放养密度对大西洋鲑循环水养殖效果的影响

Influence of st℃ king density on growth performance of the Atlantic salmon, Salmo salar, in recirculating aquaculture system

通过室内循环水养殖试验,研究了不同放养密度对大西洋鲑(Salmo salar)养殖效果的影响。试验设置6 kg/m^3,9 kg/m^3,12 kg/m^3,15 kg/m^3,18 kg/m^3共5个养殖密度,采用同来源、同批次、体重均为1.56±0.05 kg/尾的大西洋鲑幼鱼,在封闭式循环水养殖系统中养殖220d。通过分析不同养殖密度对出池均重、特定生长率、成活率、淘汰率、雄性发育率、饵料系数、饵料效率与产量的影响,以确定最佳放养密度。结果表明,大西洋鲑的不同放养密度对养殖效果有显著影响。随着养殖密度的增大,大西洋鲑生长速度逐渐减慢,过高的放养密度会显著抑制大西洋鲑的生长,并显著影响成活率和淘汰率(P<0.05),而对雄性发育率则无显著影响(P>0.05)。当放养密度超过12 kg/m^3时,鱼体出池均重、特定生长率均急剧减小,成活率急剧降低。放养密度的增加,还会加大饵料系数、降低饵料效率(P<0.05)。当放养密度为12-18 kg/m^3时,商品鱼净产量最高,且各组无显著差异。综合各指标评价,在所试验的循环水养殖系统中,放养密度为12 kg/m^3左右时,可获得最佳养殖效果和经济效益。

We performed an experiment to study the influences of different st℃king densities(SD) on the culture of Atlantic salmon(Salmo salar) in recirculating aquaculture system. Experiment was conducted with five gradient densities set as 6 kg/m3, 9 kg/m3, 12 kg/m3, 15 kg/m3 and 18 kg/m3 for 220 days, adopting homologous and the same batch of Atlantic salmon seedling with body weight varying between 1.5 and 1.6 kg in recirculating aquaculture system. By analyzing the effect of different SD on the average body weight(BW), specific growth rate(SGR), survival rate(SR), elimination rate(ER), male gonad development rate(MDR), feed conversion ratio(FCR), feed efficiency(FE) and production, the most reasonable st℃king density was determined. The results indicated that SD has a significant influence on growth and survival of the Atlantic salmon(P<0.05). With the increasing of SD, the growth rate appeared to decrease. Higher SD restrained the growth and influenced SR and ER of Atlantic salmon significantly(P<0.05), and MDR insignificantly(P>0.05). When SD was higher than 12 kg/m3, BW, SGR and SR decreased sharply. The higher SD increased also FCR and decreased FE(P<0.05). Marketable net production(MGP) was the highest when SD varied between 12 and 18 kg/m3 but the difference was not significant among groups(P>0.05). With these results, we reasoned that st℃king density of 12 kg/m3 was appropriate for achieving the optimal culture result and maximal economic benefit in the recirculating aquaculture system.