Length-age composition of icefish (Champsocephalus gunnari, perciformes, notothenioidei, Channichthyidae) from different locations of South Georgia Island subarea

Biostatistic data obtained by Soviet research and commercial vessels in 1970 to 1991 have been used to study length-age composition of Champsocephalus gunnari from different locations of South Georgia Island Subarea. An analysis of Ch.gunnari length-age groups spatial distribution over Eastern, Northern, Western, Southern Island Shelf and near Shag Rocks allowed for revealing similarity of Ch.gunnari length-age composition structure at early years of life for fish inhabiting areas to the south of Island and near Shag Rocks and finding a difference between those two groups and the eastern group. Larger number of "mature" fish in the west is related to migration from eastern area of maturing individuals as they grow. It has been defined that a part of western group of fish at the age of 2-3 years had been migrating towards the Shag Rocks. It has been found that predomination of recruitment over remaining fish had been characteristic of the whole population irrespective to absence or presence of fishery. It is obviously a natural character of the population under consideration. Ch.gunnari could rapidly set up and restore high abundance in Subarea just owing to that character in conjunction with pelagization of species, earlier age of sexual maturity as compared to notothenia and favourable oceanographic conditions.