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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the World Aquaculture Society 17 (1986), S. 0 
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: A 34-day study was conducted to estimate the effect of stocking density on growth, biomass, and yield of harvestable animals in red swamp crawfish, Procambarus clarkii (Girard). Juvenile crawfish were stocked at l, 2, 4, 8, and 16 crawfish per m2 into plastic-lined metal pools planted with rice (Oryza sativa) with three replicate pools at each density. Crawfish averaged 35 ± 1.5 mm (SE) total length at the time of stocking.Growth in total length and weight was significantly affected by density (P 〈 0.01), ranging from 91.5 mm and 20.7 g for crawfish stocked at 1 per m2 to 62.5 mm and 6.3 g for crawfish stocked at 16 per m2. The total crawfish biomass ranged from 20.7 g per m2 for crawfish stocked at 1 per m2 to 88.7 g per m2 at 16 per m2. The portion of that biomass made up of harvestable sized animals (〉75 mm total length) ranged from 100% at 1 per m2 to 0.7% at 16 per m2. Gross revenues per ha were projected for crawfish yields at each stocking density with and without a graded product.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Juveniles from all possible crosses among USDA 102. USDA 103, and Norris channel catfish Ictalurus punctatus strains were compared for: 1) survival and mix-Edwardsiella ictaluri antibody after exposure to live E. ictaluri bacterium (isolate 597-458); 2) antibody level after injection with formalin-killed E. ictaluri (597-458); and 3) pre-stress. post-stress, and stress-recovery serum Cortisol levels. Purebred and crossbred USDA 102 strain fish had higher survival (mean of five genetic groups = 87%) and lower anti- E.ictaluri antibody (mean optical density (OD) of five genetic groups = 0.167) 30 d after live E. ictaluri challenge than purebred Norris and USDA 103 strains and their crosses (means of four genetic groups = 60% survival and 0.210 OD antibody level). Significant general combining ability, line effects, and heterosis indicated that the USDA 102 strain contributed additive and dominance genetic effects for increased survival and lower antibody level after live E. ictaluri challenge. Antibody response to formalin-killed, intra-peritoneally injected E. ictaluri was not different among genetic groups (overall mean = 0.198 OD). Serum Cortisol was measured prior to (pre-stress), immediately after (post-stress), and 2 h after (stress-recovery) a standard stressor. Serum Cortisol level was highest in post-stress fish (35.8 ng/mL), intermediate in stress-recovery fish (10.9 ng/mL), and lowest in pre-stress fish (6.5 ng/mL), but was not different among genetic groups within a stress time period. Results indicate diat differences exist among genetic groups of channel catfish for survival and antibody production after live E. ictaluri challenge, but these differences were not related to antibody response to killed E. ictaluri or serum Cortisol levels.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the World Aquaculture Society 32 (2001), S. 0 
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract.— Bioelectric impedance analysis (BIA) was evaluated as a method for predicting carcass yield, fat, and moisture in live channel catfish, Ictalurus punctatus (N = 20), and fat and moisture in fillets from channel catfish (N= 20) and channel catfish female × blue catfish male, I. furcatus, hybrids (N= 20). Fish were cultured in ponds, fed a commercial catfish diet (28% protein), and harvested at market weight (450 g-900 g, ∼19 months post-hatch). Live channel catfish were tranquilized, weighed, and sexed. Resistance and reactance were measured with a four-terminal impedance analyzer. Fish were then deheaded, eviscerated, weighed, and carcass yield was calculated. Fillets from channel catfish and channel catfish × blue catfish hybrids were measured for weight, resistance, and reactance. Carcasses and fillets were ground and fat and moisture were determined by chemical analysis. Regression models including total weight, resistance, and reactance as independent variables explained 71%, 75%, and 65% of the variation in carcass yield, fat, and moisture, respectively, in live fish. Regression models with fillet weight, resistance, and reactance as independent variables explained 62% and 41% of the variation in fillet fat and moisture, respectively, in channel catfish, and 53% and 58% of the variation in fillet fat and moisture, respectively, in channel catfish × blue catfish hybrids. Models including resistance and reactance explained significantly more variation in the traits measured than did models containing only whole weight as an independent variable. Improvements in prediction accuracy will be needed to make BIA a useful tool for predicting carcass yield, carcass composition, and fillet composition in farm-raised catfish.