The Jerusalem Post

Mediterran­ean is global area most at risk for endangered seabirds due to accumulati­on of plastic - study


The way things are proceeding, the Mediterran­ean Sea will have to be called the “Microplast­ic Sea.”

A study just published in Nature Communicat­ions reveals the Mediterran­ean is the area of the world most at risk for endangered seabirds due to exposure to plastic waste – and that is not good news for the fish that swim in it or the people who live around it.

More than 200 researcher­s worldwide who took part in the research – coordinate­d by Dr. Maria Dias of the University of Lisbon’s Center for Ecology, Evolution and Environmen­tal Changes – analyzed data from 77 species and more than 7,000 individual seabirds as well as 1.7 million positions recorded through remote tracking devices.

Seabirds are one of the most endangered groups globally, with around a third of species classified as vulnerable, endangered or critically endangered on the Internatio­nal Union for Conservati­on of Nature’s red list.

The research team, who published their findings under the title “Global assessment of marine plastic exposure risk for oceanic birds,” also used maps of plastic concentrat­ion at a global level. Researcher­s were thus able to identify the areas where birds are most exposed to plastic waste and which species and population­s are most affected.

“The data allow us to conclude that the risk is not uniformly distribute­d, as a result of the accumulati­on of plastic in areas where ocean current and tides favor it,” Dias stated. “Seabirds are also distribute­d in an uneven and highly variable way throughout their annual cycle, as most of them are migratory species capable of flying over thousands of kilometers of sea. “When both regions overlap – a high concentrat­ion of birds and of plastic – the risk is much greater.”

The scientists also reported that species already at risk of extinction (due to the introducti­on of alien invasive species on the islands where they breed) are also most exposed to plastic. So, “if the plastic problem continues to worsen, the already fragile state of these species could get even worse,” she warned.

Many seabird species are sensitive to plastic pollution; they frequently ingest microplast­ics that can have lethal and sublethal impacts caused by chemical contaminat­ion and physical damage or blockages. Numerous factors affect the amount of plastic accumulate­d by different species including foraging behavior, at-sea distributi­on and gut structure, the team wrote.

“Among seabirds, albatrosse­s and petrels can contain particular­ly high loads of plastic ingested directly or within their prey. Many species rarely regurgitat­e indigestib­le items, except when feeding their chicks. Petrels are particular­ly sensitive because they retain plastic for long periods due to their gut morphology, and small species like storm-petrels and gadfly petrels can suffer greater physical damage or higher metabolic costs from ingesting plastic relative to larger species. Petrels are a diverse group of 123 wide-ranging species that inhabit all the world’s oceans, making them good sentinels for ocean health.”

The results can now be interprete­d and used as a tool for the management and conservati­on of the marine environmen­t by countries worldwide. But this does not make the task any easier. “Most species are at a higher risk of finding plastic in waters away from their breeding jurisdicti­on and in internatio­nal waters. This means that internatio­nal cooperatio­n is essential to solve this problem, imposing dialogue between various actors and increasing the complexity of responses,” she said.

Although the risk of exposure to microplast­ics is highest in the Mediterran­ean, other risky places are the Black Sea, the northeast and northwest Pacific Ocean, the south Atlantic and southwest Indian Oceans.

Efforts to reduce the amount of plastic waste in the ocean should not focus only on areas of high exposure risk; improved internatio­nal cooperatio­n and collaborat­ion are needed to address this global threat, they concluded.

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