Whale sightings during POLARSTERN cruise ANT-XXVIII/4

From 13 March to 09 April 2012 Germany conducted a fisheries survey on board RV Polarstern in the Scotia Sea (Elephant Island - South Shetland Island - Joinville Island area) under the auspices of CCAMLR. During this expedition, ANT-XXVIII/4, an opportunistic marine mammal survey was carried out. Data were collected for 26 days along the externally preset cruise track, resulting in 295 hrs on effort. Within the study area 248 sightings were collected, including three different species of baleen whales (fin whale (Balaenoptera physalus), humpback whale (Megaptera novaeangliae), and Antarctic minke whale (Balaenoptera bonaerensis) and one toothed whale species, killer whale (Orcinus orca). More than 62% of the sightings recorded were fin whales (155 sightings) which were mainly related to the Elephant Island area (116 sightings). Usual group sizes of the total fin whale sightings ranged from one to five individuals, also including young animals associated with adults during some encounters. Larger groups of more than 20 whales, and on two occasions more than 100 indivuduals, were observed as well. These large pods of fin whales were observed feeding in shallow waters (< 300 m) on the north-western shelf off Elephant Island, concordant with large aggregations of Antarctic krill (Euphausia superba). This observation suggests that Elephant Island constitutes an important feeding area for fin whales in early austral fall, with possible implications regarding the regulation of (krill) fisheries in this area.