Photo-identification of blue whales is a simple, effective and non-invasive method of identifying individual whales, using unique and distinctive pigmentation patterns on the whales’ flanks. When a whale is photographed more than once, a ‘resight’ or ‘match’ is created. Analysis of resights helps us to build a picture of the lives of individual blue whales and gain an understanding of their patterns of occupancy of the region, reproductive rates, health indices, life history and movements between areas and years. Producing an efficient, up-to-date photo-ID catalogue will enable us to monitor movements of whales between regions and seasons and better understand population dynamics and impacts from the threats they face.
The image below is a good example of a distinctive photo-ID, and is particularly interesting as it was the first blue whale that had been photo-IDed in 2004 in the Perth Canyon, WA (by our colleagues at Centre for Whale Research WA), and then resighted by BWS in 2005 in the Bonney Upwelling, providing the first confirmation of a migratory link between these two important blue whale feeding grounds.