bluuebunny/crossref_metadata_2025 huggingface dataset:
CURRENT ECONOMIC STATUS OF LOBSTER CULTURE RESEARCH1
Authors: Botsford Louis W.
Published: August 2010

The current status of lobster culture research is presented in an economic context by describing culture cost projections and their sensitivity to parameter variation. The current state of the mathematical model is described and related to recent research results. Examples of culture costs with heat recovery, thermal effluent, warmer ambient temperatures and complete recirculation as alternatives to fossil fuel heating are presented. Sensitivity analysis reveals two important areas of research: 1) development of artificial foods with higher growth rates and description of their impact on metabolism, and 2) description of excretion rates and tolerances of ammonia. Economic feasibility of communal rearing is evaluated and economically more attractive approaches suggested. The impacts of increased growth rate due to genetic selection and eyestalk ablation on culture costs are presented. Results show that the maximum cost savings due to increased growth rate when metabolic rate is increased by the same factor is 25% of total culture costs.
SOCIO‐ECONOMIC FEASIBILITY STUDIES OF (Macrohrachium rosenbergii) FARMING IN PALAU(A Preliminary Report)1
Authors: Blommestein E. , Deese H. , McVey J. P.
Published: August 2010

The economy of Palau is characterized by a large trade deficit, a large government sector, consumption higher than income, and virtually no commercial agriculture. The new Indicative Five Year Plan put a high priority on development of marine resources and agriculture. Aquaculture can be considered as a combination of both.

The Micronesian Mariculture Demonstration Center operates a freshwater prawn hatchery (Macrobrachium rosenbergii) with a production capacity of 3–6 million juveniles a year. This initial production level will he able to serve 16 to 36 ha of ponds. The first part of this paper determines a minimum price for juveniles in the culture systems being used, while the second part concerns the economic feasibility of prawn farming. This compares the minimum price per kilo of prawns using farming close to subsistence level (e.g. small farms, family labor and low productivity) with a medium scale commercial farm. The preference of one over the other is dependent on government policies, e.g. subsidies, land lease, and foreign investment.

Ultimately, any final conclusion about the feasibility of prawn farming is subject to the prices in the markets. Since this is still under research, marketing does not form a part of this study.
USE OF ANIMAL FAT IN FORMULATED DIETS FOR YELLOW PERCH (Perca flavescens)
Authors: Heck Nancy E. , Calbert Harold E.
Published: August 2010

The standard formulated diet used to grow yellow perch (Perca flavescens) in a controlled environment aquaculture system contains vegetable fats in addition to naturally occurring lipids in fish meal. Normal market prices make animal fat financially advantageous over vegetable fat. To determine if animal fat can be substituted for vegetable fat in formulated feed for perch, diets containing 15% (control) and 11.25% added soybean oil; 15% and 11.25% added animal fat; and a 50/50 mixture of 11.25% animal fat and soybean oil were fed to replicate lots of perch fingerlings for 100 days. During feeding trials fish were held in 20°C water with a photoperiod of 16 hr light and 8 hr darkness.

The diet containing 11.25% added animal fat produced significantly higher weight gains than the other diets tested. All diets were readily accepted. Both soybean oil and animal fat diets produced fish with approximately the same percentage of body fat (9.1%). Animal fat resulted in a feed pellet that was less oily and easier to handle than pellets made with soybean oil.
THE PROTEIN REQUIREMENT OF PENAEID SHRIMP AT VARIOUS LIFE‐CYCLE STAGES IN CONTROLLED ENVIRONMENT SYSTEMS
Authors: Colvin L. B. , Brand C. W.
Published: August 2010

Investigations into the nutrient requirements of penaeid shrimp in controlled environment systems using extruded diets compounded from practical ingredients have shown that the protein requirement of the early postlarval animal exceeds 40% crude protein, but decreases to less than 30% crude protein in the later life‐cycle stages. Studies of the importance of protein quality, i.e., source and amino acid balance, indicate that when marine protein sources, e.g., fish meal and shrimp meal, exceed 40% of the finished ration performance of the animal suffers. The improbability of lysine and methionine being limiting amino acids in practical rations is discussed.

In addition, the protein requirements of the Gulf of California brown shrimp, (Penaeus californiensis) is compared to non‐grooved shrimp, Penaeus stylirostris and Penaeus vannamei.
THE GROWTH RATE OF OYSTERS HELD IN THE INTAKE AND DISCHARGE CANALS OF AN ELECTRIC GENERATING STATION AND IN NATURAL WATERS
Authors: Margraf F. Joseph
Published: August 2010

Oysters (Crassostrea virginica) were held during the spring of 1976 in the intake and discharge canals at the P. H. Robinson Generating Station, Bacliff, Texas and in Galveston Bay at San Leon, Texas. Oysters in the discharge canal increased in weight significantly faster than in the intake canal or Galveston Bay. There was no significant difference between the weight increases in the intake canal and in Galveston Bay. No clear pattern of increase in length could be detected at the three stations. Although oysters in the discharge canal exhibited some degree of greening, the condition of the oysters from all three stations was good. The level of infection of Labyrinthomyxa was relatively low in oysters from all three stations; however, the incidence of infection was significantly greater in the discharge canal. Fouling organisms increased in weight in the discharge canal at a rate about twice that in the intake canal and Galveston Bay. Fouling could be controlled by exposing the oysters to air once each week for a period of 4–8 hr. Mortality, which was low at all stations, occurred early in the experiment and was probably due to initial culling stress. However, oysters held in the discharge canal beyond the study period died when water temperatures reached 37.5–39°C. The results of this experiment indicate that the growth rate of oysters can be significantly increased in a power plant discharge canal, provided that some means, such as cooling towers, are applied to keep high summer temperatures below lethal values.
DEPLETION/REPLETION OF ASCORBIC ACID IN TWO SPECIES OF PENAEID: Penaeus californiensis AND Penaeus stylirostris
Authors: Magarelli P. C. , Colvin L. B.
Published: August 2010

