Ghost fishing gear entanglement on loggerhead sea turtles (Caretta caretta) in the Mediterranean Sea

Abstract

[eng] Abandoned, lost, or otherwise discarded fishing gear (ALDFG) is one of the deadliest forms of anthropogenic debris in the marine environment. In this study, we examined the reasons for the stranding of sea turtles in the Balearic Sea. Despite entanglement causing the lowest mortality rate in comparison to the other causes, an increasing trend of their incidence was detected. We categorized the types of marine litter causing entanglement (n=110) into 7 groups. The most prevalent forms of ghost gear were fish aggregating devices (FADs) (n=47). A backtracking approach was utilized to identify the potential origin of the ghost FADs found in the Balearic Sea and general ALDFG in the Western Mediterranean Basin. Visual marks and backtracking suggest there was a large proportion of ghost FADs originated in Algerian Exclusive Economic Zones (EEZ). Nevertheless, ALDFG is present across all the Western Mediterranean, and their sources potentially involve every coastal country. Overall, the study highlights the need to address the increasing rate of ghost FADs in conservation plans at a regional level.