泥蚶与凡纳滨对虾混养比例和密度的研究

Research on the optimal proportion and stocking density of blood clam polycultured with Litopenaeus vannamei

为优化泥蚶(Tegillarca granosa)与凡纳滨对虾(Litopenaeus vannamei)混合养殖体系,利用围隔法研究了泥蚶与凡纳滨对虾的适宜混养比例及泥蚶的适宜养殖密度。比例优化试验中,设置泥蚶密度分别为750、1 150和2 250 kg/hm2,虾苗密度均为1.7×105ind/hm2,泥蚶与对虾的个数比分别为1.84(A组)、2.75(B组)和5.50(C组)。在泥蚶和对虾的优化比例(4:1)下,设计泥蚶密度梯度,分别为50 ind/m2(L组)、75 ind/m2(M组)和100 ind/m2(H组)。结果显示,B组水体氨氮浓度显著低于A组(P<0.05),而A组硝酸盐氮浓度显著低于B组(P<0.05),其它水化学指标不存在显著差异;B组对虾产量显著高于A组(P<0.05),各处理组的收益率均存在显著差异(P<0.05),依次为B组>A组>C组。泥蚶密度试验中,M组泥蚶的规格、存活率和日均生长速率均高于L和H组,水化学指标无显著差异。研究表明,混合收益最佳的条件是:泥蚶和凡纳滨对虾的个数比为4∶1,泥蚶的养殖密度为75 ind/m2。

An enclosure experiment was carried out to investigate the quantitative proportion and stocking density of clam Tegillarca granosa in polyculture with Litopenaeus vannamei to optimize the polyculture. In the ratio optimization trial, the clam was reared respectively at stocking density of 750, 1 150 and 2 250 kg/hm^2, and the shrimp density was 1. 7 × 10^4 ind/hm^2 in all groups, with the quantitative clam-shrimp ratios being 1. 84 （A ）, 2. 75 （B ） and 5. 50 （C）. While in the stocking density trial, under the optimized ratio of clam to shrimp （4：1）, the clam was reared at the stocking density of 50 （L ）, 75 （M）, and 100 （H） ind/m^2 respectively. Results showed that NH3-N concentration of Group B was significantly lower than that of Group A （P 〈0. 05） and the nitrate of Group A was significantly lower than that of Group B （ P 〈 0. 05） ; no significant differences were found in other water indexes （ P 〉 0. 05） . The shrimp yield of Group B was significantly higher than Group A （ P 〈0. 05） , and the earnings rates were significantly different （ P 〈0. 05） with Group B 〉 Group A 〉 Group C in proper sequence. In the density trial, the SGR, survival rate and growth rate of clams in Group M were all higher than those of Group L and H; no significant differences in chemistry indexes of water were found among the groups during the experiment. The research showed that the polyculture system was optimized with the clam-shrimp ratio of 4 1 and the clam density of 75 ind/m^2.