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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/25275

Title: Observed By-Catch of Taiwanese Tuna Longline Fishery in the South Atlantic Ocean
Authors: Shoou-Jeng Joung;Kwang-Ming Liu;Yih-Yia Liao;Hua-Hsun Hsu
Contributors: NTOU:Institute of Marine Affairs and Resource Managemen
Keywords: by-catch;tuna longline fishery;sharks;Prionace glauca;South Atlantic Ocean
Date: 2005
Issue Date: 2011-10-20T08:22:01Z
Publisher: Journal of the Fisheries Society of Taiwan
Abstract: abstract:This paper was based on observers' records of 8 trips of Taiwanese tuna longline fishing vessels operating in the South Atlantic Ocean from 1999 to 2003. The catches of 560 operations including 1,836,700 hooks were observed. According to target species, two areas namely, area A (50°W-20°E, 5°N-15°S) targeting on bigeye tuna and area B (15°S south, 70°W-20°E) targeting on albacore, were stratified. In area A, the major by-catch is billfishes followed by sharks, other bony fishes, and others. The blue shark, Prionace glauca, bigeye thresher shark, Alopias superciliosus, and mako sharks, Isurus spp. are the dominant species of shark by-catch and crocodile shark, Pseudocarcharias kamoharai, is the major discarded shark species. In area B, the proportion of by-catch is less than that of area A. Sharks are the major by-catch followed by other bony fishes and billfishes. The blue shark, mako sharks and silky shark, Carcharhinus falciformis, are the dominant species of shark by-catch. The mean sizes of female blue sharks were larger than males in both areas and most of the sharks were immature. More mature individuals were caught (30%, 23% for females and males) in area A than in area B (1.7%, 10% for females and males). The sex ratio was significant different from 1:1 (P<0.05) and males outnumbered females in both areas. Nominal CPUE in number of blue shark was estimated to be 1.378 and 0.444 per 1,000 hooks for area A and B, respectively.
Relation: 32(1), pp.69-77
URI: http://ntour.ntou.edu.tw/handle/987654321/25275
Appears in Collections:[海洋事務與資源管理研究所] 期刊論文

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