In the plankton samples, collected with a Nansen net in three water layers downwards to a depth of 500 m, larvae and eggs of Euphausia superba were found as well as the larvae of E. crystallorophias and E. frigida. Eggs of the species E. superba predominated and among the larvae most numerous were calyptopis I and metanauplius stages. Eggs and larvae of E. superba occurred in small quantities, mainly in Bransfield Strait. Larvae of E. crystallorophias were found in the southeastern part of Bransfield Strait. Metanauplius, calyptopis I and II stages were predominant. Larvae of E. frigida, mostly calyptopis I stage, were very scarce and occurred only at the stations located in Drake Passage.
Distribution and population age structure of krill Euphausia superba larvae is presented for four consequent years on the basis of the summer materials from 1976 to 1979. An approximate rate of growth of krill larvae was calculated on the basis of the above observations and the literature data on the occurrence of particular larval stages. This allowed to determine the main period of krill breeding in particular years. Intense breeding of krill took place from January to middle of March in summers 1976/1977 and 1977/1978, but much earlier — mid November to mid January in 1975/1976. In summer of 1978/1979 the breeding of krill was poor till March.