Using photo-identification to investigate the identity of blue whales at South Georgia: a comparison of photographs with Chile
Paula A. Olson, Barbara Galletti Vernazzani, Sonia Espanol-Jimenez
International Whaling Commission
It has long been assumed that all of the blue whales caught at South Georgia were Antarctic blue whales (Balaenoptera musculus intermedia). Recently re-evaluated catch data, genetic and acoustic studies have suggested that Chilean blue whales (Balaenoptera musculus subsp.) may occasionally, if infrequently, occur at South Georgia, but this has yet to be substantiated. This study utilized the Southern Hemisphere Blue Whale Catalogue to compare the identification photographs of 23 individual blue whales from the South Georgia region to those of 478 blue whales from Chile. If a match was found it would confirm the presence of Chilean whales at South Georgia. No matches were found between the South Georgia region and Chile. This is not a surprising result given the small sample size from South Georgia. Genetic analyses of Antarctic blue whale samples from the Southern Ocean identified only 1-2% as pygmy whales. The results here are inconclusive regarding the potential presence of Chilean whales at South Georgia and future comparisons with more identification photographs may yield different results.