普里兹湾邻近海域大磷虾幼体的分布与丰度研究

198 9/ 1 990和 1 990 / 1 991南极夏季期间在普里兹湾邻近海域进行了拖网调查 ,对这一海域大磷虾 (Euphausia superba Dana)幼体的分布和丰度进行了研究。1 990年 1月幼体的平均密度为2 6个 / 1 0 0 0米 3 ,2月增至 1 6 2个 / 1 0 0 0米 3 ,3月初达到 2 0 1 1 3个 / 1 0 0 0米 3 (3月为表层高速采集器样品 )。幼体出现高峰看来是在 3月。分布和丰度的年际变化明显。1 990年仅 1 / 2测站出现大磷虾幼体 ,以原蚤状幼体 I期和 期占优势 ,未发现蚤状幼体。1 991年幼体较多 ,2 / 3的测站都有出现 ,而且在外海较普遍地采到蚤状幼体 I到 期。这一年际变化与水温有关。在同一纬度 1月的表层水温 1 991年比 1 990年为高 (高出 0 .0 5 - 1 .2 4℃ )。幼体的平均发育期 (∑ Si Ni/ ∑Ni)平面分布表明 ,愈向北平均性愈高 ,随纬度增加发育期降低。

DISTRIBUTION AND ABUNDANCE OF LARVAE OF ANTARCTIC KRILL(EUPHAUSIA SUPERBA DANA) IN THE PRYDZ BAY REGION,INDIANOCEAN SECTOR OF THE SOUTHERN OCEAN

During the austral summer of 1989/1990 and 1990/1991 net samplling survey was carried out on the distribution and abundance of larvae of Antarctic krill(Euphausia superba Dana)in the Prydz Bay region.In 1990,the average density of larvae in January was 26 ind./1000m 3,increased to 162 ind./1000m 3 in February,reached to 20113 ind./1000m 3 in January and 1698 ind./1000m 3 (surface sampling by high-speed plankton sampler)in March.The peak abundance of krill larvae seems to occur in March.Annual fluctuation in distribution and abundance of larvae was evident.In 1990 only 1/2 of the hauls were positive,most of the larvae were calyptopis I and II and no furcilias were found.Larvae were more abundant in 1991,about 2/3 of the hauls were positive and furcilia I-Ⅳ widely distributed in the open area.This fluctuation can be attributed to the difference of the water temperature of the two years.The surface temperature at the same latitute in January was much higher(0.05-1.24℃) in 1991 than in 1990.The geographical distribution of the average developmental stages (∑S iN i/∑ N i) showed that older larvae occured to the north and the younger to the south.