An Investigation Of Tuna Long Line Fishing In Japan And The Hawaiian Islands

Author : Keith Bigelow
Publisher :
ISBN 13 :
Total Pages : 23 pages
Book Rating : 4.:/5 (1 download)

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Download or read book Evaluation of Longline Mitigation to Reduce Catches of North Pacific Striped Marlin in the Hawaii-based Tuna Fishery written by Keith Bigelow and published by . This book was released on 2010 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Striped marlin in the North Pacific are primarily harvested in longline fisheries targeting species such as tunas (Thunnus spp.) and swordfish (Xiphias gladius). Annual catches have declcined from ~17,000 mt in the early 1960s to ~3,000 mt in 2006 (Figure 1). Striped marlin are primarily harvested by longline fisheries from Japan in the northwest Pacific and the USA in the central Pacific with smaller catches from Korea and Chinese-Taipei longline fleets and are also targeted in coastal fisheries off Japan and ChineseTaipei and support valuable recreational fisheries off Australia, New Zealand, Mexico and the United States...Given the high estimated fishing mortality, the objectives of this study were to conduct analyses of potential longline catch reductions of N. Pacific striped marlin while maintaining target bigeye tuna catches. Longline mitigation was based on modification of longline gear and spatially closed areas. The analysis was conducted on the Hawaii-based longline fishery which comprises ~10% of the total N. Pacific catch of striped marlin since 2000 and is well suited to analyses of longline mitigation because detailed operational and catch data have been gathered by the Pacific Islands Regional Observer Program (PIROP) since 1994. The Hawaii-based pelagic longline fishery is composed of two sectors which target bigeye tuna (Thunnus obesus) with deep gear and swordfish (Xiphius gladius) with shallow gear. The median depth of the deepest hook on 266 deep sets was 248 m, whereas that on 333 shallow sets was 60 m (Bigelow et al. 2006). The study considered the deep set fishery due to larger striped marlin catches and potentially greater mitigation options as deep gear fishes at a greater range of depth and habitat than