Growth of young fish during winter and summer at South Georgia, Antarctica

Fish <1 year old were sampled during 1 year using nets inshore at South Georgia. Some fish were kept in aquaria. Growth rates were estimated using the exponential model. During June to October 1980, field growth rates of Parachaenichthys georgianus and Champsocephalus gunnari were 0.33 and 0.48% SL day−1, respectively. Gobionotothen marionensis (1979 cohort) grew at 0.40% SL day−1 during June to November in the field, and 0.34% SL day−1 in the laboratory from September to March. Notothenia coriiceps grew at 0.28% SL day−1 in the laboratory during September to March. During November to December, Artedidraco mirus grew at 0.82% SL day−1 in the field. The 1980 cohort of G. marionensis grew at 1.39% SL day−1 during November to January in the field. During January, the field growth rate of G. gibberifrons was 1.39% SL day−1. Growth rates increased three-fold from winter to summer. Temperature can only explain one-half of this range in growth rates, whereas all of this range can be explained by food availability. Therefore, seasonal food resource limitation has a major effect on Antarctic fish growth.