COMPETITION BETWEEN THE KRILL FISHERY AND PENGUINS IN THE SOUTH-SHETLAND-ISLANDS

Among the South Shetland Islands, the potential competition for krill (Euphausia superba) between the Japanese fishery and krill-eating bree ding penguins was assessed. A low level of competition was apparent du e to several factors. Spatial overlap between the main fishing and for aging areas was insignificant. Firstly, the large colonies of the domi nant penguin (chinstrap penguins, Pygoscelis antarctica) occurred wher e sea ice disappears early in spring, and not necessarily where krill are abundant in summer, i.e, the area of krill fishery. Secondly, over lap between trawling depth and foraging dive depth of penguins was mar ginal, with the latter depth being shallower. Moreover, overlap in the size-frequency of krill caught by trawlers and those captured by peng uins was not complete; the penguins took larger krill on average. Fina lly, the present small fishery is unlikely to impact upon local krill biomass in the region. Krill biomass was estimated to be 250-1500 x 10 (3) tonnes within the preferred fishing areas during summer. The prese nt catch rate by the fishery (less than or equal to 13 x 10(3) tonnes/ half-month period) is smaller by an order of magnitude, and the fishin g area does not include the main foraging areas of breeding penguins.