海水鱼类网箱养殖的环境效应及多营养层次的综合养殖

海水鱼类网箱养殖是世界主要渔业国家(如挪威、日本等)广泛开展的一种高密度、集约化的养鱼方式,这种养殖方式在给广大从业者带来巨大经济、社会效益的同时,对环境也造成了不可忽视的负面影响。开展多营养层次的综合养殖(IMTA)是缓解这一环境压力的有效途径,鱼类养殖过程中释放出的二氧化碳、氮、磷等物质,由无机提取单元(大型藻类)来吸收,粪便和残饵等微小颗粒则成为有机提取单元(滤食性贝类)的饵料,较大的颗粒物质沉到海底后,可以为腐食性单元(海参等)提供食物,通过这种养殖模式,最大限度地实现系统内营养物质的高效利用,在减轻养殖对环境压力的同时,使系统具有较高的容纳量和食物产出能力。

Environmental Effect of Marine fish Cage Aquaculture and Integrated Multi-Trophic Aquaculture

The cage aquaculture subsector has grown very rapidly during the past two decades and is presently undergoing rapid changes in response to pressures from globalization and a growing global demand for aquatic products.Following its rapid development,the nutrients of cage culture,mainly uneaten food,and faecal and urinary products,are released directly into the environment and result in many environmental problems.Integrating the fed aquaculture of finfish with the inorganic extractive components of seaweeds,the organic extractive components of shellfish and sea cucumber,has been advocated as an effective strategy to alleviate waste loadings and environmental impacts,the wastes of one resource user become a resource（fertilizer or food） for the others.Through Integrated Multi-Trophic Aquaculture（IMTA）,some of the food and energy considered lost in finfish monoculture are recaptured and converted into crops of commercial value.