Vertebral variation in notothenioid fishes from McMurdo Sound, Antarctica

Abstract

Vertebral variation was studied in eight species (299 specimens) of notothenioid fishes from McMurdo Sound, Antarctica. McMurdo Sound is one of the most physically stable marine environments in the world, with a nearly constant mean annual temperature. As measured by the coefficient of variation, McMurdo Sound species were slightly less variable than the temperate and arctic species used for comparison. When the F-distribution was used to test the significance of differences between mean variances of species from different localities, McMurdo Sound species were significantly different (0.01<P≤0.05) in four of the six comparisons. Variance values indicated that McMurdo Sound species were less variable than arctic and temperate species in three out of the four significant comparisons. Although it can not be proven that the stable water temperature of McMurdo Sound contributes to reduced vertebral variation, this is certainly a plausible hypothesis. Vertebral variation is discussed with reference to the biology of notothenioid fishes.