Depletion/repletion of ascorbic acid in whole body tissue was studied in 2 populations of shrimp (Penaeus californiensis and Penaeus stylirostris) using potentiometric titration. Biological half‐life (T1/2) for ascorbic acid (AsA) in P. californiensis and P. stylirostris was 12.5 days and 4 days, respectively. Depletion values for both species were in the range of 0.03 to 0.04 mg AsA g whole body tissue, while the repletion rate, given feed containing 9 and 14 g AsA/kg feed, was 0.01 mg AsA/g tissue per day. A supersaturation or “flush” phenomenon (0.06 mg AsA/g tissue per day and 0.04 mg AsA/g tissue per dayl followed by a swift depletion was observed when the shrimp were fed high doses of ascorbic acid (90 and 141 g AsA/kg feed for P. californiensis and P. stylirostris, respectively). Swift repletion of ascorbic acid tissue levels (0.08 mg AsA/g tissue per day) was also observed in P. stylirostris with access to algae.

The shrimp were maintained in flow‐through fiberglass aquaria containing no primary productivity or in a controlled environment aquacell which supported a flora of predominantly Enteromorpha sp.
GROWTH OF Homarus americanus ON Artemia salina DIETS WITH AND WITHOUT SUPPLEMENTATION
Authors: Rosemark R.
Published: August 2010

Aquaculturists rely heavily on the brine shrimp (Artemia salina) as a food source for fish larvae, decapods and cephalopods. Besides the difficulty in obtaining these cysts, they are costly. This study was designed to determine if an A. salina diet supplemented with macro algae and various scrap foods could obtain the same or better growth rate on juvenile lobsters than live A. salina fed as a single source diet.

The hepatopancreas of the lobster has been used as a criterion for determining the animal's general health. During this study, gross morphological examinations were made of the hepatopancreas of animals fed on both diets. This was done in order to determine if the characteristic color, size and firmness of the A. salina fed juveniles' hepatopancreases were accurate indicators of a “healthy” animal or characteristic of only the diet. After 90 days, the animals on the supplemented diet showed a significantly greater weight gain and increase in carapace length than the animals fed only A. salina. The hepatopancreas varied in color in the animals on the different feeding regimes. Though the size and firmness may be important criteria, the color cannot be used as a true indicator for a “healthy” animal.

The results of this study show that a supplemented diet can be an important economical factor in the application of practical aquaculture.
BRACKISH WATER POND POLYCULTURE OF ESTUARINE FISHES IN THERMAL EFFLUENT
Authors: Branch M. R. , Strawn K.
Published: August 2010

Three species of fish were cultured in 0.1 ha ponds from August 1976 to May 1977. Each pond received a constant flow of thermal effluent from the discharge canal of the Cedar Bayou Generating Station, Houston Lighting & Power Company. Striped mullet (Mugil cephalus) were maintained in polyculture with black drum (Pogonias cromis) and Atlantic croaker (Micropogon undulatus). These fish were also raised in mnoculture. Survival of mullet in polyculture with drum averaged 91.8%; in polyculture with croaker, 96.4%; in monoculture, 96.8%. Black drum survival averaged 95.5% in polyculture and 96.3% in monoculture. Croaker survived slightly better in monoculture at 39.3% compared to 33.5% in plyculture with mullet. Poor croaker survival was attributed to low cool season temperatures and handling mortalities. Growth of all species was improved in polyculture. Mean daily length and weight gains for mullet in monoculture were 0.22 mm/day and 0.35 g/day. These increased to 0.25 mm/day and 0.46 g/day in polyculture with drum, and 0.26 mm/day and 0.60 g/day in polyculture with croaker. Similarly, rates for black drum increased from 0.39 to 0.41 mm/day and from 0.76 to 0.90 g/day when raised with mullet. Monocultured croaker grew 0.21 mm/ day and 0.60 g/day, while in polyculture with mullet these increased to 0.28 mm/day and 0.69 g/day. Competition values indicated that daily yield of mullet and black drum was increased 30% and 20% respectively through polyculture. Growth of croaker was largely unaffected by addition of mullet into the system, but mullet growth was raised 78% through this association. Thermal additions to these ponds proved critical when seasonal grmth trends were examined.
UNITED STATES MARICULTURE DEVELOPMENT AND THE ECONOMIC EVOLUTION OF CATFISH SYSTEMS AS PARADIGMS OF RELEVANCE
Authors: Roberts K. , Bauer L.
Published: August 2010

Commercial catfish systems are frequently referred to as systems to be emulated in the public process of developing mariculture plans and legislation for the United States. The economic evolution of catfish culture is reviewed to identify the role of the public sector and market forces. An examination of catfish production operations of approximately 65 ha reveals near zero growth in returns on investment over the past 7 years. Following some technological improvements in the latter part of the last decade, the economic impact of technological change is not evident. High level managerial skill applied to the ponds and business are of paramount importance. A conclusion is that publicly supported pilot‐scale demonstrations should find justification in the testing and development of managerial skills as well as technologies. Thus, a training role for pilot‐scale facilities is worthy of public sector consideration.
COMPUTER TECHNOLOGY AND FARM MANAGEMENT ECONOMICS IN SHRIMP FARMING
Authors: Stamp N. H. E.
Published: August 2010

Agricultural economists and computer programmers have tended to overlook the practical managerial needs of aquacultural farmers and managers. As a result, the latter have been unable to tap the potential made available by dramatically reduced computer costs, by new programming languages, micro‐computers and simple economic optimization techniques.

