Samples gathered from research expeditions of the longliners Medvezhy (April-June 1986) as well as Maksheevo and Mirgorod (June-July 1992) have produced new data on the biology of the reproductive part of the Dissostichus eleginoides population in Subarea 48.3. Analysis and synthesis of these data have established the bathymetric distribution patterns for different size-groups of toothfish around Shag Rocks and South Georgia. A differentiation analysis of the sex structure of the D. eleginoides population was carded out. The dynamics of the maturity structure of the adult part of the D. eleginoides population are shown for the pre-spawning and spawning periods. A preliminary assessment of the reproductive ability (fecundity) of females of the species is presented. Data are also presented on the feeding patterns of D. eleginoides sampled from longline catches. Some differences in food composition in relation to fishing depth were noted.