bluuebunny/crossref_metadata_2025 huggingface dataset:
The Introduced Fish Problem and the Aquarium Fish Industry
Authors: Courtenay Walter R. , Stauffer Jay R.
Published: April 2007

Of the 46 species of foreign fishes known to be established as reproducing populations in open waters of the contiguous United States, approximately 65% are known or presumed to have originated from the aquarium fish trade. Many escaped or were released from aquarium fish culture facilities and some were introduced by aquarists. More than 50 additional, non‐established fishes, mostly aquarium species, have been collected in the wild. These introductions, with established populations, have not been restricted to the so‐called Sun Belt states, but have occurred throughout the U.S.

Because many introductions have resulted in serious negative impcts to native fishes, and most have the potential to do so, it is imperative that the aquarium fish industry and trade take measures to curtail such releases. The means of accomplishing this goal are relatively inexpensive. Industry must assist in public education to reduce introductions by aquarists.
The Effect of Different Dietary Energy Levels on Growth and Survival of Eyestalk Ablated and Intact Juvenile Lobsters Homarus americanus
Authors: Koshio Shunsuke , O'Dor Ron K. , Castell John D.
Published: April 2007

When fed formulated diets containing 45% protein derived from the rock crab Cancer irroratus, wheat gluten, gelatin, lipids adjusted from 3–14% and carbohydrates adjusted from 5–24%, the average survival of bilaterally eyestalk ablated juvenile lobsters and intact controls were 91% and 99%, respectively over a 90‐day experiment. Photopenad (13 light: 11 dark vs 3 light: 21 dark) did not have a significant effect on growth or survival of ablated or intact lobsters. The optimal digestible energy levels and protein/energy ratio for the greatest growth in both ablated and intact lobsters were 3.7 to 3.8 (kcal/g dry) and 0.12 [g protein/(kcal/g)], respectively. The best feed conversion ratios (0.97 and 1.40 diet given/weight gain) for ablated and intact lobsters were obtained with diets containing 3.83 kcal/g and 3.63 kcal/g diet, respectively. The present study also demonstrated that crab protein served as a good protein source for intact and ablated lobsters.
Bioencapsulation of Therapeutic Quantities of the Antibacterial Romet‐30 in Nauplii of the Brine Shrimp Artemia and in the Nematode Panagrellus redivivus
Authors: Mohney Leone L. , Lightner Donald V. , Williams Rodney R. , Bauerlein Michael
Published: April 2007

Nauplii of the brine shrimp, Artemia, and cultures of the soil nematode, Panagrellus redivivus, were fed a suspension of the water‐insoluble antibacterial Romet‐30 (sulfadimethoxine plus ormetoprim) to determine if they could be used as a mechanism for delivery of the drug to larval penaeid shrimp.

Romet‐30 was added to groups of brine shrimp nauplii and nematodes in 1 L beakers to achieve a concentration of 3 mg of drug per ml of seawater. After a 4 h uptake period, predetermined numbers of organisms were assayed for antibiotic content using the micro‐plate diffusion method and a Romet‐30 sensitive strain of Vibrio alginolyticus as the indicator. The resulting zones of inhibition were compared to that of a standard Kirby‐Bauer sensitivity disc containing 25 μg of the drug that was placed on each plate as standard control. Negative controls consisted of equal numbers of nauplii and nematodes that were not exposed to the antibiotic. Artemia nauplii and nematodes accumulated approximately 0.1 μg of the drug per nauplius and approximately 0.25 μg per nematode. They exhibited no signs of toxicity from exposure to the drug and contained the antibiotic in sufficient quantity to provide a theoretical therapeutic dose of the drug when fed to penaeid larvae.

In subsequent tests, normal and diseased larval Penaeus stylirostris readily accepted Romet‐30 enriched Artemia. Diseased larvae fed the drug in this manner exhibited a statistically greater overall survival and a greater survival to the post‐larval stage by Student's t‐test at the 5% significance level.
Preliminary Investigations into the Socio‐Economic Feasibility of Saltwater Cage Culture of Florida Red Tilapia in Haiti
Authors: Brass Jane L. , Rust Michael B. , Olla Bori L. , Wicklund Robert I.
Published: April 2007

The primary objective of this study was to investigate the socio‐economic feasibility of saltwater cage culture of Florida red tilapia as a new production activity in Haiti. Market outlets and potential prices for saltwater‐reared red tilapia in Haiti were examined. Availability and prices of inputs to production were considered. Although this information was collected in the context of Haiti, it is relevant to other developing countries when assessing the potential for a mariculture industry.

Two types of market outlets for saltwater‐reared red tilapia were found to exist in Haiti. The predominant rural market sector treated red tilapia as a low‐value species and paid an average price ($0.90/kg roundweight) similar to that for freshwater black tilapia. Urban specialty markets treated red tilapia as a premium quality fish and paid an average price ($2.20/kg cleaned) equal to that for snapper and grouper.

