Effect of Water Temperature on Growth, Survival, and Biochemical Composition of Largemouth Bass Micropterus salmoides

The effects of water temperature on growth rate, survival, and biochemical composition of juvenile largemouth bass Micropterus salmoides were evaluated under controlled conditions in tanks for 12 wk. Feed-trained juvenile largemouth (9.1 ± 1.9 g) were stocked into nine 3,610-L polyethylene tanks inside a greenhouse structure at 140 fish/m³ (500 fish/tank). Three treatment temperatures were evaluated (20, 26, and 32 C) with three replicates per treatment. Bass were fed to apparent satiation twice daily using a commercially available floating salmonid diet (45% crude protein and 16% lipid). After 97 d bass grown at 26 and 32 C had significantly higher ( P < 0.05) average weights, SGR, condition factor (K), and production rates (kg/m³) than those in the 20 C treatment. Bass in the 26 C treatment had significantly lower ( P 0.05) FCR and higher percent protein deposit (PPD) than bass raised at 20 and 32 C, which were not significantly different ( P >0.05). There were no significant differences ( P >0.05) in survival among treatments which averaged 97%, overall. Bass raised at 32 C had higher ( P 0.05) lipid levels in the liver than other treatments. Whole body amino acid concentrations were not significantly impacted ( P >0.05) by culture temperature. Largemouth bass raised at 26 C had significantly lower ( P 0.05) levels of stearic acid (18:0) and significantly higher ( P 0.05) levels of arachidonic acid (20:4 n-6) than bass raised at 20 or 32 C. Bass raised at 32 C had significantly higher ( P 0.05) levels of Linoleic acid (18:2 n-6), total saturates, and dienes than bass raised at 26 or 20 C. These data indicate that growth and feed conversion efficiency are reduced at 20 C. Growth is similar at 26 and 32 C, but feed and dietary protein are more efficiently utilized at 26 C.