Researchers found that roughly a quarter of the fish sampled from fish markets in California and Indonesia contained man-made plastic or fibrous material in their guts. The new study is from the University of California, Davis and Hasanuddin University in Indonesia and was published on Thursday.
Anthropogenic debris was found in 25 percent of individual fish and 67 percent of all species sampled from Half Moon Bay and Princeton in California. 80 percent of the debris in these fish was fibers, whereas not a single strand of fiber was found in the Indonesian fish. Of the fish sampled in Indonesia, plastic was found in 28 percent of individual fish and in 55 percent of all species. Man-made waste was also found in 33 percent of all sampled individual shellfish.
“It’s interesting that there isn’t a big difference in the amount of debris in the fish from each location, but in the type — plastic or fiber,” said lead author Chelsea Rochman, a David H. Smith postdoctoral fellow in the Aquatic Health Program at the UC Davis School of Veterinary Medicine. “We think the type of debris in the fish is driven by differences in local waste management.”
The United States’ advanced waste management systems for collecting and recycling plastics are in stark contrast to the lack of landfills, waste collection, and recycling in Indonesia. The researchers theorize that the fibers ingested by the sampled fish are from sewage effluent from washing machines. Over 200 wastewater treatment plants offshore California process water from the state’s washing machines.
“Indonesia has some of the highest marine life richness and biodiversity on Earth, and its coastal regions — mangroves, coral reefs and their beaches — are just awash in debris,” said co-author Susan Williams, a professor with the UC Davis Bodega Marine Laboratory who has worked on projects in Indonesia for the past several years. “You have the best and the worst situation right in front of you in Indonesia.”
Luckily, it is not very likely that the plastic and fibers are finding their way onto your dinner plate in the US. The debris is found in the fishes’ guts and therefore is only ingested by humans if the fish is eaten whole, such as with sardines and anchovies, rather than filleted. This is more common in Indonesia.
The scientists are still studying whether chemicals from ingested plastic can transfer into the meat. Rochman led research published in 2013 that found that the most commonly produced plastics absorb the most chemical pollutants and continue to absorb them for much longer than previously thought. It has been estimated that there are over 5 trillion pieces of plastic floating in the world’s oceans and Rochman studied the plastics that are the most commonly recovered as marine debris.
As she explained, “As the plastic continues to degrade, it’s potentially getting more and more hazardous to organisms as they absorb more and more contaminants.”
The largest ocean plastic expedition in history was successfully completed in August by The Ocean Cleanup in preparation for a cleanup of the Great Pacific Garbage patch, set to begin in 2020. Until then, you may want to keep filleting your fish.