This paper describes a computer system developed to aid the management of a moderate size shrimp farm. In addition to being useful and relatively inexpensive, this system is designed so as to be understood and used by non‐programmer managers and their staff.
A POPULATION DYNAMICS MODEL FOR PRAWN AQUACULTURE
Authors: Polovina J. , Brown H.
Published: August 2010

We have used a stochastic population model to simulate the prawn size distribution in the grow‐out ponds as a function of time. The model allows for growth and mortality parameters which are dependent on size class and pond biomass. We have written a computer program based on this model in which the user inputs a stocking number, a stocking size distribution, a stocking schedule, the harvest size classes, and a harvest schedule. The computer then computes the number of prawns and the prawn size distribution in the pond at specified time increments and a quarterly production economics summary.

We compare simulated growth and harvest data generated by the program to actual growth and harvest data from Hawaii and Florida. We also use the program to evaluate the effects of stocking number, stocking schedule and stocking size on annual yields from a prawn grow‐out pond.
A PRELIMINARY PHYSICAL AND ECONOMIC DESCRIPTION OF A PACIFIC SALMON HATCHERY IN SOUTHERN CHILE
Authors: Combs E. R. , Mayo R. D. , Nash C. E.
Published: August 2010

The Southern Ocean Salmon project under study by ICLARM (International Center for Living Aquatic Resources Management) and under consideration by Chile has as a major element a salmon hatchery tentatively located on the Salto Chico in southern Chile. This discussion, in the form of a progress paper, describes the physical concept on which this hatchery is based and develops a preliminary economic analysis for its operation. This analysis is, of course, very preliminary in nature although much of the cost information is taken from recent detailed studies of salmon enhancement in Washington State and Alaska.
TEMPORAL CHANGES IN THE SALINITY AND TEMPERATURE REQUIREMENTS OF TROPICAL MUSSEL LARVAE
Authors: Siddall S. E.
Published: August 2010

Two species of tropical mussels of the genus Perna are presently being cultured as food resources. The brown mussel of Venezuela (Perna perna) is raft cultured while the Philippine green mussel (P. viridis = Mytilus smaragdinus) is harvested from submerged bamboo poles. For this study, I imported, quarantined and spawned adults of both species in my laboratory and reared the larvae beyond metamorphosis (24 days) in replicate cultures at 40 different combinations of temperature and salinity. Response surface analyses of data collected at intervals show significant changes in the temperature and salinity optima for growth and survival during the planktonic stages preceding metamorphosis. However, analyses of the data taken only at the termination of the experiment predict quite different optimum conditions. These data amount to a biological summation of the varying temperature and salinity requirements of the larvae throughout the experimental culture. I have developed a generalized model for the growth responses of tropical mussel larvae which is presented as a motion picture study of the changing responses to temperature and salinity.
TECHNIQUES FOR CULTURING THE AMERICAN EEL
Authors: Rickards W. L. , Jones W. R. , Foster J. E.
Published: August 2010

American eels (Anguilla rostrata) have been cultured from the elver stage to marketable size in a flow‐through freshwater system. Elvers were captured in coastal freshwater streams using fine mesh dip nets and traps. The young eels were then held in indoor tanks where they became adapted to feeding on a prepared diet and they were treated for external parasites and diseases. When outdoor water temperatures stabilized above 18°C, the eels were transplanted to grow‐out ponds and reared to market size in 14 to 18 months.

The culture techniques described in this paper include: 1) obtaining elvers, 2) disease prophylaxis, 3) feeding adaptation, and 4) pond grow‐out. Details are presented concerning elver harvesting and transport, diets and feeding methods, and the culture system.
DEVELOPMENT OF A LARGE‐SCALE Artemia HATCHING SYSTEM UTILIZING RECIRCULATED WATER1
Authors: Smith T. I. J. , Hopkins J. S. , Sandifer P. A.
Published: August 2010

Wide variations in the production of Artemia nauplii were observed among cysts purchased from different suppliers as well as among batches obtained from the same suppliers. Some cysts hatched well after 18 or 24 hours while others required 48 hours to produce maximum availability of nauplii. Hatching salinity (12–36 ppt) appeared to be of relatively little importance as compared to batch and hatching time variations. A study which compared availability of nauplii at 2 salinities (30 and 15 ppt) and 2 hatching times (24 and 48 hours) indicated that cysts from 5 batches hatched as well or better in the lower salinity water (15 ppt). Finally, the hatching of cysts in solutions of synthetic sea salts or block salt (NaCl) resulted in the availability of similar numbers of nauplii.

A detailed description of a large‐scale Artemia hatching system using recirculated water is provided. The system consists basically of 2 950‐liter conical bottom hatching tanks, a nauplii/cyst separation tank, and a biological filter and water reservoir. It was designed to eliminate electrical hazards and to be semi‐automated. The system is relatively simple to operate and results in efficient hatching of cysts. The incorporation of a recirculating water system permits maintenance of optimal water quality throughout the hatching period and results in the conservation of materials and energy.
SYSTEM CONFIGURATION AND PERFORMANCE: BIVALVE MOLLUSCAN MARICULTURE
Authors: Pruder G. D. , Bolton E. T.
Published: August 2010

The University of Delaware Maricultural Project is working toward development of commercial, closed‐cycle, controlled environment shellfish mariculture. As the result of several years effort, the technical feasibility of raising bivalve molluscs from egg to market size in a re‐circulating system on a diet of cultured algae has been demonstrated.

