Enhancing pond production of large food size-fish by controlling social costs [abstract]

Abstract

The primary study objective determined whether rearing high-percentage-male (> 70 % male) bluegill groups in intensively-managed standard production ponds results in higher fish growth rates and production of higher numbers of large, food-size sunfish (> 227 g; 0.5 lb), versus when balanced-sex-ratio (~ 50% male) groups are reared over a two-year period. A cull harvesting approach was also implemented in an attempt to increase the number of food-size sunfish produced in the balanced-sex-ratio and high-percentage-male groups. The research project proposed herein is related to an initiative through the North Central Regional Aquaculture Center (NCRAC) to develop capacity to efficiently rear sunfishes (Lepomis spp.) to large sizes (> 227 g; 0.5 lbs) as food fish (NCRAC 1999). Strong demand has been repeatedly indicated for sunfish as a food fish, however, incapacity to efficiently rear these fish to required sizes has kept this demand from being tested (Hayward and Wang 2006). A method of topping-off harvest was implemented to control the presence of social hierarchies which will improve the rearing efficiency of bluegill for the purpose of marketable sized food fish. Mostly male skewed sex-ratios will indicate that larger growth is attainable without the presence of a large female population. The results of this study have not shown statistically significant differences between the treatment and control ponds (formulas are still being calculated). This study will support the need for improved rearing techniques, as the demand for innovative food production becomes greater. As the United States starts becoming more reliant on aquaculture, the support and demand for related research will become more widely accepted and encouraged. In addition, the ability to improve the rearing efficiency of bluegill can ultimately be applied to many other species of aquaculture food-fish.