Oxygen consumption of five species of fish from south Georgia

The oxygen consumption rates of five species of sub-Antarctic fish, Notothenia rossii Fischer, 1885; Notothenia angustifrons Fischer, 1885; Notothenia nudifrons Lonnberg, 1905; Trematomus hansom Boulenger, 1902; and Harpagifer georgianus Richardson, 1844, have been measured with particular emphasis on the previously unstudied early stages of the life history. The time courses for acclimation to the experimental apparatus show an initial elevation and increased variability of oxygen consumption followed by a decrease to a plateau within 12–24 h. Data on the relationship between size of fish and size of experimental chamber show the effects of these variables on acclimation, if the ratio of fish volume to chamber volume is < 4%. Oxygen consumption rates are compared with published data and related to observations on the ecological niches and changes in morphology of the different stages of the various species. Intra-specific changes in the ecology of the various developmental stages are not reflected by discontinuities in the relationship between oxygen uptake and weight. Inter-specific differences in metabolic rate do, however, show a correlation with the activity level of species.