A previous estimate of the quantity of algal cells required to support vigorous growth of oysters is revised. An indoor recycle system and a prototype greenhouse system are described. Results of work in the mass outdoor cultivation of algae, which contribute to establishing an abundant and reliable supply of food for bivalve molluscan mariculture, are discussed.
EVALUATION OP A RECIRCULATING FRESHWATER SALMON REARING FACILITY USING CLINOPTILOLITE FOR AMMONIA REMOVAL
Authors: Mumaw Laura , Bruin William , Nightingale John
Published: August 2010

The Seattle Aquarium has reared coho and Chinook fingerlings since 1978 in a 36,000 liter recirculating freshwater system utilizing clinoptilolite (clino) for ammonia removal. The system has effectively produced 140,000 smolts, due in large part to the efficient removal of fish‐excreted ammonia by the clino filters. Quantitative studies were performed to assess clino filter loading capacity and to establish effective recharging techniques. The operational characteristics of the clino filters and suggestions for using them in freshwater recirculating culture systems are discussed.
EASILY CONSTRUCTED, ECONOMICAL SEAWATER INTAKE AND SUPPLY SYSTEM
Authors: Bouck Gerald R.
Published: August 2010

A water intake system was designed and installed in Admiralty Inlet, Puget Sound, Washington. The dual system consisted of polyvinylchloride (PVC) pipes, a concrete pit and pumps located on shore at zero tide; and cables attached laterally to the pipelines and terminally between a shoreward anchor and to a seaward intake sled held in place with an 1800 kg Dansforth anchor. The overall construction costs were much lower than those for concrete‐lined ductile iron pipe. Nearly three years after its construction, this system has withstood tides and storms without apparent adverse effect. Its application to lakes or rivers is equally possible.
PERFORMANCE EVALUATION OF A SUSPENSION TRAY SYSTEM FOR THE CULTURE OF PACIFIC OYSTERS,Crassostrea gigas, IN TREVENEN BAY, BRITISH COLUMBIA
Authors: Wiley Kent , Zahradnik John
Published: August 2010

The objective was to design and evaluate a suspension oyster tray unit to optimize conditions necessary for the successful commercial culture of Pacific oysters for the half‐shell trade.

Units were located at two sites in Trevenen Bay. One location was sheltered and calm; the other was a natural tidal raceway with intense current flow. The purpose was to test the ability of the design to provide uniform growth, retard fouling, be handled efficiently and be economically feasible to construct. Assessing performance was based on monitoring shell growth, condition index, fouling occurrence, materials handling and the capital costs of the system. Field experimentation began in June and terminated in October 1979. Suspension tray units performed similarly at both sites, exhibited little variation in shell growth in the series of five trays in an assembly, retarded fouling and proved economically feasible for commercial use.
BUDGET ANALYSIS OF SHRIMP MATURATION FACILITY
Authors: Johns Michael , Griffin Wade , Lawrence Addison , Hutchins David
Published: August 2010

Shrimp maturation and reproduction has long been one of the hurdles that must be surmounted to make shrimp farming commercially feasible. Nauplii are now successfully being produced and the commercial feasibility of their production is investigated in this study. The generalized budget simulation model for aquacultural facilities recently developed at Texas A&M University was used for the analysis.

An annual budget was estimated to determine costs, returns and profit. Annual cash flow was generated for a 10‐year planning horizon. Opportunity cost, initial investment, costs and break‐even quantities and prices were also determined.
GROWTH OF WHITE STURGEON (Acipenser transmontanus) UNDER HATCHERY CONDITIONS
Authors: Monaco George , Buddington R. K. , Doroshov S. I.
Published: August 2010

White sturgeon juveniles were raised for 10 months posthatch under various regimens of feeding, water temperature, and stocking density. Transition to external feeding in larvae occurred 9 to 11 days posthatch and was accompanied by major changes in allometric growth and larval behavior. Condition factor, hepatosomatic index, and survival rate varied significantly throughout the rearing period in the 4 progenies investigated. Growth in body weight for all progenies was largely dependent on water temperature and feeding. On the average, fingerlings raised on natural diets (brine shrimp and tubifex, followed by ground fish) grew 6% of their body weight per day, whereas fingerlings fed artificial pelleted diets (Oregon Moist Pellets) or a mixture of pelleted and natural feeds grew 1–4% per day. Certain individuals (20% of population investigated), however, established a strong feeding performance on artificial diets and exhibited twice the growth rate of fish raised on natural diets; these fish reached a mean body weight of 282 g at 10 months post‐hatch. Assuming more efficient procedures are developed for weaning this fish onto artificial diets, the white sturgeon has demonstrated a potential for use in intensive grow‐out systems.
PRELIMINARY REPORT ON THE AQUACULTURAL DEVELOPMENT OF THE DOLPHIN FISH, Coryphaena hippurus (LINNAEUS)
Authors: Hagood R. W. , Rothwelly G. N. , Swafford M. , Tosaki M.
Published: August 2010

First and second generation (F1 and F2), laboratory reared juvenile Coryphaena hippurus were used in preliminary growth studies. Fish were stocked in circular tanks and fed a diet of chopped herring and squid. Initial size and age of fish used in these studies were as follows: 61 mm TL, 1.6 g, and 45 days old for F1 and 87 mm TL, 5.95 g, and 65 days old for F2. Mean size at 130 days of age was 560 mm TL and 1,305 g for F1 and 540 mm TL and 1,150 g for F2. Food conversion ratios were 3.05 and 2.9 4 for F1 and F2 fish, respectively.
COMMERCIALIZATION OF HARD CLAM (Mercenaria mercenaria) MARICULTURE IN SOUTH CAROLINA: PRELIMINARY REPORT1
Authors: Manzi John J. , Burrell Victor G. , Clawson Harry Q. M.
Published: August 2010

