Considerations of diet, stocking density, distribution, population estimation and economics in the pond culture of blue shrimp (Penaeus stylirostris Stimpson).
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Blue shrimp (Penaeus stylirostris Stimpson) were cultured in 10 0.1 ha ponds from July 18 to December 7. Four ponds were stocked at each density of 10,000 and 15,000 shrimp. Remaining shrimp were stocked into two ponds at densities of 4,200 and 5,100 shrimp. Four ponds (two at each density of 10,000 and 15,000) received a 25% protein ration, MR-25. All other ponds received 96.9..R, also a 25% protein ration. Additional research was performed as a supplement to the main pond experiment. Specifically, a common technique for counting large numbers of shrimp postlarvae, volumetric subsampling, was tested for accuracy under various conditions of temperature and postlarval size. Also, random sampling with cast nets was assayed for its utility in predicting pond population sizes and determining patterns of shrimp distribution in ponds. Finally, an aquarium experiment was performed to determine if differences in the palatability of the two pond rations existed. Growth during the initial 70 days in ponds appeared to be insignificantly influenced by population density and significantly influenced by diet. Faster growth tended to occur in ponds receiving MR-25, a result probably linked to weights and lengths at day 71 ranged from 6.3 to 10.1 g and 96 to 113 mm. Severe mortalities occurred in 4 of the 10 ponds on the 71st day. This was attributed to pollution of the affected ponds with lead-based paint. Unaffected ponds demonstrated an inverse relationship between initial stocking density and survival. Survivals ranged from 70 to 100% in these ponds. Yield was positively affected by stocking density in the unaffected ponds, ranging from 51.6 to 124.4 kg. Volumetric subsampling tended to consistently underestimate postlarval shrimp numbers by 30 to 40%, depending on temperature and shrimp length. Random sampling with cast nets allowed a highly linear relationship to be developed between mean catch and population density. A tendency was also discovered for shrimp to prefer a pond's end to it's middle. Enterprise budget analysis indicated that with the above conditions as an example, blue shrimp culture would be unprofitable at Cedar Bayou.