Abstract:

This study documents horizontal distribution and demography of Antarctic krill (Euphausia superba Dana), which collected by IKMT along three transects from the Prydz Bay during January 2002. E. superba dominated south of 64°S, and few krill was found north of 64°S. The average density/biomass, estimated from trawl catches, was 68.85 ind/1000 m3 or 24.16 g/1000 m3. The four stations with highest values were located in the open sea. Body length ranged from 30 to 55 mm (N = 1758), with a mean of 38.45 ± 3.68 mm (SD). The overall sex ratio was 1:1, 47.6% females (31.9% sub-adults and 5.7% adults), 46.6% males (42.7% sub-adults and 3.9% adults), while 5.8% were juveniles. The population structure of E. superba showed geographical difference. The high proportion of juvenile, low sexual maturity stage of male and good growth condition was found in the western part of the survey area, and the reverse was presented in the eastern part. The latitudinal difference was found at stations along 70.5°E and 73°E: the body length was small and sex ratio was high in the region of high latitude, while the size was large and sex ratio was low in the region of low latitude.

Key words: Euphausia superba, distribution, density, population structure, Prydz Bay