The impact of plastic pollution in the Indian Ocean on filter-feeding megafauna, particularly reef manta rays (Mobula alfredi)

Plastic is ubiquitous in the environment and is known to have major negative impacts on marine ecosystems. Marine organisms can entangle in discarded fishing gear, ingest plastic debris, and accumulate leached toxic chemicals in their systems, which can affect their development and physiology. Reef manta rays are large charismatic filter-feeders, that are exposed to those risks, due to their low trophic level and their habitat overlap with plastic pollution. They could therefore act as indicators of the sea health. This project will use plastic dispersion models to examine the sources, pathways and sinks of macro- and microplastic pollution in the Central Indian Ocean, focussing on the British Indian Ocean Territory (BIOT), a near-pristine remote island, the Maldives, a highly touristic location, and Indonesia, the largest plastic polluter in the area. It will then investigate the reef manta ray's risk of entanglement in discarded fishing gear and microplastic ingestion. It will finally develop a methodology to explore the presence of leached toxic plastic additives in reef manta ray tissues and their feeding grounds. We hope this project will allow us to assess the current plastic pollution management solutions in the Central Indian Ocean and inform potential mitigation policies and initiatives.