Reproduction of the mackerel icefish (Champsocephalus gunnari) and its implications for fisheries management in the Atlantic sector of the Southern Ocean
Available information on key reproduction parameters of the mackerel icefish (Champsocephalus gunnari) has been reviewed and discussed in the light of existing conservation measures. Length at first spawning is approximately 25 cm around South Georgia and Kerguelen Islands, but approximately 35 cm around the South Orkney Islands and in the South Shetland Islands/Antarctic Peninsula region. Around South Georgia spawning takes place from March to May. Spawning around the South Orkney Islands and the South Shetland Islands probably occurs in June/July. Around South Georgia males start their spawning migration earlier than females. Fjords have been reported to be important spawning grounds. Fecundity is highest around South Georgia and Kerguelen but is decreasing towards higher latitudes.
Mesh size regulations presently in force offer very little protection to first spawners around South Georgia and juveniles and first spawners on the other South Atlantic fishing grounds. Spawning activities of C. gunnari and those of other exploited species could be best protected by the establishment of a permanent closed fishing season from 1 March to the end of each year's meeting of CCAMLR which is usually held in late October or early November.