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Updated: Oct 1, 2025
Protocol for Microplastics Sampling on the Sea Surface and Sample Analysis
Published on: December 16, 2016
Using a non-invasive technique to identify suspected microplastics in grey seals (Halichoerus grypus) living in the
Lucas Desclos-Dukes1, Andrew Butterworth2, Tristan Cogan1
1University of Bristol, Bristol Veterinary School, Langford, Bristol, UK.
Background:
Plastic pollution is of growing concern in marine ecosystems worldwide. Specifically, microplastics (<5 mm) may interact with a variety of biota with the potential to cause harm to organism health. Studies investigating microplastics are increasing, yet their occurrence within free-ranging and living marine mammals remains largely unexplored.
Methods:
By using a protocol involving enzymatic digestion, filtration and microscopic identification, faecal samples collected from a grey seal (Halichoerus grypus) haul-out site in the North Sea were investigated for microplastic presence.
Results:
Altogether, 71 suspected microplastic particles, consisting of both fibres and fragments in a variety of colours and sizes, were identified across 66 analysed faecal subsamples.
Conclusion:
The present study indicates that marine mammals are ingesting microplastics and that faecal material can be used to indirectly and non-invasively record microplastic uptake data in pinnipeds. Since the current paper is the first to document potential microplastic exposure among wild, living and free-ranging grey seals of the western North Sea, further research is needed to begin to understand the biological significance of these findings.