Comparison of production costs to potential market prices indicates that saltwater cage culture of tilapia is not economically feasible on an artisanal scale and is a high financial risk on a commercial scale. Break‐even prices are higher than prices in the large rural market sector. No data exists to indicate sufficient demand in the smaller urban specialty market sector or export markets.
Use of Dietary Yeast Saccharomyces cerevisiae Nitrogen by Lake Trout
Authors: Rumsey Gary L. , Hughes Steven G. , Kinsella John L.
Published: April 2007

In a 12 week experiment, lake trout (Salvelinus namaycush) were fed diets in which 50% of the nitrogen was provided by one of six preparations of Saccharomyces yeast. Fish fed baker's yeast with disrupted cell walls grew at a rate equal to that of fish fed the control diet and faster than fish fed intact yeast cells. Fish fed a diet containing disrupted yeast cells previously washed in a saline solution did not perform as well. The results of this study indicated that it may be possible to use more than 50% yeast in the diets of salmonid fishes.
An Econometric Estimation of Market Growth for the U.S. Processed Catfish Industry
Authors: Zidack Walter , Hatch Upton
Published: April 2007

Inadequate information pertaining to the growth potential of the US. processed catfish industry has been a major factor leading to cyclical periods of excess supply or demand resulting in misal‐location of resources and price instability. Better information for industry planners (e.g., producers, processors, government regulatory agencies, and university researchers) on future sales potential would assist in decreasing the misuse of resources. An econometric model of wholesale demand for US. processed catfish was developed to provide estimates of future sales under various scenarios. In addition to the standard variables included in models of demand for food items—price, income, and population—the effects of product life cycle and industry‐sponsored generic advertising are quantitatively incorporated. Seasonality of demand and rigidities in marketing and consumer behavior are additional considerations explicitly modeled via monthly dummy variables and a Ner‐lovian partial adjustment mechanism, respectively.

Model results indicate the impact of alternative future price scenarios on wholesale processed caffish sales. At the mean real wholesale price of $1.60 (December 1988 dollars) for whole‐dressed caffish and a real generic advertising expenditure of one million dollars postulated for 1995, projected aggregate sales are 219.2 million pounds, a 23% increase over 1989 sales. Projected 1995 wholesale sales are very sensitive to price with alternative price postulations of $1.40 and $1.80 resulting in projected sales of 252.3 and 193.6 million processed pounds, respectively. An estimated 7% average increase in wholesale sales of catfish was attributed to the industry‐sponsored generic advertising campaign. Model projection estimates and impacts are posed as a quantitative source of information to be used with other information in resource allocation issues faced by industry decision makers.
Effects of Diffused Aeration and Stocking Density on Growth, Feed Conversion, and Production of Florida Red Tilapia in Cages
Authors: Hargreaves John A. , Kakocy James E. , Bailey Donald S.
Published: April 2007

The effects of four levels of diffused aeration (0, 6, 12, and 24 hours/day) and two stocking densities (400 and 600 fish/m3) on the culture performance of caged Florida red tilapia were evaluated in 1 m3 cages in a 2 ha watershed pond on St. Croix, U.S. Virgin Islands. Fish obtained a nutritionally‐complete (36% protein), floating feed from demand feeders for 143 to 146 days. Diffused aeration had no significant (P > 0.05) effect on fish growth, survival, feed conversion, and production in cages. Combined across all levels of diffused aeration, fish stocked at 400/cage had a greater growth rate (2.21 vs. 1.97 g/day), larger final body weight (370 vs. 335 g), and a lower feed conversion ratio (1.69 vs. 1.80) than fish stocked at 600/cage (P < 0.05). The final biomass of fish stocked at the higher density (181 kg/m3) was greater than at the lower density (140 kg/m3). The enhancement of water exchange rates by diffused aeration did not increase tilapia growth rate or production in cages.
Lethal Effect of Nitrite on Metapenaeus ensis Larvae
Authors: Chen Jiann‐Chu , Nan Fan‐Hua
Published: April 2007

Metupenaeus ensis larvae at different stages were exposed to a series of nitrite‐N (nitrite as nitrogen) concentrations in static renewal toxicity tests. Larvae at zoea stage were the most susceptible, and postlarvae were the most tolerant to nitrite among the larvae tested. The 24 h LC50s were 31.29, 16.05, 47.60 and 70.06 mg/L nitrite‐N for third nauplius substage (N3). second zoea substage (Z2), second mysis stage (M2), and first postlarva substage (PL1), respectively, in 33 ppt seawater at a pH of 8.20 and a water temperature of 30 C. The 48 h LC50 for M2 and PL1 were 20.67 and 27.10 mg/L nitrite‐N, respectively. The “threshold time” was 108 h, and the “incipient LC50” for M. ensis PL1 was 7.06 mg/L nitrite‐N. A “safe level” for rearing M. ensis larvae was estimated to be 0.71 mg/L nitrite‐N in the hatchery.
Water Quality and Microbial Dynamics in Shrimp Ponds Receiving Bagasse‐Based Feed
Authors: Visscher Pieter T. , Duerr Eirik O.
Published: April 2007

Pond water quality and associated microbial biomass were studied in relation to the type of feed applied during the culture of the marine shrimp Penaeus vannamei. The feeds tested included conventional feedlot manure as well as two feeds based on bagasse, a sugarcane waste product. Physical and chemical parameters were studied during a 100 day trial in 200 m2 earthen ponds. Both bagasse‐based feeds supported a significantly larger microbial community as measured by specific biomass numbers (P < 0.01), ATP content (P < 0.001) and amount of the particulate organic matter present on pond bottoms (P < 0.025). For both bagasse‐based treatments, the estimated bacterial cell number in the flocculent layer was 3.11 ± 1012/m2, compared to the much lower cell number of 7.53 ± 1010/m2 for control ponds. Harvest data suggest that bagasse forms a potential base for feeds when applied to extensive shrimp cultures.
Production Characteristics of PanSize Channel Catfish in Cages and Open Ponds1
Authors: Davis Scott A. , Schwedler Thomas E. , Tomasso Joseph R. , Collier John A.
Published: April 2007

