Ingestion of plastic marine debris by Common and Thick-billed Murres in the northwestern Atlantic from 1985 to 2012.

Plastic ingestion by seabirds is a growing conservation issue, but there are few time series of plastic ingestion with large sample sizes for which one can assess temporal trends. Common and Thick-billed Murres (Uria aalge and U. lomvia) are pursuit-diving auks that are legally harvested in Newfoundland and Labrador, Canada. Here, we combined previously unpublished data on plastic ingestion (from the 1980s to the 1990s) with contemporary samples (2011-2012) to evaluate changes in murres' plastic ingestion. Approximately 7% of murres had ingested plastic, with no significant change in the frequency of ingestion among species or periods. The number of pieces of plastic/bird, and mass of plastic/bird were highest in the 1980s, lowest in the late 1990s, and intermediate in contemporary samples. Studying plastic ingestion in harvested seabird populations links harvesters to conservation and health-related issues and is a useful source of large samples for diet and plastic ingestion studies.