Plastic ingestion by harbour seals (Phoca vitulina) in The Netherlands

► Harbour seals from the Netherlands were examined for ingested debris. ► Combined for stomachs plus intestines, 12.2% of 107 seals had ingested plastic. ► The observed level of plastic ingestion is of environmental concern. ► Dutch seals live in a relatively polluted area. ► This indicates that incidence may be too low for EU regional monitoring. Abundance of ingested debris by seals has been mentioned as a potential indicator of marine litter in the European Marine Strategy Framework Directive (MSFD). A sample of 107 stomachs, 100 intestines and 125 scats of harbour seals from the Netherlands was analysed for the presence of plastics. Incidence of plastic was 11% for stomachs, 1% for intestines, and 0% for scats. Younger animals, up to 3years of age, were most affected. This is the first quantitative study of plastic ingestion by phocid seals. The observed level of incidence is of environmental concern, but is low in the sense of suitability of seals for MSFD monitoring purposes.