent general management problems, planning and integration of hatchery and pond stocking phases, theory behind calculation of critical standing crop values for a minimum feed level application, long range financial and cash flow planning using computer based spread sheet models, practical considerations of growth management, and finally the importance of the stochasticity associated with production and survival in hatchery and ponds.
1Hawaii Aquaculture Company, P.O. Box 61970
Honolulu, Hawaii, HI 96839.
2Pacific Business Center Program, University of Hawaii, Honolulu, HI 96822 USA.
102. DEVELOPMENTAL CHANGES IN PROTEIN-NUCLEIC ACID LEVELS OF PENAEUS VANNAMEI TAIL MUSCLE.
Kimiaki Maruyama*, Department of Animal Sciences
College of Tropical Agriculture and Human Resources
University of Hawaii at Manoa, 1800 East-West Road
Honolulu, HI 96822 USA.ominy
Anthony C. Ostrowski and Warren G. Dakapuu Point
The Oceanic Institute, MWaimanalo, HI 96795 USA.
Marine shrimp (Penaeus vannamei) were raised in Taiwanese-type grow-out ponds at the Oceanic Institute in Hawaii. Samplings of animals were made at weekly intervals for four consecutive weeks, starting from the estimated age of approximately 16 weeks. A total of 20 animals per week were randomly selected for the determination of tail weights and tail muscle weights to study allo-metric growth of tail muscle in marine shrimp. Animals were sexed to study sexual dimorphism, as well as variations within a population regarding body weights and muscle development.
In addition to gross measurements of body weights, tail weights and tail muscle weights, tail muscle samples were subjected to tissue fractionation by a modified method of Wannemacher et al. to determine protein, RNA and DNA con-tents . Protein and nucleic acid contents were then used to estimate physiological changes associated with age and sex in the course of muscle growth. Physiological changes are discussed in terms of accumulation of muscle nuclei protein accre-tion, DNA space and translational capacity of nuclei for protein synthesis.
103. INSTANTANEOUS GROWTH RATE OF TILAPIA GENOTYPES IN UNDISTURBED AQUACULTURE SYSTEMS. I. “RED” AND “GREY” MORPHS IN INDONESIA.
Titiek Matricia, Research Institute for Freshwater Fisheries, 1 Jl. Sempur, Bogor, Java, Indonesia.
Andre J. Talbot and Roger W. Doyle, Biology Department
Dalhousie University, 1355 Oxford Street
Halifax, NS B3H 4J1, Canada.
Genetic improvements of growth rate is a potential method of increasing fish production. Tests of genetic variability are often limited to laboratory environments quite different than the environment from which the studied fish originate. Strain, family or even individual variation in growth rate may be partially masked by genotype-environment interactions. Conclusions from such studies may bear little resemblance to true differences under natural conditions. The objectives of this study were:1) to compare the growth rate of different strains of Tilapia; and 2) to determine the amount of variation in growth rate among traditional farming systems in Indonesia. We used spacing of circuli on scales (CIRC) to estimate size-specific growth rates. This technique allows growth rate to be quantified from a single sample. Growth of fish from 7 farms and 2 colour morphs were compared, at 2 standard fish sizes.
Repeatability of CIRC is high under the present farming conditions. Overall, gray morphs grew faster than reds, but a significant interaction between colour morph and farm makes farm-wise comparison necessary. Growth rates were significantly greater for gray tilapia on 2 farms but never greater for red. Growth between farms differed significantly. The body length/scale radius allometry varied significantly between farms and colour morphs, indica-ting genetic variability in this trait. This data 1) confirms that the gray colour morph is faster growing under natural conditions and 2) allows manage-ment practice to be directly related to growth, from which adjustments in density, feeding levels and other growth-related factors can be made.
104. MANAGEMENT STRATEGIES FOR PENAEUS VANNAMEI BROODSTOCK.
Kathleen M. McGovern*.
Data collected from earlier trials at Amorient Aquafarm showed that indi-vidual Penaeus vannamei do not contribute equally to the nauplii production of a maturation population. Impregnation of individual females did not occur at random but favored a select group of females in each maturation population. Using this information trials were conducted using female selection in an attempt to increase the nauplii production from a maturation population.
Females in each maturation tank were tagged and their nauplii production recorded. In two trials females producing few or no nauplii were replaced. In two other trials, the highest producing females from two maturation populations were combined into one population.
Results suggest that culling and selective replacement of females, based on records of individual performance in the maturation system, can result in improved yields of nauplii.
