For more than 25 years, the marine mammal researchers of the Archipelagos Institute have been working at sea throughout the year, collecting – among other data – hundreds of photographs of the cetaceans we document during each expedition.

Through photo-identification, we recognize individual animals based on their unique markings. These markings result from interactions with other members of their social group, with other marine species, or, in some cases, from human-related activities.

To date, we have photo-identified more than 600 different individuals from six species: Risso’s dolphins, striped dolphins, bottlenose dolphins, common dolphins, sperm whales, and goose-beaked whales. At the same time, through the analysis of their communication sounds, we also carry out acoustic identification of individuals.

In dolphins, identification photographs focus on the dorsal fin, which is the most distinctive feature for recognizing each individual – comparable to a human fingerprint. In sperm whales, identification focuses on the tail flukes. In this way, we create catalogues of all the cetaceans we have identified in each area of the Greek seas we study.

Through photo-identification, we collect valuable data on population behavior and migration patterns, while also gaining a better understanding of the factors that threaten them.

Photo-identification is a non-invasive research method that allows us to monitor cetaceans over time without burdening them with tracking devices. By exchanging photo-identification images with organizations conducting similar research, we are able to track the movements and migrations of cetaceans across different regions of the Mediterranean.