The Antarctic Blue Whale Catalogue: new data from 2015-2019
Paula A. Olson, Michael C. Double, Koji Matsuoka, Luis A. Pastene, Ken Findlay
International Whaling Commission
Recently available identification (2015-2019) photographs of 62 individual Antarctic blue whales were compared to the images of 457 individuals in the Antarctic Blue Whale Catalogue. The five sources of photographs include the Australian Antarctic Division, the Institute of Cetacean Research, and opportunistic photographs collected by scientists conducting other (non-blue whale) research in the Antarctic region. Sixty new individual blue whales were identified and two whales were recognized as inter-annual photographic recaptures. The resighted whales had time intervals of 6 years and 12 years, with sighting locations separated by 384km and 3,307km, respectively. The 60 new identifications bring the total number of photo-identified Antarctic blue whales up to 517 whales, represented by 389 left sides and 383 right sides. The minimum (383) and maximum (517) number of unique individuals represents 17% and 23%, respectively, of the most recent accepted estimate of abundance of Antarctic blue whales, 2,280 in 1997/1998 (Branch, 2007). The majority of identifications in the Catalogue (almost 75%) derive from IWC Management Areas III and V. The collection of Antarctic blue whale identification photographs provide data for capture-recapture estimates of abundance as well as information on the movement of individual blue whales within the Antarctic region.