Endangered birds suffer from plastic waste in the sea – 7/6/2023 – Environment

Around 1 in 4 of endangered seabird species suffer from high plastic accumulation in the oceans where they inhabit. In these areas, the risk of exposure to plastic can affect up to half of the animals observed, including critically endangered species.

About a quarter of all plastic pollution is in offshore areas, which are the preferred feeding grounds for these birds.

Many of them are migratory and travel long distances during breeding season to find a suitable place to nest. Along the way, they may have contact with this high accumulation of plastic waste in the oceans.

These conclusions are in a study conducted by 200 scientists in 27 countries, published last Tuesday (4), in the specialized journal Nature Communications. The survey included institutions from the United Kingdom, Italy, France, Australia, New Zealand and Brazil, among other countries, and BirdLife International, the largest organization to support bird conservation.

The study monitored 7,137 adult individuals of 77 species of petrels, a group of seabirds that currently comprises 123 species with a global distribution in all oceans. Approximately half (64) of the species in the group are classified as vulnerable or near vulnerable, 16 are endangered and another 12 are critically endangered, according to the IUCN (International Union for Conservation of Nature).

According to the researchers, the animals’ anatomy and the fact that they are long-distance migratory birds put them at greater risk for ingesting plastic found in the oceans, even in remote places like the islands of the Pacific Northwest.

To analyze the risk of exposure to plastic, the scientists estimated the areas with the highest density of this type of garbage in the sea from 1995 to 2020. Then, they crossed the plastic density estimates with the birds’ locomotion data, thus obtaining a level of exposure risk.

Of the total species studied, at least 19 (24.6%) are considered to be at very high risk from plastic exposure, including the critically endangered Mediterranean Shearwater (Puffinus mauretanicus), Newell’s Shearwater (Puffinus newelli) and Hawaiian petrel (Pterodroma sandwichensis), as well as threatened as the Yelkouan shearwater (puffinus yelkouan), Cook’s petrel (pterodroma cookii) and spectacled petrel (Procellaria conspicillata).

The highest risk places for plastic exposure include the Mediterranean and Black Seas, the Northwest Pacific, the Northeast Pacific, the South Atlantic and the Southwest Indian Ocean. The last three are part of the so-called ocean gyres, which are regions of high concentration of plastic waste in the sea.

Finally, as the birds are migratory and visit different places during the breeding seasons, the researchers calculated whether the risks of plastic exposure would be the same. What they observed is that some of the species with a low risk of exposure to plastic content during the migratory phase had a high risk in the breeding grounds.

This is the case of the big jester (Calonectris diomedea), a species of petrel that migrates during the winter to the eastern Atlantic, where there is low exposure to plastic waste, but breeds in Malta, in the middle of the Mediterranean, a region with a high concentration of pollution.

For Bethany Clark, a researcher at BirdLife International and first author of the study, the little knowledge we have about some of the species that inhabit remote islands in the Pacific limits the work, which must now investigate the association between exposure, ingestion and impact.

“It is important that plastic ingestion and tracking studies in areas with little data, such as Southeast Asia and parts of the Pacific, are also encouraged in the future, including places where these birds are difficult to study but are still affected by activity. human,” he said.

The authors of the article emphasize, however, that the high risk of exposure to plastic does not necessarily indicate the ingestion of the material. In reality, studies that monitor feeding behavior and the ingestion of plastic waste and toxic substances by birds are complex and there is little global data, which makes the standardization of this type of information more difficult.

As most birds have the feeding behavior of regurgitating the contents directly into the mouths of the chicks, the plastic exposure of the chicks depends on the type of exposure of the parents during the reproductive period, explains Clark.

“It is difficult to accurately calculate lifetime risk, but long-term studies can be very valuable in this regard,” he says.

Ana Carneiro, a Brazilian who is a researcher at BirdLife International and also participated in the study, points out that the study is unique in identifying the so-called “hotspots” (regions of high plastic concentration) that can determine public conservation policies.

“Detecting the highest risk areas was only possible with the sharing of information and the collaboration of more than 200 scientists together with the Seabird Tracking Database [coleção internacional de dados]”, he explains.

As for Brazil, according to Clark, although the country has a relatively lower risk, some coastal regions present a high risk of plastic exposure, especially towards the south, including places that are important for endangered seabirds, such as the Eurasian petrel. spectacled petrel, the Atlantic petrel (critically endangered) and the Trinidad petrel (endangered).

“Further research on solutions to reduce plastic in the seas would be valuable, including reducing the use of disposables, improving recycling and waste management, and creating specific legislation that prohibits the disposal of plastic from vessels,” he said.