Abstract:

The results presented in this paper are based on the net sampling carried out on two marine science cruises,in 1989/1990 and 1990/1991 austral summer ,in Prydz Bay region by Chinese Antarctic R/V "Jidi".The population structures of Antarctic krill(Euphausia superba Dana)were studied.Length/Frequency distribution shows that krill population in this area mainly consists of four age groups,i.e.1 +,2 +,3 +and 4 +,except the larvae.5 +and >5 +age groups account for a very small proportion of the population (less than 3%).Regional differences in population structure are evident.Samples collcected from the north of the Prydz Bay presented typical bimodal L/F distribution,with a strong 1 +age group.Catches from the east and west part of the research area presented a monomodal L/F distribution,with the subadults and adults as the bulk of the population,no or very few juveniles appeared.Annual variation in population structure between the two years was obvious especially in the strength of 1 + age group.