Results from both previous and ongoing investigations on hard clam culture in South Carolina indicate a reasonable commercial potential for intensive clam culture on an industrial scale. To assess this potential and provide an appropriate economic feasibility analysis, the State of South Carolina, in cooperation with private industry and the U.S. Office of Sea Grant, has established a demonstration scale hard clam culture project near Charleston, S.C. The project operates on a two‐stage grow‐out protocol: raceways are used to provide initial grow‐out (to 10 mm) and allow acclimation and disease monitoring for imported seed; final grow‐out is accomplished in field units which provide protection from predators and substrate for support and orientation. Seed clams ranging in size from 300 μ to 10 mm are imported from commercial hatcheries, held in the raceway system for growth and observation and transferred to field units as they acclimate or attain minimum field planting size. Using this protocol, over 2.7 million seed are being planted in South Carolina estuaries over a 13‐month period (October 1980‐October 1981). Field units are stocked at three densities, 2,150, 4,300, and 6,450 m‐2, using both intertidal and floating (raft) formats and a variety of substrates (crushed granite, chromium oxide slag, coarse sand, etc.). Units are sampled monthly to determine growth and survival, and these data are correlated with coincidental monitoring of various environmental parameters (temperature, salinity, particulate, dissolved, and total organic carbon, chlorophyll a, and turbidity). This paper reviews results to date and provides descriptive data concerning the raceway system, field units, and support equipment.
MONO‐ AND POLYCULTURE OF Penaeus vannamei AND P. stylirostris IN PONDS
Authors: Chamberlain George W. , Hutchins David L. , Lawrence Addison L.
Published: August 2010

Polyculture of fish has been shown to be an effective means of increasing production beyond that achieved in monoculture, but little research has been conducted to evaluate the effect of polyculture on production of shrimp species. This research was designed to investigate performance of Penaeus vannamei (v) and P. stylirostris (s) in monoculture (treatments 100v and 100s) as well as in polyculture at various species ratios (75v:25s, 50v:50s, and 25v:75s) at a constant density of 1.8 × 105 /ha. Shrimp were stocked into fifteen 0.1‐ha ponds at the Texas A&M University Mariculture Facility for 123–134 days. Results indicate a higher mean survival rate (73 vs 22%) but lower mean growth rate (0.09 vs 0.14 g/day) of P. vannamei than P. stylirostris. Survival rates of neither species differed significantly among treatments. Final weight of each species significantly decreased with increasing density of the same species but significantly increased with increasing density of the other species. Best growth of both species occurred in the 75v:25s treatment. Observed differences in distribution and diel activity of the two species within ponds may partly explain the compatability of these two species in polyculture. Production rates (range, 690 to 2,180 kg/ha) and value (range, US$2,720 to US$5,740/ha) among treatments generally increased with increasing composition of P. vannamei; however, no significant difference in mean value was detected between the 100v and 75v:25s treatments.

As a secondary objective of this study, performance of shrimp (25v: 75s treatment) in a single‐phase pond system was compared to that in a three‐phase (nursery, intermediate, and grow‐out) system. Survival, growth, production, and value were found to be similar between systems.
PARASITES AND PARASITOSIS IN FISH CULTURE IN PORTUGAL
Authors: Carvalho‐Varela M. , Cunha‐Ferreira V. , e Silva M. P. Cruz , Monteiro M. T. , Grazina‐Freitas M. S.
Published: August 2010

This paper deals with research work covering the period from May 1979 up to May 1981 and presents results of parasites and parasitosis diagnosed in a total of 195 complete dissections of six fish species from cultured and feral populations in Portugal: European eel (Anguilla anguilla) (49); mirror carp (Cyprinus carpio specularis) (29); common grey mullet (Mugil cephalus) (18); European plaice (Pleuronectes platessa) (11); rainbow trout (Salmo gairdneri) (42); common sole (Solea solea) (46).

A list of protozoans and helminths identified with respective incidence is given:

A) Feral fish: 1) European eel (17)—Echinorhynchus clavula 11.8% and Rhabdochona anguilla 5.9%; 2) common grey mullet (18)—Haploporus benedenii 16.7%, Neoechinorhynchus sp. 5.6%, and Raphidascaris sp. 5.6%; 3) European plaice (11)—Bothriocephalus sp. larvae 9.1%, Contracaecum aduncum 9.1%, and Cryptocotyle lingua 9.1%; 4) common sole (46)—Cucullanellus minutus 8.7%, Gyrodactylus elegans 4.3%, and Cestodes larvae 2.2%.

B) Cultured fish: 1) European eel (32)—Trichodina anguillae 3.1% and Ichthyophthirius multifiliis 18.8%; 2) rainbow trout (42)—Eimeria truttae 2.4%, Hexamita intestinalis 4.8%, Holophrya simplex 2.4%, and Trichodina truttae 4.8%.

The results show that feral fish harbor predominantly indirect life cycle helminths, in contrast with cultured fish only affected with protozoans, due mainly to overcrowding and deficient management, which propitiate a significant background infection. It was in these specimens that some lesions characteristic of protozoosis were found.
NOCTURNAL ACTIVITY OF BIRDS ON SHRIMP MARICULTURE PONDS
Authors: Beynon Jeffrey L. , Hutchins David L. , Rubino Anthony J. , Lawrence Addison L. , Chapman Brian R.
Published: August 2010

Birds can reduce production of shrimp in mariculture grow‐out ponds through predation and competition for feed. This study involved weekly nocturnal enumeration of bird populations and observation of nocturnal avian habits on a series of 0.1 ha experimental ponds at the Texas A&M University Shrimp Mariculture Facility at Corpus Christi, Texas. Observations were conducted hourly from sunset to sunrise during October through December 1980. The rate of predation was evaluated every three hours by comparing the number of feeding attempts to the number of successful prey captures over a known time period.

