Distribution of marine mammals and its relationship with krill in Bransfield Strait. ANTAR XXI

Abstract

The observations were made along 332.14 nm, during the Expedition Peru Antar XXI, from 15th to 22nd February 2013 along the Bransfield Strait and surroundings of Gibbs island. A total of 86 sightings of marine mammals were recorded: 55 cetaceans and 31 pinnipeds. Out of the 135 individuals of marine mammals; 96 were cetaceans and 39 were pinnipeds. The three species of cetaceans identified belonged to the Family Balaenopteridae: humpback whale (Megaptera novaeangliae), fin whale (Balaenoptera physalus) and minke whale (Balaenoptera bonaerensis). The relative abundances indices were: 0.361 individual per 10 nm observed for fin whales, 0.481 individuals per 10 nm observed minke whales and 0.840 individuals per 10 nm observed for humpback whales. The pinnipeds identified belonged to a single species of the Familiy Otariidae: Antarctic fur seals (Arctocephalus gazella), which accounted for 36.05% of the mammal sightings. Relative abundance of pinnipeds was 1.174 individuals per 10 miles observed. Humpback whales were associated with krill aggregations on top of the water column, while minke whales were associated with krill aggregations in deeper areas.