印度洋长鳍金枪鱼资源评估

Stock assessment of albacore Thunnus alalunga in the Indian Ocean

中文关键词: 长鳍金枪鱼  资源评估  管理  印度洋 

英文关键词: Thunnus alalunga  Stock assessment  Management  Indian Ocean

中文摘要:

      本研究运用年龄结构资源评估模型ASAP，利用最新的渔业数据和生物学研究成果，对印度洋长鳍金枪鱼资源进行了评估。结果显示，主要资源变量、捕捞死亡系数(F)、产卵亲体生物量(SSB)和生物学参考点受亲体-补充量关系的陡度参数(h)的影响很大。假设陡度参数h=0.7，0.8，0.9时，最大持续产量（MSY）分别为25268 t、27414 t、51924 t，当前(2010年初) F与FMSY之比分别为2.85、2.32、1.11，当前渔获量与MSY之比分别为1.65、1.52、0.80。1984年以来，F总体处于上升趋势，SSB处于下降趋势。基本模型条件下(h=0.8)，当前资源状况为“趋向于过度捕捞”(Overfishing)，且已接近于“过度捕捞”(Overfished)。若h=0.7、h=0.9，当前资源状况分别为“捕捞过度”、“趋向于过度捕捞”。

英文摘要:

      Albacore Thunnus alalunga is one of the main tuna species in Indian Ocean (IO). The stock status of IO albacore was uncertain due to the lack of reliable data. We assessed the albacore based on the most available fishery data and biological information using an age-structured assessment program (ASAP) . The estimated fishing mortality (F), spawning stock biomass (SSB) and biological reference points were sensitive to the assumed assumption of steepness (h) in stock-recruitment relationship. At the assumptions of h=0.7, 0.8 (base-case) and 0.9, the maximum sustainable yield (MSY) were 25,268 t, 27,414 t and 51,924 t; the ratio of current (year 2010) F to FMSY was 2.85, 2.32 and 1.11; and the ratio of current catch to MSY was 1.65, 1.52 and 0.80, respectively. The F value has been increasing and SSB has been decreasing since 1984. At the base-case, the current stock status was “overfishing” and approaching to “overfished”. At the sensitivity analyses of h=0.7 and h=0.9, the current stock status was “overfished” and “overfishing”, respectively.