Overview
- Based on roughly 10,000 necropsies, researchers estimate about a 90% mortality risk after ingesting ~23 plastic pieces for seabirds, ~29 for marine mammals, and about 405 for sea turtles.
- Nearly half of examined sea turtles, about one third of seabirds, and roughly one in ten marine mammals had plastic in their digestive tracts at death.
- Material type matters: synthetic rubber is especially dangerous to seabirds, soft plastics and fishing debris pose the greatest risk to marine mammals, and both hard and soft plastics threaten sea turtles.
- Tiny amounts can be fatal, including six pea-sized rubber fragments for seabirds and less than a soccer ball of soft plastic for a porpoise or dolphin around 1.8 meters long, with about two baseballs of plastic near-fatal for a turtle.
- Authors note the analysis covers only ingested plastics and excludes chemical and entanglement harms, and they urge cutting plastic production, improving collection and recycling, and removing existing debris.