基于营养通道模型的海州湾中国明对虾生态容纳量

通过增殖放流,增加优质渔业资源、改善种群结构是渔业资源养护的重要手段,而增殖生态容量的研究是科学实施增殖放流的前提。为确定海州湾中国明对虾的生态容纳量,根据2013年连云港海州湾渔业生态修复水域的调查资料,应用Ecopath with Ecosim(EwE)软件中的Ecopath模块,构建了该区域的生态系统能量流动简易模型,计算了放流种类中国明对虾的增殖生态容纳量。结果表明:系统各功能组营养级范围在1~4.42。系统总流量9335.191 t·km~(–2)·a~(–1),系统总初级生产力3892.630 t·km~(–2)·a~(–1),系统初级生产力与总呼吸量的比值为1.331,连接指数为0.415,杂食指数为0.174,Finn循环指数为11.4%,平均能流路径为2.8系统尚处于由衰竭状态向恢复状态转变,还未恢复到成熟态。中国明对虾不是本海域的关键种,当前中国明对虾的生物量为0.04 t·km–2·a–1,中国明对虾的生态容纳量为0.846 t·km~(–2)·a~(–1)。

Ecological carrying capacity of Chinese shrimp stock enhancement in Haizhou Bay of East China based on Ecopath model

In order to protect the wild population and genetic resources of Chinese shrimp (Fenneropenaeus chinensis), stock enhancement activities about Chinese shrimp had been carried out since 1980s in Haizhou Bay. Stock enhancement is an important way of fishery resources conservation, which can increase the high quality fishery resources and improve the fish population structure. However, scientific management of stock enhance-ment need to understand the carrying capacity of target species. Based on the data of biological resources obtained from an investigation of Haizhou Bay in 2013, a balanced trophic model of the area was constructed using the Ecopath with Ecosim software package. The effects of uncertainty of input parameters and Ecopath analysis sensi-tivity were explored. Trophic flow and system attributes of the Haizhou Bay ecosystem were analyzed. The eco-logical carrying capacity for Chinese shrimp were also predicted. The model consisted of 16 functional groups, which covered the main trophic flow in the Haizhou Bay ecosystem. The results showed that the pedigree index of the model was 0.588, indicated that the model input parameters were robust and reliable. The input parameters hav-ing the greatest effects on the output parameters were the ecotrophic efficiency (EE). Trophic levels of functional groups varied from 1?4.42. The total system throughput in ecosystem was estimated to be 9335.191 t·km–2·a–1, sum of all production was 3892.630 t·km–2·a–1, and sum of all consumption was 3838.019 t·km–2·a–1, total net system production was 822.042 t·km–2·a–1. The total energy transfer efficiency was 7.9%, transfer efficiency from primary producers and detritus was 6.6% and 9.4%, respectively. The proportion of the total flow originating from detritus was 40%, and that from primary producers was 60%, indicating that the energy flow was dominated by grazing food chain. The ratio of TPP/TR was 1.331, the connectivity index was 0.415, the omnivory index was 0.174, the Finn cycling index and the mean path length were 11.4% and 2.8 respectively. This study showed that the ecosys-tem of Haizhou Bay was still on a relatively low maturity and stability condition, and at a developing stage. The analysis on the keystone species showed that Chinese shrimp was not a keystone species of this ecosystem. The ecological carrying capacity was defined as the level of enhancement that could be introduced without signifi-cantly changing the major trophic fluxes or structure of the food web. At present, the biomass of Chinese shrimp in the ecosystem was 0.04 t·km–2·a–1, with a greater potential of continued enhancement. The ecological carrying capacity biomass of the Chinese shrimp was 0.846 t·km–2·a–1, meaning there is further potential for stock en-hancement. Our results will contribute to manage the stock enhancement activities and be a good example for the carrying capacity research of other species.