中西太平洋鲣渔场时空分布研究

Spatial and temporal distribution analysis of high catch fishing ground for Katsuwonus pelamis in the Western and Central Pacific

中西太平洋海域是全球鲣(Katsuwonus pelamis)作业的主要渔场,该海域鲣渔场的时空分布规律,尤其是高产海域,是渔情预报研究的基础和前提。根据太平洋共同体秘书处提供的1995-2014年中西太平洋鲣围网捕捞生产统计数据,对各年各月的鲣产量和捕捞努力量渔获量(CPUE)进行统计分析,通过产量重心分析和聚类分析,找出渔场重心变化规律,同时选取高产的22个渔区(分辨率5°×5°),研究时间和空间因素对CPUE的影响。研究结果表明,中西太平洋鲣历年产量逐步上升,CPUE波动较大,而各月产量和CPUE差异较大,高产月份主要集中在上半年;历年产量重心分布不均,经度方向上分布差异较大,聚类分析可分为4类;各月产量重心变化呈现顺时针变化规律,从南到北,自西向东,再从北向南移动,聚类分析可分为3类;渔获量主要分布于5°S～5°N、120°～175°E,因此对该海域CPUE进行统计,以年份、月份和渔区为影响因素,分析发现,极端气候年份与其它年份的CPUE有明显不同,月份间的变化与产量月间重心变化类似,上、下半年有着明显不同;不同空间下,经度间差异大于纬度间差异,135°～145°E为经度CPUE差异的分界线,而南北纬间的差异不明显。上述鲣的时空分布变化主要与ENSO现象引起的西太平洋暖池的变化有着密切关系,同时太平洋岛国的相关入渔政策也对其产生一定的影响。

The Western and Central Pacific is the world’s most important fishing ground for Katsuwonus pelamis and is also very sensitive to the changing ambient environment,so exploring the spatial and temporal variation,especially in the high catch area,is the basis and precondition for fishing forecasting. According to the catch data of Katsuwonus pelamis in the Western and Central Pacific during 1995-2014,using statistical analysis based on the above data with the monthly and annual interval,the fishing ground variations were detected through catch gravity analysis and cluster analysis. And a total of 22 fishing zones(5° latitude and 5° longitude) with the high catch were selected to analyze the spatial and temporal variation of catch and CPUE for Katsuwonus pelamis in the Western and Central Pacific. The results showed that the annual catch of Katsuwonus pelamis increased gradually with high fluctuation of CPUE,and high monthly catch mainly appeared in the first half year;catch gravity was inhomogeneous in longitudinal direction,four groups can be divided with cluster analysis;monthly gravity position changed clockwise,from west to east,from south to north,three groups can be divided with cluster analysis;main catch focused in the area of 5°S ~ 5°N,120°~175°E,CPUE in extreme years had significant differences with other years,and the CPUE of the first half year and second half year had significant differences;135°~ 145°E was the boundary of longitude variation,and there was no significant difference in latitude variation. The above spatial and temporal variation may be caused by the change of warm pool in the west Pacific,and also have some relationship with the fishing access strategy in the island countries in the Pacific.