Galeus melastomus (Rafinesque, 1810) diet and feeding habits of five populations from the Central Mediterranean Sea.

With its wide distribution between 50 and 1400 m, Galeus melastomus (Rafinesque, 1810) represents one of the most abundant Scyliorhinidae in the Mediterranean Sea. Opportunistic feeder and scavenger; little is known about its feeding habits mostly in the Tyrrhenian Sea. The aim of this work is to investigate the diet of the blackmouth catshark by analysing the stomach contents. The specimens analysed in this study came from four populations of the Tyrrhenian Sea and one of the Ionian Sea caught at an average depth between 40 and 700m, from October 2020 to August 2021. A total of 302 specimens and 253 stomachs were analysed. All the stomach contents were sub-divided into macro-categories and identified with the help of some taxonomic guide at the lower taxa possible. Cephalopods as Abralia veranyi and Heteroteuthis dispar; Crustaceans as Parapeneus longirostris and Osteichthyes above all specimens of Mychtiophidae were found. Plastictics debris were detected in the stomach contents and classified according to their shape and colour. Except for the Tuscany population, where Cephalopods and Crustaceans were dominant, the most abundant item found was represented by Osteichthyes. It was observed a difference regarding plastics debris with a higher percentage of fibres in the Tuscany population and a higher percentage of fragments in the others. These differences could be explained by the different depths at which the blackmouth catshark populations live. Indeed, the population of Tuscany was sampled at – 600m.