Production characteristics of pan‐size (approximately 227 g) channel catfish (Ictalurus puncturus) were determined in cages and open ponds stocked with fingerlings to densities of 20,000 and 12,500 fish/ha. After 145 days, mean fish weight in all treatments exceeded 227 g. Mean survival was similar in all treatments. Food conversion ratios were significantly better in ponds than in cages but density did not affect the ratios. Neither density nor production system affected production (as measured by total weight produced) when initial density differences were considered (analysis of covariance). Variability in total length at harvest was similar between production systems; however, low density treatments were less variable than high density treatments. Results of this study indicate that pan‐size channel catfish can be cultured efficiently at stocking densities well above the 12,500 fish/ha (5,000 fishlacre) generally used when culturing fish to larger sizes.
Effects of Dietary Magnesium on Growth and Tissue Magnesium Content of Blue Tilapia Oreochromis aureus
Authors: Reigh Robert C. , Robinson Edwin H. , Brown Paul B.
Published: April 2007

Juvenile blue tilapia Oreochrornis aureus (mean weight 0.5 ± 0.05 g) were stocked into 38 liter glass aquaria receiving Row‐through well water containing 0.1 mg magnesium/L and fed semipurified, casein‐based diets containing graded levels of magnesium (0.003, 0.008, 0.023, 0.037, 0.050 and 0.065% magnesium, dry weight). Magnesium supplements were provided as anhydrous magnesium sulfate (MgSO4). No treatment‐related mortalities occurred and no visible magnesium deficiency symptoms were observed in any treatment group during the 18 week experimental period. Magnesium concentrations in scale and bone of tilapia fed diets containing 0.023 to 0.065% magnesium were greater (P < 0.05) than in fish fed diets containing 0.003 to 0.008%. Scale and bone magnesium concentrations did not differ (P > 0.05) among fish that received dietary magnesium levels of 0.023% or greater. The magnesium content of muscle was higher (P < 0.05) in fish fed 0.037 to 0.065% magnesium than in those fed 0.003 to 0.008% magnesium. Muscle magnesium concentrations did not differ (P > 0.05) among fish that received 0.037% or more dietary magnesium. Adequate weight gain and superior feed efficiency occurred in fish fed 0.05 to 0.065% magnesium. Results indicated that diets for O. aureus should contain at least 0.05% magnesium (500 mg Mg/kg dry diet) for optimum growth and normal tissue mineralization.
Effect of Source and Dietary Concentration of Ascorbic Acid on Tissue Concentrations of Ascorbic Acid in Channel Catfish
Authors: El Naggar Gamal O. , Bvell Richard T.
Published: April 2007

Semipurified diets containing either no ascorbic acid or supplemental amounts of 11, 22, 44 and 132 mg/kg from Gascorbic acid (AA), L‐ascorbyl‐2‐monophosphate (AAP) or L‐ascorbyl‐2‐sulfate (AAS) were fed to channel catfish fingerlings (13 ± 2.1 g average initial weight) in aquaria. After a feeding period of 14 wk, weight gain was measured and ascorbic acid content of liver and anterior kidney of the fish was determined. Growth was normal for fish fed all dietary levels of AA and AAP, but lower in fish fed the control and diets supplemented with all levels of AAS; however, growth improved as the concentration of AAS increased. Liver and kidney ascorbic acid increased with level of dietary supplementation in fish fed AA and AAP but only traces or no detectable levels were found in the tissues of fish fed AAS or the controls. Liver and kidney levels of ascorbic acid were significantly higher in fish fed AAP than in fish fed corresponding levels of ascorbic acid from AA. Regression of liver ascorbic acid content on diet concentration indicated that the potency of AAP for maintaining liver storage of ascorbic acid at a minimum acceptable level is 1.74 times higher than that of AA on an ascorbic acid equivalent basis. These results demonstrate that AAP and AA have similar vitamin activity for growth in channel catfish, but AAP is markedly more effective for maintaining tissue levels of ascorbic acid, and that AAS has limited vitamin activity for growth and its contribution to the tissue ascorbic acid pool is negligible.
Geosmin Production by Cyanobacteria (Blue‐green Algae) in Fish Ponds at Auburn, Alabama
Authors: van der Ploeg Martine , Boyd Claude E.
Published: April 2007

Studies on production of geosmin, the compound responsible for earthy‐muddy flavor in water and fish, were carried out at the Auburn University Fisheries Research Station. Water was collected from ponds during 44 cyanobacterial bloom periods from April to September. Geosmin (trans‐1, 10‐dimethyl‐trans‐9‐decalol) was detected at levels averaging 4.77 μg/L when Anabaena species with straight trichomes were predominant. Lower geosmin concentrations were associated with blooms of Anabaena species with coiled trichomes, Microcystis aeruginosa, and Aphanizomenon flos‐aquae, and averaged 0.24, 0.12, and 0.07 μg/L, respectively. Study of four Anabaena blooms over a period of 4–8 weeks showed that changes in geosmin were correlated significantly with changes in trichome abundance. Geosmin disappeared from the water in seven days when Anabaena died. Comparison of geosmin concentrations in raw and filtered water showed that, on average, 90% of the geosmin could be associated with the particulate fraction. Dissolved geosmin concentrations ranged from 0.07–0.85 μg/L.
Increasing Yields of Channel Catfish Using a Combination of Cage and Open Pond Production Systems1
Authors: Terhune Jeffery s. , Tomasso Joseph R. , Schwedler Thomas E. , Collier John A.
Published: April 2007

