Whales swimming in the California coast can ingest up to 10 million pieces of microplastics per day. This alarming estimate was developed by scientists at Stanford University and California State University, who published an article in the journal Nature to release the results of their work. The team, led by Shirel Kahane-Rapport and Matthew Savoca, developed models to calculate how much microplastic these mammals may ingest on a daily basis. Whales, which include blue, humpback and fin whales, are particularly at risk of ingesting microplastics because of their filtering behavior, immense prey consumption and habitat overlap with polluted regions.
The researchers combined microplastic data from the California Current with high-resolution foraging behavior measurements from 191 specimens.
These animals, the authors reveal, feed primarily at depths of 50-250 meters, where most of the microplastics are found. Based on the measurements, the scholars estimated that blue whales could consume about 10 million pieces of microplastics per day, while humpback whales could ingest up to four million fragments each day. Although the long-term effects of ingesting these substances are unknown, the scientists suggest that whales could face physiological and toxicological risks from microplastics.
These findings, the experts conclude, highlight that microplastics are an important stressor for the whale population, so understanding the consequences of microplastics on marine wildlife will be critical in future investigations.