西北太平洋灯光围网主要渔获物组成及渔场变动研究

西北太平洋公海灯光围网渔业是中国近年新兴的一种远洋渔业,具有一定开发潜力,掌握灯光围网的渔获物组成及渔场变动情况对于西北太平洋的渔业管理和开发具有一定意义。文章根据2014—2019年西北太平洋公海灯光围网渔业统计资料,对渔获量、单位捕捞努力量渔获量(CPUE)以及主要的渔获物组成进行统计分析,同时采用渔获量重心法和聚类分析,探讨了渔场重心分布的季节变化。结果表明:1)渔获物产量和CPUE的年间差异均较大,产量大体呈现先增后降趋势,CPUE连年下降。2)共统计到8种渔获,其中日本鲭(Scomber japonicus)是主捕品种,月间出现频率均为100%;其次是远东拟沙丁鱼(Sardinops sagax),月间出现频率为87.5%;其他种类渔获量相对较少。3)渔场重心具有明显的季节性变化,且统计年间每年均具有相似的移动轨迹,即从4月起逐渐向东北方向移动,8—10月到达东北端后向西南方向折返;年间渔场重心呈现向东北方向移动的趋势,2014—2019年,重心在经度方向上东移0.92°,在纬度方向上北移1.57°。4)聚类结果显示,月产量重心可以分为4类(7、8、9和10月,4月,5、11月,6月),年产量重心也可以分为4类(2016、2017、2018年,2019年,2014年,2015年),表明西北太平洋灯光围网渔场具有一定的年际和季节变化。

Study on main catch composition and fishing ground change of light purse seine in Northwest Pacific

The light purse seine fishery in the high seas of the Northwest Pacific has been a new kind of pelagic fishery developed in China in recent years,with certain development potential.Understanding the catch composition and fishery change of light purse seine is important for the fishery management and development in the Northwest Pacific.Based on the statistical data from 2014 to 2019,we made a statistical analysis on the catch,investigating the catch per unit effort(CPUE)and the main catch composition of light purse seine in Northwest Pacific.Besides,we analyzed the seasonal variation of the distribution of the fishing ground had gravity center by the method of gravity center of catch and cluster analysis.The results show that:1)There was a big difference in the annual catch yield and catch per unit effort(CPUE).Generally,the yield increased first and then decreased,and CPUE decreased year after year.2)A total of eight species had been found,among which Scomber japonicus was the main catch species with a frequency of 100%,followed by Sardinops sagax with a frequency of 87.5%,and the catch of other species was relatively small.3)The center of gravity of the fishing ground had gradually moved to the northeast since April,and turned back to the Southwest after reaching the northeast from August to October,showing a certain anticlockwise variation.The center of gravity of the fishing ground gradually moved to the northeast,and the center of gravity moved 0.92°east in longitude and 1.57°north in latitude from 2014 to 2019.4)The clustering results show that the monthly yield barycenters could be divided into four categories(July,August,September and October,May and November,April,June).The annual yield barycenters could also be divided into four categories(2016,2017 and 2018,2019,2014,2015),indicating that there were certain interannual and seasonal changes in the light purse seine fishing grounds in the Northwest Pacific.