摘要:

AbstractTo establish the practical use of microbound diets (MBD) for larval fish in mass seedling production, rearing experiments of larval red sea bream,Pagrus major, and Japanese flounder,Paralichthys olivaeeus, were conducted. A mixture of various protein sources was used, and dietary amino acid patterns were approximated to those of larval whole body protein. Two thousand red sea bream larvae and 1,000 Japanese flounder larvae, all 10 days old, were placed in 100 liter tanks with running sea water under ambient water temperature, which ranged from 18 to 20C. The particle size of MBD was 125 μm at the beginning of the experiment and adjusted as fish size increased thereafter. Employing MBD together with a small amount of live food could sustain the growth and survival of larval red sea bream and Japanese flounder. Thus, data from the present study indicates that substitution of artificial feeds for live foods is possible for larval fish production, although improvements in MBD diets may be necessary before they are adequate for large scale seedling production

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1989.tb00521.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe polyunsaturated fatty acids of the n‐3 family associated with fish and fish oils have been shown to have beneficial effects on prevention of heart disease in humans. However, in considering the potential health benefits of fish oil in human health, it is important to realize that the fatty acid composition and total lipid content of fish vary greatly. These variations may be due to species differences or variations within a species due to temperature, diet, developmental stage, sex or seasonal differences.The purpose of the study described here was to determine the effects of season, size class, and sex on the Occurrence of individual fatty acids in striped bass (Morone saxrrtilis). Fish were collected in June, July, August, September, and October. Filets with skin were analyzed for total lipid content. Methyl esters of fatty acids were separated and identified using capillary gas chromatography. Total mean lipid varied from as low as 12% to as high as 30%. There were no significant changes in total crude lipid content due to month collected or sex. However, total lipid content of filets increased significantly (P ≤ 0.05) as size increased.The fatty acids 18:1n–9 and 16:0 made up the majority (62%) of the fatty acids present in any season, size class, or sex. The monounsaturated fatty acids dominated in all fish. There were no significant differences in individual fatty acids due to sex. However, fish size had a significant influence on fatty acid composition. Overall, saturated fatty acids decreased as size increased, while polyunsaturated fatty acids increased or remained constant. There were no significant changes in mean percent saturated or monounsaturated fatty acids with respect to month when controlling for size. However, total percent polyunsaturated fatty acids decreased significantly in October compared to August and September. This overall decrease was due mainly to a decrease in 22:6n–3. Conversely there was a significant increase in 16:11n–9 in October. All other fatty acids remained constant. When data from this study were compared to fatty acid data from the literature, striped bass was not as good a source of 20:5n–3 and 22:61n–3 as sardines, anchovie

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1989.tb00522.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractWater quality variables and plankton were monitored and compared between ponds that were stocked or not stocked with golden shiners in order to determine what changes occur in the plankton community and water quality of ponds managed for intensive production. Ponds with shiners had significantly lower phosphate and carbon dioxide concentrations and lower carbonate alkalinity than ponds without shiners. No significant difference in nitrite, nitrate, ammonia, temperature, secchi disk readings, or turbidity levels was found between the treatments. The standing crop of phytoplankton was nearly twice as great in ponds with fish. Ponds with fish had significantly fewer copepods but more rotifers than fishless ponds. Although the fish were offered a commercial feed with 29.5% protein and 1.5% crude fat at 3% of their biomass daily, they apparently continued to feed on crustacean zooplankton.

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1989.tb00523.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractBudgets for water, nitrogen, phosphorus, chemical oxygen demand (COD), and dissolved oxygen (DO) were estimated from May to October 1986 in three 0.09 ha ponds stocked with striped bassMorone saxatilis(Walbaum). Ponds were lined with highdensity polyethylene sheeting to prevent seepage. Pond bottoms, except for side slopes, were covered with soil. Total rainfall roughly equalled evaporation. Liner runoff augmented rainfall inflow by 43%. The largest source of nitrogen input was feed ‐88% of the measured input. Overflow was the greatest measured loss of nitrogen. Denitrification and ammonia volatilization apparently removed large amounts of nitrogen. Feed applications and runoff were the major phosphorus inputs. Fish harvest and uptake by mud represented the major losses of phosphorus. The production of each kilogram of fish required 2.09kg of feed and released to the water, as metabolic waste, 118.55g nitrogen, 1.2g phosphorus, and 1.67kg COD. Metabolic wastes from fish resulted in the production of an additional 3.71kg of COD in phytoplankton and benthic algae. Thus, 1kg of live striped bass resulted in a total of 5.38kg of COD. Benthic respiration exceeded respiration of microorganisms in the water column. Total respiration exceeded oxygen produced by photosynthesis, but diffusion of oxygen from the atmosphere into the ponds was sufficient to maintain adequate DO concentrations for fish surviva

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1989.tb00524.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractPenueus vannumeilarvae (P2through M3) and early postlarvae (<24 h old postlarva) were fed diets consisting of algae‐only, nematodes (Panugrellus redivivus) plus algae orArtemiaplus algae. Growth (dry biomass gain) of second and third stage protozoea larvae fed the nematodealgae diet was significantly better than that of larvae fed theArtemia‐algaediet. From the first mysis through the postlarval substage (<24 h old), growth of shrimp fed the nematodealgae diet equalled that of larvae fed theArtemia‐algaediet. All larval substages fed nematodes plus algae accumulated significantly greater biomass than those fed a diet of only algae. Survival and percent metamorphosis of larvae fed nematodes plus algae did not differ significantly from that of larvae fed eitherArtemiaplus algae or algae alone. A nematodealgae feeding regime, which potentially yields growth, survival and metamorphosis equal to that obtained on the standardArtemiaplus algae regime, is proposed forP. van

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1989.tb00525.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractAn economic and investment analysis was performed to determine the viability of bait‐shrimp farming in Texas. A single pond analysis producing 5–5.5g shrimp always had higher returns above selected cost (RASC) than producing 4–4.5g shrimp. Stocking 0.01g shrimp had a higher RASC than stocking 0.25g, 0.50g or 0.75g shrimp. In the 20 pond analysis, which accounted for marketing considerations, stocking 0.25g shrimp had the highest RASC. The investment analysis, assuming average management, was declared bankrupt by the end of the fifth year. Under “excellent” management the internal rate of return was only 11.7%. It is unlikely that bait‐shrimp farming will become a viable industry in Texas in the

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1989.tb00526.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractJuvenile freshwater prawnsMucrobruchium rosenkrgii(mean wet weight = 0.75, 1986 or 0.17g, 1985) were stocked into 0.06–0.07 ha earthen ponds at densities ranging from 39,536 to 118,608/ha during two separate growing seasons. After growout periods ranging from 135 to 142 days, survival was from 54.3% to 89.9% (x = 77.0%). Mean prawn weight at harvest ranged from 15.0 to 44.3g and decreased with increasing stocking density. The larger stocking weight of prawns was associated with harvest weights that were 16.8 to 39.6% greater than those achieved with the smaller stocking weight at comparable stocking densities.Stocking of juveniles of the proper size and the effective management of the social structure ofM. rosenkrgiiappear to be critical to the success of intensive pond culture in temperate climates where the length of the growing season is restricte

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1989.tb00527.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0893-8849    

DOI:10.1111/j.1749-7345.1989.tb00528.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY