通过对现有资料的系统分析,简化了渤海生态系统食物网,并剖析了近50年来渤海主要渔业资源结构的变化特征.这对进一步阐明渤海生态系统动力学的变化特征以及研究渔业资源衰退的原因有重要的科学意义。研究表明,渤海主要鱼类可聚为4类:游泳动物食性鱼类、底栖动物食性鱼类、浮游动物食性鱼类和腐屑食性鱼类,在此基础上渤海生态系统食物网可简化为3条食物链:浮游植物一浮游动物一浮游动物食性鱼类一游泳动物食性鱼类(第一条食物链);浮游植物和碎屑一底栖动物一底栖动物食性鱼类和头足类一游泳动物食性鱼类(第二条食物链):碎屑一腐屑食性鱼类(第三条食物链)。20世纪50年代末以来,第一条食物链渔业资源已取代第二条食物链渔业资源成为最主要的渔业资源,第三条食物链渔业资源生物量百分比呈上升趋势,近年来已成为继第一条食物链渔业资源的第二大类渔业资源。渔业捕捞、渤海次级生产力结构的变化以及各渔业资源生物自身生长和繁殖特点的不同是导致渤海主要渔业资源结构变化的重要因素。
Based on the integrated historical data in the last 50 years, we simplified the food web in the Bohai Sea ecosystem, and analyzed the structural changes of the major fishery resources in the Bohai Sea, which was of sci- entific significance for further elucidating the dynamics of the Bohai Sea ecosystem in light of the decline of fishery and the reasons leading to such decline. The primary fishes in the Bohai Sea could be classified into four types: nektivore fish, benthivorous fish, zooplanktivorous fish, and detrivorous fish. Based on this classification, the Bohai Sea ecosystem could be simplified into three major food chains: phytoplankton→zooplankton→zooplanktivorous fish→ektivore fish (the first food chain), phytoplankton and detritus → benthos →benthivorous fish and cephalopod →nektivore fish (the second food chain), and detritus→ detrivorous fish (the third food chain). Fisheries in the first food chain had replaced those in the second food chain and became the first primary fisheries in the Bohai Sea since late 1950s. Percentage of biomass made up by fisheries in the third food chain increased continu- ously and became the second primary fisheries in the Bohai Sea in recent years. Fishing activities, change of the structure of secondary production, and the characteristics of the growth and reproduction of the fishery species were the important factors influencing the structural changes of major fishery resources in the Bohai Sea.