Dolphins: their protection in the Ionian Sea also relies on photo-identification
A new photo-identification system, tested in the Gulf of Taranto, is now available among the tools and perspectives used for the protection of dolphins in the Ionian Sea.
The new tool is the result of a study conducted by the Institute of Intelligent Industrial Systems and Technologies for Advanced Manufacturing of the National Research Council (CNR-STIIMA) in Bari, the Biology Department of Aldo Moro University of Bari, and Jonian Dolphin Conservation.
The research, based on the latest Computer Science techniques, allowed the certain identification of many individuals of Risso’s dolphin (Grampus griseus): a species of dolphin that is rare and little known worldwide, found in the north Ionian Sea.
The result was obtained thanks to the monitoring activity carried out by the research group in the Gulf of Taranto, in the context of a large Citizen Science project involving students and tourists alike.
Risso’s dolphin has a distinctive feature: the presence of numerous pale scars on its body. As the dolphin ages, its skin becomes covered with scars and its colour changes to almost white, especially in the anterior part of the body.
“Thanks to the combination of our different skills, we developed the first automated photo-identification algorithm for this species, based on the analysis of the scratches on the dorsal fin of each dolphin. These scratches are considered as human fingerprints allowing the identification of individual dolphins, thanks to the use of a statistical detector of the local features of the image, characterized by a short computational time”, explained Rosalia Maglietta, CNR-STIIMA.
Photo-identification is carried out by comparing the digital images of the dorsal fins of dolphins to be identified with the images of previously identified individuals stored in a database. A major advantage of this method is the use of the algorithm that allows the analysis of large amounts of images more quickly and without human intervention.
The tool developed for data collection and study is also innovative: the DolFin digital platform, accessible online.
“In the future, it will be possible to use DolFin to carry out in-depth studies on the spatial distribution of this or other species of cetaceans in the Mediterranean or on a global scale”, explained Roberto Carlucci, University of Bari. “Despite being considered a regular inhabitant of the Mediterranean Sea, Risso’s dolphin remains one of the least-known cetacean species in the basin. DolFin will help us learn whether the identified dolphin remains in the same stretch of sea or whether it moves, what are its travelling companions and the reasons for these migrations”.
Information on the presence of these animals can provide an important indicator of the health of the Gulf of Taranto, while directing the administrations towards more targeted measures for the conservation of biological diversity.