Age-Length Composition of the Mackerel Icefish Champsocephalus gunnari (Channichthyidae) at Various Sites off South Georgia Island (Antarctic Regions)

摘要

The age-length composition of the Mackerel Icefish Champsocephalus gunneri at various sites of the South Georgia subarea is studied taking into consideration the material obtained in research, fish- searching, and fishing voyages of Soviet vessels during the years 1970-1991. There is a similarity in the size-age structure of C. gunnari groups to the west of South Georgia Island and at Shag Cliffs and a difference in these two groups from the eastern group in the first years of life. The greater abundance of mature icefish in the west is related to the migration here of fish that have attained maturity. It is supposed that a part of the western group in the second-third year migrates to Shag Cliffs. The whole population is generally characterized bythe prevalence of recruitment over the remainder of the stock irrespective of the presence or absence of fishery. Due to this fact, in combination with pelagization of this species and earlier maturation in comparison with Notothenia rossii marmorata under favorable oceanological conditions, C. gunnari may rapidly create or restore a high abundance in the area of South Georgia Island.