南极半岛周边水域南极磷虾渔场特征分析

Characteristics of Antarctic krill fishing ground around Antarctic Peninsula

为了解南极半岛周边水域内南极磷虾(以下简称磷虾)拖网渔场的特征,基于2013年1月至2019年5月"福荣海"轮在南极半岛周边水域的生产数据,分析了水域内磷虾中心渔场年际空间分布和生产特征。结果表明,南极半岛周边水域内磷虾拖网渔场主要分布于布兰斯菲尔德海峡(Bransfield Strait)、乔治王岛(King George Island)和斯诺岛(Snow Island)3个区域;其中布兰斯菲尔德海峡内是历年磷虾生产最稳定的区域,尤以海峡中部靠近南极半岛一侧水域(58°~60°W、63°~64°S)的作业天数和年产量占比最高;乔治王岛和斯诺岛区域的作业天数和年产量占比较低,且主要分布在岛屿周边近岸水域;布兰斯菲尔德海峡内区域、乔治王岛区域和斯诺岛区域的历年产量占比分别为60.00%~99.97%、0.03%~21.15%和0.01%~17.25%,历年作业天数占比分别为61.76%~98.75%、1.25%~28.68%和0.84%~16.67%。布兰斯菲尔德海峡内渔场的生产主要在3—5月,日产量主要为150 t以下;乔治王岛区域生产主要在1月份,日产量以150 t以下为主;斯诺岛区域的日产量在3月份较高,主要以150~250 t为主。各年度的连续生产期分布区域以布兰斯菲尔德海峡中部水域为主;各日产量区间的生产日历年主要分布在布兰斯菲尔德海峡中部,各日单位小时产量生产日也呈现逐渐集中到布兰斯菲尔德海峡的趋势;各级别亚渔场历年主要分布区域均在布兰斯菲尔德海峡内。

Annual spatial distribution and fishing strategy characteristics of the central fishing ground for Antarctic krill were analyzed based on the fishing data from Chinses fishing vessel“Furong”operated around Antarctic Peninsula(FAO Subarea 48.1)from December 2012 to May 2019.The fishing grounds were gridded into statistical cells with a spatial resolution of 0.4°latitude×0.2°meridian,and the krill catches were summed over day and averaged by hour.In addition,the daily-catch-weighted center was also estimated in order to investigate the variability of spatial distribution of krill catches.The results showed that there were three main fishing areas,which located in the middle of Bransfield Strait(BS),north and east of King George Island(KG)and north of Snow Island(SI).The annual catch from the BS area,with the majority from the region within 58°-60°W,63°-64°S,occupied more than 60%of the total annual catch in Subarea 48.1.The fishing days and annual catch of KG and SI took only a small part of the total,and it was mainly in waters around the islands.The annual catch proportion of BS,KG and SI was 60.00%-99.97%,0.03%-21.15%,0.01%-17.25%,and the annual proportion of fishing days was 61.76%-98.75%,1.25%-28.68%,0.84%-16.67%.Regarding the fishing periods,most of the fishing operation in the BS region was from March to May,and the daily catch was mainly<150 t;most of the fishing operation in the KG region was in January,and the daily catch was mainly<150 t;while for the SI region,it was in March,and the daily catch was mainly 150-250 t.In the BS region,the occurrence frequencies of both high daily catch(>200)and hourly catches(>10)were markedly higher than that of the other two areas.In addition,the fishing days in the BS area occupied more than 60%of the total fishing days in Subarea 48.1 in each fishing season.The results highlighted that the BS area was the most important fishing ground especially during the austral autumn and winter seasons from 2012 to 2019.