对虾与鱼、贝类封闭式综合养殖的实验研究

SUMMARY OF STUDIES ON CLOSED-POLYCULTURE OF PENAEID SHRIMP WITH TILAPIA AND MOLLUSCANS

于 1 995— 1 999年采用陆基实验围隔法系统地研究了对虾与鱼、贝类封闭式综合养殖的基础问题 ,所选取的材料为中国对虾、台湾红罗非鱼、缢蛏与海湾扇贝 ,研究出了 4种优化结构养殖模式。结果表明 ,4种模式的组成及各成分间生物量 (收获前 )的比值分别为 :对虾-缢蛏 1∶ 3 ;对虾 -扇贝 1∶ 1 ;对虾 -罗非鱼 1∶ 1 ;对虾 -罗非鱼 -缢蛏 ,1∶ 0 .3∶ 2。所有这些模式的养殖效果都比同样条件下的对虾单养模式显著优越 ;其中最好的虾、鱼、贝三元综合养殖模式将产量提高了 2 8% ,投入氮的利用率提高了 85 %。同时采取封闭式的养殖方法 ,向浅海输出的氮只占养殖输入氮的 6 %— 8% 。

Closed polyculture of penaeid shrimp ( Penaeus chinensis) , Taiwan red tilapia ( Oreochromis mossambicus×O. niloticus ), and molluscans [constricted tagelus ( Sinonovacula constricta) and scallop ( Argopecten irradians) ] was studied from 1995 to 1997 with the enclosure experiment method. Four structure optimized closed polyculture systems, i. e., the 'shrimp tagelus' system with a biomass ratio of 1∶3, the 'shrimp scallop' system with a biomass ratio of 1∶1, the 'shrimp tilapia' system with a biomass ratio of 1∶1, and the 'shrimp tilapia tagelus' system with a biomass ratio of 1∶0 3∶2, were worked out. All these polyculture systems were superior to shrimp monoculture system both in economic and ecological efficiencies. The order of these polyculture systems in priority was 'shrimp tilapia tagelus'>'shrimp tagelus'>'shrimp tilapia'>'shrimp scallop'. The 'shrimp tilapia tagelus' system raised the production by 28% and the utilization efficiency of input nitrogen by 85%. These closed polyculture systems reduced the nitrogen discharge ratio to 6%-8%, instead of 40%-90% in the usual open culture systems. The ecological features, including that of the energy flow, of the systems were also investigated and many meaningful results have been obtained. Meanwhile, a technique for preventing the viral epidemic diseases has been developed. The mechanism enhancing the efficiencies of these systems, the significance of the viral diseases prevention technique and the possibility of developing a sustainable shrimp farming are discussed.