Background

This study will provide enhanced baseline information on the species composition, abundance, distribution, and ecology of the pelagic and demersal communities of the Northern Bering and Chukchi Seas. Our previous research in the region has provided important insights into diversity, community structure and food webs of the area. Briefly, zooplankton and ichthyoplankon communities are structured primarily by water mass characteristics (Hopcroft et al. 2010, Norcross et al. 2010), while sediment features are more prominent in structuring demersal and epibenthic communities (Bluhm et al. 2009, Norcross et al. 2010). Food webs were similiarly structured across the region, but differed with respect to their stable isotopic signatures by water mass based on differences in food sources signatures (Iken et al. 2010).

Although these and many other studies in recent years have uncovered a great deal of information in the circulation and biological communities in the region, most of these studies have been limited in geographic scope or have largely focused on the infauna (Grebmeier 2012). Our understanding of the benthic and pelagic fish community remains limited due to the lack of a comprehensive survey covering the entire shelf area, the relative lack of mid-water and pelagic sampling, and the predominant use of small-mesh sampling gear that does not adequately sample larger fishes should they be present. As a consequence, the population structure, total abundance, and basic life history parameters of key species, such as Arctic cod (Boreogadus saida), saffron cod (Eleginus gracilis), and snow crab (Chionoecetes opilio) remain poorly understood. This project is designed to take advantage of existing and planned sampling efforts in the Bering and Chukchi Seas to provide a comprehensive, integrated survey of the oceanography, plankton, and fish and epibenthic invertebrate communities.

In addition to enhanced baseline information, this study will allow direct comparisons of the abundance and species composition of pelagic and demersal communities both with earlier studies, such as similar (but regionally limited) bottom trawl surveys in the early 1990s, and with adjacent regions, such as the eastern Bering Sea and the Beaufort Sea. This study will complement other ongoing projects that sample smaller areas at a higher resolution (e.g. COMIDA, industry-funded Chukchi Sea Environmental Studies Program), larger regions including the Russian part of the Chukchi Sea at lower spatial resolution (RUSALCA), or focus on the nearshore areas (e.g. AKMAP). We further propose a number of specific biological studies that were selected to complement ongoing studies and to fill in existing gaps by focusing on aspects of the life history of key species that have previously received little attention. Hence this project continues baseline species assessments in the region, providing information on the marine environment as a basis for a better understanding of the distribution and ecology of plankton, crab, and demersal and pelagic fish communities through field studies, modeling, retrospective analyses, and data synthesis.

The project will benefit the State of Alaska by contributing to a comprehensive, ecosystem-wide assessment of Chukchi Sea fish and crab resources. This information is required to assess the impacts on and risks for fish and shellfish populations in the Chukchi Sea from potential exploitation, oil and gas development, and climate change, as well as to develop appropriate mitigation measures. Stakeholders, including subsistence and potential commercial fisheries participants, who are impacted by climate change and activities of the oil and gas industry benefit from research that will lead to better management. Alaska and North Slope Borough residents have expressed in written comments within environmental impact statements for Lease Sale 193 that more information is needed for the marine environment. Additionally, the Alaska OCS Region identified a need for continued fish and invertebrate baseline monitoring to provide useful information to upcoming NEPA reviews and post sale needs during the 2007 MMS-sponsored “Chukchi Sea Information Status and Research Planning Meeting.” The workshop described the importance of the physical environment through the primary and secondary producers that support Arctic marine food webs to the numerous fish species utilizing the area. This study addresses the collectively identified information need for the marine environment in the Chukchi Sea by developing a broader understanding of abundance and distribution of plankton, fish, and crab communities.

In addition to benefiting the State of Alaska and its residents, this study will also constitute a component of Chukchi Sea environmental studies for the Bureau of Ocean Energy Management (BOEM) pertinent to Chukchi Sea Lease Sales. The project directly responds to the needs of BOEM for environmental analyses to evaluate offshore impacts. Results will be useful to BOEM for assessing and managing the potential environmental effects of offshore development on marine fish in the Chukchi Sea. Interim results from a current BOEM funded Coastal Marine Institute (CMI) project, “Current and Historic Distribution and Ecology of Demersal Fish in the Chukchi Sea Planning Area,” have identified temporal, seasonal, and spatial gaps in data on fish in the Chukchi Sea. This study was designed specifically to fill these information needs. It will build upon recent information on fish and invertebrate communities in the Chukchi offshore lease area obtained by the 2009 study “Chukchi Sea Offshore Monitoring in Drilling Area (COMIDA): Chemistry and Benthos (CAB).”, and by the ongoing NOAA-funded Russian-American Long-term Census of the Arctic (RUSALCA), and will also complement the 2010 LGL component of COMIDA CAB that undertook midwater and benthic fishery sampling at 20 sites within the COMIDA CAB study area. The proposed study will extend previous surveys to cover the entire northeastern Bering Sea north of St. Lawrence Island and the eastern Chukchi Sea shelf. To the extent possible, results from the proposed study will be compared to previous studies to place our results in a broader historical and spatial context.

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