Channel catfish (lctalurus punctatus) fingerlings stocked at a rate of 450 fish/0.04 ha pond were simultaneously cultured with fingerlings stocked in 1.25 m3 cages (0, 250, 350, or 450 fishlcage; one cage/pond). The fish in the cages were cultured and harvested for a 90–330 g (whole fish) market. The fish in the open ponds were cultured and harvested for a 490–1,140 g market. Harvest weights of open pond fish in all treatments were similar indicating that the presence of the caged fish and the associated higher daily pond feeding rates did not affect open pond production. Ninety‐five to 99% of the caged fish and 96 to 98% of the open pond fish were of marketable size at harvest. Survival and food conversion ratios were similar among treatments. Results of this study indicate that total pond production can be increased (in this case up to 19%) by using a combination of open pond and cage techniques and by simultaneously producing fish for two markets.
Effects of Dietary Carbohydrate: Lipid Ratio on Growth and Body Composition of Hybrid Striped Bass
Authors: Nematipour Gholam R. , Brown Michael L. , Gatlin Delbert M.
Published: April 2007

A study was conducted to determine the ability of juvenile hybrid striped bass, Morone crysops ♀× M. saxatilis ♂, to utilize dietary carbohydrate and lipid for energy. Four semipurified diets containing 35% crude protein were formulated to be isocaloric with various levels of dextrin and menhaden fish oil 50 the carbohydrate: lipid ratio (CHO:L) ranged from 2510 to 42:2.5. Diets were fed in triplicate to groups of hybrid striped bass initially averaging 1.5 g/fish in 38 L aquaria receiving a constant supply of hard (> 180 mg/L as CaCO3) freshwater for a period of eight weeks. Weight gain, feed and protein efficiencies were similar among all dietary groups. Hepatosomatic index (liver weight × 100/body weight), muscle ratio (whole muscle weight × 100/body weight) and condition factor were also similar, while intraperitoneal fat (IPF) ratio (IPF weight × 100/ body weight) was significantly (P × 0.05) increased as CHO:L decreased. Proximate composition of muscle did not show any effects of diet. However, dry matter and lipid of whole‐body increased significantly as CHO:L decreased; conversely whole‐body protein was significantly reduced. Moreover, liver glycogen significantly increased as CHO:L decreased. These data indicate hybrid striped bass are able to efficiently utilize carbohydrate for energy; and dietary lipid, which generally caused increased lipid deposition in various tissues, could be partially replaced with carbohydrate to improve fish quality and productivity.
Density‐Dependent Pond Growout of Single Year‐Class Cohorts of a Freshwater Crayfish Cherux tenuimanus (Smith) to Two Years of Age
Authors: Morrissy Noel M.
Published: April 2007

Pond growout of Cherax tenuimanus to two years of age provided data for mean crayfish weight, surviving density and distribution of individual sizes at intervals and final harvest for 12 single year‐class cohorts. Final mean size (47–156 g) was most significantly related to surviving density (4.5–0.7/m2). A hyperbolic model with a harvest date variable accounted for 89% of the variation in mean weight. The biological basis of this model is that the reciprocal of density, i.e., pond area per crayfish, represents food supply for a bottom‐dwelling crayfish. By incorporating the Richards growth function, the hyperbolic model can be more realistically fitted to include the limit to potential size at very low densities. The growth‐density relationship developed after an initial period of 300 days of low growth (to ∼ 10% of final size) and high mortality. Then, mean weight increased rapidly and density stabilized. Final cumulative production (1.401–3,922 kg/ha) and harvest biomass (1,110–2,991 kg/ha) both increased linearly with density. Survival of the total amount of crayfish produced was about 75% at harvest. Although cohort size distributions were positively skewed, the arithmetic mean size employed in the model was very closely and linearly related to the geometric mean of the lognormal distribution, The causal basis and assumptions of the growthdensity model are discussed in relation to resource sharing by individuals and the disproportionate influence of size‐related dominance behaviour.
Reporting Fish Growth: A Review of the Basics1
Authors: Hopkins Kevin D.
Published: April 2007

Aquaculturists typically report growth using absolute (g/d), relative (% increase in body weight), and specific growth rates (%d). Less frequently, von Bertalanffy Growth Functions (VBGF) are used. Each of these rates is a numerical representation of growth which assumes a specific relationship between size and time (linear, exponential, or asymptotic). Aquaculturists typically determine size at time throughout their experiments. Unfortunately, the intermediate data points are usually ignored when computing growth rates (except for VBGF) and the appropriateness of the method for calculating growth for a particular data set is not tested. This paper reviews the basis and computation of each of the growth rates in an effort to encourage aquaculturists to use the appropriate growth rates.
Recent Progress in Research and Development of Marine Cold Water Species for Aquaculture Production in Norway
Authors: Tilseth Snorre , Blom Geir , Naas Kiell
Published: April 2007

The paper reviews recent progress in larviculture of Atlantic cod and Atlantic halibut in different experimental enclosed seawater systems in Norway. More than 240,000 cod juveniles have been produced in a 270,000 m3 seawater pond. However, very promising production results of cod have been achieved in plastic enclosures with volumes > 100 m3. Halibut juveniles have been successfully produced in plastic enclosures and tanks by using natural zooplankton as food. The enclosure technique could be adapted to commercial scale production of juvenile halibut. However, scaling up experiments are necessary.
The Influence of Different Rotifer and Artemia Enrichment Diets on Growth, Survival and Pigmentation in Turbot (Scophthalmus maximus L.) Larvae
Authors: Støttrup Josianne G. , Attramadal Y.
Published: April 2007

