World Aquaculture Society Meetings


Luke A. Roy*, Anita M. Kelly, Carl D. Webster, Steven D. Rawles, Nathan Stone, Jeonghwan Park
Aquaculture/Fisheries Center
University of Arkansas at Pine Bluff, Pine Bluff, AR

Winter mortality is a common problem for baitfish farmers in Arkansas that produce fathead minnows (Pimephales promelas) and golden shiners (Notemigonus crysoleucas). Bird predation, water quality issues, disease, and harsh fluctuating winter temperatures all contribute to winter fish losses and in turn affect farm profitability. Winter feeding programs have been suggested as a potential avenue to improve survival, condition, and reduce weight loss of baitfish during the winter. Methods of winter feeding vary widely among baitfish farms and currently there are no recognized best management practices for winter feeding. Hence, the impact of different winter feeding regimes on fish survival, growth, and lipid storage, were evaluated in a series of experiments conducted with fathead minnows (2014) and golden shiners (2015) at the UAPB Lonoke Fish Disease Diagnostic Laboratory in Lonoke, Arkansas. A fathead minnow trial was carried out in a temperature-controlled aquarium system (900 L) consisting of nine aquaria. Fathead minnows (0.88 ± 0.04 g) were stocked at ambient water temperature and water temperature was reduced to 7°C over the course of 7 days to mimic winter conditions. Once the target water temperature was reached, three dietary feeding regimes (35% protein) were implemented (3 replicates per treatment) that included feeding 1) ad libitum twice per week (2x/wk), 2) once per week (1x/wk), or 3) once per month (1x/mo). Whole fish were frozen at the beginning and end of the experiment to assess the response of fatty acid profile to feeding regime. After 13-weeks, there were significant differences (P<0.05) in weight gain, condition factor, and specific growth rate. Fathead minnows fed 2x/wk had weight gains of nearly 3%, while the fish offered feed 1x/wk and 1x/month lost weight (-2.3 and -10.1%, respectively). Fathead minnow fatty acid profiles also differed significantly (P<0.05) among treatments. The golden shiner winter feeding trial was stocked (0.88 ± 0.02 g), temperature acclimated, and fed identical to the fathead minnow trial except a smaller (600-L) temperature controlled recirculating system was utilized. After 12-weeks, there were no significant differences in golden shiner final weight (0.79 - 0.82 g), survival (65.0 - 88.3%), or weight gain (-6.84 - -9.50%) among treatments. Condition factors of fish from the 2x/wk treatment were significantly (P<0.05) higher than those of fish from the other two winter feeding regimes. Fatty acid profiles of golden shiners are currently being analyzed. Results of both trials suggest that implementation of a feeding program during the winter months, albeit at reduced feed rates compared to spring and summer, would benefit commercial baitfish producers.

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