Movement-informed projections of Bristol Bay red king crab distribution to support spatial management decisions

Seasonal patterns in Bristol Bay red king crab (BBRKC; Paralithodes camtschaticus) distribution are largely informed by fisheries-independent surveys during the late spring and catch observations from the directed fishery in the following autumn. These data suggest that the stock undertakes a spring-autumn migration, although the environmental drivers associated with this migration are not well characterized. We fit an advection-diffusion model to pop-up satellite archival tag data to estimate the habitat preferences of mature male BBRKC during the late spring-autumn migration, and used this model to project BBRKC distribution from the late spring to the autumn during 2005-2024. We found that BBRKC movements were explained by a preference for cooler temperatures in central Bristol Bay in October, with preference for shallow habitats at low tidal current velocities and deeper habitats at higher velocities. Overlap analysis showed that projected distributions skillfully predicted interannual spatial variation in directed BBRKC fishery catches. Our results offer new insights into the environmental drivers of seasonal BBRKC migration and demonstrate the utility of movement-integrated species distribution models.