An experiment was carried out on turbot larvae fed three different rotifer enrichment diets: Dry Selco, Protein Selco and ICES low‐HUFA (an enrichment emulsion containing low amounts of highly unsaturated fatty acids—HUFA). Seven tanks were set up for each diet. After the rotifer stage, approximately seven days after hatching, the larvae were fed newly‐hatched Artemia salina nauplii (AT‐1; Brazil strain). From day 10, enriched Great Salt Lake Artemia nauplii were introduced. Each set of seven tanks was further subdivided and the larvae fed Arternia nauplii enriched with one of four enrichment diets: Dry Selco, Protein Selco, ICES low‐HUFA or Super Selco. The rotifer enrichments had no significant effect on larval growth and survival. The nutritional value of the Artemia stage (day 13 to 26) was more important for the overall larval survival.
Larval Nutritional Physiology: Studies with Clarias gariepinus, Coregonus lavaretus and Scophthalmus maximus
Authors: Segner Helmut , Rösch Roland , Verreth Johan , Witt Ulrich
Published: April 2007

Studies on the nutritional physiology of larval fish should provide the basis for defining the length of the larval period and for understanding the quantitative and the qualitative feed requirements of the larvae. For these purposes, it is necessary to perform both descriptive investigations on the ontogenesis of structures and functions as well as experimental investigations on adaptive strategies of the larvae under changing feeding regimes. In the present communication, examples of both approaches are discussed comparing three species: African catfish Clarias gariepinus, whitefish Coregonus lavaretus, and turbot Scophthalmus maximus.

At the onset of exogenous feeding, the digestive system of all three species is sufficiently developed to ensure efficient utilization of live food, but not of dry food. A major event during the subsequent development is the differentiation of the stomach. Evidence exists that for turbot and catfish, a functional stomach is necessary to utilize dry feeds as efficiently as live feeds. Therefore, from a nutritional point of view, in those two species the larval period, during which a special larval diet has to be given, ends with the completion of stomach differentiation.

The capacity of the larvae to acclimate physiologically to different nutritional conditions seems to be limited. Using general nutritional indices such as protease activity, RNA/DNA ratio, midgut cell height or nuclear diameter of hepatocytes, larvae of the three species show partly starvation symptoms when reared on dry food. This effect can be explained to some extent by quantitative considerations, i.e., lower food consumption and digestibility is less for dry diets than for live diets. The contribution of the qualitative factors involved in the different performance of larvae reared on dry or live food is presently not well understood. Future studies should: 1) investigate why utilization of dry diets depends on presence of the stomach; 2) define more precisely the quantitative feed requirements of larvae; and 3) search those diet‐induced qualitative differences of larval metabolism which affect growth performance.
Protein Synthesis in Juvenile Tilapia Oreochromis mossambicus
Authors: Houlihan D. F. , Pannevis M. , Heba H.
Published: April 2007

A method for measuring protein synthesis has been developed for small juvenile fish. A flooding dose of [3H] phenylalanine (Houlihan et al. 1988b) was added to the water containing the animals. Using juvenile tilapia O. mossambicus of approximately 15 mg, stability of the phenylalanine free pool specific radioactivity was achieved within 10 h. A linear increase in the whole body specific radioactivity of protein‐bound phenylalanine occurred 3 h after [3H] phenylalanine was added to the water. In larger animals the flooding dose was injected into the peritoneum, and stable free pool phenylalanine specific radioactivities were achieved over 2 h. In the small fish the rate of protein synthesis exhibited a diurnal pattern. Scaling relationships for growth, protein synthesis and protein degradation were similar. The energy cost of protein synthesis in small juvenile animals, determined from the difference before and after the addition of the protein synthesis inhibitor cycloheximide, was close to the theoretical minimal cost.
Recent Advances in Nutrition of Penaeus monodon
Authors: Chen Houng‐Yung
Published: April 2007

This paper provides a brief summary of information on recent advances in the nutrition of Penaeus monodon. The nutritional requirements of P. monodon have been little known despite its importance in aquaculture. Recent findings indicate a noticeable difference between some important nutrient requirements of P. monodon and P. japonicus, the most studied shrimp species. For example, the thiamin requirement for P. monodon was estimated to be 14 mg/kg diet, while for P. japonicus it is 60‐120 mg/kg diet for juveniles and 40‐80 mg/kg diet for larvae. The same contrast was also observed in the requirements of riboflavin (22.5 mg/kg in juvenile P. monodon vs. 80 mg/kg in larval P. japonicus), niacin (6.4 mg/kg vs. 400 mg/kg) and vitamin C (2,000‐2,500 mg/kg vs. 10,000 mg/kg).

Research efforts to understand the lack of ability for shrimp to effectively use dietary crystalline amino acids have resulted in the development of a microencapsulated amino acid that can be assimilated by P. monodon which is incapable of utilizing the essential amino acid in crystalline form. This development enables the quantification of requirements of the amino acid and other essential amino acids for shrimp. A study using cellulose‐acetate‐phthalate encapsulated arginine indicated that the arginine requirement of postlarval P. monodon is 5.47 g/100 g protein (2.50 g/100 g diet).

