Late summer distribution and abundance of larval snow crab (Chionoecetes opilio) and pelagic crab communities in the U.S. Pacific Arctic Gateway

This multi-year study establishes a critical assessment of late summer larval crab abundance and distribution across the northern Bering Sea and Chukchi Sea in Alaska. Interannual variability in the distribution and composition of the larval community was relatively low and largely driven by the timing of the survey and water mass location. We found a higher proportion of advanced developmental stages in warmer years (2013 and 2017) relative to the colder year (2012). We hypothesize warmer conditions may accelerate pelagic larval development, benthic adult spawning, or both. Snow crab larvae were the most abundant and widely distributed taxon. Stage-based evidence suggests snow crab on the north Chukchi Shelf originate from either the Bering Sea due to the northward advection of mostly late-stage larvae or are supplied by local or Chukchi / Beaufort Slope spawning adults which contribute an early-stage larval cohort in late summer. The northern Bering Sea appears to be an important post-larval settlement area for snow crab and advection from both eastern and western shelves likely delivers settlers to the Chirikov Basin. Blue and red king crab larvae were rarely observed suggesting surveys occurred too late in the season for pelagic assessment.