But slicing open defrosted stomachs, some over a decade old, is no easy feat\u2014you need a strong stomach of your own. \u201cSome of them had parasitic roundworms and those were a bit smellier than the others,\u201d says Bourdages.<\/p>\n
While 31 seal stomachs turned out to be empty, several were full of either tiny crustaceans called krill or small fish. Some had both. Ten had only roundworms while two had kelp. One particularly heavy stomach was brimming with three and a half kilograms of sand and rocks. Yet when the researchers sifted through these stomach contents searching for pieces of plastic, they couldn\u2019t find any.<\/p>\n
![\"rocks](\"https:\/\/hakaimagazine.com\/wp-content\/uploads\/rocks-plastic-free-seals-1200x1041.jpg\")
<\/a>A vast quantity of rocks, but no plastic, was found in the stomach of one seal from Canada\u2019s eastern Arctic. Photo by Madelaine Bourdages<\/p><\/div>\n
Jan Andries van Franeker, a marine biologist at Wageningen Marine Research in the Netherlands, says the scientists could have gone beyond visual inspection* by dissolving the seals\u2019 stomach contents in a strong base and examining the slurry for all remaining plastics. But even so, he\u2019s not surprised there was no plastic in these Arctic seals. \u201cIn harbor seals from the polluted southern North Sea, we only found about 11 percent of stomachs with some plastic. The Canadian Arctic is a lot cleaner,\u201d he says.<\/p>\n
While it appears that Arctic seals are not ingesting, or at least not retaining, any plastics bigger than 425 micrometers, Bourdages and her colleagues have reason to believe that they might ingest smaller plastics indirectly from their prey. Previous studies<\/a>, for instance, have found microplastics\u2014plastics up to 5,000 micrometers in diameter\u2014in polar cod<\/a>, a common prey of Arctic seals. Studies have also detected microplastics and macroplastics in the stomachs, intestines, and scats of South American fur seals<\/a>, northern fur seals<\/a>, and gray seals<\/a> of the Atlantic and Pacific Oceans.<\/p>\n And given how plastic has turned up in remote locations\u2014from Antarctica<\/a> to an uninhabited South Pacific island<\/a> to the deepest reaches of the seafloor in the Mariana Trench<\/a>\u2014perhaps it is only a matter of time before it starts to accumulate in seals in the eastern Canadian Arctic.<\/p>\n Correction: This sentence originally said that by dissolving the slurry in a base it could reveal smaller pieces of plastic. This is inaccurate. Dissolving the stomach contents would instead reveal different types of plastics.<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":" Whales, seabirds, turtles, crabs, and worms\u2014all kinds of marine animals are afflicted with plastic pollution. But seals living in the eastern Canadian Arctic seem to have so far escaped this modern plight. When scientists examined the stomach contents of the <\/p>\n