105. CARBON LIMITATION IN FERTILIZED FISHPONDS IN JAVA.
CD. McNabb* and T.R. Batter son, Department of Fisheries and Wildlife, Michigan State University East Lansing, Michigan, 48823 USA.
H.M. Eidman and Komar Sumantadinata, Institut Pertanian Bogor,
Fakultas Perikanan, Jalan Raya Pajajaran, Bogor, West Java, Indonesia.
The backbone of Java consists of a chain at some 25 major volcanic peaks. Among the peaks are ridges of uplifted limestone reefs. Groundwater and runoff from volcanic regions were mineral poor carbonate-bicarbonate alkalinity was on the order of 20 mg L-1. By contrast, water emerging from limestone regions had alkalinity near 160 mg L-1. When phosphorus and nitrogen fertilizers were added to low alkalinity water in ponds in a volcanic region, the growth of algae and subsequent yield of Nile Tilapia were low:1.1 g C m-2 day-1 and 1,080 kg fish ha-1 per 150 day grow-out period, respectively. With low alkalinity, carbon dioxide limited pond production, and phosphorus, and nitrogen remained in pond water unused by the algae. When alkalinity was increased to 50–60 mg L-1 and fertilizer was applied at the same rate, algae productivity and fish yield increased to 1.5 g C m-2 day-1 and 1,475 kg fish ha-1 per 150 day grow-out period. With increased abundance of CO2 and increased growth of algae, phosphorus and nitrogen uptake from pond water increased, thus improving fertilizer efficiency. CO2 continued to be in short supply at the highest levels of pond production obtained in the experiment. Fertilizer applied at the same rate to ponds in limestone drainage systems of Java with greater alkalinity would likely support pond productivity in excess of that obtained here. This work shows that CO2 availability needs to be assessed during design of fertilizer application schemes in order to use fertilizers economically and to obtain consistent fertilizer-based yields from site to site in Java.
106. USE OF SCALE CIRCULUS SPACING TO DETECT GROWTH-RATEDIFFERENCES BETWEEN CARP (CYPRINUS CARPIO) IN FARMING SYSTEMS IN INDONESIA.
Andrew McNaughton, M.E.S., POB 8500, Ottawa, Ontario KIG 3H9, Canada. Roger W. Doyle, Ph.D., Department of Biology, Dalhousie University, Halifax B3H 4H6 Canada. Andre J. Talbot, M.Sc, Department of Biology, Dalhousie University, Halifax B3H 4H6 Canada. *Titiek Matricia, B.Sc., Balai Penelitian Perikanan Air Tawar, (Research Institute for Freshwater Fisheries). 1 Jalan Sempur, Bogor, Indonesia.
Methods for determination of short-term individual growth rates in fish are desirable for aquacultural stock improvement, and for comparisons of response to various management regimes and to environmental conditions. The direct determination of growth rate of individually identified fish by repeated measurement of length is impractical in most aquacultural situations, because of problems arising from management practices (frequent addition of new stock, large numbers, labour costs, unreliable markirg). This is especially so in extensive production systems in the Third World.
Significant positive linear relationships were demonstrated between growth rate and scale circulus spacing (CIRC) of goldfish (Carassiois auratus) and' of common carp (Cyprinus carpio). Use of this relationship as a simple and inexpensive estimator of mean growth rates in differing carp fanning systems in Indonesia is described.
Potential utility of CIRC as a tool for optimizing finfish aquaculture production operations, and as a selection criterion in stock improvement is discussed.
This work is part of a collaborative research project between the Research Institute for Freshwater Fisheries, in Bogor, Indonesia and the Department of Biology of Dalhousie University in Halifax, Canada, part of the Network of Aquaculture Genetics in Asia, funded by the International Research Centre of Canada.
107. INTENSIVE NURSERY REARING OF PENAEUS VANNAMEI IN ROUND PONDS.
E.S. MeSweeny*, J.N. Sweeney and R.A. Kanna
Oceanic Institute, Makapuu Point
Waimanalo, HI 96795 USA.
Results of high-density nursery trials currently in progress in a 337 m2 round earthen pond at the Oceanic Institute, Waimanalo, HI are reported. Post-larvae are stocked at 1,000/m2 and grown to 1 g average weight at harvest. Water quality is controlled by constant exchange and periodic removal of solid wastes through a center drain. Data include water quality parameters, final survival, weekly growth and size distribution at harvest.
108. PRACTICAL FEEDS AND FEEDING SCHEDULES FOR POST-LARVAL FRESHWATER PRAWNS, MACROBRACHIUM ROSENBERGII.
Michael J. Mensi, Jr.* and John M. Heinen, Department of Wildlife and Fisheries, P.O. Drawer LW, Mississippi State, MS 39762 USA.
