Microplastics on the Menu: Plastics Pollute Indonesian Manta Ray and Whale Shark Feeding Grounds

Plastic pollution, particularly microplastics, poses significant threats to marine ecosystems, yet its impact on filter-feeding megafauna remains understudied. A study conducted in Komodo National Park and nearby coastal areas of Indonesia revealed alarming levels of plastic contamination in the feeding grounds of manta rays (Mobula alfredi) and whale sharks (Rhincodon typus). Researchers found that plastic abundance varied widely, with up to 44 times more microplastics during the wet season compared to the dry season. Small plastic pieces dominated the debris, and theoretical ingestion rates suggested manta rays could consume up to 63 pieces per hour in Nusa Penida and 25 pieces per hour in Komodo, while whale sharks faced even higher exposure in Java. The study used a combination of trawl surveys and visual transects to sample microplastics and larger floating plastics, confirming plastic ingestion in manta rays through analysis of their egested material. These findings highlight the urgent need for local governments to address plastic pollution to protect these critical marine species.

Germanov, E. S., Marshall, A. D., Hendrawan, I. G., Admiraal, R., Rohner, C. A., Argeswara, J., Wulandari, R., Himawan, M. R., & Loneragan, N. R. (2019). Microplastics on the Menu: Plastics Pollute Indonesian Manta Ray and Whale Shark Feeding Grounds. Frontiers in Marine Science, 6. https://doi.org/10.3389/fmars.2019.00679