ESR prepress abstract  -  DOI: https://doi.org/10.3354/esr00964

A global review of shark and ray entanglement in anthropogenic marine debris

Kristian J. Parton*, Tamara S. Galloway, Brendan J. Godley

*Email: kp336@exeter.ac.uk

ABSTRACT: Numerous marine taxa become entangled in anthropogenic marine debris, including cartilaginous fishes (Class Chondrichthyes e.g. elasmobranchs: sharks, skates and rays, holocephalans: chimaeras). Here we review research that has been conducted on the susceptibility of these taxa to entanglement in marine debris by conducting a systematic literature review complemented by novel data collection from the social media site ‘Twitter’”. Our literature review yielded 47 published elasmobranch entanglement events (N = 557 animals) in 26 scientific papers, with 16 different families and 34 species in all 3 major ocean basins affected. The most common entangling objects were ghost fishing gear (74% of animals), followed by polypropylene strapping bands (11% of animals) with other entangling materials such as: circular plastic debris, polythene bags and rubber tyres comprising 1% of total entangled animals. Most cases were from the Pacific and Atlantic Oceans (49% & 46%, respectively) with a bias towards the USA (44% of animals), the UK (30% of animals) and South Africa (10% of animals). While investigating Twitter, we found 74 cases of elasmobranch entanglement, representing 14 families and 26 species. On Twitter, ghost fishing gear was again the most common entangling material (94.9% of animals), with the majority of entanglement records originating from the Atlantic Ocean (89.4% of total entangled animals). Entanglement in marine debris is symptomatic of a degraded marine environment and is a clear animal welfare issue. Our evidence suggests, however, that this issue is likely a far lesser threat to this taxon than direct or indirect take in marine fisheries. We highlight, however, a relative paucity of scientific data on this subject and recommend a standardisation of reporting in an attempt to accurately quantify elasmobranch entanglement risks and locate interaction hotspots.