Lessons from seabird conservation in Alaskan longline fisheries |
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Authors: | Edward F Melvin Kimberly S Dietrich Robert M Suryan Shannon M Fitzgerald |
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Institution: | 1. Washington Sea Grant, University of Washington, 3716 Brooklyn Avenue NE, Seattle, WA, 98105 U.S.A.;2. 5091 Starfish Drive SE, St. Petersburg, FL 33705 U.S.A.;3. Department of Fisheries and Wildlife, Oregon State University, Hatfield Marine Science Center, 2030 SE Marine Science Drive, Newport, OR, 97365 U.S.A.;4. Resource Ecology and Fisheries Management Division, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, 7600 Sand Point Way NE, Seattle, WA, 98115 U.S.A. |
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Abstract: | Although bycatch of seabirds and other long-lived species is a critical conservation issue in world fisheries, case studies documenting significant reductions in the mortality of these low-productivity species in a fishery are rare. We studied progress toward seabird conservation in the Alaskan longline fisheries, one of the largest and most diverse demersal fisheries. We generated annual seabird bycatch rates in 4 target fisheries and all fisheries combined from 23 years of fisheries observer data. We used 0-inflated negative binomial models to evaluate variables influencing seabird bycatch per unit effort (BPUE) in 2 target fisheries. Following adoption of streamer lines, at first voluntarily and then mandatorily, seabird BPUE was reduced by 77–90%, preventing mortality of thousands of birds per year. Despite this, BPUE increased significantly in 2 of 4 target fisheries since streamer lines were adopted. Although night setting yielded significant reductions (74–97%) in seabird BPUE and significant increases (7–11%) in fish catch per unit effort over daytime setting, nighttime setting increased the BPUE of Northern Fulmar (Fulmarus glacialis) by 40% and nontarget fish species by 5–17%. Thus, best practices to prevent seabird mortalities in longline fisheries varied by species assemblage and fishery. Our results inform global efforts toward fisheries bycatch reduction by illustrating that successful conservation requires fishery-specific solutions, strong industry support, constant vigilance in analysis and reporting observer data, and ongoing outreach to fleets, especially to vessels with anomalously high BPUE. |
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Keywords: | best practice mitigation bird scaring lines case history demersal longline fisheries fishery specific solutions night setting seabird bycatch captura accesoria de aves marinas historia de caso líneas espanta aves mitigación de mejor práctica pesquerías demersales con palangre puesta nocturna soluciones específicas por pesquería 海鸟兼捕 底层延绳钓渔场 鸟类警戒线 夜间布设钓竿 减缓影响的最佳实践 历史案例 渔场特异的解决方案 |
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