极地研究 ›› 1988, Vol. 1 ›› Issue (2): 15-21.

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乔治王岛东北海域大磷虾虾群构成分析

王荣;陈时华   

  • 出版日期:1988-06-30 发布日期:1988-06-30

SWARM STRUCTURE OF ANTARCTIC KRILL (Euphausia Superba DANA) IN WATER NORTHEAT OF KING GEORGE ISLAND, JANUARY 1985

  • Online:1988-06-30 Published:1988-06-30

摘要:

1985年1月在乔治王岛东北约25海里(水深460米)海域,曾观测到范围较大的大磷虾群.在约4海里范围内用垂直探鱼仪记录了虾群的映象,进行了水平拖网.对6网样品的分析结果表明,虾群组成相当均一.体长频数分布样品间的百分比相似性指数平均为84.3%,性成熟度组成频数分布的相似性指数平均为75.6%,说明这些样品属同一虾群.磷虾平均体长为46.8毫米,成体虾占群体的96.5%,表明它们为一生殖群体.群体分布水层在20—50米深,厚度一般为20米,平均密度为1400尾/千立方米.

关键词: 南极大磷虾;南大洋;虾群组成

Abstract:

During the First Chinese Antarctic Expedition, in water northeast of King George Island krill (Euphausia superba Dana) swarms were found and observed by echosounder (200 kHz) , and 15 IKMT (Isaacs-Kidd midwater trawl) tows were made in an area of 3 x 5 nautical mile. The population structure of 6 samples were analysed by means of L-F distribution and sexual maturity stage composition. The percent similarity indices of L-F distribution between samples are very high, 84.3% in average. That of sexual maturity stage composition is 75.6% in average. The population structures inside the searched area are quite similar. Echograms show that the swarms are distributed mainly in a layer at 20-50 m depth. Its upper limit is quite stable, but the lower limit varies greatly according to the thickness of the swarm. The highest density observed is 4418 individuals/ 1000 cubic meter, . only 1400 individuals / 1000 cubic meter in average, and much lower than that of swarms commercially harvested. The temperature of water in which swarms occurred ranges from 0.85 to 1.65℃, and the salinity 34.003-34.163‰. Adults constitute the great majority (96.5%) of the population. Among females, gravid female accounts for 33.6%, spent female 2.3% .Judging from the sexual maturity stage composition, the maximum spawning for the swarms in this area would occur in late February.