Photo-identification is a non-invasive method of individual identification. Consists on taking photographs of a certain part of an animal’s body that has unique characteristics for each individual. For the majority of the cetaceans, their dorsal fins are unique, they work like a fingerprint. Each dorsal has a shape, collar, inclination and markings (scars and cuts) which, through detailed analysis, make it possible to identify individuals.
However, some species have stronger characteristics in other parts of the body, for example, for humpback whales and sperm whales we often use the tail fin; in killer whales, in addition to the dorsal fin, the saddle and the eye patch give us a clearer idea of the differences between individuals. Then, depending on the species we want to identify, we focus the photograph on the specific part of each animal. These photographs are then analysed and cross-referenced to create identification catalogues for each species. With each sighting, more photographs are collected and thus, over several years,
information can be extracted about the seasonality of populations and their dynamics, estimates of population numbers and even migratory routes.
As it is a non-evasive method (it doesn’t harm the animal), it is very important for better management, monitoring and conservation of the cetacean species in our coast.
At Mar Ilimitado we already have a catalogue of orcas, risso’s dolphins and fin whales, available to see here. Catalogues of other seen species, such as bottlenose dolphins and minke whales are on the making.