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: These studies were conducted to evaluate the efficacy of a live attenuated Edwardsiella ictaluri vaccine against enteric septicemia of catfish. In one study channel catfish fingerlings (72 d of age post hatch) were immersed for 30 min in water containing E. ictaluri RE-33 at dosages of 1 × 106, 1 × 107 and 2 × 107 CFU/ML of water. No mortalities were observed following vaccination. Following exposure to virulent Edwardsiella ictaluri the cumulative mortality of fish vaccinated with dosages of at least 1 × 107 CFU/mL were significantly lower than that of non-vacccinated fish in both laboratory and field challenges. Vaccination with 1 × 106 CFU RE-33mL provided some protection during the laboratory challenge but failed to protect fish under field conditions. In a second study, vaccination of 6 full-sib families of channel catfish at a vaccine dosage of 1 × 107 CFU/mL resulted in a relative percent survival among families ranging from 67.1 to 100%. Significant differences in mortality were found among families and between vaccinated and unvaccinated groups, but there was no family by vaccine interaction. Families with the highest mortality after vaccination were also shown to have the highest mortality without vaccination (r = 0.82; P= 0.04).
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the World Aquaculture Society 27 (1996), S. 0 
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The potential for commercial culture of hybrid striped bass is promising in many areas of the United States. While several different striped bass hybrids are candidates for culture, differential performance has not been thoroughly evaluated. Comparative performance of two striped bass hybrids was evaluated in six, 757–1, fiberglass tanks receiving a continuous flow of ambient pond water for 397 d. Three replicate tanks were stocked with 50 fingerlings (66 fish/m3) of either striped bass female × white bass male (mean weight 23 g) or striped bass female × yellow bass male hybrids. Fish were fed a 35% protein ration throughout the study, and weight was recorded for all fish at stocking and at 21-d intervals. White bass hybrids grew significantly faster (0.94 g/d) than yellow bass hybrids (0.59 g/d). Survival to harvest averaged 65% and 44% for yellow bass and white bass hybrids, respectively. A significant difference from the expected 1:1 sex ratio occurred for yellow bass hybrids (100% female), but not for white bass hybrids (56% female). Mean condition factor, 1.63 and 1.39, and fillet percentage, 30.7% and 28.4%, was significantly higher for white bass hybrids compared to yellow bass hybrids.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract.— This study evaluated the effects of dietary protein concentration (26, 28, and 32%) on growth. feed efficiency, processing yield, and body composition of USDA103 and Mississippi “normal” (MN) strains of channel catfish raised in ponds. Fin-gerling channel catfish (average weight = 32.5 and 47.3 g/fish for USDA103 and MN strains, respectively) were stocked into 24 0.04-ha ponds (12 ponds/ strain) at a density of 18,530 fish/ha. Fish were fed once daily to apparent satiation from May to October 1999. There were no interactions between fish strain and dietary protein concentration for any parameters measured. Regardless of dietary protein concentrations, the USDA103 strain consumed more feed and gained more weight than the MN strain. There were no differences in feed conversion ratio (FCR) or survival between the two strains. Feed consumption, weight gain, FCR, and survival were not affected by dietary protein concentration. The USDA103 strain exhibited a lower level of visceral fat, a higher carcass yield, a lower level of fillet moisture, and a higher level of fillet fat than the MN strain. Regardless of fish strains, fish fed the 32% protein diet had a lower level of visceral fat and a higher fillet yield than fish fed the 26% protein diet. Fish fed the 32% protein diet were also higher in carcass yield as compared to those fed the 28% protein diet. Fillet moisture, protein, and fat concentrations were not affected by dietary protein concentration. Results from this study indicate that the USDA103 strain of channel catfish appears to possess superior traits in growth characteristics compared with the MN strain that is currently cultured commercially. Both strains appear to have the same dietary protein requirement.