Biomass of Birds and Mammals in the Ross Sea

Abstract

The distribution and biomass of birds and mammals were determined for the Ross Sea, Antarctica. A total of 548 30-min strip (4–10 km long) censuses were made during 5 cruises south of 65°S between 15 December and 18 January in 1976–1980. Within the boundaries of the Ross Sea, the biomass of birds, seals and whales was estimated to be 0.044–0.070, 0.068-0.089 and 0.182–0.394 g m−2, respectively. The difference between bird and seal biomass was not statistically significant. The bird community was dominated in abundance (no. individuals) by Antarctic Petrels, Thalassoica antarctica, and in biomass by penguins. The mammal community was dominted in abundance by Crabeater Seals, Lobo-don carcinophagus, and in biomass by Crabeater Seals and Minke Whales, Balaenoptera acutorostrata. Birds and mammals were concentrated in the same areas, in conjunction with oceanographic fronts, while large areas were devoid of these upper-trophic-level predators. Characteristics of pack-ice also affected the animals’ distributions, especially those of mammals.