利用水温垂直结构研究中西太平洋鲣鱼栖息地指数

根据1990~2001年中西太平洋海域(20°N~25°S、175°W以西)金枪鱼围网鲣鱼作业产量和作业次数,结合不同水层的水温及其温差数据(海表温度SST,12.5 m、237.5 m和287.5 m温度,137.5 m与287.5 m温差),以高产频次的相对比值分别建立各因素的栖息地指数SI,建立单因素一元非线形回归模型。采用连乘法、最小值法、最大值法、算术平均法和几何平均法建立综合栖息地指数HSI,并对1990~2001年各月HSI值与实际作业产量进行验证。结果表明,采用连乘法和最小值法时,主要产量分布在HSI<0.5以下的区域;采用算术平均法和几何平均法时,主要产量分布在0.30.7的区域,其产量占总产量的87%。五种模型结果比较,认为最大值法能更好地反映中心渔场分布和符合鲣鱼的分布特征。采用最大值法推算2003年各月HSI值,并与实际产量分布进行实证分析,发现其各月产量主要分布在HSI>0.8的区域,说明利用HSI模型来预测中心渔场是可行的。

Studies on the habitat suitability index based on the vertical structure of water temperature for skipjack Katsywonus pelamis purse-seine fishery in the Western-central Pacific Ocean

According to the catch data and fishing times of skipjack in the purse-seine fishery in the Western-central Pacific Ocean(WCPO)(20°N-25°S,120°E-175°W),and the environment data of different water layer temperature(sea surface temperature,water temperatures of 12.5 m,237.5 m and 287.5 m layer,temperature difference per meter between 137.5 m and 187.5 m layer),the relative ratio of fishing times with high yield was considered as the habitat suitability index(SI),and SI model with single variable is established by nonlinear regression methods.Five methods(Continued product,Minimum,Maximum,Arithmetic mean and Geometric mean) were used to establish the multi-factor habitat suitability index(HSI) model.The results indicated that when Continued product and Minimum method were applied,the yield of skipjack was mainly located in the area with HSI<0.5.When Geometric mean and Arithmetic mean method were applied,the yield of skipjack was mainly distributed in the area with HSI ranging from 0.3 to 0.8.When Maximum method was used,the yield of skipjack was mainly located in the area with HSI>0.8,which occupied 87%of the total catch.We found that the Maximum method could best fit the fishing ground of skipjack distribution.Based on the data of water temperature in 2003,the monthly HSI was estimated by the Maximum method and verified by the catch distribution of skipjack,which showed that it was feasible to forecast the fishing ground with HSI method.