Structure and quality of offshore fishery resources in China.

Marine fishery resources play a crucial role in ensuring food safety, promoting economic development, and maintaining ecosystem stability. The scientific management and sustainable utilization of offshore marine fishery resources are crucial for promoting harmonious economic and environmental development. To explore the changes in the structure and quality of China's offshore marine fishery resources, this study investigated the relationship between human fishing activities, sea surface temperature (SST) changes, Mean Trophic Level (MTL), and Fishing-in-Balance Index (FIB) of the catch in each of the Chinese offshore fishing zones (Bohai Sea and Yellow Sea, East China Sea, and South China Sea) from 1990 to 2020. The study aimed to analyze the impact of human fishing activities and SST changes on the structure and quality of marine fishery resources and the health of fishery ecosystems in offshore China. The results indicated that during the 30 years of the experimental period, human overfishing led to a gradual dominance of low-trophic fish species in the fishery resource structure of the Bohai Sea and Yellow Sea as well as East China Sea fishing zones, resulting in a significant decrease in the quality of fishery resources, but with little impact on the South China Sea. In terms of climate change impact, the rapid SST warming in the Bohai Sea and Yellow Sea fishing zone from May to June inhibited the growth of high-trophic-level fish, and also exacerbated the trend of declining fishery resource quality and structural changes towards low-trophic-level fish. The autumn warming trend in the East China Sea fishing zone had a certain contribution to its quality decline and structural changes towards low-trophic- level fish, but in the South China Sea, the overall SST increase had negligible impacts. Human fishing activities had a minimal impact on the health of China's offshore fishery ecosystem, mainly due to the balance effect of increased catch. SST changes had a relatively small impact on the health of the fishing ecosystem in the Bohai, Yellow, and East China Seas. However, in the South China Sea, the SST warming in autumn was beneficial for the healthy development of its fishing ecosystem. Based on the research results, this study proposes relevant suggestions to improve the structure and quality of fishery resources in various fishing zones, enhance the health of fishery ecosystems, and provide management reference for the sustainable utilization of marine fishery resources in China's offshore fishing zones. [ABSTRACT FROM AUTHOR]