大西洋金枪鱼延绳钓渔场的地统计分析

Geostatistical analysis of tuna(Thunnus obesus) longline fishing grounds in the Atlantic Ocean

使用地统计方法研究大西洋金枪鱼延绳钓渔场空间变异特征及时空分布,分析数据为1982―2010年日本大西洋大眼金枪鱼（Thunnus obesus）延绳钓渔捞数据。结果表明,大眼金枪鱼渔场分布具有较强的空间相关性,6月、10月和11月空间相关性显著（P＆lt;0.05）,其他月份空间相关性极显著（P＆lt;0.01）;指数模型能够较好地表达渔场的空间变异特征,其相关系数介于0.6~0.9之间,模型拟合较好;预测图表明大眼金枪鱼渔场变化呈现出两种轨迹,一种是大西洋中部与美洲近岸之间的循环变化,另一种是大西洋中部与非洲近岸之间的循环变化;预测结果验证表明,地统计能较好地对渔场空间分布进行预测,但是单位捕捞努力量渔获量（CPUE）预测值显著高于2009―2010年实测值,资源状况差异可能是引起本次研究预测值偏高的主要原因。

We analyzed the spatial distribution of tuna long-line fishing grounds in Atlantic using geostatistics.The data consisted of Japanese tuna long-line fishing logs from the Atlantic Ocean between 1982–2008.There was a strong spatial correlation for the big-eye tuna long-line fishing ground.The correlation was significant in June, October,and November（P0.05）,and extremely significant in all other months（P0.01）.The exponential model was best able to explain the spatial variability across the fishing ground（related coefficients between 0.6 and 0.9）. Based on the model forecast,there were two patterns across the fishing ground： One cyclical changed between the mid-Atlantic and America,and the Second cyclical changed between the mid-Atlantic and Africa.According to the forecast results,geostatistics are better for fishing ground distribution forecasting.However,the predicted CPUE was higher than the measured value,likely because of differences in resource status.Our results can be used as a guideline for the development of the big-eye tuna fishery and exploration of long-line fishing grounds.