Identifying biological interaction effects in the spatiotemporal dynamics of multiple fish species

Determining how different fish species respond to biologically driven changes is one of the key prerequisites for understanding fish population dynamics and designing effective fisheries management strategies. This study developed a joint dynamic species distribution model for 10 important fish species in the Bohai Sea summer ecosystem from 2010 to 2019. The model was used to explore the biological drivers in the spatio-temporal dynamics of four economically important fish species: Engraulis japonicus, Larimichthys polyactis, Setipinna taty, and Pampus argenteus. The results showed that the low-economic-value predators Liparis tanakae and Lophius litulon appeared more frequently in E. japonicus hotspots, which is consistent with the idea that E. japonicus is an important food source of these two fish species. The biomass of L. tanakae and L. litulon was supported by key prey species such as E. japonicus, whilst exerting negative interaction effects on other fish stocks, including those of L. polyactis, S. taty and P. argenteus (predation and competitive interactions were reflected by negative covariation in spatiotemporal densities). Because of the "food-predation risk trade-off", L. polyactis and E. japonicus (often accompanied by top predators) exhibited greater differentiation in density hotspots. The model revealed the four species assemblages with their own clear spatio-temporal patterns, providing support for decoupling fisheries for species caught together and regulating the abundance of low-economic-value predatory fish to minimize adverse biologically driven effects on the recovery of economically valuable fish stocks. Our study can serve as a management decision-making framework for multispecies fisheries.