陆基圆池循环水条件下养殖密度对大口黑鲈生长及养殖效能的影响

Effects of different densities on growth and aquaculture efficiency of largemouth bass(Micropterus salmoides)cultured in land-based recirculating aquaculture system

为研究陆基圆池循环水养殖条件下大口黑鲈(Micropterus salmoides)适宜的养殖密度,设置55、65、75、85、95尾/m^(2)等5种养殖密度(分别标记为A1、A2、A3、A4、A5组),进行了63 d的大口黑鲈养殖试验,通过测定和分析试验鱼的体质量日增长率、体长日增长率、饲料系数、体质量均匀度和单位面积产量等指标,评价不同养殖密度对大口黑鲈生长和主要养殖效能的影响。结果显示:(1)从次低密度的A2组(65尾/m^(2))至密度最高的A5组(95尾/m^(2)),试验鱼的体长日增长率基本上随着养殖密度的提高而下降,最高的A2组比A3、A4和A5组分别高了31.6%、82.9%和92.3%,并且差异显著(P<0.05);(2)从A2组至A5组,试验鱼的体质量日增长率和特定生长率均随着养殖密度的提高而下降;(3)A2组的饲料系数比A1、A3、A4和A5组分别降低了16.7%、28.6%、55.4%和56.9%;(4)单位面积产量和产品均匀度均在A2组达到最高。基于生长性能及养殖效能的综合评价,陆基圆池循环水养殖条件下大口黑鲈成鱼养殖阶段较适宜的养殖密度为65尾/m^(2)。

To study the optimal density of largemouth bass(Micropterus salmoides)under the condition of circulating water in land-based round tank,five densities of M.salmoides were cultured at 55 tails/m^(2)(group A1),65 tails/m^(2)(group A2),75 tails/m^(2)(group A3),85 tails/m^(2)(group A4)and 95 tails/m^(2)(group A5).The weight gain rate(WGR),specific growth rate(SGR),length gain rate(LGR),feed conversion ratio(FCR),body weight evenness and yield were evaluated to investigate the effects of stocking densities on the growth and main culture efficiency of M.salmoides.The results showed:(1)The WGR,SGR and LGR significantly decreased with stocking density increasing from group A2 to group A5,and the WGR of A2 individuals was 31.6%,82.9%and 92.3%higher than A3,A4 and A5 groups,respectively(P<0.05).(2)FCR increased with stocking density increasing from group A2 to group A5,and the values of A2 individuals were 16.7%,28.6%,55.4%and 56.9%lower than that in groups A1,A3,A4 and A5,respectively.(3)At the absolute level of yield,when the breeding density was in the range of 65-85 tails/m^(2),the yield per unit area decreased with the increase of breeding density.Based on the comprehensive evaluation of growth performance and culture efficiency,the optimal stocking density of adult largemouth bass could be 65 tails/m^(2)(group A2)under the condition of land-based recirculating aquaculture system.