珠江口南沙海域秋季渔业资源群落结构特征

增殖放流是渔业资源养护的重要方式。放流前对放流海域进行生态容纳量评估，有计划地实施增殖放流活动，可避免对原有生态系统造成破坏。文章根据2016年珠江口渔业资源数据，构建了由29个功能组组成的基于珠江口的生态系统通道(Ecopath)模型，利用该模型分析了生态系统的总体特征、食物网结构与混合营养效应，估算了适宜于该水域的6种不同增殖放流种类的生态容纳量。结果表明，功能组营养级范围为1~4.2级，6种适宜放流种类营养级介于2.2~3.7，最高营养级功能组为哺乳动物，系统总流量9 092.447 t·(km²·a)^–1，系统总能量转化效率12.23%，连接指数0.370，系统杂食指数0.287。食物链通道主要有2类，以碎屑食物链为主。花鲈(Lateolabrax japonicus)、黑鲷(Acanthopagrus schlegelii)、黄鳍鲷(A. latus)、长毛对虾(Penaeus penicillatus)、墨吉对虾(P. monodon)和波纹巴非蛤(Paphia undulata)的最大容纳量分别为0.094 t·km^–2、0.500 t·km^–2、0.650 t·km^–2、1.580 t·km^–2、1.610 t·km^–2和75.870 t·km^–2。

Best practice in Ecopath with Ecosim food-web models for ecosystem-based management

Stock enhancement is important for conservation of exploitable resources. Assessment of ecological capacity of the discharged sea area before discharge and planned implementation of proliferation and discharge activities can avoid damage to the original ecosystem. Based on the survey data of the fishery resources of Pearl River estuary in 2016, an Ecopath mass-balance model of the Pearl River estuary ecosystem consisting of 29 functional groups was constructed. Thus, the overall characteristics of the ecosystem, the food-web structure and the mixed trophic impact were analyzed. The ecological carrying capacities of six species of stock enhancement which were suitable for this area were estimated. The results show that the fractional trophic levels ranged from 1 to 4.2, and those of the six species ranged from 2.2 to 3.7, with marine mammals occupying the highest trophic level. The total system throughput of the ecosystem was 9 092.447 t·(km²·a)^–1, and the total energy transfer efficiency was 12.23%. The connectance index and system omnivory index were 0.370 and 0.287, respectively. There were two main channels of food chain in the ecsystem, and the energy flow was dominated by grazing food chain. The ecological carrying capacities of biomass for Lateolabrax japonicus, Acanthopagrus schlegelii, A. latus, Penaeus penicillatus, P. monodon and Paphia undulata were 0.094 t·km^–2, 0.500 t·km^–2, 0.650 t·km^–2, 1.580 t·km^–2, 1.610 t·km^–2 and 75.870 t·km^–2, respectively.