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Marketable Size (marketable + size)
Selected AbstractsPilot Production of Hatchery-Reared Summer Flounder Paralichthys dentatus in a Marine Recirculating Aquaculture System: The Effects of Ration Level on Growth, Feed Conversion, and SurvivalJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2005Patrick M. Carroll Pilot-scale trials were conducted to evaluate growout performance of hatchery-reared summer flounder fingerlings in a state-of-the-art recirculating aquaculture system (RAS). The outdoor RAS consisted of four 4.57-m dia × 0.69-m deep (vol. =11.3 m3) covered, insulated tanks and associated water treatment components. Fingerlings (85.1 g mean initial weight) supplied by a commercial hatchery were stocked into two tanks at a density of 1,014 fish/tank (7.63 kg/m3). Fish were fed an extruded dry floating diet consisting of 50% protein and 12% lipid. The temperature was maintained between 20 C and 23 C and the salinity was 34 ppt. Under these conditions, growth, growth variation (CVwt), feed utilization, and survival of fish fed to 100% and 82% of a satiation rate were compared. Due to clear changes in growth patterns during the study, data was analyzed in three phases. During phase 1 (d 1,d 196), fish showed rapid growth, reaching a mean weight of 288 g ± 105 and 316 g ± 102, with a CVwt of 0.36 and 0.32 and FCR's of 1.38 and 1.36 in the subsatiation and satiation groups, respectively. During phase 2 (d 196,d 454), fish displayed slower growth reaching mean weights of 392 g ± 144 and 436 g ± 121, with a CVwt of 0.37 and 0.28, and increasing FCR's of 3.45 and 3.12 in the subsatiation and satiation groups, respectively. During phase 3 (d 454,d 614), fish showed little growth reaching mean weights of 399 g ± 153 and 440 g ± 129, with a CVwt of 0.38 and 0.29 in the subsatiation and satiation groups, respectively. Over the entire growout period (d 1,d 614), feed conversion ratios were 2.39 and 2.37 and survival was 75% and 81 % in the subsatiation and satiation treatments, respectively. The maximum biomass density reached during the study was 32.3 kg/m3. The satiation feed rate was superior to the 82% satiation rate, since it maximized growth rates, with no effect on FCR. The higher CVwt in the subsatiation group suggests increased competition for a restricted ration led to a slower growth with more growth variation. The decrease in growth in phases 2 and 3 was probably related to a high percentage of slower growing male fish in the population and the onset of sexual maturity. This study demonstrated that under commercial scale conditions, summer flounder can be successfully grown to a marketable size in a recirculating aquaculture system. Based on these results, it is recommended that a farmer feed at a satiation rate to minimize growout time. More research is needed to maintain high growth rates through marketable sizes through all-female production and/or inhibition of sexual maturity. [source] Effect of Dietary Protein Concentration and Stocking Density on Production Characteristics of Pond-Raised Channel Catfish Ictalurus punctatusJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2003Menghe H. Li Diets containing 28% and 32% crude protein were compared for pond-raised channel catfish Ictalurus punctatus stocked at densities of 14,820, 29,640, or 44,460 fish/ha. Fingerling channel catfish with average initial weight of 48.5 g/fish were stocked into 30 0.04-ha ponds. Five ponds were randomly allotted for each dietary protein ± stocking density combination. Fish were fed once daily to satiation for two growing seasons. There were no interactions between dietary protein concentration and stocking density for any variables. Dietary protein concentrations (28% or 32%) did not affect net production, feed consumption and weight gain per fish, feed conversion ratio, survival, processing yields, fillet moisture, protein and ash concentrations, or pond water ammonia and nitrite concentrations. Fish fed the 32% protein diet had slightly but significantly lower levels of visceral and fillet fat than fish fed the 28% protein diet. As stocking density increased, net production increased, while weight gain of individual fish, feed efficiency, and survival decreased. Stocking densities did not affect processing yield and fillet composition of the fish. Although highly variable among different ponds and weekly measurements, ponds stocked at the highest density exhibited higher average levels of total ammonia-nitrogen (TAN) and nitrite-nitrogen (NO2 -N) than ponds stocked at lower densities. However, stocking density had no significant effect on un-ionized ammonia-nitrogen (NH3 -N) concentrations, calculated based on water temperature, pH, and TAN. By comparing to the reported critical concentration, a threshold below which is considered not harmful to the fish, these potentially toxic nitrogenous compounds in the pond