Endangered Mediterranean Seabirds Threatened by Plastic Pollution

It turns out that seabirds don't just have to worry about fishing lines and nets; they also have to deal with plastic pollution. About 94 percent of Cory's shearwaters on the Catalan coast are impacted by plastic ingestions.

"This is the first assessment of plastic ingestion in Mediterranean seabirds," said Jacob Gonzalez Solis, one of the researchers, in a news release. "The Mediterranean Sea has been recognized as a singularly sensitive ecosystem because its coast is very industrialized, shipping activity is intense and it contains high density floating plastic areas."

Floating plastic in the ocean can be eaten by seabirds, mistaken for actual food. This plastic can cause a host of health issues for birds, and can eventually kill them. Not only that, but plastics can drastically impact chicks, who can't regurgitate like adults do.

In order to make this assessment of how much plastic birds eate, the researchers analyzed 171 birds accidentally caught by fishing lines in the Catalan coast from 2003 to 2010. The scientists took these seabirds and studied how much plastic they ate; in all, they studied nine particularly endangered seabird species, including Cory's shearwater, Yelkouan shearwater, Balearic shearwater, gannet, Audouin's gull, Mediterranean gull, yellow-legged gull, black-legged kittiwake and great skua.

The researchers found that 66 percent of these seabirds had at least one piece of plastic in their stomachs. Not only that, but Cory's shearwaters were the worst affected with 94 percent containing plastics. A total of 70 percent of Balearic shearwaters and Yelkouan shearwaters had plastic.

"Results are alarming," said Solis in a news release. "All three of the worst affected are of conservation concern, particularly the Balearic shearwater, which is listed as critically endangered by the International Union for Conservation of Nature (IUCN). It is a Balearic endemic species; there are only around 3,000 breeding pairs in the world. We do not know its impact but it is necessary to study if it affects populations in a negative way."

The findings are published in the journal Marine Pollution Bulletin.