Gulls (Family Laridae) acted primarily as competitors for feed. Active feeding by gulls was restricted to daylight hours, consequently feed loss decreased when the feed was distributed at or after dusk. Major preadatory birds included herons and egrets (F. Ardeidae), migratory ducks (F. Anatidae), and, to a lesser extent, grebes (F. Podicipedidae) and shorebirds (Order Charadriiformes). Bird predation decreased pond production by 75% in some ponds.
THE EFFECT OF FISH MEAL CONTAINING DIFFERENT LEVELS OF FISH SOLUBLES ON THE GROWTH OF RAINBOW TROUT (Salmo gairdneri)
Authors: Gulbrandsen K. E. , Utne F.
Published: August 2010

Two experiments were conducted to examine the effect of fish soluble additives in fish meal used as a protein source in dry diets to rainbow trout. Experiment I was made up by 3 dietary groups, run with 4 replicates of 100 trout on each diet. The protein sources examined were as follows: (1) presscakemeal, (2) whole meal, and (3) whole meal + lysine to the same levels as (1). The experiment was run for 12 weeks with ad libitum feeding three times a day. The results showed significantly lower (P < 0.05) weight gain for trout given presscakemeal as compared with whole meal. Experiment II evaluated 3 diets, run in triplicates with 100 trout in each aquarium. Presscakemeal (1), whole meal (2), and whole meal + extra addition of fish solubles (3) were examined as protein sources. The experiment was conducted for 16 weeks. The average weight gains were not significantly different among the dietary groups. The conclusion drawn from the experiments is that fish meal with fish soluble additives is preferred as a protein source in feed for rainbow trout.
NET‐PEN CULTURE OF STRIPED BASS X WHITE BASS HYBRIDS IN ESTUARINE WATERS OF SOUTH CAROLINA: A PILOT STUDY1
Authors: Williams Josephine E. , Sandifer Paul A. , Lindbergh Jon M.
Published: August 2010

In 1978 a cooperative pilot study was initiated by the Marine Resources Research Institute and DØMSEA Farms, Inc. to examine the feasibility of rearing striped bass (Morone saxatilis) x white bass (M. chrysops) hybrids to marketable pan‐size in estuarine net‐pens. The first study was begun in July 1978 when a total of 1,070 hybrid fingerlings (mean weight, 1.7 g) were stocked in 3.05 × 2.44 × 1.83 m deep net‐pens moored to a commercial marina dock on the Stono River near Charleston, S.C. During the first month these fish suffered a 76% mortality, apparently as a result of feeding only a dry salmon ration. Thereafter, the remaining fish were fed the dry ration mixed approximately half‐and‐half with ground fish. At the end of one year, these fish had attained a mean weight of 523.0 g, with 74.6% survival.

A second experiment was begun in July 1979 when 900 hybrid fingerlings (mean weight, 3.0 g) were stocked in each of three 3.05 × 2.44 × 1.83 m net‐pens at the marina (stocking density, ˜66 fish/m3). The fish were fed a mixture of dry salmon feed and ground fish throughout. At the end of one year, survival and weight averaged 88% and 310.2 g, respectively. Biomass in the pens at this time averaged 16 kg/m3.

Little growth or active feeding occurred at temperatures < 15°C. In contrast, salinity variations had no apparent effect on growth. However, a period of decreasing salinity in early spring coincided with an outbreak of a bacterial disease (cf. Vibrio anguillarum) among striped bass fingerlings reared in adjacent pens. Fish which had been treated with a vaccine solution did not succumb to the disease, while approximately 50% mortality occurred among non‐vaccinated fingerlings.
ACUTE TOXICITY OF NITRITE TO SEA BASS (Dicentrarchus labrax) AND EUROPEAN EEL (Anguilla anguilla)
Authors: Saroglia M. G. , Scarano G. , Tibaldi E.
Published: August 2010

Static acute toxicity tests of 4 and 7 days duration were performed on sea bass (Dicentrarchus labrax) and European eel (Anguilla anguilla). The 96‐hour LC50 for sea bass (x̄; = 5 cm) was 274, 220, and 154 mg/liter N‐NO2 at water temperatures of 17, 23 and 27°C, respectively, in sea water. The 96‐hour LC50 for eel elvers was 84, 213, 264, 503, 812 and 974 at salinities of 0, 6, 12, 24, 30 and 36 g/liter.
RELATIVE EFFICACY OF TWO ARTIFICIAL SUBSTRATES IN THE COLLECTION OF SEA SCALLOP (Placopecten magellanicus) SPAT
Authors: Naidu K. S. , Cahill F. M. , Lewis D. B.
Published: August 2010

Relative efficacy of two substrates commonly employed for procuring scallop spat is described. Monofilament gillnetting was superior to flexible polyethylene insofar as collecting greater numbers of sea scallops was concerned. Overlapping in sheet polyethylene resulted in rapid substrate saturation thus reducing substrate surface for larval attachment.
THE CONTROLLED REPRODUCTION OF THE CARPET‐SHELL CLAM (Venerupis decussata [L.]): PRELIMINARY RESULTS
Authors: Breber Paolo
Published: August 2010

