Mackerel icefish (Champsocephalus gunnari) grow rapidly to a size of 55 cm on a diet that largely consists of krill. They form large aggregations in shelf waters all round South Georgia and Shag Rocks. A pelagic trawl fishery for mackerel icefish operates within South Georgia waters, mostly in the summer months. In 2010, the South Georgia mackerel icefish fishery was certified as sustainable by the MSC.
Fishing for mackerel icefish began in South Georgia waters in the 1970s, when large catches were taken by vessels from the then Eastern-bloc. Following concerns about the depletion of stocks CCAMLR closed the fishery in 1989. The fishery was later re-opened but with a highly conservative quota and was restricted to pelagic trawling to avoid impact on non-target species. In recent years, catches have been less than 5,000 tonnes, with most fishing activity focused on an area to the north-west of South Georgia.
In the past, there have been some issues concerning seabird bycatch in the icefish fishery. Birds attempting to feed on fish caught in the mesh of the net could become trapped and drown. Measures, including net cleaning and binding before shooting, are now required under the license conditions and dramatically reduce the risk of seabird bycatch.