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Resource Ecology & Ecosystem Modeling Program

Fish Stomach Collection and Lab Analysis

During the third quarter of 2009, Resource Ecology and Ecosystem Modeling (REEM) staff participated in seven legs of the AFSC's summer groundfish trawl surveys in the eastern Bering Sea and the Gulf of Alaska to collect stomach and tissue samples. These samples provide trophic information for continued monitoring of predatory impacts on commercially important species and quantifying energy flow through Alaskan marine foodwebs.

In addition, stomach and tissue samples were collected for targeted studies on flatfish prey selectivity in the eastern Bering Sea, genetic identification of difficult to distinguish larvae and prey, items, and functional foraging response of fish to predator, prey and environmental fields.

Overall, 6,587 stomach samples and about 285 tissue samples were collected from the eastern Bering Sea. In the Gulf of Alaska, 4,636 stomach samples and 300 tissue samples were collected, and 2,014 stomach samples were analyzed at sea. Stomach samples were also returned by fisheries observers; 473 from the Gulf of Alaska and 881 from the eastern Bering Sea.

Survey participation reduces the amount of time spent analyzing stomach samples in the laboratory. During the third quarter, 931 samples from the eastern Bering Sea and 207 stomach samples from the Gulf of Alaska were analyzed in the laboratory. This resulted in 2,113 records added to the REEM food habits database.

By Troy Buckley, Geoff Lang, and Mei-Sun Yang

Ecosystem Modeling and Assessment

The Ecosystems Considerations appendix to the Stock Assessment and Fisheries Evaluation (SAFE) report is updated annually by REEM staff to provide information on relevant ecosystem components to the North Pacific Fishery Management Council for consideration in management decisions. This appendix is composed of three parts: 1) an integrated ecosystem assessment, 2) time series of ecosystem indicators that measure components of the ecosystem, and 3) management indices that reflect the impact of humans on the marine ecosystem. The last two parts are composed of individual contributions from a broad range of scientists.

A draft has been completed for inclusion in the 2010 SAFE report. As of September, twenty-two contributions have been updated, and two new contributions have been added. One provides measurements of the potential area disturbed by trawl fishing gear in the eastern Bering Sea from 1990 to 2008. The second describes the spatial distribution of groundfish in the eastern Bering Sea from 1982 to 2008. Highlights from the draft were presented to the joint North Pacific Fishery Management Council plan teams in mid-September.

The second NMFS National Ecosystem Modeling Workshop (NEMoW II) was held 25-27 August 2009 at the Chesapeake Bay Foundation's Merrill Center in Annapolis, Maryland. NEMoW II continued work started at the first NEMoW in Santa Cruz, California, in 2007 to develop a regular ecosystem modeling (EM) workshop analogous to the National Stock Assessment Workshops and National Economist Meetings. In this context, EM includes a wide range of biophysical, multispecies, and ecosystem modeling methods. Where NEMoW classified major ecosystem model types and began a list of "best practices" for using the models, NEMoW II focused on sources of uncertainty in EM and how to provide management advice that appropriately expresses but is not hampered by uncertainty. Thirty-three NMFS participants and 6 outside observers attended the meeting.

Dr. Kerim Aydin (REEM Program) served on the steering committee and made a presentation outlining processes and audiences for EM review across NMFS science centers. Dr. Sarah Gaichas (REEM Program) contributed to meeting organization and made a presentation reviewing single-species and EM comparisons across science centers. Drs. Buck Stockhausen (AFSC/REFM Division) and Bern Megrey (AFSC/RACE Division) also represented the AFSC and contributed to presentations and the meeting report.

Data and information gaps for modeling were identified across science centers and prioritized to address major sources of EM uncertainty. Common types of uncertainty were identified, as well as approaches for addressing that uncertainty. Establishing and refining our list of best practices to address EM uncertainty should be continually re-evaluated. This workshop provided a strong basis for identifying those best-practices. A key conclusion from the workshop was that we need to better engage our stakeholders in terms of communicating, interacting and discussing ecosystem model rationales, uses, applications, and benefits.

A report to be issued in the future will include recommendations stemming from the workshop. The four preliminary major recommendations are suggestions to: 1) establish distinct EM review panels, 2) identify and note sources of EM uncertainty as a must for EM use, 3) bolster the value of strategic advice, and 4) bolster ecosystem modeling capacity.

By Sarah Gaichas and Stephani Zador, with contributions from Jason Link (Northeast Fisheries Science Center)

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