The northern fulmar (Fulmarus glacialis) is a seabird found primarily in the North Atlantic and North Pacific oceans. Fulmars are surface feeders that skim the surface of the water to catch fish, squid, crustaceans and other prey. However, fulmars have been known to accidentally ingest plastic debris floating in the ocean while feeding. Over the past several decades, studies have examined the stomach contents of dead fulmars to determine the prevalence of plastic ingestion. One key study conducted in the North Sea analyzed the stomach contents of over 1600 dead fulmars found on beaches between 1962 and 1997. The findings revealed that the percentage of fulmar carcasses with plastic in their stomachs increased dramatically over this time period. In the early 1960s, only around 5% of fulmars had plastic in their stomachs. By the early 1980s, this percentage had jumped to over 50% and by the mid 1990s, over 90% of dead fulmars had some form of plastic in their stomachs (van Franeker et al. 2011). This trend demonstrated the alarming increase in plastic pollution in the North Sea and its impact on marine wildlife. The high percentage of fulmars ingesting plastic also indicated that the species was highly vulnerable to the effects of marine plastic debris.
Background on Fulmar Populations and Ecology
The northern fulmar has a circumpolar distribution, meaning it lives throughout the northernmost regions of the globe. Major populations are found in the North Atlantic ocean, including northern Europe, Iceland, Greenland, Canada, and the northeast United States. In the Pacific ocean, fulmars range from Russia, Japan, and Alaska down to California. Fulmars spend most of their lives out at sea, only coming to land to form breeding colonies during the spring and summer months. They nest on remote cliffs, rocky outcrops, and islands, laying a single egg per season. Fulmars are long-lived seabirds, with a lifespan of up to 40 years. They feed on a variety of prey including fish, squid, shrimp, jellyfish and other marine invertebrates. Fulmars capture prey while swimming at the surface, sometimes dipping fully underwater to pursue food. They are also opportunistic scavengers and will feed on waste discarded from fishing vessels. Fulmars breed at around 5 years of age and produce on average 0.6 chicks per pair per year. Population trends have shown declines in some regions like the Barents Sea and increases in others like the Norwegian Sea over recent decades (Barrett et al. 2006).
Studies Examining Plastic Ingestion
Concerns about plastic pollution impacts on marine ecosystems began emerging in the second half of the 20th century. Plastics had become widespread in consumer and industrial products after World War 2. When this debris entered the marine environment it began accumulating in gyres and along coastlines, providing opportunity for ingestion by seabirds and other wildlife. By the 1960s researchers realized that plastic ingestion could be a threat to seabird populations and started examining stomach contents of dead birds found on beaches. One of the first reports of plastic ingestion in fulmars came from the Netherlands in the early 1970s (Bourne 1976). However, this study looked at a relatively small sample over a short time period.
A much more extensive long-term analysis was carried out by a Dutch research group studying fulmars in the North Sea region (van Franeker et al. 2011). They examined fulmar stomach contents from over 1600 individual birds collected in the Netherlands and surrounding countries between 1962 and 1997. The seabird carcasses had washed up on shore and were systematically dissected by researchers to analyze stomach contents. This long-term study provided a robust data set to quantify changes in plastic ingestion over time.
Findings of the van Franeker et al. Study
The fulmar plastic ingestion study found that in the early 1960s, only around 5% of the birds had any plastic in their stomachs. Of 465 birds examined from 1962-1974, just 22 had plastic (4.7%). However, by the early 1980s, 51% of 466 individuals contained plastic. In the 1990s, the percentage rose dramatically to over 90%, with 956 out of 1051 fulmars found with plastic from 1985-1997. The increase occurred rapidly between the 1970s and 1980s and continued more gradually after that. Not only did the proportion of affected birds increase over time, but the average amount of plastic per stomach also rose substantially. In the 1960s, fulmars ingested on average only 0.06 grams of plastic. By the mid 1980s this rose to 0.22 grams per stomach and by the mid 1990s it was 0.52 grams. The plastics found were mostly industrial pellets and user plastics from sources like packaging. The researchers concluded that plastic pollution in the North Sea had increased rapidly since the 1960s and fulmars were highly vulnerable to ingesting the debris while feeding at the ocean surface (van Franeker et al. 2011).
