CCAMLR

Experimental acoustic survey in shelf areas off South Georgia and Shag Rocks in CCAMLR Subarea 48.3 aimed at demersal fishes abundance and distribution assessment is described. Data on trawl stations location, catch length compostion, per cent proportion of various fish species in trawls samples, data of biological and oceanologica3 researches are presented. The data on target strengths obtained in- situ for icefish (Champsocephalus gunnari), the latter per cent proportion in trawl catches, velocity and length-weight factors, affecting the genera3 estimation of biomass are analysed.

The examination of the sexual ratio of D. eleginoides between the first week of March and the third week of July 1996, in the subarea 48.3 shows that the sex ratio departs from the expected 1:l ratio being the females more abundant in the longline samples, except during May, when the males at size of first maturity join the female population. After the first week of June, the sex ratio turns back to a higher number of females. Because the longline remains most of the time close to the bottom habitats, this finding suggests that: or the females remain in higher proportion in the habitat sampled by the longline because the males move to other habitats or, the females are more vulnerable to the longline fishing techniques, or both sexes rise in the water column for spawn. No one of these hypotheses could be tested using the fishery data.