water were generally in the range acceptable for channel catfish. It appears that a 28% protein diet can provide equivalent net production, feed efficiency, and processing yields as a 32% protein diet for channel catfish raised in ponds from advanced fingerlings to marketable size at densities varying from 14,820 to 44,460 fish/ha under single-batch cropping systems. Optimum dietary protein concentration for pond-raised channel catfish does not appear to be affected by stocking density. [source] Growth and Survival of the Blood Ark Anadara ovalis (Bruguière, 1789) Cultured in Mesh Bags on Soft-Bottom Sediments in the Coastal Waters of GeorgiaJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 3 2001Alan J. Power Annual growth and survival rates were measured for blood arks Anadara ovalis (Bruguière 1789) cultured in mesh bags that were placed at the spring-low-water mark in soft-bottom sediments of the Skidaway River, Georgia. The feasibility of growing the arks to a marketable size using this technique was assessed by determining the effects of stocking density and biofouling on growth and survival. Two replicate densities of 190 (low) and 400 (high) arks per mesh bag (mean shell length 31.97 mm) were planted in early September 1999. In April 2000, the arks cultured at the lower density had a significantly larger size (44.99 mm) than at the higher density (43.83 mm), with growth rates of 1.85 mdmo, and 1.69 mm/mo, respectively. Growth decreased considerably in the subsequent months (low: 0.17 mm/mo; high: 0.30 mm/mo). There was no significant difference in ark size between treatments after a year's growth in late August 2000 (low: 45.76 mm, 1.15 mm/mo; high: 45.31 mm, 1.11 mm/mo). Similarly, no significant difference in annual survival rates between stocking densities occurred (low: 42.89%; high: 40.25%). The present findings indicate that this method of growing arks to market size has potential to contribute to future endeavors to develop an aquaculture fishery for the blood ark in the coastal waters of Georgia. [source] Evaluation of Various Concentrations of Dietary Protein and Animal Protein for Pond-Raised Channel Catfish Ictalurus punctatus Fed to Satiation or at a Restricted RateJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2000Edwin H. Robinson A factorial experiment was conducted to evaluate effect of dietary protein (28% or 32%), animal protein (0, 3, or 6%), and feeding rate (satiation or >90 kg/ha per d) on production characteristics, processing yield, and body composition of pond-raised channel catfish Ictalurus punctatus. Fingerling channel catfish (average weight: 55 g/fish) were stocked into 60, 0.04-ha ponds at a rate of 18,530 fish/ha. Five ponds were used for each dietary treatment. Fish were fed once daily to satiation or no more than 90 kg/ha per d for 147 d. Fish fed at a rate of >90 kg/ha per d consumed about 85% of the amount of feed consumed by fish fed to satiation. Dietary protein did not affect the total amount of feed fed, amount of feed consumed per fish, weight gain, feed conversion efficiency, or fillet protein. Animal protein had no effect on the total amount of feed fed, amount of feed consumed per fish, weight gain, or fillet protein and ash. Fish fed a diet containing 6% animal protein converted feed more efficiently than fish fed diets containing 0% and 3% animal protein. Fish fed to satiation daily consumed more feed, gained more weight, converted the feed less efficiently, and had a higher carcass yield, a higher level of visceral fat as compared to fish fed at a rate of >90 kg/ha per d. Feeding rate had no effect on fillet protein. Results from this study indicated that both a 28% and a 32% protein diet with or without animal protein provided the same growth rate of channel catfish raised in ponds from fingerlings to marketable size if feed is not restricted below a maximum rate of 90 kg/ha per d. Even though there were some interactions among the three factors evaluated, dietary protein levels of 28% to 32% and animal protein levels of 0% to 6% do not appear to markedly affect carcass yield and fillet proximate composition of pond-raised channel catfish. [source] Growth and production of hatchery-reared juvenile spotted babylon Babylonia areolata Link 1807 cultured to marketable size in intensive flowthrough and semi-closed recirculating water systemsAQUACULTURE RESEARCH, Issue 5 2000N Chaitanawisuti Hatchery-reared juvenile spotted babylon Babylonia areolata (mean initial shell length 12.8 mm) were cultured intensively to marketable size in three 3.0 × 2.5 × 0.7 m indoor canvas rectangular tanks. The duplicate treatments of flowthrough and semi-closed recirculating sea-water systems were compared at an initial stocking density of 300 individuals m,2 (2250 juveniles per tank). The animals were fed ad libitum with fresh carangid fish Selaroides leptolepis once daily. During 240 culture days, average growth rates in shell