Plastic pollution kills one marine mammal or sea bird every 30 seconds, with an estimated 100,000 marine mammals and turtles and 1 million sea birds killed by marine plastic pollution each year.
Nearly 700 species of marine mammals, including endangered ones, are known to have been affected by plastic. Some are harmed visibly – strangled by abandoned fishing nets or discarded six-pack rings – and many more are probably harmed invisibly, says this article in National Geographic.
Plastic ingestion by seabirds reduces the storage volume of their stomachs, causing starvation. It is estimated that 60% of all seabird species have eaten pieces of plastic, with that number predicted to increase to 99% by 2050, claims the Center for Biological Diversity.