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Resource Ecology & Fisheries Management (REFM) Division

Resource Ecology & Ecosystem Modeling Program

AFSC Seabird Program

  photo of third wire cable
Figure 2.  View of third wire cable astern of catcher-processor vessel while net is being towed.

The AFSC Seabird Program is working on several projects including the study of seabird food availability through discards and offal from the commercial fisheries. The program is working with the Washington Sea Grant Program (WSGP) and the North Pacific Groundfish Observer Program (NPGOP) in preparation for WSGP’s demersal longline integrated weight studies in July through November 2005. Seabird stationary sighting surveys were again implemented for the AFSC summer groundfish survey charters, but were also expanded in 2005 to include hydroacoustic surveys and cod pot research charters. This work depends on many AFSC employees who staff these cruises to take extra time to complete the surveys. Their work is critical to this effort.

Most work currently undertaken by the Seabird Program focuses on seabird interactions with the trawl fleet. Seabirds are known to sometimes collide with the main warp cables used for towing the net or with the trawl sonar third wire cable used for monitoring net performance and catch while towing. The rates of these interactions are not known. No short-tailed albatross, an endangered species, have been documented as interacting with this gear, but there is concern that this might occur.

Efforts are under way to both develop deterrent devices and better characterize the interaction rates. These efforts involve close collaboration with the trawl industry, WSGP, and the University of Washington. We are coordinating with the Pollock Conservation Cooperative (PCC) and WSGP to develop seabird deterrent devices for trawl catcher processor vessels. Funds to support materials and installation have come from the NMFS National Cooperative Research Program and from the PCC.

Gear was pilot tested on one vessel during the Pollock A season January through April 2005 and will be fitted for an additional vessel for the pollock B season, June through October 2005. With support from the U.S. Fish and Wildlife Service Ecological Services Division and the NMFS Cooperative Research Program, funding was provided to support a research team boarding these two vessels to complete some experimental trials during late July and August. Ed Melvin of WSGP is the principle investigator for that work.

In addition to developing mitigation devices, NMFS is working to better characterize seabird bycatch on trawl vessels. A NPGOP special project is ongoing throughout the 2005 season for all trawl observers. Information derived from this project will allow us to better understand seabird interactions with trawl warp and third wire cables by fishery sector. Finally, we are working on meeting nondiscretionary requirements under one of the two short-tailed albatross biological opinions to provide reports on trawl effort and the use of trawl sonar technology, and have implemented work with the UW to develop a risk-assessment model for trawl fishery sectors on the likelihood of interactions with short-tailed albatross.

Seabird Provisioning by Commercial Fisheries

  photo of a Laysan Albatross flight feather
Figure 3. Feather with three pieces clipped out for stable isotope analysis. Using stable isotope analysis, samples collected from different sections of this Laysan Albatross flight feather will be used to asses the bird’s diet at different times of year. Diet over a period of 7 weeks can be sampled from a single feather, and diet over a 4-month period can be sampled from five flight feathers.

The impact of commercial fishing on food availability for seabirds through discards and offal is being explored on two fronts by Dr. Ann Edwards, a National Research Council postdoctoral fellow with the REFM Division’s REEM Program. The diets of Laysan and black-footed albatrosses are being compared across seasons, between age classes, and before and after the presence of large-scale fishing operations in the North Pacific (pre-1930s vs. the present). Comparisons are made using the stable isotopic signatures of feather samples obtained from birds salvaged from longlines and from museum specimens (Fig. 2). As part of this study, research cruises in the North Pacific and Bering Sea are collecting samples for isotopic analysis of 1) the albatrosses’ natural prey, squid, and 2) the most abundant species made available to seabirds by the Alaska groundfish fishery, such as walleye pollock and Pacific cod.

Progress continues towards developing a quantifiable map in space and time of discards and offal returned to the sea, and thus made available to seabirds and the marine ecosystem as a whole. Data from the NMFS Alaska Regional Office’s Catch Accounting System on retained and discarded catch provide the foundation for this map. John Hansen, a graduate student at the UW School of Marine Affairs is working with Dr. Edwards to review federal regulations mandating fish retention and utilization standards. The goal of this review is to more accurately track the fate of all parts of all fish pulled on board fishing vessels. This review as well as consultations with industry may suggest adjustments to the Catch Accounting System data to more accurately reflect a birds’ eye view of food availability.

By Shannon Fitzgerald and Ann Edwards


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