Other aspects concerning the importance of digestive enzymes, dietary requirements of protein, carbohydrate, lipid and vitamin, energy and larval feeding for P. monodon were reviewed.
An Intensive Approach to Atlantic Halibut Fry Production
Authors: Holmefjord Ivar , Gulbrandsen Jon , Lein Ingrid , Refstie Terje , Léger Philippe , Huse Ingvar , Harboe Torstein , Sorgeloos Patrick , Olsen Yngvar , Bolla Sylvie , Reitan Kjell Inge , Vadstein Olav , ØIe Gunvor , Danielsberg Anne
Published: April 2007

The larval stage is regarded to be the main bottleneck of halibut production. Halibut eggs were obtained from captive broodstock both by stripping and by natural spawning. Artificial photoperiods were used to increase the total spawning season. Yolk sac larvae are presently produced either in small stagnant units or in large flow through systems. A major consideration is to avoid stress of the larvae, caused by mechanical disturbances of the larvae and by high bacterial load or high ammonia levels in the water.

The experiments showed that halibut larvae began to ingest algae earlier than rotifers Brachionus sp. Supplementation of algae to first feeding tanks resulted in enhanced survival and growth rate of the larvae. Both rotifers and Artemia can be enriched with very high levels of highly unsaturated n‐3 fatty acids (n‐3 HUFA). Enriched live feed, containing high levels of n‐3 HUFA and total lipids, enhanced both survival and growth of the halibut larvae. The highest growth rates were obtained with wild zooplankton and addition of algae, but enriched cultivated feed combined with algae resulted in growth of the same magnitude as with wild zooplankton.
Manipulations of Shrimp Embryos: A Viable Technique for the Removal of the Hatching Envelope
Authors: Lynn John W. , Glas Patricia S. , Hertzler Philip L. , Clark Wallis H. , Green Jeffrdy D.
Published: April 2007

The hatching envelope elevated around the spawned eggs of penaeoidean eggs presents a formidable barrier for manipulation of the embryo. By spawning eggs into seawater containing 3‐amino‐1,2,4‐triazole and subsequently passing the eggs through Nitex screening approximately 45 min after spawning, the hatching envelope can be effectively removed with little or no damage to the embryos. The time and extent to which the envelope is removed can be varied. Embryos treated in this manner continue to develop and the method provides a new technique with which investigators can gain access to the surface of the egg or embryo.
Economic Evaluation of Different Stocking Densities for Various Sized in Texas
Authors: Lambregts Johannes A. D. , Thacker Sayra G. , Griffin Wade L.
Published: April 2007

There has been a trend toward intensification of shrimp farming in the U.S. FiCteen simulated farms were used to evaluate economies of scale and to compare three Penaeus vannclmei commercial production strategies: semi‐intensive, intensive, and very‐intensive. Large economies of scale were associated with each production strategy. Over the range of farm sizes considered, investment cost per hectare decreased approximately 50% and production cost decreased approximately 25%. Farms' returns were measured with Internal Rate of Return (IRR). When investment was greater than $0.75 million, the intensive strategy provided slightly better returns to the investor than semi‐intensive or very‐intensive strategies. At investment levels less than $0.75 million, the semi‐intensive strategy provided the highest IRR.
The Impact of Aquaculture Pond Engineering Design on the Returns to Shrimp Farms
Authors: Griffin Wade L. , Lambregts Johannes A. D. , Yates M. W. , Garcia A.
Published: April 2007

The effects of pond design on the internal rate of return of a 40 ha shrimp farm is evaluated. The influence of four pond construction parameters (pond size, pond shape, levee crown size and canal bank slope) on the total amount of earth moved and construction costs is determined using an engineering design model. The bioeconomic model, MARSIM, calculates returns to farms with the design modifications. Of the four parameters, the pond shape is the most influential over the range considered (from 17% to 8%). Pond size is the second most important parameter (from 17% to 21%). Levee width and canal bank slope influence are of lesser importance (<1% change).
Molting and Mortality of Red Swamp and White River Crawfish Subjected to Eyestalk Ablation: A Preliminary Study for Commercial Soft‐Shell Crawfish Production
Authors: Chen Shulin , Malone Ronald F. , Huner Jay V.
Published: April 2007

Eyestalk ablation may reduce the cost of soft‐shell crawfish production by reducing the molt interval. In this study, both immature and mature red swamp crawfish Procambarus clarkii and white river crawfish Procambarus zonangulus, formally Procambarus actus actus (Hobbs and Hobbs 1990), were ablated using a pair of modified pliers and placed in a recirculating system. Molting percentages, mortalities and mean molt intervals of the ablated crawfish were analyzed.

Eyestalk ablation resulted in dramatic reduction of molt intervals and mortalities comparable with the current commercial (non‐ablation) soft‐shell crawfish production systems. The mean molt intervals of the ablated red swamp crawfish ranged from 6.7 to 7.8 days for immature and 9.2 days for mature animals; whereas, the molt interval of ablated white river crawfish was 8.9 and 11.2 days for immature and mature animals, respectively. Mortalities obtained in this study ranged from 20 to 48% and 32 to 66% for immature and mature crawfish, respectively. During the experiments, molting percentages and mortalities were not consistent. Secondary treatments such as air clotting and cauterization did not alter mortality significantly.
Energy Balance of Callinectes rathbunae Contreras 1930 in Floating Cages in a Tropical Coastal Lagoon
Authors: Rosas Carlos , Vanegas Cecilia , Tabares Isaac , Ramirez Judith
Published: April 2007

