春季珠江口万山群岛毗邻海域渔业生态环境状况评价

Evaluation of fisheries ecological environment in adjacent sea areas of Wanshan Archipelago in Pearl River Estuary in spring

万山群岛在珠江口渔业资源养护过程中发挥着重要作用,但目前对该区域岛礁毗邻海域的渔业生态状况尚缺乏足够研究。分析了2021年4月万山群岛毗邻海域的水环境状况和浮游动物群落特征,以此评价该区域渔业生态环境状况。结果表明,万山群岛海水环境状况受珠江口径流输入的影响较大,造成该区域西北侧的桂山岛和东澳岛海水中的无机氮浓度、营养状态质量指数和富营养化指数较高,部分水体为富营养状态,并且初级生产力水平相对较高,但多为中低水平。万山群岛海域浮游动物群落具有区域性分布特点,可聚为3大类,其中桂山岛临近区域内的浮游动物香农多样性指数相对较低,表明该区域水体可能受到了一定的污染;桂山岛海域的鱼卵和仔稚鱼丰度却较高,分别为133粒·m^(−3)和18尾·m^(−3),表明桂山岛可能是珠江口鱼类产卵的重要场所。海水初级生产力和浮游动物均匀度指数可很好地反映万山群岛水环境和浮游动物群落之间的关联性,并可指示水体富营养化状态。

Wanshan Archipelago plays an important role in the conservation of fishery resources in the Pearl River Estuary.However,there is still a lack of sufficient research on the fishery ecological status of the adjacent waters of islands and reefs in this region.Thus,we analyzed the characteristics of the seawater environment and zooplankton community in Wanshan Archipelago in April 2021.The results show that the seawater environment of Wanshan Archipelago was greatly influenced by fresh water input from the Pearl River coastal channels.Consequently,the concentration of dissolved inorganic nitrogen,nutrient quality index and eutrophication index were higher in the adjacent sea areas of Guishan Island and Dong'ao Island which are located in the northwestern Wanshan Archipelago.Eutrophication was observed in this area.Furthermore,the primary production in the seawater of these two islands was also higher,most with medium and low levels.The zooplankton communities of Wanshan Archipelago can be divided into three groups,and one of them affiliated to the adjacent sea areas of Guishan Island had a low Shannon-Wiener index value,indicating a potentially polluted seawater environment.However,high abundances of spawning and larval fish were observed at Guishan Island(133 egg·m^(−3) and 18 ind·m^(−3),respectively),suggesting that it is an important fish spawning area.The primary production and Pielou evenness index of zooplankton can reflect the correlation between water environment and zooplankton community in Wanshan Archipelago,and can indicate the state of water eutrophication.