Effects of Feeding Rate and Water Temperature on Growth and Body Composition of Juvenile Korean Rockfish, Sebastes schlegeli (Hilgendorf 1880)

Three feeding trials were conducted to evaluate the effects of feeding rate and water temperature on growth and body composition of juvenile Korean rockfish, Sebastes schlegeli rearing at 3 different water temperatures. A total of 270 fish (each experiment) individual body weight (BW) averaging 16 +/- 0.3 g (mean +/- SD) were fed a commercial diet for 4 wk at 16 degrees C, 20 degrees C, and 24 degrees C. At each temperature, triplicate tanks were assigned to one of 6 feeding rates: 1.5%, 2.5%, 2.8%, 3.1%, 3.4%, and satiation (3.7% BW/d) at 16 degrees C, 1.9%, 2.9%, 3.2%, 3.5%, 3.8% and satiation (4.1% BW/d) at 20 degrees C and 1.7%, 2.7%, 3.0%, 3.3%, 3.6%, and satiation (3.9% BW/d) at 24 degrees C water temperature. Weight gains of fish in satiation and 3.4% groups at 16 degrees C, in satiation and 3.8% groups at 20 degrees C and in satiation and 3.6% groups at 24 degrees C were significantly higher than those of fish in the other treatments (p<0.05). A broken line regression analysis of weight gain indicated that optimum feeding rates of juvenile Korean rockfish were 3.41% at 16 degrees C, 3.75% at 20 degrees C and 3.34% at 24 degrees C water temperature. Results of the present study indicate that the optimum feeding rate could be >3.1% but <3.41% at 16 degrees C, >3.5% but <3.75% at 20 degrees C and >3.0% but <3.34% at 24 degrees C. As we expected results suggest that fish performed better at 20 degrees C than 16 degrees C or 24 degrees C water temperature and the optimum feeding rate could be 3.1% BW/d to 3.7% BW/d in 16 g of juvenile Korean rockfish.