Download or read book Analysis of 2004-2007 Vessel-specific Seabird Bycatch Data in Alaska Demersal Longline Fisheries written by Kimberly S. Dietrich and published by . This book was released on 2010 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The annual incidental bycatch of seabirds by demersal groundfish longline vessels in Alaska has ranged between 4,100 and 26,300 during the period 1993 through 2006. However, average annual bycatch has declined by 73% in the last 5 years (2002-2006) compared to bycatch from the late 1990s. Despite the recent reductions resulting from mandatory mitigation requirements, seabirds continue to be caught at higher rates than would be expected given results of controlled studies that demonstrated bycatch reductions of nearly 100% with paired streamer lines. We characterize recent seabird bycatch data (2004-2007) from the Alaska demersal longline fisheries and analyze factors influencing seabird bycatch for two fisheries - Pacific cod (Gadus macrocephalus) and sablefish (Anoplopoma fimbria). Previous analyses of 1995-2000 bycatch data showed that individual vessel was the single most important source of variability in seabird bycatch rates in Alaska longline fisheries. Certain vessels consistently caught a higher proportion of birds across years and fisheries. Our results demonstrate that a few individual vessels continue to be responsible for the majority of seabird bycatch. Six vessels out of 39 contribute 38% of all birds caught in the cod demersal longline fishery when sampled rates are extrapolated to hooks deployed in observed sets. Based on this analysis, we recommend a variety of methods to further reduce seabird bycatch by longline vessels in Alaska."--P. iii.