Trials to obtain out‐of‐season spawning in 13 lots of V. decussata are described. When the animals are considered to be ripe they are treated by thermal and chemical stimulus to set off spawning. A preliminary trial clearly indicated the necessity of feeding the animals undergoing conditioning. Spawning with development of larvae was achieved in two instances after conditioning for two months at 20°C. But inconsistent results in other attempts question the reliability of this method. The culture of 2 lots of larvae is described. After 3 months from egg fertilization clams reach 5 mm mean size with 1% survival.
L‐LACTIC ACID ACCUMULATION DURING ACTIVITY STRESS IN Macrobrachium rosenbergii AND Penaeus duorarum
Authors: Spotts Daniel G. , Lutz Peter L.
Published: August 2010

Energy demand during the stress of activity and handling of aquaculture animals often induces anaerobic metabolism causing lactic acidosis. Although noted in fish and some crustaceans the extent, or rate of lactic acid accumulation in commercial species of shrimp and prawns during exercise is unknown. Whole body lactic acid concentrations in resting and exhausted Macrobrachium rosenbergii and Penaeus duorarum were obtained after immersion in liquid nitrogen. Lactic acid increased sixfold from 0.091 ± .015 mg lactic acid/g body weight to 0.610 ± 0.045 mg/g after an average of 1.4 minutes of activity in M. rosenbergii. Similarly, concentrations increased over five‐fold from 0.121 ± 0.040 mg/g to 0.630 ± 0.250 mg/g after an average of 0.9 minutes in P. duorarum. The implications of these large and rapid accumulations of lactic acid following handling stress are discussed with reference to disease and mortality as well as product quality.
CONSUMPTION OF FROZEN AND LIVE Artemia BY PROTOZOEA OF Penaeus setiferus
Authors: Wilkenfeld Joshua S. , Fox Joe M. , Lawrence Addison L.
Published: August 2010

The role of an animal component in the diet of protozoeal penaeid shrimp larvae is not known. Short‐term experiments were performed on the larvae of Penaeus setiferus (L.) to determine the ability of each protozoeal substage to consume frozen and live Artemia nauplii. Significant consumption of frozen Artemia took place during the protozoea 2 and 3 substages at rates of 1.0 and 1.6 Artemia nauplii/penaeid larva/hour respectively. Consumption of live Artemia occurred in the protozoea 3 substage, at a rate of 0.7 Artemia nauplii/penaeid larva/hour. Data suggesting that there is a beneficial role of an animal component in the diet of protozoeal penaeid shrimp larvae are discussed.
USE OF Spirulina IN SHRIMP (penaeus japonicus) DIET
Authors: Cuzon Gérard , Santos Rossana Dos , Hew Meng , Poullaouec Gilles
Published: August 2010

Spirulina is a unicellular algae with good nutritional value. Its efficiency has been shown in Artemia salina and penaeid shrimp diets. To investigate the origin of this good nutritional value in shrimp, experiments were carried out on Penaeus japonicus juveniles. Pelleted diets containing various proportions of Spirulina from 0 to 8% were fed to shrimp. Good growth, survival and pigmentation were obtained with the diet containing 8% Spirulina.

When replacing Spirulina completely by another single‐cell ingredient source, lactic yeast, shrimp pigmentation was markedly reduced. Otherwise, growth performances were nearly similar.

To identify the active fraction of Spirulina powder, an extraction was performed to separate two fractions, the lipidic and the lipid‐free. Preliminary growth results of shrimp fed diets containing these extracted fractions showed that the active fraction of Spirulina was more likely found within the lipid‐free fraction, rather than the lipidic fraction.

Even though Spirulina can contribute positively to formulation of shrimp diets, it is too expensive (within the French economic context) to be incorporated at high percentage. But a substitution of lactic yeast for Spirulina is feasible as far as shrimp growth and survival are concerned.
BUDGET ANALYSIS OF PENAEID SHRIMP HATCHERY FACILITIES
Authors: Johns Michael , Lawrence Addison , Fox Joe , Griffin Wade
Published: August 2010

One of the critical factors in commercial penaeid shrimp culture production is the availability of postlarvae to stock grow‐out ponds. This study investigates the economic feasibility of rearing penaeid shrimp from nauplii to postlarvae (hatchery phase). The facility design used is based on the hatchery operated by Texas A&M university at Galveston, Texas. The Generalized Budget Simulation Model for Aquaculture developed at Texas A&M University was used for the analysis.

A ten‐year planning horizon was used for the analysis. Six different systems ranging in size from 5 ten‐metric ton tanks to 60 ten‐metric ton tanks were examined. Annual cost and return budgets were developed for the six systems assuming they operated 6 and 12 months per year. Investment costs, break‐even prices and quantities, and net present value were estimated for each system.

Results show that commercial hatcheries, using 10‐metric ton tanks, could be profitable above and including 20 tanks for those operating only six months annually and above and including 10 tanks for those operating 12 months annually.
ARTIFICIAL REPRODUCTION OF Penaeus japonicus BATE AS A BASIS FOR THE MASS PRODUCTION OF EGGS AND LARVAE1
Authors: Lumare Febo
Published: August 2010

Penaeus japonicus Bate is absent on the Italian coasts, but it is considered a very promising species for national aquaculture.

To develop the shrimp‐culture on a commercial basis, a convenient method for producing eggs and larvae of Penaeus japonicus was studied. A stock of 156 females, age class 1+ and F3, underwent unilateral eyestalk ablation and they were stocked with males in three plastic tanks (bottom area 14 m2) at a density of 25 individuals/m2 and a sex ratio of 1:1. Conditions of environment and management consisted of: temperature 21±3°C; natural light and photoperiod; total exchange of sea water every day; feeding on mussels. A month after eyestalk ablation the females were inspected every 7–10 days; mature females were transferred to the spawning tanks. Females with well developed gonads averaged 25.0% of the population of females at every inspection; 51.3% of spawners were impregnated with spermatophores; others were inseminated artificially by the method of introducing spermatophores into the thelycum.

