The recent decline in recruitment of Gobionotothen gibberifrons in the South Shetland Islands (CCAMLR Subarea 48.1)

Commercial exploitation of fish stocks around Elephant Island and the lower South Shetland Islands ceased after the 1989/90 season. One of the larger and most abundant species in the area, Gobionotothen gibberifons, was only lightly exploited compared to more northerly fishing grounds such as South Georgia. Six surveys were conducted by the US and Germany from 1998 to 2012 to investigate if and to what extent Antarctic fish stocks recover from exploitation and how natural causes may add to man-made perturbations on a fish stock by recruitment failure as one of them.



Data from the 1980’s and 1990’s (1983, 1985, 1986, 1987, 1996 and 1998: Kock, 1986, Kock 1987, Kock, 1998, Jones et al., 1998) demonstrated that recruitment of G. gibberifrons was normal. Recruitment began to decline substantially at the turn to the 2000’s. In 2012, the proportion of immature fish (<30 cm) in the population was less than 10%. Recruitment failure was restricted to Elephant Island and the lower South Shetland Islands. Surveys in the Antarctic Peninsula in 2006 and in the South Orkney Islands in 2009 demonstrated normal recruitment. What caused a number of years of very low recruitment around Elephant Island and the lower South Shetland Islands is still unknown.