Sighting of Risso’s dolphin (Grampus griseus) during scientific research of the Calabrian Southern Ionian Sea (Central Eastern Mediterranean)

Abstract

The presence of Risso’s dolphins (Grampus griseus) in Southern Calabrian waters of the Ionian Sea is poorly known. During dedicated cetacean research started in the summer of 2019 in the stretch of Calabrian waters between Brancaleone and Botricello, a pod of Risso’s dolphins was recorded for the first time. This observation occurred of Siderno and Locri at about 8.3 km from the shore where the sea depth is 720 m, a bathymetric feature that is in line with the known deeper water habitat preference of the species. This Risso’s dolphin pod was composed of at least 14 individuals. The latter were photo-identified. One individual showed signs of a serious injury due to a probable vessel accident that severed partly into its back behind its dorsal fin. Most of the individuals observed were mature to old with their frontal area already light grey to white. This scientific report contributes new knowledge on the distribution of the species in the Central Mediterranean Sea which may better address effective conservation management efforts for the species. Further monitoring and management are needed for this endangered species, especially in a geographic area that was previously unstudied for an extended period, despite past stranding events and citizen sightings of cetaceans being recorded occasionally.