Spatial variation of functional structure of fish communities in the Bohai Sea

Functional space and diversity are powerful methods for understanding ecological patterns and describing changes in fish communities. To better understand spatial variation in the functional structure of the fish communities in the Bohai Sea, the composition of 10 functional traits such as diet, migration type, and thermophily, for 47 species collected from four subareas in the summer of 2022, was analyzed using community-weighted mean trait values (CWM), functional space, and functional diversity. The results showed that there were significant spatial differences in CWM traits of diet, relative mouth size, resilience, body shape, salt tolerance, growth coefficient, and trophic level. The functional space occupied by fish communities in Laizhou Bay and Bohai Center was relatively high. Functional evenness and divergence were extremely high in Bohai Center and Liaodong Bay, and were lowest in Bohai Bay. These results indicated that the fish community in Laizhou Bay occupied the largest spatial niche and had the most habitat resources. Weak competition, and more comprehensive and efficient utilization of habitat resources were in Bohai Center and Liaodong Bay. Competition among fish in Bohai Bay was extreme, placing its fish community in a state of competitive exclusion. Temperature, salinity, pH, and chlorophyll were the main factors affecting the functional structure of the fish communities in the Bohai Sea, and in fisheries management based on functional structure, attention should be paid to changes in environmental factors. This study can provide a scientific reference from the perspective of functional ecology for fisheries management in the Bohai Sea.