Identifying the spatio-temporal distribution patterns of mixed fisheries to inform multispecies management in the Yellow and Bohai Seas

Abstract

Mixed fisheries contribute to a substantial proportion of global landings and pose great challenges to fisheries management. In order to construct the management scheme for multiple species simultaneously, the species co-occurrence needs to be explicitly delineated in mixed fisheries. However, the task is hindered by the lack of survey coverage and the constraints of common species distribution models in ignoring biotic interactions. In the present study, we investigated the spatio-temporal distribution patterns of mixed fisheries over large spatial and temporal scales, by implementing the Vector Autoregressive Spatio-Temporal model (VAST) on the basis of fishery-dependent data collected from fishing logs. The fishery-dependent surveys were conducted among the commercial fishing vessels operating in the Yellow and Bohai Seas from 2012 to 2022. We used the VAST to handle the problem of unbalanced sampling, inflated zeros and interspecific interactions, and divided the species into species complexes with clustering analyses according to their correlation in the spatial or spatio-temporal distributions. Our results indicated that the studied species in mixed fisheries could be divided into three species complexes, and the composition within each group depended on consideration of spatial or spatio-temporal correlations. We demonstrated significant differences in the spatial distribution and aggregation areas among the species complexes, and substantial seasonal variations in occurrence of spatio-temporal complexes, which should be informative for the assignment of management unit within the mixed fisheries. Our study demonstrated the approach to assessing the species co-occurrence of mixed fisheries using fishery-dependent data, which offers the opportunity for guiding the future management of mixed fisheries.