Genome-wide detection of fine-scale population stratification and long-distance dispersal of the Chinese mitten crab (Eriocheir sinensis)

Understanding the population genetic structure of marine decapods is essential for their effective conservation and management, particularly for species like the Chinese mitten crab (Eriocheir sinensis), which exhibits a complex life cycle and high invasive potential. In this study, we applied a population genomics approach using SLAF-seq to generate genome-wide SNP data from 120 unrelated individuals collected across six locations in China and Korea. We found a fine-scale but discernible level of genetic differentiation by regional populations correlated with geography. Individuals from Seocheon (Korea) and Wenzhou (southeastern China) exclusively share a distinct genetic ancestry component that makes them divergent from the rest, which we speculate may have been introduced by hybridization with congeneric species. We detected genetic outliers (9 out of 120 individuals) that show ongoing long-distance dispersal along the coastline of the Yellow Sea, likely happening during the planktonic larval phase. Collectively, our findings provide a genomic basis for delineating management strategies, supporting informed stock enhancement, and guiding region-specific conservation efforts for E. sinensis across East Asia.