Cetaceans in the Mediterranean Sea: Encounter Rate, Dominant Species, and Diversity Hotspots

• Published in: Diversity
• Main Authors: Guido Gnone, Michela Bellingeri, Sabina Airoldi, Joan Gonzalvo, Léa David, Nathalie Di-Méglio, Ana M. Cañadas, Aylin Akkaya, Tim Awbery, Barbara Mussi, Ilaria Campana, Marta Azzolin, Ayhan Dede, Arda M. Tonay, Clara Monaco, Giuliana Pellegrino, Paola Tepsich, Aurelie Moulins, Antonella Arcangeli, Hélène Labach, Aviad P. Scheinin, Yaly Mevorach, Roberto Carlucci, Francesca C. Santacesaria, Carla A. Chicote, Manel Gazo, Beatriz Tintore, Jessica Alessi, Alberta Mandich, Luca Bittau, Bruno Diaz Lopez, Caroline Azzinari, Gabriella La Manna, Daniela Silvia Pace, Donatella Decandia, Alberto Castelli, Silvio Nuti, Marie-Catherine Santoni, Alessandro Verga, Nicolas Tomasi, Cristina Giacoma, Matteo Costantino, Marta Falabrino, Arianna Azzellino
• Format: Text
• Language: English
• Published: Multidisciplinary Digital Publishing Institute 2023
• Subjects: Shannon index; prevalence; primary production; chlorophyll; habitat; seabed; bathymetry; Western Basin; Fin whale; Sperm whale
• Online Access: https://doi.org/10.3390/d15030321

We investigated the presence and diversity of cetaceans in the Mediterranean Sea, analysing the data collected by 32 different research units, over a period of 15 years (2004–2018), and shared on the common web-GIS platform named Intercet. We used the encounter rate, the species prevalence, and the Shannon diversity index as parameters for data analysis. The results show that cetacean diversity, in the context of the Mediterranean basin, is generally quite low when compared with the eastern Atlantic, as few species, namely the striped dolphin, the bottlenose dolphin, the fin whale, and the sperm whale, dominate over all the others. However, some areas, such as the Alboran Sea or the north-western Mediterranean Sea, which includes the Pelagos Sanctuary (the Specially Protected Area of Mediterranean Interest located in the northern portion of the western basin), show higher levels of diversity and should be considered hotspots to be preserved. Primary production and seabed profile seem to be the two main drivers influencing the presence and distribution of cetaceans, with the highest levels of diversity observed in areas characterized by high levels of primary production and high bathymetric variability and gradient. This collective work underlines the importance of data sharing to deepen our knowledge on marine fauna at the scale of the whole Mediterranean Sea and encourages greater efforts in the networking process, also to accomplish the requirements of the Marine Strategy Framework Directive, with particular reference to Descriptor 1: biological diversity is maintained.