Colonial seabirds have been used for decades as sentinels of the health of the marine environment, because they integrate changes in marine ecosystems through their diets and physical condition, and then reflect this in physiological metrics or reproductive effort and success. In the Canadian Arctic, seabirds are found in a few relatively large colonies, and must contend with sea-ice covering their foraging areas for much of the year, which places constraints on them not experienced by conspecifics or similar species breeding farther south. However, the marine environment is changing in the Arctic, and seabirds are responding. The northern fulmar (Fulmarus glacialis) is a medium-sized petrel that breeds in the Canadian Arctic in cliff-side colonies of several thousand pairs. They are opportunistic, generalist foragers with an advanced sense of smell, and can travel hundreds of kilometers to locate food. Their diet can consist of zooplankton, fish, marine mammal carcasses, and fisheries discards, and varies seasonally (typically feeding lower in the food web in winter) and regionally (typically consuming more fisheries discards in the northeastern Atlantic). Fulmars are also vulnerable to ingesting plastic debris in the ocean. They can mistake pieces of plastic as food and ingest it directly, or they can ingest it through trophic transfer by eating prey that in turn have consumed plastic. Northern fulmars are monitored across the North Atlantic for plastic ingestion rates, and are the only biomonitor of plastic debris in Canada. Previous studies in the Canadian Arctic have demonstrated that fulmars eat proportionally more invertebrates if they inhabit the high Arctic compared to birds at low Arctic colonies, and that there appears to be a pattern in eastern Canada with a lower frequency of plastic occurrence in fulmars breeding at higher latitudes. As environmental conditions change in the Arctic (increased shipping, sea-ice breaking up sooner and forming later, warming oceans), scientists expect this to be reflected through dietary changes in seabirds such as fulmars. Warming conditions may lead to a greater proportion of fish than invertebrates in their diet, along with more plastic because it is expected to continue to spread into Arctic waters. In this thesis, I examined diet and frequency of occurrence of plastic debris in northern fulmars collected by Inuit hunters at two colonies in Nunavut, Canada: Qikiqtarjuaq and Pond Inlet. I found that the diet was dominated by fish and squid, contrasting earlier studies in the region showing proportionally more invertebrate prey. I also found that plastic debris had been ingested by fulmars, but at a lower frequency of occurrence than in earlier studies. However, my power analysis demonstrated that I would need to sample more than triple the amount of birds to confidently detect a trend in numbers of fulmars containing plastic. Overall, my results suggest interannual and regional differences in diet and plastic ingestion rates by northern fulmars, but additional monitoring is required to determine if this likely reflects typical, interannual variation, or in fact a directional trend, likely influenced by habitat degradation through climate change and the proliferation of marine plastic pollution.
Call Number
LE3 .A278 2025
Date Issued
2025
Supervisor
Degree Name
Master of Science
Degree Level
Masters
Degree Discipline
Affiliation
Abstract
Publisher
Acadia University