A new classification method to simplify blue whale photo-identification technique

ABSTRACT Individual identification of blue whales is based on unique pigmentation patterns. Historically photo-identification has been based on thepigmentation patterns observed on a large portion of the animal’s flanks. The new classification method presented here is based primarily on sevendorsal fin shapes and secondarily on five pigmentation patterns selected from a minor portion of the flank adjacent to the dorsal fin. This classificationis then applied to a blue whale catalogue that comprises 621 individuals photo-identified in the waters adjacent to the Baja California Peninsula inMexico. The classification system adequately divides the number of individuals per dorsal fin category and pigmentation patterns. It has been usefulnot only for reducing time and for matching photographs more efficiently but also has facilitated the finding of intra-catalogue photographicrecaptures or photo-recaptures and has enhanced the efficiency of the field work. This new classification method should be considered by otherblue whale researchers and for future inter-catalogue comparisons. KEYWORDS: TECHNIQUE; PHOTO-ID; BLUE WHALE