To achieve profitable pond culture in temperate regions, M. rosenbergii must apparently be stocked as juveniles which have been raised in a temperature-controlled nursery facility. This study investigated some commercially available feeds, feeding schedules, and feed supplements for growing postlarvae to a juvenile size of about 0.5 g. Postlarvae were grown for nine weeks at a density of 2.0/L and a water temperature of 28 ± 0.5°C in 76-L aquaria equipped with outside biological filtration. Feeding rates were adjusted daily so that generally only a little uneaten food remained at the next feeding time. Uneaten food was siphoned out once daily just before a feeding time. There were three or four replicates per treatment. Experiment 1 tested four commercially available feeds; MFC Clover Brand Catfish Fingerling Crumbles (38% protein), Purina Trout Chow No. 2 (50% protein), Silver Cup Fish Feed-Salmon (49% protein), Rangen No. 2 Postlarval Shrimp Diet (45% protein), and a reference diet (EXD-86). Purina No. 2 Trout Chow gave the best survival and yield and was used as the sole or main food in subsequent experiments. Experiment 2 tested four feeding schedules:once per day (at 1600. h), twice per day (at 0800 hand 1600 h), twice per day (at 0800 h and 2000 h), and three times per day (at 0800 h, 1600 h, and 2400 h). The once-per-day treatment gave the best growth, survival and yield. Experiment 3 tested the effects of supplementing trout chow with several fresh or frozen foods; no results were available at the time of this writing.
109. KNOW YOUR MARKET POTENTIAL BEFORE YOU BUILD YOUR FARM:EXPERIENCES AT AMORIENT AQUAFARM IN HAWAII.
Philip L. Meyer*, Amorient Aquaculture International
P.O. Box 6669, Laguna Niguel California 92677 USA.
Linden A. Burzell, Amorient Aquafarm, Inc.
P.O. Box 131, Kahuku, Hawaii 96731 USA.
A natural progression for aquaculture projects is the development of expertise in raising a particular aquatic species and then the promotion of the development of a facility to mass produce that product. For commercial success, this must be done in conjunction with careful market factor analysis. Among the questions to be considered are:
Is there a large and knowledgeable consumer population close to the production site?
How many producers of the product are in commercial operation and how long have they been in business?.
What forms of the product are acceptable to the present consumer group?
Have product handling, marketing personnel and product transporta tion costs been adequately budgeted?
The frequent result of failure to consider these and other important marketing factors is the construction of a successful production facility but a failed commercial venture. Proper business planning can reduce the risk of this happening.
110. APPLICATION OF EUCHEUMA CARRAGEENAN PHYCOCOLLOIDS AS BINDERS IN AQUATIC DIETS.
Samuel P. Meyers, Food Science Department
Louisiana State University Baton Rouge, Louisiana.
Pinij Kungvankij, FAO/UNDP Seafarming Development Project, Jl. Bhayangkara, Bandar Lampung, Indonesia.
Marylou G. Llanto and Iain C. Neish, FMC International AG,
P.O. Box 66, Mandaue City, Cebu, Philippines.
Cultivation of species of Eucheuma comprises a major red seaweed aqua-culture industry throughout Asia, especially in Indonesia and in the Philip-pines. Production of E. cottonii in the latter country alone exceeds 45,000 tons annually. The species E. cottonii and E. spinosum are commercially processed to yield kappa and iota type carrageenan, respectively, which form polysaccharide gels with various textural and setting properties. Pellet texture can be altered with cations and use of synergistic gums. These unique features can be used to produce a variety of water stable diets, including pellets and flake products, utilizing relatively simple processing techniques. Combinations of both dry and wet ingredients can be utilized to produce a well-balanced diet. Extruded gel formulations exhibit good rehydration properties without excessive loss of solids.
Crude Eucheuma extracts, as well as appropriate combinations of kappa/iota type semi-refined carrageenans, have been effective as nutrient “delivery systems” for seabass (Lates calcarifer) and siganids (Signanus spp) as well as providing a water stable digestible matrix for potential delivery of vitamins and specific chemoattractants at various stages of fish growth. Adjustment of the hydrocolloid mixture allows control of physical tactile properties and nutritional composition that directly affect acceptance and feeding response. The Eucheuma gel systems lends itself to a variety of aquatic dietary applications, including possible use in penaeid maturation for feeding of natural and compound food in a composite flexible, soft-textured and stable “worm-like” configuration.