In six inspections (carried out during a period of 89 days), 3,028,525 eggs were released; a female released 17,500 eggs on the average (maximum was 123,000 eggs, minimum 4,340). The mean rate of fertilized eggs was 52.7%—67.7% from naturally inseminated females and 7.5% from the artificially inseminated ones. The mean hatching rate was 30.9%—40.1% from natural insemination and 3.3% from artificial insemination. Total amount of viable nauplii was 820,550.
EFFECT OF LIGHT INTENSITY AND MALE AND FEMALE EYESTALK ABLATION ON REPRODUCTION OF Penaeus stylirostris AND P. vannamei
Authors: Chamberlain George W. , Lawrence Addison L.
Published: August 2010

This 97‐day study, conducted during midwinter using a recirculating water system, was designed to evaluate the effect of light intensity and male and female eyestalk ablation on reproduction of P. vannamei and P. stylirostris.

Four light intensities were established using various levels of fluorescent lighting (bright, 14.7 μEm‐2s‐1; moderate, 4.4 μEm‐2s‐1; dim, 0.6 μEm‐2s‐1; and dark, 0.0 μEm‐2s‐1) and the fifth consisted of artificial lighting supplemented with natural light through a translucent skylight (skylight, 4.7–9.3 μEm‐2s‐1). Unilateral eyestalk ablation was performed on all male P. vannamei in one of each pair of tanks within a treatment. In addition, half of the females in each tank were unilaterally ablated. Ovarian maturation, spawning, molting rate, and survival were monitored daily within each tank. Growth and gonad development were measured at termination.

The optimum light intensity for P. stylirostris appeared to be lower than that for P. vannamei. P. stylirostris matured and spawned more frequently in the skylight and dim treatments than in the moderate, dark, and bright treatments. P. vannamei matured and spawned more frequently in the skylight, bright, and moderate treatments than in the dim and dark treatments. Natural light supplementation beneficially affected reproduction of both species.

Male eyestalk ablation increased gonad size and doubled mating frequency of P. vannamei in comparison to unablated controls. This is the first documentation of increased penaeid shrimp reproduction by unilateral eyestalk ablation of males. Even more significant may be recognition that male gonadal development is a limiting factor in reproduction of shrimp in captivity.
CALCIUM REQUIREMENTS FOR MOLTING IN Macrobrachium rosenbergii
Authors: Fieber Lynne A. , Lutz Peter L.
Published: August 2010

Calcification of the new exoskeleton is the culmination of a successful molt in crustaceans. This study showed that in Macrobrachium rosenbergii calcium present in the intermolt exoskeleton is moved internally as the molt approaches. Cyclic variations in the calcium concentrations of hemolymph, hepatopancreas and exoskeleton occur between successive intermolt periods. During premolt, hemolymph calcium concentration increases from an intermolt level of 7.67 to 14.8 mmole Ca+2 liter‐1 while in the hepatopancreas the change is from 0.77 to 1.22 mmole Ca+2·g dry wt‐1. An increase in calcium concentration of the exoskeleton appears to occur over this period (from intermolt 2.92 to 6.68 mmole Ca+2· g dry wt‐1). Thus, there is a mobilization of calcium to internal storage sites during premolt. Both the hemolymph and the hepatopancreas store calcium during premolt. Hemolymph and hepatopancreas stores are exhausted b the mid‐postmolt phase, falling to a minimum of 4.61 mmole Ca+2 liter‐1 and 0.31 mmole Ca+2·g dry wt‐1, respectively, while total calcium increases, from 0.56 to 1.39 mmole ·g dry wt‐1. The molting process causes a total calcium deficit that must be repaid from internally compartmentalized stores or from some external calcium source. Although internal sources of calcium are important for postmolt calcification in M. rosenbergii, our study indicates that additional uptake of calcium from freshwater may be necessary for complete calcification of the exoskeleton.
MARKETING OF CULTURED PRAWNS, Macrobrachium rosenbergii, IN SOUTH CAROLINA1
Authors: Liao David S. , Smith Theodore I. J.
Published: August 2010

Three marketing approaches were investigated for small‐scale aquaculture of prawns: 1) seafood retail markets, 2) seafood restaurants, and 3) direct sales to consumers. A market test with locally produced pond‐reared prawns was conducted in four seafood retail stores and seven seafood restaurants in South Carolina. Prawns, sold as ungraded tails at prices ranging from $8.79‐11.01/kg, were highly saleable in the retail markets. All retailers indicated that they would add this aquafood to existing product lines and stated a preference for fresh prawns in the medium size category (78–110 tails/kg).

Restaurants prepared the prawns as sauteed, steamed, broiled, stuffed, and microwave‐oven cooked. The prices charged for the prawn dinners ranged from $5.95 to $12.00 per serving. Five of the seven seafood restaurants who participated in the marketing trials indicated that they would purchase prawns for their restaurant operation if a suitable supply were available. Depending on the entree, prawns might be marketed as tails or as whole animals in the seafood restaurant trade.

Some prawn producers who participated in cooperative rearing trials during 1981 sold their crop directly to consumers as ungraded prawn tails at prices of $10.90 and $13.20/kg. This marketing approach greatly reduces the producer's costs for processing, packaging, storage, and transportation. In addition, direct consumer sales have fewer restrictions in regard to: size of the product; volume of orders; and packaging, as compared to purchases by seafood restaurants and retail markets. For the predicted near term production of prawns in South Carolina, this marketing approach appears most attractive.