At least 11 million metric tons of plastics enter the ocean annually, and marine wildlife are crushingly impacted. Many species are at risk of extinction due to plastic pollution. A new study shows the disturbing effects of plastic consumption on seabirds, sea turtles, and marine mammals. Our researchers have determined that even microscopic amounts of plastic are lethal to these little fellows. This new, shocking discovery uncovers a hidden and significant danger to our ocean biodiversity.
Under the leadership of Dr. Erin Murphy of Ocean Conservancy, scientists conducted a detailed evaluation. They investigated the impacts from 1,537 seabirds across 57 species, 1,306 sea turtles from all seven species, and 7,569 marine mammals covering 31 species. The results were stark: nearly half of the sea turtles (47%) had plastics in their digestive tracts at the time of death, alongside 35% of seabirds and 12% of marine mammals.
Dr. Murphy stressed the need for research to discover what those lethal doses of plastic are for various species. “The lethal dose varies based on the species, the animal’s size, the type of plastic it’s consuming, and other factors, but overall it’s much smaller than you might think,” she stated. This discovery is especially troubling considering that more than the equivalent of a garbage truck’s worth of plastics is entering the ocean every minute.
Soft plastics like plastic bags are particularly harmful to sea turtles. Only 342 of these pieces, each about the size of a pea, would be fatal in 90% of cases. And marine mammals, especially endangered species such as the North Atlantic right whale, are more threatened by fishing debris. Only 28 pieces of plastic smaller than a tennis ball can kill a sperm whale.
What we found was even more surprising. A high majority of seabirds and sea turtles that ate plastic ingested these specific types. For seabirds that accumulated plastic in their guts, a shocking 92% ate hard plastics. Furthermore, 69% of sea turtles ingested soft plastics and of marine mammals, 72% fed on fishing debris.
Nicholas Mallos, vice president of Ocean Conservancy’s Ending Ocean Plastics program and co-author of the study, expressed grave concerns regarding the implications of these findings. “This research really drives home how ocean plastics are an existential threat to the diversity of life on our planet,” he remarked. In his testimony, he pointed out that plastic ingestion is only one threat posed by plastic pollution. Entanglement and toxic chemical leaching contribute equally dangerous risks to marine life.
Dr. Chelsea Rochman, an associate professor at the University of Toronto, emphasized the need for scientific insight into this issue. “Governments around the world are grappling with how to address plastic pollution, and they are looking for science-based targets to inform policy decisions,” she stated.