中西太平洋鲣鱼空间聚类特征及其与ENSO的关系

Spatial Clustering Characteristics of Katsuwonus pelamis in West and Central Pacific Ocean and Its Relationship with ENSO

为了解在不同厄尔尼诺-南方涛动(ENSO)事件下中西太平洋鲣鱼(Katsuwonus pelamis)资源的变动规律,本研究根据中西太平洋渔业委员会(WCPFC)2008—2018年中西太平洋鲣鱼的生产数据,结合海洋尼诺指数(ONI),利用聚类分析和灰色关联分析,研究季时间尺度下鲣鱼的自由鱼群和随附鱼群的渔场空间特征及其与ENSO事件的关系。季尺度下渔场重心聚类分析表明,各簇所包含季度发生的异常气候事件具有一致性。拉尼娜时期,两种鱼群的主要渔场都有向西移动的趋势,厄尔尼诺时期则相反。在异常气候事件下,随附鱼群的迁移幅度小于自由鱼群,且随附鱼群渔场的经向分布更稳定。不同ENSO模态下,资源丰度的空间分布存在差异。对自由鱼群而言,在拉尼娜事件发生于第1、2季度时165°E以西海域的资源丰度最高,灰色关联度为0.650,在拉尼娜事件发生于第3、4季度时165°E—180°海域的资源丰度最高,灰色关联度为0.411,在厄尔尼诺时期,180°以东海域的资源丰度最高,灰色关联度为0.727。对随附鱼群而言,165°E以西海域及165°E—180°海域资源丰度最高时期为拉尼娜时期,灰色关联度分别为0.852和1.000,180°以东海域资源丰度最高时期为厄尔尼诺时期,灰色关联度为1.000。研究结果可用于气候变化背景下鲣鱼渔情的预报。

To understand the variation regularity of Katsuwonus pelamis in the Western and Central Pacific Ocean based on catch data of Katsuwonus pelamis from Western and Central Pacific Fisheries Commission(WCPFC)in combination with Oceanic El Ni o index,we studied the spatial and temporal variation of free swimming school and associated school and their relationship with El Ni o-Southern Oscillation(ENSO)through cluster analysis and grey correlation analysis.Seasonal fishing ground barycenter cluster analysis showed that extreme climate events in each cluster had uniformity.During La Ni a,the main fishing ground of the two schools had a trend of moving westwards while the situation was on the contrary during El Ni o.The moving amplitude and meridional distribution of associated school under extreme climate events was smaller than that of free-swimming school.There existed difference in the distribution of skipjack tuna resource abundance under different ENSO patterns.As to free-swimming school,an area to the west of 165°E had the highest abundance when La Ni a events happened in the first two quarters with grey correlation of 0.650,and the area between 165°E and 180°had the highest abundance when La Ni a events happened in the last two quarters with grey correlation of 0.411.When it came to associated school,the area to the west of 165°E and the area between 165°E and 180°had the highest abundance with grey correlation of 0.852 and 1.000.However,under El Ni o events,both two schools had the highest abundance to the east of 180°with grey correlation of 1.000 and 0.727.The result is conductive to improving the accuracy of fishing forecasting in the context of climatic oscillation.