사육밀도와 먹이 공급 횟수가 대구(Gadus macrocephalus)의 성장에 미치는 영향

Abstract

This study investigated the effects of stocking density and feeding frequency (three and five times per week) on the growth of Pacific cod, Gadus macrocephalus. In the first experiment, experimental groups of fish (mean weight <TEX>$167.8{\pm}41.4\;g$</TEX>) were reared at three stocking densities (4, 8 and 12 kg/<TEX>$m^3$</TEX>) for 16 weeks. The total weight gain was 17.8, 17.1 and 35.4% at 4, 8 and 12 kg/<TEX>$m^3$</TEX>, respectively. The specific growth rates, survival rates and feeding efficiency increased with the density, but there were no significant differences (P>0.05). The daily feed intake decreased as the stocking density increased, whereas the condition factors increased with the stocking density (P<0.05). In the second experiment, groups of fish (<TEX>$194.1{\pm}68.3\;g$</TEX>) were fed either three or five times a week. The total wight gain was 14.4 and 18.5% for the fish fed three and five times per week, respectively. The specific growth rates of Pacific cod fed to satiation increased with the feeding frequency, although the difference was not significant (P>0.05). The survival rates, daily feed intake, feed efficiency, and condition factors of the Pacific cod were not significantly different (P>0.05). Based on these results, the optimum stocking density for juvenile cod is above 12 kg/<TEX>$m^3$</TEX>, and the best feeding frequency is three times a week, under the conditions used in this experiment.