The genus Callinecres is ecologically important in the coastal lagoon region of the Gulf of Mexico. This study was conducted to test the feasibility of raising these crabs in a system of floating cages and to measure their scope for growth in a tropical coastal lagoon of the Gulf of Mexico. The equation P = As ‐ (R + E + N) was used to estimate the scope for growth (P) for C. rathbunae under experimental conditions for 21 days. Ingested food was 3% of body weight. Assimilation (As) was 73% of assimilated energy, 21.4% was channeled to respiration (R), 2% to excretion (N) and 0.16% to exuvia (E). The remainder of the energy was channeled to growth at a net efficiency of 76%. Significant differences were not found between the calculated scope for growth and the growth achieved in the culture system (P > 0.05). These results support the energy balance equation and suggest that the cultivation of C. rathbunae in floating cages is possible.
Effect of Water Exchange Rate on Production, Water Quality, Effluent Characteristics and Nitrogen Budgets of Intensive Shrimp Ponds
Authors: Hopkins J. Stephen , Hamilton Richard D. , Sandier Paul A. , Browdy Craig L. , Stokes Alvin D.
Published: April 2007

Water exchange is routinely used in shrimp culture. However, there are few, if any, systematic investigations upon which to base exchange rates. Furthermore, environmental impacts of pond effluent threaten to hinder further development of shrimp farming in the U.S. The present study was designed to determine effects of normal (25.0%/d), reduced (2.5%/d) and no (0%/d) water exchange on water quality and production in intensive shrimp ponds stocked with Penaeus setiferus at 44 postlarvae/m2. Additional no‐exchange ponds were stocked with 22 and 66 postlarvae/m2 to explore density effects. Water exchange rates and stocking density influenced most water quality parameters measured, including dissolved oxygen, pH, ammonia, nitrite, nitrate, Kjeldahl nitrogen, soluble orthophosphate, biochemical oxygen demand, phytoplankton and salinity. Reduced‐exchange and no‐exchange treatments resulted in reduced potential for environmental impact. Mass balance of nitrogen for the system indicates that 13–46% of nitrogen input via feed is lost through nitrification and atmospheric diffusion. Growth and survival were excellent in ponds with normal exchange, reduced exchange, and a combination of low density with no water exchange. A combination of higher stocking density and no water exchange resulted in mass mortalities. Mortalities could not be attributed to a toxic effect of any one water quality parameter. Production was 6,400 kg/ha/crop with moderate stocking density (44/m2) and reduced (2.5%/d) water exchange and 3,200 kg/ha/crop with lower stocking density (22/m2) and no water exchange. Results indicate that typical water exchange rates used in intensive shrimp farms may be drastically reduced resulting in a cost savings to farms and reduced potential for environmental impact from effluent.
Acute Toxicity of Copper Sulfate and Chelated Copper to Channel Catfish Ictalurus punctatus
Authors: Straus David L. , Tucker Craig s.
Published: April 2007

Channel catfish fingerlings Ictalurus punctatus were exposed to copper sulfate or a commercial chelated copper product in a series of static toxicity tests conducted using waters with a wide range of total alkalinity and hardness values. Estimates of mean 96 h LC50 values were 0.05, 0.73, 0.95, and 0.98 mg/L as Cu for copper sulfate and 0.06, 1.51, 1.97, and 1.74 mg/L as Cu for the chelated copper product in waters having total alkalinities of 16, 76, 127, and 240 mg/L CaCO3 respectively. On a copper basis, the chelated product was significantly (P < 0.05) less toxic to fish than copper sulfate in all waters except that of the lowest total alkalinity. Highly significant (P < 0.01) linear relationships were found between LC50 values for copper from copper sulfate and pH, log [total alkalinity], and log [total hardness], of test waters. These results cast doubt on the validity of the formula commonly used to calculate practical copper sulfate pond treatment rates, which is based upon a simple linear relationship between application rate and total alkalinity.
Larviculture of the Mahimahi Coryphaena hippurus in Hawaii, USA
Authors: Kraul Syd
Published: April 2007

The Mahimahi Coryphaena hippurus has excellent potential for aquaculture due to its fast growth, good food conversion ratio, high fecundity with natural captive spawns, and high price. Using current technology, three crops a year could yield 288,000 kg/ha of water/yr with a potential profit of US $1,280,000/ha water/yr.

Hatchery methods are now adequate for pilot‐scale production, and two venture capital companies are pursuing this course. Significant improvement could be made in egg quality, plankton nutrition, plankton substitutes, disease control, reduced aggression, and weaning feeds. More research is needed to learn about digestive physiology, weaning behavior, and the effects of crowding on mahimahi health. Hatchery production is limited most often by the amount of grown out Artemia or yolk‐sac mahi larvae provided for postlarval feeding. Problems that occur at the broodstock, hatching, first feeding, second feeding, third feeding, weaning, and early juvenile stages are discussed.

Using the current technology, the cost of post‐hatchery mahimahi is 33 cents per fry. This cost could be reduced to 6 cents per fry by successfully (consistently) weaning postlarvae from live feeds by 25 days.
Comparison of Satiate and Restricted Feeding of Channel Catfish with Diets of Varying Protein Quality in Production Ponds
Authors: Munsiri Prasert , Lovell Richard T.
Published: April 2007

A 2 × 3 factorial experiment was conducted using satiate and restricted feeding with 32% crude protein diets containing low, medium, and high quality protein. Protein quality in the experimental diets was varied primarily by substituting peanut meal and cottonseed meal for soybean meal. Percentages of lysine, the first‐limiting amino acid, were 1.14, 1.33, and 1.61 in the low, medium, and high quality protein diets respectively. Digestible energy concentration of the diets was 2.9 kcal/g. Channel catfish were grown from an average weight of 47 g to marketable size over a 15 wk period at a stocking density of 13,750 fish/ha in 400 m2 earthen ponds. Each treatment was replicated in three ponds. Fish in the satiation group were fed as much as they would consume each day for the 15 wk experimental period. Fish in the restricted group were fed as much as they would consume until the daily feed allowance reached 65 kg/ha, which was reached at approximately week 5 of the experiment, and thereafter, there was no further increase in feed allowance.

