Large numbers of by-caught seals have been reported in set-net gears along south and west coasts of Ireland. These seals are a good source of data to investigate the ecology and health status of one of the most common top predators in Irish waters. Between 2012 and 2015, 14 digestive tracts (stomach and intestines) from by-caught seals recovered from trammel nets targeting monkfish and rays off the south coast were analysed. Routinely, the diet analysis and parasitic infection were performed (see other presentations), and as a novel study anthropogenic debris occurrence was also investigated. Microplastic separation and identification was carried out following previous methodology used in other marine mammal studies in Ireland. The incidence of microplastic was found to be over 80% of the seals, were fibres were the most common microplastic item found. We hypothesized two sources of microplastic ingestion: 1) trophic transfer through their prey, and 2) the ingestion of net fibres from the nets as they have been reported actively depredating fish from static gear.