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采用18个36m2的围隔进行对虾单养和对虾–罗非鱼混养试验,研究其水质动态及产出效果的差异。试验分为6组,每组3个围隔。各围隔放养凡纳滨对虾(全长为0.045cm)3000尾,放养罗非鱼(体重为201±25g)分别为0(F组)、4(A组)、8(B组)、12(C组)、18(D组)和24尾(E组),放养对虾1个月后放养罗非鱼。试验期间各围隔均不进行水交换,试验周期为70d。结果显示,放养罗非鱼之前各实验围隔水质指标接近;放养罗非鱼之后,混养各组水体的氨氮浓度、亚硝氮浓度、COD和弧菌数量均小于单养组,其中C组水体的氨氮浓度、亚硝氮浓度和弧菌数量与单养组差异显著(p﹤0.05),且混养组中C组水体的上述指标小于其他混养组。混养各组对虾的规格、特定生长率、成活率和净产量均大于单养组,其中C组与单养组差异显著(p﹤0.05),且混养组中C组水体的上述指标大于其他混养组。结果表明,混养各组的水质状况和产出效果优于单养组,凡纳滨对虾(放养密度为8.3×105尾/hm2)和罗非鱼(放养密度为3320尾/hm2)混养的生态效益和经济效益最佳。
18 36m2 enclosures were used to conduct shrimp monoculture and shrimp-tilapia polyculture experiments to study the differences in water quality dynamics and output effects. The experiment was divided into 6 groups of 3 enclosures. There were 3000 reared shrimp (0.045 cm in total length) and 0 (F group), 4 (group A), 8 (group B) and 12 (Group C), 18 (group D) and 24 (group E). One month after stocking shrimp, tilapia were stocked. During the test, there was no water exchange between the enclosures, and the test period was 70 days. The results showed that before tilapia were stocked, the water quality index of each enclosure was similar. After tilapia were stocked, the ammonia nitrogen concentration, nitrite nitrogen concentration, COD and Vibrio were all less than polyculture group The ammonia nitrogen concentration, nitrite nitrogen concentration and the number of vibrios in water body were significantly different from those in monoculture group (p <0.05), and the above indexes in group C water body in polyculture group were less than those in other polyculture groups. The specific growth rate, survival rate and net yield of shrimp in polyculture group were higher than that in monoculture group, of which the difference was significant (P <0.05) between C group and monoculture group, and the above indexes in C group were higher than those in polyculture group Other polyculture group. The results showed that water quality status and output effect of polyculture groups were better than that of monoculture group. Polyculture of Litopenaeus vannamei (stocking density of 8.3 × 105 / hm2) and tilapia (stocking density of 3320 / hm2) The best ecological and economic benefits.