沉积环境对鱼类网箱养殖的响应

Responses of sediment environment to fish cage culture

网箱养殖是鱼类集约化养殖的主要方式,近年来得到大力发展,但是网箱养殖也带来诸多的环境问题。本文从沉积环境改变的角度阐述了网箱养殖对环境的影响,包括底层水环境要素、底质理化环境要素和底栖生物环境要素对网箱养殖的响应,并探讨了有机负荷的消减对策。网箱养殖区水环境中溶解氧(DO)通常下降,而化学耗氧量(COD)、氨氮(NH4-N)和无机磷(D IP)增多;底泥沉积物中N、P、硫化物、有机质等大量富集,其中富集现象最明显的是P、硫化物和NH4-N,其次是总氮(TN)和有机质;一般情况下,网箱养殖区底栖生物尤其是多毛类增加,而当污染严重时,会使底栖生物缺失。有机负荷的消减对策包括收集残饵粪便等沉积物、利用生物方法去除有机碎屑和加强养殖管理提高饲料利用率等。

Cage mariculture developed rapidly,and had become the main pattern of intensive fish culture in China.However,this culture pattern also resulted in a series of environment problems.The article summarized the effect of cage culture on the environment from sedimentary environment changing perspective,including the responses of bottom water environmental elements,quality of the bottom environmental elements and benthon environmental elements to cage culture.The strategy of the organic load removing was also discussed.In the sea water of the cage culture region,the dissolved oxygen（DO） usually decreased,but the chemical oxygen demand（COD）,ammonium（NH4-N） and inorganic phosphorus（DIP） usually increased;the nitrogen,phosphorus,sulfide and organic matter plentifully enriched in the bottom sediment,the phosphorus,sulfide and ammonium enriching was more evident than the TN and organic matter enriching;Generally,the benthon,especially the polychaeta of the cage culture region increased,but they would decrease sharply when the contamination got severe.The methods to remove the organic load included the collection of sediment of residual feed and faeces,decreasing the organic debris feeding by some animals and increasing the food efficiency by enhancing the cultivation management.