There was no significant interaction between feeding regimen and dietary protein quality for weight gain or feed conversion. Weight gain and feed efficiency under both satiation and restricted feeding increased linearly as protein quality increased. Protein quality had no influence on protein efficiency ratio (PER) under satiate feeding but had a positive effect on PER under restricted feeding. Protein quality had a positive linear effect on dressing percentage under restricted feeding, but in those fish fed to satiation, dressing percentage only increased between the low and high quality protein treatments. Protein quality had a negative linear effect on muscle fat but had no effect on visceral fat under satiate or restricted feeding. These results indicate that channel catfish are sensitive to protein quality differences in practical feeds at both satiate and restricted feeding rates, and that reduction in protein quality reduces dressing yield and increases muscle fat in food size fish.
Seasonal Changes in Water Quality in Commercial Channel Catfish Ponds in Mississippi
Authors: Tucker Craig S. , van der Ploeg Martine
Published: April 2007

Selected water quality variables were measured at monthly intervals for 1 yr in 10 commercial channel catfish ponds in northwest Mississippi. Temporal changes in most variables appeared to be related to seasonal periodicity of phytoplankton abundance. Phytoplankton standing crops and total organic matter were highest in summer months when primary production was favored by warm water temperatures, high solar irradiance, and large inputs of nutrients resulting from high summer fish feed allowances. As day length, water temperature, and feed inputs decreased in autumn and winter, phytoplankton abundance and organic matter concentrations decreased. Seasonal changes in total nitrogen and total phosphorus concentrations were similar to phytoplankton abundance because much of the total nitrogen and phosphorus was contained within phytoplankton cells. Contrasting to the seasonal trend for total nitrogen, concentrations of dissolved inorganic nitrogen were lowest in the summer and highest in the cooler months. Rapid assimilation by phytoplankton served to maintain relatively low concentrations of dissolved inorganic nitrogen during the summer despite highest nitrogen loading rates during that period. Low water temperatures and generally less favorable conditions for phytoplankton growth decreased rates of nitrogen assimilation in the winter and ammonia, nitrite, and nitrate accumulated. Soluble reactive phosphorus concentrations were low throughout the year because physico‐chemical processes, such as precipitation and adsorption to bottom muds acted to continually remove inorganic phosphorus from the water column.
Neutral Buoyancy Salinity of Pacific Halibut Hippoglossus stenolepis Eggs and Larvae
Authors: Liu Han Wu , Stickney Robert R. , Dickhoff Walton W. , McCaughran Donald A.
Published: April 2007

Samples of halibut eggs in nature have led to theories that development occurs near the sea bed and, alternatively, well up in the water column. Resolution of the conflicting theories and information which should assist culturists in providing the proper environmental conditions for egg development and hatching were the subjects of this study. The neutral buoyancy salinity (NBS) of Pacific halibut eggs and larvae ranged between 29.8–34%. Eggs and larvae with higher NBS (> 35%) were usually abnormal or stressed. Thus, eggs found near the seabed may be nonviable.
On the Structure and Molt Controlling Function of the Y‐Organ in the Prawn Penaeus indicus
Authors: Vijayan K. , Mohamed Sunilkumar , Diwan Arvind D.
Published: April 2007

The morphological and histological structure of the Y‐organ of Penaeus indicus is described. The gland 1–2 × 0.3 mm (LXW) is located in between the mandibular and posterior dorsoventral muscle at the junction of prebranchial and branchial chambers. Histochemical tests were performed to determine the chemical nature of the Y‐organ cells. Significant changes in the size and tinctorial affinity of the Y‐organ cells were observed in relation to the molt cycle. Y‐organectomy experiments revealed that the onset of premolt development was inhibited, suggesting the presence of molt inducing factor in the Y‐organ.
Growth of the Pearl Oysters Pinctada mazatlanica and Pteria sterna in Different Culture Structures at La Paz Bay, Baja California Sur, México
Authors: Gaytan‐Mondragon Isabel , Caceres‐Martinez Carlos , Tobias‐Sanchez Marcos
Published: April 2007

A growth study of Pinctada mazatlanica and Pteria sterna was conducted to explain the basic steps required for the development of a pearl culture program in México. Seed for both species was collected using onion bags filled with black polyethylene sheets (40 ± 80 cm) and 5 g of vexar filament. The spatfall was July‐August 1987 for P. mazatlanica and December 1987‐February 1988 for P. sterna. The seed (12.8 ± 1.2 and 13.0 ± 0.6 mm respectively) was placed in pearl‐nets for intermediate culture (to attain 30 mm height). Populations were subsequently divided into three groups, two groups at 10 m depth in lantern and pocket nets and a third placed over a submerged shelf at 10 m depth in plastic net cages. Growth in height, survival and temperature were monitored. After 22 mo P. mazatlanica showed no significant differences in growth between culture structures. Nevertheless, the survival obtained in cages (99%) was larger than that obtained in hanging structures (65%). After 18 mo of culture, significant differences (F = 5.199 P = 0.05) in growth were observed for P. sterna. Larger animals were found in pockets (106.6 ± 0.8 mm) followed by lanterns (104.0 ± 0.7 mm) and finally in cages (103.5 ± 0.6 mm). Survival in pockets was 99%, 84% in lanterns and 98% in cages. With the operation of the different culture structures used in this study, the bottom cage system seems optimal to begin a culture program to obtain pearl‐oysters for nucleus implantation.