Better the devil you know

This project contributes to wider PhD research, aiming to address the data gaps required for comprehensive status assessment of devil rays in the Indian Ocean and to facilitate effective evidence-based management. The objectives of this aspect of the study are to clarify taxonomy, investigate population structure, and define management units.

This project is unique in the data-poor species it focuses on in a region with recognised population declines. Devil rays have received less research and consequently conservation attention compared to manta rays, yet they also face increasing fishing pressure and exhibit decreasing population trends. Without access to the knowledge necessary to allow effective evidence-based management, no real difference will be made to ensure species’ survival. By defining management and conservation units, and making these data available to the scientific and management communities, this project has the capacity to make a tangible difference to both species and fisheries sustainability. Established collaborations across the Indian Ocean provides the unique opportunity to engage with researchers, managers, and communities on a large geographic scale, widening the project’s reach and maximising impact on an oceanic scale.

Devil rays are threatened by fisheries exploitation, both targeted and bycatch, exacerbated by an increasing international market for their gill plates. Devil ray skin, cartilage, and meat are also consumed and traded in local markets. Given their conservative life history, it is unlikely that current exploitation is sustainable. Consequently, all species have been added to CITES Appendix II and CMS Appendices I and II. Taxonomic uncertainty exists, with both eight and ten species proposed. Devil rays are highly mobile species, yet their movement patterns and population structure are poorly understood. Taxonomic clarification and population structure are required to define effective conservation and management units. Four or five devil ray species IUCN Red List classifications of endangered, near threatened, and data deficient are present in the Indian Ocean where they are caught in both industrial and small-scale fisheries (SSF). SSF are crucial for livelihood and food security in coastal communities across the Indian Ocean, many of which are located in developing countries where fisheries catch is the main source of protein. Defined conservation and management units are therefore crucial to ensure sustainable fisheries, protecting these vulnerable species and supporting local communities.

• To create a sampling network of established collaborators in ten countries across the India Ocean who will collect photographs, biological data (length measurements and sex), and tissue samples from devil ray species caught in key landing or market sites.
• To utilise the data and samples collected to clarify taxonomy and population structure for devil ray species in the Indian Ocean. The results will be used to propose effective conservation and management units for the species in this region.