黄河调水调沙对河口及邻近海域鱼卵、仔稚鱼群落结构的影响
THE WATER-SEDIMENT REGULATION SCHEME ON THE COMMUNITY STRUCTURE OF ICHTHYOPLANKTON IN THE YELLOW RIVER ESTUARY
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摘要: 为了解调水调沙(Water-Sediment Regulation Scheme, WSRS)对黄河口海域鱼卵、仔稚鱼的群落结构和时空分布格局的影响, 分别于2017年(非调水调沙年)和2018年(调水调沙年)的6—7月在黄河口海域利用水平拖网开展了6个航次的鱼卵、仔稚鱼调查。运用聚类分析和冗余分析(RDA)等方法对该海域非调水调沙年和调水调沙年的鱼卵、仔稚鱼丰度和群落结构的空间分布及环境因子状况等进行了综合的分析比较, 结果表明: 6个航次调查共采获鱼卵6212粒, 仔稚鱼431尾, 隶属于8目12科14属, 其中, 河口定居性鱼类短吻红舌鳎(Cynoglossus joyeri)为控制黄河口及邻近海域夏季鱼类浮游生物群落演替格局的主要种类; 鱼卵受环流和调水调沙的共同影响, 其空间分布在各调查阶段有所不同, 仔稚鱼则趋向于在河口近岸海域分布; 河口东北部及东南部靠近莱州湾区域是黄河口及邻近海域鱼类浮游生物群落的主要聚集区; 调水调沙年鱼卵、仔稚鱼的采获总量以及底层鱼类鱼卵的采获数量均明显高于非调水调沙年, 调水调沙带来的丰富径流和泥沙有利于黄河口海域渔业资源的补充; 冗余分析结果表明, 海洋鱼类的群落结构与环境因子关系密切, 研究区域鱼卵、仔稚鱼的群落结构与盐度、水温、水深及浮游生物密度等因素息息相关, 环境条件影响着鱼类对栖息地的选择。黄河调水调沙输送的丰富入海淡水和泥沙与其邻近海域的海洋生态环境及海洋生物资源构成了密切的响应关系, 随着我们对调水调沙实践经验的不断积累, 建议应在今后的工作中进一步加强对调水调沙的目标、时间和频次优化等问题的关注。Abstract: The rapid transfer of large amounts of water and sand to the Yellow River basin during the implementation of the Water-Sediment Regulation Scheme (WSRS) can significantly alter the physicochemical environment of the ecosystem in the Yellow River estuary and its surrounding sea areas. In order to understand the effects of WSRS on the community structure and spatial and temporal distribution patterns in the Yellow River estuary, a survey of ichthyoplankton was conducted in June and July of 2017 (a non-WSRS year) and 2018 (a WSRS year) using horizontal trawl methods. The results showed that a total of 6212 eggs and 431 larvae belonging to 14 genera and 12 families in 8 orders were collected during the six surveys. Cynoglossus joyeri was the main species controlling the succession pattern of ichthyoplankton community during the summer in the Yellow River estuary. WSRS exerted its influence on the ichthyoplankton community structure by changing the runoff, salinity and water temperature in the estuary. The dominant species, quantity, and diversity index of ichthyoplankton displayed fluctuations during the process of WSRS. The spatial distribution of fish eggs varied among investigation stages due to the combined effects of circulation and WSRS, with larvae tending to be distributed in nearshore waters of the estuary. The northeastern and southeastern part of the estuary, near Laizhou Bay, were the main aggregation areas of the ichthyoplankton community in the Yellow River estuary. In 2018, there was a significant increase in the number of ichthyoplankton and demersal fish eggs compared to 2017, as the abundant runoff and sediment brought by the water and sand transfer were favorable to replenish the fishery resources in the waters of the Yellow River estuary. The community structure of ichthyoplankton in the study area is closely related to salinity, water temperature, water depth, and plankton abundance. The environmental conditions played a crucial role in determining the habitat preferences of fish. The abundant freshwater and sediment transported by the Yellow River water and sand transfer constituted a close response relationship with the marine ecological environment and marine biological resources in its neighboring waters. With the accumulation of practical experience in water and sand transfer, it is suggested that we should further strengthen the attention to the optimization of water transfer and sand transfer in terms of its target, time and frequency in our future work.