Preliminary observations of nursehound Scyliorhinus stellaris (Linnaeus, 1758) spawning areas in coastal waters of Tuscany, Italy

Abstract

In the circalittoral zone of the Mediterranean Sea, the nursehound Scyliorhinus stellaris lays eggs in spawning areas located at depths between 25 and 50 m in the red gorgonian meadows. Given the evident decline of the nursehound population in the Mediterranean and its high vulnerability, investigating spawning and potential nursery areas is crucial for the conservation of this species. Using non-invasive techniques such as diving activities with the help of R.O.V. (Remote Operated Vehicle), spawning areas have been identified along the Tuscany coast in Italy. In addition, B.R.U.V.S. (Baited Remote Underwater Video System) was used as an auxiliary method to diving activities in order to record the presence of nursehound individuals. Between 2018 and 2024 (except for 2022), 66 eggs were spotted around Monte Argentario peninsula on the Argentarola Island, Grotta del Corallo, Cala Grande, Capo D’Uomo, Cala della Maddalena and around Giannutri Island in Punta Scaletta. The highest number of eggs was observed around the Argentarola Island, Grotta del Corallo, and Cala Grande, both daily and during the entire study period, which suggests that these three sites represent spawning areas. Furthermore, two adult nursehound individuals have also been sighted near Argentarola Island, suggesting this site could represent a potential nursery area. Further data will be collected in these sites through more in-depth investigation in order to understand spatial distribution patterns, relative abundance, population estimates and behavior of this species along the Tuscany coast.