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研究報告

更新日期: 2015-02-09
點閱數: 1,258

北大西洋長鰭鮪資源評估研究

年度 2013
計劃名稱 北大西洋長鰭鮪資源評估研究
中文摘要 本計畫主要重點為:(1) 利用不同的方法區分標的魚種為長鰭鮪與標的魚種非長鰭鮪之我國遠洋鮪釣漁業北大西洋長鰭鲔漁獲統計資料,並利用GLM等模式方法,標準化北大西洋長鰭鮪資源豐度指標(CPUE),以解析其年間變動趨勢;(2) 利用體長年齡成長關係式,轉換我國北大西洋長鰭鲔漁獲體長組成性狀為年齡組成; (3) 利用年齡結構化餘量模式(ASPM),評估北大西洋長鰭鲔之資源狀態.  研究結果如下:(1)檢視台灣漁船在北大西洋作業之漁撈日誌,漁船投放鈎數之資料顯示,鈎數別努力量分布呈現雙峰的型式,分別在9-10鈎及16-17鈎出現最大的努力量,唯每匡鈎數為6-13鈎時,長鰭鮪有明顯較大的漁獲比率;(2) 使用1999至2012年間作業日誌資料,依(1)之結果將台灣延繩釣中每筐投放鈎數小於16者,視其標的漁獲為長鰭鮪,且使用於本研究中,標準化CPUE每年持續增加至2004年,此後,它仍然是相對穩定的(2005-2009年),然後2010-2011年間逐步增加;此結果與利用TASK II資料,經不同模式較正後,顯示 2005年至今,北大西洋長鰭鮪資源豐度指標持續保持穩定之結果稍有不同;(3) 台灣在北大西洋長鰭鮪主要漁獲年齡從早期至現今有變大之趨勢,1981~1997主要漁獲年齡在5-8齡、1999~2006約在6-10齡,而2007年之後則約在7-11齡;32區的漁獲年齡大都大於4,而31區大都大於3; (4) ASPM估計近五年平均之MSY為 34500噸、BCUR /BMSY =0.952及FCUR/FMSY 0.61,亦即表示,北大西洋長鰭鮪目前資源處於過漁狀態(overfished, BCUR /BMSY <1), 但近幾年(2008年後)此資源未處於過漁中(overfishing, FCUR/FMSY <1)。
英文摘要 The main tasks of this project are : (1) to use various methods to distinguish the fishing data targeted at albacore from targeted nonealbacore species and to use GLM model to standardize the Taiwanese distant long line fisheries effort statistics in the north Atlantic to obtain more correct CPUE trend; (2) to convert, based on age and growth equation, on Taiwanese CAS (catch at size) into CAA (catch in age) of Taiwanese albacore harvested in the North Atlantic; (3) to use ASPM to assess the albacore resource condition.   The results indicated (1) the effort distribution for hook per basket of Taiwanese logbook data indicated two modes, and the most effort was separately found in 9-10 and 16-17 hooks; the bigger catch rate of albacore was obtained by 6-13 hooks; (2) to remove the effect of target species, the Taiwanese long-line logbook data identified as albacore targeting (less than 16 hooks per basket) from 1999 to 2012 were used here and shown that the yearly-standardized CPUE continuously increased up to 2004, thereafter, it remained relative stable (2005-2009), and then further increased during 2010-2011; (3) the main age of Taiwanese catch of albacore got bigger from 1981 to 2010; the main age of Taiwanese catch was 5-8 from 1981 to 1997, the one was 6-10 from 1999 to 2006, and the one was 7-11 from 2007 to 2010 . In general, albacore caught in area 32 is bigger than caught from area 31. The majority of Taiwanese catch of albacore is greater than age 3 in area 31 and is greater than age 4 in area 32; (4) the averages of last five year results obtained from ASPM for MSY,、BCUR /BMSY and FCUR/FMSY are 34500 ton, 0.952 and 0.61, respectively, and we agree the conclusion for Stock Conditions of Albacore Resource in the North Atlantic Ocean from ICCAT (2013) that the stock is slightly overfished, but is no longer undergoing overfishing.
計畫編號 102農科-11.1.1-漁-F4(2)
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