A global review of marine turtle entanglement in anthropogenic debris: A baseline for further action
Endangered Species Research
© The authors 2017. Open Access under Creative Commons by Attribution Licence. Use, distribution and reproduction are un - restricted. Authors and original publication must be credited.
Entanglement in anthropogenic debris poses a threat to marine wildlife. Although this is recognised as a cause of marine turtle mortality, there remain quantitative knowledge gaps on entanglement rates and population implications. We provide a global summary of this issue in this taxon using a mixed methods approach, including a literature review and expert opinions from conservation scientists and practitioners worldwide. The literature review yielded 23 reports of marine turtle entanglement in anthropogenic debris, which included records for 6 species, in all ocean basins. Our experts reported the occurrence of marine turtles found entangled across all species, life stages and ocean basins, with suggestions of particular vulnerability in pelagic juvenile life stages. Numbers of stranded turtles encountered by our 106 respondents were in the thousands per year, with 5.5% of turtles encountered entangled; 90.6% of these dead. Of our experts questioned, 84% consider that this issue could be causing population level effects in some areas. Lost or discarded fishing materials, known as 'ghost gear', contributed to the majority of reported entanglements with debris from land-based sources in the distinct minority. Surveyed experts rated entanglement a greater threat to marine turtles than oil pollution, climate change and direct exploitation but less of a threat than plastic ingestion and fisheries bycatch. The challenges, research needs and priority actions facing marine turtle entanglement are discussed as pathways to begin to resolve and further understand the issue. Collaboration among stakeholder groups such as strandings networks, the fisheries sector and the scientific community will facilitate the development of mitigating actions.
The authors thank all respondents of the questionnaires for their invaluable knowledge and insights regarding this issue. We are grateful to Karen Eckert of WIDECAST for granting access to turtle graphics. E.M.D. received generous support from Roger de Freitas, the Sea Life Trust and the University of Exeter. B.J.G. and A.C.B. received support from NERC and the Darwin Initiative, and B.J.G. and P.K.L. were funded by a University of Exeter — Plymouth Marine Laboratory collaboration award which supported E.M.D. We acknowledge funding to T.S.G. from the EU Seventh Framework Programme under Grant Agreement 308370, and P.K.L. and T.S.G. received funding from a NERC Discovery Grant (NE/L007010/1). This work was ap proved by the University of Exeter, CLES ethics committee (Ref. 2017/1572).
This is the final version of the article. Available from Inter Research via the DOI in this record.
Vol. 34, pp. 431 - 448