夏季南大洋南极大磷虾种群分布、结构及生长研究

利用2007/2008年和2008/2009年南极夏季高速采集器和IKMT网走航采样样品,结合同步环境调查资料,研究了南极大磷虾(Euphausia superba)的水平分布、生长状况及种群结构。结果表明,南极大磷虾在威德尔海域丰度高于普里兹湾海域,两个海域的磷虾丰度都低于历史同期。从两个年度南极考察的整个调查海区来看,南极大磷虾处于正常生长状态,但也存在个别生长状况较差站位,推测与海冰回退时间较晚或叶绿素浓度较低有关。利用高速采集器采集的大磷虾样品,在海冰边缘区域站位,未成体磷虾占有很大比例;而在海冰已经消退较长时间的海域,成体磷虾占比例较大,这反映了大磷虾未成体与成体不同的分布特征。南极大磷虾在不同海域种群结构存在一定的差异,对种群补充产生一定的影响。

THE POPULATION DISTRIBUTION,STRUCTURE,ANDGROWTH CONDITION OF ANTARCTIC KRILL (EUPHAUSIA SUPERBA DANA) DURING THE AUSTRAL SUMMER IN THE SOUTHERN OCEAN

Antarctic krill (Euphausia superba Dana) were collected in the circumpolar region and in the Prydz Bay region of the Southern Ocean during the austral summer of 2007/2008 and 2008/2009, respectively, using a High Speed Collector and an IKMT net. The spatial distribution, population structure, and growing conditions of E. superba were studied with simultaneously measured environmental parameters. The abundance of E. superba was higher in the Weddell Sea than in Prydz Bay. The abundance of E. superba in both the Weddell Sea and Prydz Bay was lower than the abundance recorded in earlier surveys conducted during the same season (austral summer). Over the study area as a whole, E. superba showed normal growth during the two summer expeditions. However, at some stations, the growth of E. superba was limited, possibly as a result of delayed sea ice retreat or lower chlorophyll a concentrations. Analysis of the population structure of E. superba showed that juvenile krill accounted for a large proportion of the population at stations located near the edge of the sea ice, while adult krill predominated in stations in ice-free areas. This phenomenon reflects the different features of distribution between juvenile and adult krill. The population structure of E. superba varied among study areas, which may have affected the population recruitment.