Abstract:

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.