Abstract:

Based on the data of fishery resources survey in the coastal waters of Zhoushan Islands in November 2015 (autumn) and May 2016 (spring), the index of relative importance, clumping index and probability of interspecific encounter were used to measure and analyze the collected fish species, focusing on the proportion of juvenile fish of major fish species (IRI>100), and estimating the fishery resources in the investigated sea area according to the density of fishery resources. The results showed that there were 11 species of major fish species in spring, including 3 dominant species: Sebastiscus marmoratus, Collichthys lucidus and Amblychaeturichthys hexanema. There were 6 species of major fish species in autumn, while only Harpodon nehereus was dominant fish, indicating that the high-intensity fishing effort after the end of the fishing moratorium will consume fishery resources in a short period of time. There were differences in the fishery resources and the proportion of juvenile fishes in spring and autumn. The fishery resources in autumn were higher, while the proportion of juvenile fishes was lower, and the maintenance effect of short-term temporary maintenance during the summer fishing moratorium was obvious. The results of clumping index and probability of interspecific encounter were consistent, which indicated that the community dominance was higher, the species distribution density and species association degree were higher, and the population aggregation was obvious. The study concluded that the protection of marine fishery resources and the sustainable development of the marine fishing industry should give priority to protect juvenile fish resources in order to increase fishery production and restore coastal fishing grounds.