S7.4 Thursday, Jan. 6 Assessing distribution and structure of unexploited snow crab populations in Alaskan waters HARDY, S M*; ALBRECHT, G; HUNDERTMARK, K; BLUHM, B; HUETTMANN, F; University of Alaska, Fairbanks; University of Alaska, Fairbanks; University of Alaska, Fairbanks; University of Alaska, Fairbanks; University of Alaska, Fairbanks email@example.com
Arctic climate trends are impacting marine species distributions and community structure on multiple trophic levels while human impacts, including fishing pressures and petroleum resource development, increase concurrently. In the face of these pressures, we are examining distribution, ecology, and genetic population structure in the commercially-valuable snow crab, Chionoecetes opilio, which is thought to be undergoing a range contraction to the north. Snow-crab stocks have been little-explored north of the Bering Strait, and not yet targeted by fisheries. We conducted quantitative sampling of epibenthic megafaunal invertebrate communities in the Northern Bering and Chukchi Seas between 2004 and 2009, and found crustaceans, especially crabs and shrimps to dominate at several locations. Although snow crab were particularly abundant in northern waters, populations consisted mostly of smaller-sized individuals. Multi-variate statistical analysis showed substrate type to be the most important predictor of overall community structure, but spatial modeling of snow crab distribution suggested water mass characteristics and measures of sediment organic content may be governing distribution in this taxon. We are currently investigating degrees of population connectivity between exploited Bering Sea regions and more northerly waters. Prevailing hydrographic conditions suggest that the long-lived planktonic larvae produced by this species might have the capacity for long-distance travel with northerly currents passing through the Bering Strait, into the Chukchi Sea, and along the Beaufort Shelf. However, early results from our microsatellite analyses suggest the Bering Strait may represent a semi-permeable barrier to dispersal in this species.