Technical report on the Photo-Identification Project 2015 – 2016
Associació Cetàcea is pleased to present the technical report in which we analyse the results of the Project Photo-Identification: Whales and dolphins along the Catalan coast 2015 and 2016 seasons. The project was started in 2014 and its main aim is to deepen our knowledge on the cetacean communities that can be frequently seen off the central Catalan coast. In 2015 and 2016, we conducted 20 sighting surveys, covering slightly more than 1000 nautical miles, during which we recorded 31 sightings of four different species of cetaceans including the fin whale (Balaenoptera physalus), the bottlenose dolphin (Tursiops truncatus), the striped dolphin (Stenella coeruleoalba) and the Risso’s dolphin (Grampus griseus).
The results confirm that, as we already observed in previous seasons and as it has already been observed in other regions from the Mediterranean Sea, the different species show a differential distribution within the area of study, mainly influenced by depth. The striped and the Risso’s dolphins showed an offshore distribution, with their sightings located in waters deeper than 400 metres, usually associated with the continental slope or with underwater canyons. On the contrary, bottlenose dolphins showed a coastal distribution, usually observed in waters shallower than 200 metres, located above the continental platform. Lastly, the fin whale showed an intermediate distribution with their sightings being located in waters between 86 and 1090 metres deep.
The report also presents the first review on the photo-identification catalogues of both the bottlenose and the Risso’s dolphins, which include 45 individuals so far. These catalogues have shown that some of the identified individuals have been observed in the area of study in several occasions in different years, suggesting that there could be some resident bottlenose and Risso’s dolphin communities in the area. The identified individuals have also been compared to individuals of other catalogues from the Western Mediterranean Sea and we have seen, that at least, one bottlenose dolphin was previously seen in areas close to the Gibraltar Strait, showing the ranging capacity of some individuals of this species.
You can access the full technical report on this link.