后水湾深水网箱养殖区水环境的时空变化和营养状态分析

Temporal-Spatial Variations and Nutrient Status in the Aquatic Environment of Deep-Water Cage Aquaculture in Houshui Bay

关键词:  后水湾  深水网箱养殖  水环境  富营养化

Key words:  Houshui Bay  deep-water cage aquaculture  aquatic environment  eutrophication

摘要:

为探究鱼类网箱养殖对水环境的影响，利用后水湾深水网箱养殖海域2018年5月、8月、10月和2019年1月的水环境调查数据，分析网箱区与对照区的环境因子差异，采用有机污染评价指数法和营养指数法对后水湾深水网箱养殖海域水质污染现状进行评价。结果表明，水体的pH值、溶解态无机氮(DIN)、溶解氧(DO)、溶解态无机磷(DIP)和化学需氧量(COD_Mn)整体符合国家第一类海水水质标准，网箱区与对照区的水环境因子无显著性差异(P＞0.05)。在春季和冬季，后水湾养殖海域较适合浮游植物生长，而在夏季和秋季，浮游植物的生长繁殖会受到DIP限制。有机污染评价指数结果表明，后水湾养殖海域海水水质较好，未出现有机污染的状况。营养指数结果表明，养殖投饵高峰期水体的富营养化程度相对较高，网箱区局部海域富营养化问题较为突出，总磷(TP)和总氮(TN)是主要影响因子。今后应加强对后水湾深水网箱养殖海域的环境监测，避免养殖活动对水质造成长期的污染积累影响。

Abstract:

The effects of cage aquaculture on the aquatic environment of Houshui Bay were studied.The data from aquatic environment surveys for deep-water cage aquaculture that were conducted in May,August,October 2018 and January 2019 were collected.The environmental factors were compared between the cage area and control area.The organic pollution index and eutrophication index were adopted to evaluate the eutrophication level of the marine area with deep-water cage aquaculture and explore the relationship between eutrophication and environmental factors.The results showed that pH values,Dissolved Inorganic Nitrogen (DIN),Dissolved Oxygen (DO),Dissolved Inorganic Phosphorus (DIP),and Chemical Oxygen Demand (COD_Mn) met the standards of class I seawater quality.There was no significant difference in environmental factors between the cage area and the control area(P＞0.05).Spring and winter were more suitable for the growth of phytoplankton,while in summer and autumn,phytoplankton growth and reproduction were limited by DIP.The organic pollution index indicated that the seawater in Houshui Bay had good quality and no organic pollution.The eutrophication index indicated that the eutrophication level was high during the peak period of feeding in aquaculture,and the eutrophication was serious in the cage area,which was mainly influenced by Total Phosphorus (TP) and Total Nitrogen (TN).In the future,efforts should be made to strengthen the environmental monitoring of deep-water cage aquaculture in Houshui Bay,so as to avoid the long-term cumulative impact of aquaculture on the water quality.