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Resource Ecology & Ecosystem Modeling Program

Ecosystems Considerations

The Ecosystems Considerations chapter of the 2005 Stock Assessment and Fisheries Evaluation (SAFE) Report was made available in a browseable online format at This new format provides links and documentation for data sources and also offers direct access to subsets of the data used in the yearly ecosystem assessment.

By Jennifer Boldt

Ecosystem Modeling

A database of life history characteristics of Alaska groundfish, as determined by extensive literature review, was made available to the public at These life history parameters will be a key to developing the next generation of multispecies models. Modeling results, including trends of estimated population consumption by key groundfish in the eastern Bering Sea, were also made available to the public. These results are from multispecies virtual population analysis (MSVPA) ( and the multispecies statistical model (

By Kerim Aydin, Todd TenBrink, Jesus Jurado-Molina, and Geoff Lang


Seabird Interactions

The annual estimates of seabird bycatch have been posted on the AFSC website seabird page ( These estimates provide bycatch numbers by certain species groups or species from 1993 through 2004 for all gear types (longline, pot, trawl) in Alaskan waters. Numbers are provided for the Bering Sea, Aleutian Islands, and Gulf of Alaska regions as well. The estimate of seabird bycatch is completed by National Marine Mammal Laboratory (NMML) staff each year and is provided to the REEM Program.

Two data sources are necessary for these estimates: 1) data provided by groundfish observers (managed by the Fishery Monitoring and Analysis Division), and 2) fisheries catch information maintained by the Alaska Regional Office's Sustainable Fisheries Division. While data are provided for all gear types, much of the focus has been on longline fisheries.

Figure 2, see caption
Figure 2.  Total incidental take of seabirds in Alaskan combined demersal longline groundfish fisheries.

Overall seabird bycatch has dropped in those fisheries to current levels of less than 5,000 birds (Fig. 2). This is primarily due to the voluntary adoption of paired streamer lines by the freezer-longliner fleet in 2002 after a Washington Sea Grant study showed that paired streamer lines were the most effective seabird deterrent measure. Paired streamer lines are now required for all vessels over 55 feet through regulatory rulemaking completed in February 2004. Prior to the use of paired streamer lines which began in 2002, the average annual bycatch of seabirds in the combined Alaskan demersal groundfish fleet was 15,888 birds. Since then (2002-04) the average has been 4,910, a 70% reduction.

By Shannon Fitzgerald


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