Arctic Ecosystem Integrated Survey Final Report on Distribution of Fish, Crab, and Lower Trophic Communities in the Northeastern Bering Sea and Chukchi Sea.
This study on the Distribution of Fish, Crab, and Lower Trophic Communities in the Northeastern Bering Sea and Chukchi Sea formed a large part of the broader Arctic Ecosystem Integrated Survey, the first comprehensive fisheries ecosystem assessment of the northern Bering Sea and Chukchi Sea. Surveys were conducted in the summers of 2012 and 2013 from several platforms to sample demersal as well as pelagic fish communities. Oceanographic and biological samples collected during these surveys provided a trove of new information on the distribution, abundance, biology and population dynamics of pelagic and demersal fish and invertebrate populations in the northern Bering Sea and Chukchi Sea, in addition to new insights into the physical forcing and plankton dynamics of the system.
Among the scientific highlights were: (1) Large differences in oceanographic conditions between 2012 and 2013, associated with differences in local winds and in the flow of water through Bering Strait and its advection in the Chukchi Sea, reverberated throughout the ecosystem and apparently affected the distribution and abundance of biota at all trophic levels; (2) High densities of larval and young-of-year Arctic cod (Boreogadus saida) were, for the first time, observed in the northeast Chukchi Sea in both survey years, suggesting that the northeast portion of the Chukchi Sea is an important nursery area for the early life history stages of Arctic cod in the Pacific Arctic; (3) Plankton, fish and invertebrate species of Pacific origin dominate demersal and pelagic communities throughout the region, but distinct Arctic populations of some species were associated with Arctic water masses on the northeast Chukchi Sea shelf; (4) Juvenile salmon of western Alaska origin, in particular chum (Oncorhynchus keta), pink (O. gorbuscha), and Chinook salmon (O. tshawytscha), were widespread and abundant in the northern Bering Sea, extending into the Chukchi Sea and mixing with local populations from Kotzebue Sound; (5) Arctic cod and snow crab (Chionoecetes opilio), two of the most abundant species by weight in Chukchi Sea catches, are continuous with and directly connected to populations in the Bering Sea. To what extent the Chukchi Sea populations of these species originate from spawning areas to the South or to the North of Bering Strait remains an area of active investigation.
Major results from these studies were published in a special issue in Deep-Sea Research (Mueter et al. 2017), but data collected during these surveys will continue to contribute to new and ongoing studies. A major legacy of the project will be the databases and maps available through the Alaska Ocean Observing System's Arctic Portal (http://portal.aoos.org/arctic), as well as through national archives. In addition to the databases and published studies, a major benefit of the project was the training that was provided for a number of students and post-docs. Both from a scientific and educational standpoint, the project has met its goals and has exceeded our expectations in terms of scientific output. This is in no small part due to our success in leveraging external resources and forging productive collaborations with investigators at multiple universities and agencies.