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    Solutions to seabird by-catch in Alaska’s demersal longline fisheries

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    Numéro du document:
    E.F. Melvin, J.K. Parrish, K.S. Dietrich and O.S. Hamel (USA)
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    This research program compared seabird bycatch mitigation strategies over 2 years (1999 and 2000) in 2 major Alaska demersal longline fisheries: the Gulf of Alaska /Aleutian Island Individual Fishing Quota fishery for sablefish and halibut and the Bering Sea catcher-processor longline fishery for Pacific cod. We conducted tests over two years to account for inter-annual variation and allow for improvement and innovation. A key feature of this program was an industry-agency-academic collaboration to identify possible deterrents and test them on active fishing vessels under typical fishing conditions. We report the results of experimentally rigorous tests of seabird bycatch deterrents on the local abundance, attack rate, and hooking rate of seabirds in both fisheries. Based on our results, we recommend a suite of bycatch mitigation measures. Among all deterrents tested, paired streamer lines proved to be the most comprehensive solution. Paired streamer lines successfully reduced seabird bycatch in all years, regions, and fleets (88% to 100% relative to controls with no deterrent), despite the fact that we saw orders of magnitude variation in bycatch across years and in the case of the sablefish fishery, among regions. Paired streamer lines were robust in a wide range of wind conditions and required little adjustment as physical conditions changed. Functionally, paired streamer lines created a moving fence that precluded seabird attacks. Most significantly, this success came with no consequence to catch rates of target-fish or the rate of capture of other bycatch species, thus satisfying our primary goal. Several additional measures are discussed, including eliminating directed discharge of residual bait and offal while setting gear and the need for report card and peer-review systems, as well as the need for national and international action. The full report is available at Hard copies will be available at the meeting from Kim Rivera, NMFS, USA