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Resource Ecology & Ecosystem Modeling Program

Ecosystem Considerations for 2012

The Ecosystem Considerations report is produced annually for the North Pacific Fishery Management Council (NPFMC) as part of the Stock Assessment and Fishery Evaluation (SAFE) report. The goal of the Ecosystem Considerations report is to provide an overview of marine ecosystems in Alaska through ecosystem assessments and tracking time series of ecosystem indicators. The ecosystems currently under consideration are the eastern Bering Sea, the Aleutian Islands, and the Gulf of Alaska.

This year the report includes both new and updated sections. The section describing ecosystem and management indicators includes updates to 44 individual contributions and presents 7 new contributions. These include: 1) Phytoplankton biomass and size structure during late summer to early fall in the eastern Bering Sea; 2) Gulf of Alaska chlorophyll a concentration off the Alexander archipelago; 3) Long-term zooplankton trends in Icy Strait, Southeast Alaska; 4) Forecasting pink salmon harvest in Southeast Alaska; 5) Biodiversity (evenness) of the groundfish and invertebrate community for the eastern Bering sea slope; 6) A multivariate seabird index for the eastern Bering Sea; and 7) Indicators of Alaska-wide community regime shifts.

The ecosystem assessment section includes a new Aleutian Islands Ecosystem Assessment developed by a multidisciplinary team of experts during a workshop in September 2011. The team was tasked with choosing a suite of indicators that together provide a comprehensive view of the Aleutian Islands ecosystem reflecting across trophic levels from the physical environment to top predators and humans, as well as both the nearshore and offshore.

Numerous gaps in available time series were noted and discussed. Following presentations and review of existing physical and biological data, the team concluded that the significant variability in the island chain ecosystem warranted structuring the assessment by three ecoregions: Western, Central, and Eastern. Although a single suite of indicators was chosen for the entire ecosystem, not all of the indicators are available or applicable in each of the three ecoregions. The assessment will be updated annually, and the suite of indicators will be re-evaluated every few years.

The updated eastern Bering Sea ecosystem assessment is included in this report, as well as a new section evaluating the predictions made in last year’s ecosystem assessment. An assessment of the Gulf of Alaska ecosystem is not included, but the development of a new assessment following the methods of the eastern Bering Sea and Aleutian Islands assessments is planned for 2012.

The ecosystem assessment section also includes a Hot Topics subsection, which was designed to present a succinct overview of potential concerns for fishery management, including endangered species issues and early warnings of potential future fishery management interest. Last year, Hot Topics were presented for the first time as part of the new eastern Bering Sea assessment. This year, they extend to all three ecosystems.

The topics for the eastern Bering Sea include endangered short-tailed albatross bycatch that occurred during fall in the Pacific cod longline fishery and recent increases in jellyfish seen in both summer and fall scientific surveys. For the Gulf of Alaska, the topics include the recent increased prevalence of "mushy" halibut syndrome and the controversial finding of infectious salmon anemia. For the Aleutian Islands, the topics include a discussion of fishery changes in the western and central ecoregions in 2011 and the release of the new Aleutian Islands risk assessment, which evaluates shipping traffic and oil spill trends.

Findings from the Ecosystem Considerations report were presented to the NPFMC joint plan teams in September and November and to the Science and Statistical Committee in December. To see the chapter in its entirety, see the AFSC website at

By Stephani Zador

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