Environmental pollution, particularly in the marine environment, has become a significant concern due to the increasing presence of pollutants and their adverse effects on ecosystems and human health. This study focuses on the bioaccumulation of trace elements in the muscle tissue of the blackmouth catshark (Galeus melastomus) from different areas in the Mediterranean Sea. Trace elements are of interest due to their persistence, toxicity, and potential for bioaccumulation. This research aims to assess the distribution and accumulation of trace elements in the muscle tissue of G. melastomus and investigate their potential impact on the deep-sea environment of the Mediterranean. The focused areas include the Ligurian Sea, the northern and central Tyrrhenian Sea, the southern Tyrrhenian Sea, the Ionian Sea, the Pantelleria Waters, and the Gela Waters. Samples were collected following established protocols, and trace element analysis was conducted using inductively coupled plasma mass spectrometry. The study provides data on the concentrations of 17 trace elements, namely aluminum, arsenic, cadmium, cobalt, copper, manganese, molybdenum, nickel, zinc, selenium, strontium, lead, chromium, iron, barium, bismuth, and uranium. The findings contribute to a better understanding of trace element bioaccumulation patterns in elasmobranch species, specifically G. melastomus, and highlight the potential risks associated with chemical contamination in the Mediterranean Sea. This research emphasizes the importance of studying the impacts of pollutants on marine organisms, particularly those occupying key ecological roles, like sharks, to support effective conservation and management strategies.

This contribution aims to increase the information of the MEDLEM (Mediterranean Large Elasmobranchs Monitoring) program, presenting the results of the analyzes on the data collected and acquired in the last 5 years (from 2017 to 2022). There are a further 989 records, relating to 35 taxa from 17 countries and representative of almost all the GSAs of the Mediterranean. The most frequent species reported is the sandbar shark (Carcharhinus plumbeus, 31,5% of the records), followed by the bluntnose sixgill shark (Hexanchus griseus, 20,5% of the records). New data on other rare and endangered species of elasmobranchs are reported.

Predation and/or scavenging on terrestrial birds by sharks is a poorly documented issue especially in the Mediterranean. The present study reports the first record of blackmouth catshark and blue shark predation/scavenging on terrestrial birds (common blackbird, typical warbler and European quail) in the Central Mediterranean. This case could imply the intentional and opportunistic predation, especially by blue sharks, on terrestrial birds flying on the surface of the water. On the other hand, exhausted migrating terrestrial birds could fall into the sea and thus become prey.