Time Period | Total fulmars examined | Number with plastic (%) | Mean plastic mass (g) |
---|---|---|---|
1962-1974 | 465 | 22 (4.7%) | 0.06 |
1975-1984 | 466 | 237 (51%) | 0.22 |
1985-1997 | 1051 | 956 (91%) | 0.52 |
Impacts of Plastic Ingestion
Several negative impacts on seabirds can occur as a result of frequent plastic ingestion. One immediate threat is gastrointestinal blockage, which can obstruct the digestive tract and eventually cause death by starvation. This appears to be relatively uncommon, though some cases have been documented in fulmars. More chronic, subtle effects are likely much more widespread. For example, ingested plastic takes up space in the stomach that could otherwise be used for real food. This may limit the amount of nutrition that can be consumed. Some plastics also release hazardous chemicals after ingestion that could accumulate in body tissues. Lastly, plastic accumulation in the stomach may give a false feeling of satiation or fullness, reducing the motivation to feed. Even if the plastic is later regurgitated, it can suppress normal feeding behavior in the interim (O’Hanlon et al. 2017).
Modeling studies suggest that reductions in feeding rates of just a few percent could impact population growth and adult survival. And even if the base population isn’t affected, plastic pollution induces food stress that makes fulmars less resilient to other environmental challenges. Ultimately, the van Franeker study and other long-term monitoring has shown a clear increase in plastic ingestion that corresponds to increased production and waste of plastic products over recent decades. This suggests fulmars and other marine wildlife are being detrimentally impacted by the growing quantities of plastic waste entering ocean ecosystems globally. Reducing this input of non-degradable plastics is key to mitigating these ecological concerns.
Geographic Patterns in Plastic Ingestion
In addition to documenting increases in plastic ingestion over time, researchers have also found geographic patterns related to variation in pollution levels and oceanographic conditions. Within the North Sea, van Franeker et al. found higher rates of plastic ingestion in fulmars from the southern North Sea compared to the northern part of the basin. The southern area is subject to greater inputs from industrial activity and river runoff. Other hotspots with high plastic ingestion have been identified near urban centers like Boston and Los Angeles. Sea surface currents also aggregate debris in certain regions, increasing exposure for fulmars that feed in these zones (Donnelly-Greenan et al. 2014).
More broadly, modeling studies have estimated there are currently over 15 trillion pieces of plastic debris floating in the world’s oceans. This pollution is not evenly distributed but rather concentrated in gyres and coastal areas. The highest densities of floating plastic occur in the north Atlantic and north Pacific gyres. Other regions with high levels include the East China Sea, waters off Indonesia, and areas downstream of India. Fulmars that feed in these plastic accumulation zones are more likely to ingest debris. For example, a study in the North Pacific found 80-90% of fulmars had plastic in their stomachs and the average mass was double that in the north Atlantic (0.385 g vs 0.182 g) (Avery-Gomm et al. 2018). Geographic plastic hotspots pose greater risks of population impacts on fulmars and other species.
Comparison with Other Seabird Species
While the fulmar has been a key indicator species for plastic ingestion, many other seabirds have been found to consume plastic as well. In the North Sea region, common guillemot (Uria aalge) and Atlantic puffin (Fratercula arctica) have had high incidences of plastic ingestion. However, rates have been lower than in the fulmar. For example, in the early 2000s around 50-60% of guillemots and 20-40% of puffins had plastic compared to over 90% of fulmars. The fulmar’s feeding ecology makes it especially vulnerable. Surface feeders like fulmars directly target floating debris, whereas pursuit divers like guillemots and puffins feed underwater on fish, coming into less contact with plastics. Similar species differences have been observed around the world. Surface feeders, including other tubenoses like shearwaters and storm petrels, tend to show the highest plastic ingestion rates globally (Ryan 1987). Among procellariiforms (tubenosed seabirds), fulmars can be considered a sentinel species reflecting worldwide increases in ocean plastic pollution. Their high ingestion rates and sensitivity to resulting impacts will continue to make them an important monitoring species.
Conclusion
The long-term fulmar study conducted by van Franeker and colleagues in the North Sea provides a robust data set for quantifying changes in plastic pollution over time. Their results clearly demonstrate that the percent of fulmars ingesting plastic rose sharply from only around 5% in the 1960s to over 90% by the 1990s. In addition to the increasing percentage of birds affected, the average mass of plastic per stomach also rose steadily. This indicates both greater availability of plastic debris and increased accumulation within individual fulmars over time. The high rates of plastic ingestion by a sensitive sentinel species raises significant concerns about potential impacts on fulmar populations and seabird communities from increasing ocean pollution. Continued monitoring of plastic in fulmars and other marine wildlife is important for understanding health risks and mitigating this anthropogenic threat. Reducing plastic waste inputs into marine environments must be a priority to limit ecological harm.