热带印度洋黄鳍金枪鱼渔场时空分布与温跃层的关系

根据Argo浮标剖面温度数据重构热带印度洋各月月平均温跃层特征参数,并结合印度洋金枪鱼委员会(IOTC)黄鳍金枪鱼延绳钓数据,绘制了月平均温跃层特征参数和月平均CPUE的空间叠加图,用于分析热带印度洋黄鳍金枪鱼渔场时空分布和温跃层特征参数的关系。结果表明:热带印度洋温跃层上界深度、温度和下界深度,以及黄鳍金枪鱼中心渔场分布都具有明显的季节性变化特征,黄鳍金枪鱼中心渔场分布和温跃层季节性变化有关。在东北季风期间,高值CPUE渔区的温跃层上界深度的范围为30-40m,超过70m的渔区CPUE值普遍偏低;在西南季风期间温跃层上界最深达到120m。在东北季风期间,高值CPUE渔区温跃层下界深度不超过200m,在西南季风期间,深度会超过300m。在东北季风期间,高值CPUE渔区对应的温跃层上界温度都超过25℃,温度小于24℃的渔区CPUE值普遍较低;在西南季风期间,高值CUPE区域对应的温跃层上界温度范围变大,温跃层上界温度延伸到22℃,在22℃以下渔区CPUE值都很低。采用频次分析和经验累积分布函数计算其最适温跃层特征参数分布,得出黄鳍金枪鱼最适的温跃层上、下界温度范围分别是25-29℃和13-16℃;其上、下界深度范围分别为30-70m和140-200m。K-S检验结果表明,上述结论可靠。

The relationship between the temporal-spatial distribution of fishing ground of yellowfin tuna (Thunnus albacares) and themocline characteristics in the tropic Indian Ocean

Based on the monthly themocline characteristic parameters of tropic Indian Ocean obtained by the Argo profile data from China Argo Real-time Data Center(CARDC),along with the longline fisheries data of yellowfin tuna(Thunnus albacares) provided by the Indian Ocean Tuna Commission(IOTC),the spatial overlay maps of the average monthly at themocline characteristic parameters and CPUE value of yellowfin tuna were plotted to analyze the relationship between the fishing grounds distribution of yellowfin tuna and themocline characteristics parameters.The seasonal variety of the upper bound depth,temperature and the lower boundary depth and the fishing ground distribution of yellowfin tuna were found from the analysis results.Meanwhile,the relationship between the fishing ground distribution of yellowfin tuna and the seasonal variety of the themocline were remarkable.During the northeast monsoon,the range of the upper boundary depth in the higher value of CPUE fishing area was 30—50m,and the CPUE value was lower where the upper boundary was over than 70m.While the upper boundary depth was more than 120m during the southwest monsoon.The lower boundary depth in the higher value of CPUE fishing area was less than 200m during the northeast monsoon,while that was over than 300m during the southwest monsoon.During the northeast monsoon,the upper boundary temperature was more than 25℃ and the CPUE value was generally lower in the area with the temperature less than 24℃,while that during the southwest monsoon ranged wildly,extended to 22℃,and the CPUE value was lower under 22℃.Based on the frequency analysis and empirical cumulative distribution function(ECDF),the optimum range of the upper boundary temperature and depth were 25—29℃ and 30—70m,respectively,while that of lower boundary temperature and depth were 13—16℃ and 140—200m,respectively.The results were trusted test by K-S test.