No accumulation of microplastics detected in western Canadian ringed seals (Pusa hispida).

Ringed seals (Pusa hispida) play a crucial role in Arctic food webs as important pelagic predators and represent an essential component of Inuvialuit culture and food security. Plastic pollution is recognized as a global threat of concern, and Arctic regions may act as sinks for anthropogenic debris. To date, mixed evidence exists concerning the propensity for Canadian Arctic marine mammals to ingest and retain plastic. Our study builds on existing literature by offering the first assessment of plastic ingestion in ringed seals harvested in the western Canadian Arctic. We detected no evidence of microplastic (particles ≥80 µm) retention in the stomachs of ten ringed seals from the Inuvialuit Settlement Region (ISR) in the Northwest Territories, Canada. These results are consistent with previous studies that have found that some marine mammals do not accumulate microplastics in evaluated regions.

Annual plastic ingestion and isotopic niche patterns of two sympatric gull species at Newfoundland, Canada.

Ingestion of plastic pollution by pelagic seabirds is well-documented globally, but increasingly, researchers are investigating plastic ingestion in generalist predators and scavengers like gulls. We studied the gut contents of two sympatric gull species, American herring gulls (Larus smithsoniansus) and great black-backed gulls (L. marinus), collected year-round as part of "kill-to-scare" measures at the regional sanitary landfill in St. John's, Newfoundland and Labrador, Canada, to compare ingested anthropogenic debris, trophic position and diet breadth through the year. Although great black-backed gulls fed at a higher trophic level, frequency of occurrence of plastic ingestion was similar to American herring gulls, and varied little through the year. Diet breadth (isotopic niche size) was similar between species, but American herring gulls fed at a lower trophic level during winter, perhaps indicating a change in their reliance on anthropogenic food subsidies throughout their annual cycle.