Seabirds are birds that spend most of their lives at sea, feeding on fish, squid, crustaceans, and other marine organisms.
However, they also facing many threats to their survival, such as habitat loss, overfishing, bycatch, invasive species, pollution, and diseases.
One of the main factors behind the decline of many seabird populations is plastic pollution, which is caused by the accumulation of plastic waste in the oceans from human activities, such as manufacturing, consumption, and disposal.
The consequences of plastic exposure for petrels
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Petrels are a group of seabirds that belong to the order Procellariiformes, which also includes albatrosses, shearwaters, and storm petrels, as per Phys.org.
These birds are characterized by their long wings, tubular nostrils, hooked bills, and salt glands. Petrels feed mainly on fish, squid, and crustaceans that they catch by diving or surface-seizing.
They breed in colonies on islands or coastal cliffs, where they nest in burrows or crevices.
According to the IUCN Red List, petrels are among the most threatened groups of seabirds in the world, with more than half of their species classified as vulnerable, endangered, or critically endangered as they face multiple threats, such as habitat loss, invasive predators, bycatch, climate change, and plastic pollution.
Plastic pollution poses a serious threat to petrels, as they are highly susceptible to ingesting plastic debris.
Petrels may mistake plastic fragments for prey items, or ingest plastic that has already been eaten by their prey, and may also be attracted to plastic debris by its color, shape, or smell.
Unfortunately, these birds have difficulty regurgitating plastic once swallowed, and may accumulate large amounts of plastic in their stomachs or intestines.
Ingesting plastic can have various negative impacts on petrels, such as reducing their stomach capacity, affecting their digestion, causing internal injuries, releasing toxins, or transmitting pathogens.
It can also affect their reproduction, as they may feed plastic to their chicks or use plastic as nest material, and ultimately increase their mortality, as they may die from starvation, poisoning, or infection.
Plastic exposure is not only a problem for petrels near human sources of plastic waste, but also for petrels in remote areas of the oceans where plastics accumulate due to ocean currents.
These areas are often rich in food resources for petrels, but also pose a high risk of plastic ingestion.
New Study Revealed The Hidden Plastic Threat To Seabirds
A new study published in the journal Royal Society Open Science has found that the world's most threatened seabirds visit remote plastic pollution hotspots, as per ScienceDaily.
The study was led by scientists from Brown University who used global tracking data to assess the plastic exposure risk for 77 species of petrel.
The new research used data from a large-scale collaborative bird banding program run by the Institute for Bird Populations.
The program tracked the movements of 7,137 individual birds from 77 species of petrel using satellite transmitters or geolocators attached to their legs or backs.
It collected data from 2001 to 2018, covering the entire range of petrel distribution across the oceans.
The paper overlaid the tracking data onto global maps of plastic distribution in the oceans, based on models that estimate the concentration of plastic debris at the sea surface using data from ship surveys and satellite imagery.
Through the study, experts were able to calculate the plastic exposure risk for each petrel species by multiplying the probability of encountering plastic by the duration of exposure.
The study found that plastic pollution threatens marine life on a scale that transcends national boundaries: a quarter of all plastic exposure risk occurs in the high seas, which are areas beyond national jurisdiction that cover about two-thirds of the ocean surface.
These areas are largely linked to gyres, where vast accumulations of plastics form, fed by waste entering the sea from boats, and from many different countries.
It also found that some petrel species are more exposed to plastic than others, depending on their foraging behavior, migration patterns, and habitat preferences.
The study identified 10 petrel species that have more than 50% of their plastic exposure risk in the high seas, including the critically endangered Newell's shearwater and the endangered black-capped petrel.
These species are among the most threatened seabirds in the world, and may face additional challenges from plastic pollution.
Pastic pollution exposes the world's most threatened seabirds to plastic debris in remote areas of the oceans, according to the study's findings.
The study also suggested that reducing plastic pollution requires international collaboration and action, as well as local efforts and awareness.
