FEEDING REGIMES FOR LARGEMOUTH BASS AT LOW WINTER TEMPERATURES

Over the last few decades, largemouth bass (LMB; Micropterus salmoides) research has expanded as a result of an increase in the food fish market. LMB researchers have investigated pond intensification, improvement of genetics, out-of-season spawning, indoor recirculating aquaculture systems, and alternative feed ingredients, among others to decrease costs and improve production. During consultation with LMB farmers, it became clear to UAPB Extension personnel that there were concerns about the effects of harsh summer and low winter temperatures on the growth of their fish. Particularly, they were uncertain about feeding regimes during these seasons. In order to address the winter feeding issue, the UAPB Lonoke Fish Health Services Laboratory responded by developing a low winter temperature trial to obtain preliminary data on the feeding frequency necessary in order to either improve growth or at least limit weight loss over winter. In this trial, juvenile LMB (19.7 ± 0.4 g) were stocked into a 908 L recirculating system with nine aquaria (38 L each, 10 fish/tank). Samples of fish prior to the study and at the end of the study were frozen for future lipid analysis. The study ran for 93 days and temperature was maintained at approximately 7.1°C throughout the trial. Fish were fed a commercial LMB diet (Skretting, 45% protein, 18% lipid) at 1% of their body weight every 3 days, every 7 days, or every 14 days with three replicates per treatment. Water quality remained within acceptable levels necessary for LMB and survival was 100% in all aquaria. Feeding at least once a week contributed to weight gain while maintaining acceptable feed conversion ratios (Table 1). Feed is often the largest cost on a fish farm and improved winter feeding regimes should assist farmers in deciding the correct amount of feed to sustain or improve growth over winter.