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The severity of gill damage (percentage of gill lamellae with lytic lesions) was determined in juveniles from 10 USDA 103 line channel catfish Ictalurus punctatus full-sib families, 10 channel catfish×blue catfish I. furcatus backcross hybrid (7/8 channel catfish, 1/8 blue catfish) full-sib families and a mixed-family group of blue catfish placed in a commercial catfish pond experiencing proliferative gill disease (PGD)-related fish mortalities. An initial challenge was conducted with all families, and a second challenge was conducted using the two most susceptible (most gill damage) channel catfish and backcross hybrid families and the two most resistant (least gill damage) channel catfish and backcross hybrid families. In the initial challenge, percentage gill damage was not different between channel catfish (12.3%) and backcross hybrids (11.6%), but was lower in blue catfish (0.2%). Mean percentage gill damage in the second challenge was not different among resistant backcross hybrid families (6.9%), resistant channel catfish families (7.6%) and blue catfish (4.8%), but was higher in susceptible backcross hybrid and channel catfish families (19.0% and 11.9% respectively). The correlation among family means for gill damage from challenge 1 and challenge 2 was r=0.87. Consistent differences between channel catfish and blue catfish and between resistant and susceptible families within genetic groups for gill damage after PGD challenge suggest that there is a genetic component for resistance to PGD and that improving PGD resistance through selection may be possible.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the World Aquaculture Society 25 (1994), S. 0 
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Juvenile red drum Sciaenops ocellatus were tank-reared in two, separate 30-d trials to assess effects of total water hardness and chloride concentratlon on growth, survival, and feed conversion. Two levels of total hardness and chloride were used in 2 × 2 factorial designs to obtain total hardness and chloride levels in trial one of 100 and 200mg/L CaCO3 and 125 and 250mg/L Cl−, and hardness and chloride levels of 100 and 400mg/L CaCO3 and 150 and 500mg/L Cl− in trial two. In trial one, average daily growth and feed conversion were significantly (P≤ 0.05) improved at 100mg/L hardness levels compared to 200mg/L at both chloride levels. Average daily growth was 0.11 ± 0.02g/d at 100mg/L hardness and 125mg/L Cl− compared to 0.06 ± 0.01g/d at 200 mg/L hardness and 125mg/L chlorides. No significant (P≥ 0.05) difference in survival could be attributed to levels of total hardness or chloride. In trial two, 500 mg/L Cl− treatments produced significantly (P≤ 0.01) better growth, survival and feed conversion than 150mg/L Cl− at either level of total hardness (100 and 400mg/L). Survival at 150mg/L chloride and 100mg/L hardness was 48.8 ± 18.7%, while at 500mg/L chloride and 400mg/L hardness survival increased to 96.6 ± 2.1%. Growth also increased from 0.14 ± 0.03 to 0.27 ± 0.01g/d and feed conversion improved from 5.77 ± 1.56 to 1.87 ± 0.06 at the same levels. No interactions between levels of hardness or chlorides were shown to affect red drum growth, survival, or feed conversion in either trial.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the World Aquaculture Society 22 (1991), S. 0 
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Acute toxicity of chelated copper to juvenile red drum (x̄= 3.1 g) was determined in a static test at 25 C and 8 ppt salinity. The 12, 24, 48, 72, and 96 h LC50s were 1.90, 0.84, 0.75, 0.64, and 0.52 mg/L copper, respectively. Effects of temperature and salinity on the 96 h LC50 (0.5 mg/L copper) for juvenile red drum (x̄= 5.0 g) were tested at two temperatures, 25 and 30 C, and three salinities, 0.5, 8, and 30 ppt. Temperature significantly affected mortality; mortality in 0.5 and 8 ppt salinities was significantly higher at 30 C than at 25 C. An increase in salinity significantly reduced the mortality of juvenile red drum. Total mortality occurred in 0.5 ppt salinity within 48 h at 25 C and within 12 h at 30 C. Total mortality occurred in 8 ppt salinity within 72 h at 25 C and within 48 h at 30 C. No mortality occurred during 96 h in 30 ppt salinity at 25 C or 30 C.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the World Aquaculture Society 35 (2004), S. 0 
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
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