In a new study published in the journal, Scientific Reports, on Sept. 24, researchers found that about one-quarter of fish marketed in California and Indonesia have small pieces of man-made fibres and plastic in their guts.
The study’s lead authors, who come from the University of California (UC), Davis, and Hasanuddin University in Indonesia, examined 64 fish spanning 12 different species from Half Moon Bay and Princeton in California, and 76 fish across 11 species from markets in Makassar, Indonesia. The species sampled included herring, bass, mackerel, and oysters.
Oddly enough, there wasn’t much of a difference between the amount of debris found in the fish of Indonesia and California, notes lead author Chelsea Rochman, a David H. Smith post-doctoral fellow in the Aquatic Health Program at the UC Davis School of Veterinary Medicine.
“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. We think the type of debris in the fish is driven by differences in local waste management.”
Fibres made up about 80 percent of the garbage in the California fish, but plastic made up most of the debris found in fish marketed in Indonesia. Despite the U.S. putting many resources towards collecting and recycling plastic, water from the millions of washing machines in the state winds up in more than 200 offshore waste-water treatment plants. What may be happening, suggest the researchers, is the leakage of synthetic fibres into the sea where they can be consumed by fish. Even though these water treatment processes greatly reduce contaminants, fibres from the washing machines can remain in the sewage effluent and may find their way to aquatic habitats through waste-water outfalls.
Then Indonesia, due to the fact that is has few landfills, recycling, or waste collection plants, has its fish supply contaminated from large amounts of plastic getting thrown onto the country’s beaches and into the sea.
“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,” says co-author Susan Williams, a professor with the UC Davis Bodega Marine Laboratory who has worked in Indonesia for a large part of her career. “You have the best and the worst situation right in front of you in Indonesia.”
This anthropogenic, or human-made, debris in seafood doesn’t only considerably impact marine life. For human consumption, ingesting even small amounts of these foreign substances can lead to bodily inflammation, damage to the gastrointestinal tract, and the death of cells. Furthermore, scientists have identified “a cocktail of chemicals, including chemicals accumulated from ambient water” in the ocean debris.
Fortunately the fibres and plastic were only discovered in the fishes’ guts, thus only when the fish is eaten whole, like with sardines, are people at risk for directly ingesting the materials. However, the scientists are still analysing the possibility of the chemicals in plastic seeping into the meat itself, so the danger may still be there with filleted fish.