ORCID
- Joanna Harris: 0000-0001-8684-9096
Abstract
Remote islands receive plastic debris from elsewhere, ranging from microplastics (>5 mm) to macroplastics, which can further breakdown into microplastics. The ingestion of microplastics by marine species has been linked to decreased fitness. Reef manta rays, Mobula alfredi, are liable to ingest microplastics due to their filter-feeding strategy and habitat overlap with plastic hotspots. Their population is in decline due to unsustainable fishing pressures and a slow life history, with potential additional demographic pressure from plastic pollution. This study investigates the concentration and characteristics of microplastics in the top 0.5 m of the water column in reef manta rays feeding areas around the Chagos Archipelago, a large remote marine protected area that is highly contaminated by macroplastic debris. Across all samples, a mean of 1.1 microparticle/m3 was found, the majority of which were blue and black fibers. Half of the particles were confirmed as synthetic (53.6%, n = 305 out of 569 Fourier transform infrared spectroscopy'd particles), with the main synthetic polymers being polyester (21.1%), polypropylene (8.8%) and nylon (4.6%). Egmont Atoll, an International Union for Conservation of Nature “Important Shark and Ray Area” for its importance to reef manta rays, was the most contaminated atoll around the archipelago (1.6 microparticle/m3). Continued regular beach cleans in important areas for biodiversity are recommended, as well as implementing new methods to reduce local input of microplastics, such as washing machine filters, and ultimately a global continued effort to reduce plastic usage and improve its disposal.
DOI Link
Publication Date
2025-05-25
Publication Title
Conservation Biology
ISSN
0888-8892
Acceptance Date
2025-04-08
Deposit Date
2025-07-31
Funding
We are grateful for logistical support provided by BF BIOT and NAV‐FAC PWD DG Environment Department, in particular, the Environmental Officers Milly Fellows, Lindsey Hollingsworth, and Caroline Gittings for logistic and sampling support. The research was conducted under permit numbers 0006SE22 for the June–July 2022 expedition and 0004SE24 for the January 2024 expedition. This work was supported by the Bertarelli Foundation as part of the Bertarelli Programme of Marine Science (grant number BPMS‐2017‐4), and we thank Rachel Jones, Fiona Llewellyn, Coretta Granbury, Emma Levy, Clara Diaz, and Isha from the Marine.Science programme for logistics and sampling support. This work was also supported by Natural England Research Council as part of the London NERC Doctoral Training Programme studentship (grant number of J. Savage: NE/S007229/1), Zoological Society of London, and Royal Holloway University of London Doctoral School Travel Grant. We are grateful to Dr. Wren Montgomery (Imaging and Analysis Centre, Natural History Museum, London) for providing training and access to FTIR spectroscopy equipment, as well as Dr. Paul Clark for facilitating access. We also thank Dr. Neil Morley at Royal Holloway University of London for laboratory support.
Keywords
elasmobranch, filter-feeder, island conservation, marine pollution, marine protected area, microplastic
Recommended Citation
Savage, J., Harris, J., Koldewey, H., Letessier, T., Rowcliffe, M., & Morritt, D. (2025) 'No escape from microplastics: Contamination of reef manta ray feeding areas in a remote, protected archipelago', Conservation Biology, . Available at: 10.1111/csp2.70059
