Study on conservation of Bostrychus sinensis in buried pipe system of mangrove area in Zhanjiang

We investigated the effects of three stocking densities on the growth, and physiological and biochemical indices of Bostrychus sinensis in the buried pipe system of the semi-diurnal tidal mangrove area in Zhanjiang. The fingerlings of B.sinensis with initial body mass of (45.39±2.36) g and body length of (12.51± 0.35) cm were reared at three stocking densities Group A (4.3 kg·m^–3), Group B (5.0 kg·m^–3), Group C (5.7 kg·m^–3), each with three replicates in the system for 80 d. The results show that the survival rates were above 94.9% at all three stocking densities in the end, and the differences in the final body length, specific growth rate, growth rate, fatness, average daily gain and weight gain rates among the groups were not significant (P>0.05), but the average body mass of Group A was higher than that of Group C in the end (P<0.05). The rate of feed conversion in Group C was significantly higher than that in Group A (P<0.05). There was no significant difference in the coefficient of variation of body length among different groups in the end (P>0.05), but the coefficients of variation of the final body mass among all groups increased with the increase of stocking density, while that in Group A was significantly lower than that in Group B and C (P<0.05). The activities of SOD and lysozyme of Group A were significantly higher than those in Group C (P<0.05), while MDA content in Group A was significantly lower than those in Group B and Group C (P<0.05).