Nearly 1,800 animals from 40 different species swallowed or became entangled in plastic between 2009 and 2018, the report, by ocean conservation group Oceana, found. About 88% were animals listed as endangered or threatened under the Endangered Species Act, including Hawaiian monk seals, Stellar sea lions, manatees and all six species of sea turtle found in the U.S.
The plastic was found to have affected the animals at all life stages, from recently hatched sea turtles to seal mothers with nursing pups. More than 800 animals listed in the report were sea turtles, and more than 900 were marine mammals.
Researches added that the numbers in the report are likely conservative estimates, as not every affected animal is reported.
The pieces of plastic chronicled in the report ranged from microplastics that perforated the gastrointestinal tract of a baby sea turtle to DVD cases and "huge plastic sheets" that had been swallowed by whales.
Plastic packing straps, bags, balloons with strings, and sheeting were the items most commonly reported.
The animals also came into contact with items such as zip ties, dental floss and mesh produce bags seen at grocery stores, Dr. Kimberly Warner, the author of the report and a senior scientist at Oceana, said in a statement. Other incidents involved items including bottle caps, water bottles, straws, buckets, plastic chairs, plastic forks, toothbrushes, children's toys, buckets, bubble wrap, sponges, swim goggles, plastic holiday grass, sandwich bags and polystyrene cups, the report said.
The animals often mistake plastic for food or swallow it while swimming or feeding, according to experts. After it's consumed, the plastic can lacerate their intestines or obstruct digestion, according to the report. When the plastic remains in an animal's stomach, they may believe they are full and not seek to eat, leading to starvation or death, scientists say.
In some cases, just one piece of ingested plastic may have been enough to contribute to an animal's death, like in the case of a pygmy sperm whale whose dead body was discovered in New Jersey with just one plastic bag in its stomach, according to the report.
And when entangled in plastic, some marine life can drown, choke or suffer physical trauma or amputation, which can then lead to infection, the report said.
In one case study, a Kemp's ridley sea turtle drowned after a plastic bag filled with sand wrapped around its neck, according to the study. Scientists believe the turtle drowned from the weight of the bag.
Scientists estimate that 15 million metric tons of plastic flow into the ocean every year -- the equivalent of about two garbage trucks' worth every minute, according to the report.
Plastic production is expected to quadruple in the coming decades, and the amount of plastic flowing into the oceans will triple by 2040 if nothing changes, Christy Leavitt, one of the report's coauthors, said in a statement.
Researchers complied the report by surveying dozens of governmental agencies, organizations and institutions that collect data on the impact of plastics on wildlife.
Stopping plastic from entering the ocean will take a combination of action by both government and big business, according to the researchers. To do so, not only must companies reduce the production of plastic, especially single-use plastic, but they must offer plastic-free choices to consumers. In addition, governments at all levels must pass policies to reduce the production of single-use plastics, and federal agencies tasked with protecting oceans and the species within them must require standardized reporting of all plastic interaction cases, the researchers said.
"The world is hooked on plastic because the industry continues to find increasingly more ways to force this persistent pollutant into our everyday routines -- and it's choking, strangling and drowning marine life," Warner said in a statement. "We can only expect these cases to increase as the industry continues to push single-use plastic into consumers' hands."