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چکیده
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To evaluate the effect of stocking density on survival and growth rate of goldfish (Carassius auratus), after 2 weeks adaptation to the new condition, 126 of fish with initial body weight 3.50±0.27 g were distributed randomly among 12 aquaria (76 liter) to stocking densities 6, 9, 12 and 15 fish per aquarium, respectively. The experiments were continued for 5 months in triplicates. Fish were hand-fed two times daily up to 3% body weight/day. Biometric characteristics of fish including total length (cm), weight (g), growth rate (g), specific growth rate (g/day), feed conversion ratio (FCR) and condition factor were determined every two weeks. After the end of the trial period, the average weight of fish in each group was recorded 14.79±2.61, 15.98±0.32, 33.15±1.47 and 14.2±0.30 g, respectively. With the increasing density of goldfish, growth indices, including secondary weight, weight gain, specific growth rate and feed conversion ratio showed a significant difference (P<0.05), but condition factor did not show significant different (P<0.05). Survival rate were not significantly different among different densities (P>0.05). The results of this study indicate that density is significantly affected the growth, but had no significant effect on survival.
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