length and body weight were 3.86 mm month,1 and 1.47 g month,1 for the flowthrough system and 3.21 mm month,1 and 1.10 g month,1 for those in the semi-closed recirculating system. Survival in the flowthrough system (95.77%) was significantly higher than that in the semi-closed recirculating system (79.28%). Feed conversion ratios were 1.68 and 1.96 for flowthrough and semi-closed recirculating systems respectively. [source] Pilot Production of Hatchery-Reared Summer Flounder Paralichthys dentatus in a Marine Recirculating Aquaculture System: The Effects of Ration Level on Growth, Feed Conversion, and SurvivalJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2005Patrick M. Carroll Pilot-scale trials were conducted to evaluate growout performance of hatchery-reared summer flounder fingerlings in a state-of-the-art recirculating aquaculture system (RAS). The outdoor RAS consisted of four 4.57-m dia × 0.69-m deep (vol. =11.3 m3) covered, insulated tanks and associated water treatment components. Fingerlings (85.1 g mean initial weight) supplied by a commercial hatchery were stocked into two tanks at a density of 1,014 fish/tank (7.63 kg/m3). Fish were fed an extruded dry floating diet consisting of 50% protein and 12% lipid. The temperature was maintained between 20 C and 23 C and the salinity was 34 ppt. Under these conditions, growth, growth variation (CVwt), feed utilization, and survival of fish fed to 100% and 82% of a satiation rate were compared. Due to clear changes in growth patterns during the study, data was analyzed in three phases. During phase 1 (d 1,d 196), fish showed rapid growth, reaching a mean weight of 288 g ± 105 and 316 g ± 102, with a CVwt of 0.36 and 0.32 and FCR's of 1.38 and 1.36 in the subsatiation and satiation groups, respectively. During phase 2 (d 196,d 454), fish displayed slower growth reaching mean weights of 392 g ± 144 and 436 g ± 121, with a CVwt of 0.37 and 0.28, and increasing FCR's of 3.45 and 3.12 in the subsatiation and satiation groups, respectively. During phase 3 (d 454,d 614), fish showed little growth reaching mean weights of 399 g ± 153 and 440 g ± 129, with a CVwt of 0.38 and 0.29 in the subsatiation and satiation groups, respectively. Over the entire growout period (d 1,d 614), feed conversion ratios were 2.39 and 2.37 and survival was 75% and 81 % in the subsatiation and satiation treatments, respectively. The maximum biomass density reached during the study was 32.3 kg/m3. The satiation feed rate was superior to the 82% satiation rate, since it maximized growth rates, with no effect on FCR. The higher CVwt in the subsatiation group suggests increased competition for a restricted ration led to a slower growth with more growth variation. The decrease in growth in phases 2 and 3 was probably related to a high percentage of slower growing male fish in the population and the onset of sexual maturity. This study demonstrated that under commercial scale conditions, summer flounder can be successfully grown to a marketable size in a recirculating aquaculture system. Based on these results, it is recommended that a farmer feed at a satiation rate to minimize growout time. More research is needed to maintain high growth rates through marketable sizes through all-female production and/or inhibition of sexual maturity. [source] Growth performances for monoculture and polyculture of hatchery-reared juvenile spotted babylon, Babylonia areolata Link, 1807, in large-scale earthen pondsAQUACULTURE RESEARCH, Issue 14 2008Sirusa Kritsanapuntu Abstract This study was conducted to determine the feasibility of growing out hatchery-reared spotted babylon juvenile (Babylonia areolata) in earthen ponds. The growth, survival and water quality for monoculture of spotted babylon were compared with the two polyculture trials with sea bass (Lates calcarifer) or milkfish (Chanos chanos). This study provided good results for growth and survival of spotted babylon in earthen ponds. The mean body weight gain of snails held in the monoculture was 5.39±0.08 g, and 4.07±0.16 and 4.25±0.11 g for those held in the polyculture with sea bass or milkfish respectively. Food conversion ratios (FCR) were 2.69, 2.96 and 2.71 for snails held in the monoculture and polyculture with sea bass and milkfish, respectively, and the final survival rates were 84.94%, 74.30% and 81.20% respectively. There were no significant differences in each parameter of water quality among the treatments but significant differences among the culture period were present (P<0.05). Salinity and total alkalinity showed the greatest changes during the culture period for all treatments. Seawater temperature, pH, dissolved oxygen, nitrite,nitrogen and ammonia,nitrogen gradually changed over the culture period for all the treatments. The present study indicated the technical feasibility for monoculture and polyculture of B. areolata to marketable sizes in earthen ponds. [source] | ||||||||||