Total mercury (Hg) concentrations were measured in archived fur from adult female little brown bats sampled at maternity roosts across Atlantic Canada. Mercury concentrations varied significantly among regions and roosts. Bats from Nova Scotia and Newfoundland had the highest median Hg concentrations (9.67 μg/g and 9.51 μg/g) among regions, and individuals from Kejimkujik National Park had the highest Hg (median: 28.38 μg/g) among roosts. Over one third of individuals sampled had fur Hg concentrations exceeding thresholds associated with neurochemical responses. Within-roost examinations of stable carbon and nitrogen isotopes in fur showed inconsistent associations with Hg concentrations. Therefore, the hypothesis that within-roost variation in Hg is driven by variation in diet is not supported by this data, and it is recommended that key prey items be included in future mercury bioaccumulation studies for bats. The elevated mercury fur concentrations for bats from southern Nova Scotia remains an anomaly of concern even when placed in the larger context of Atlantic Canada.

Quantification of plastic ingestion across a range of seabirds is required to assess the prevalence of plastics in marine food webs. We quantified plastic ingestion in beached Dovekies (Alle alle), following a wreck in Newfoundland, Canada. Of 171 birds, 30.4% had ingested plastic (mean 0.81±0.30 SE pieces per bird, mass 0.005±0.002 SE g per bird). Most plastics were fragments of polyethylene and polypropylene. Surprisingly, 37% were burned or melted, indicating a previously unreported source of ingested plastics (incinerated waste). We found no relationship between plastic ingestion and age, sex or body condition. By comparing our results with a similar nearby study, we illustrate the need for researchers to adopt standardized methods for plastic ingestion studies. We underline the importance of using histological techniques to reliably identify gastric pathologies, and advise caution when inferring population level trends in plastic ingestion from studies of emaciated, wrecked birds.

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 Here, we combined previously unpublished data on plastic ingestion (from the 1980s to the 1990s) with contemporary samples (2011–2012) to evaluate changes in murres’ plastic ingestion.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.

Most anthropogenic marine debris shoreline studies are conducted on sandy shores, rather than rocky coastlines. We amended a standardized protocol for monitoring marine debris on a high-loading beach composed of small rocks and cobbles in Newfoundland, Canada. Our protocol had two parts: we conducted stratified sampling to a depth of ~20cm below the surface of the rocks (standing survey), and surveyed accumulation of items on the surface of rocks every other day (loading survey). We found the vast majority of smaller items were below the surface. Only 17.2% of debris were microplastics (<5mm). Types of anthropogenic debris differed significantly between the standing survey and the loading survey. We found no relationship between either wind direction or wind speed, and distributions of debris. This study allows for a better understanding of marine debris detection along rocky coasts, and the limitations of protocols for studying them.