We already know that some fish contain high levels of mercury, DDT, and PCBs, but now a new study shows they are also full of trash. The study, published in Scientific Reports, found that almost 25 percent of fish tested had man-made particles of plastic or fiber in their guts. Researchers at the University of California, Davis and Hasanuddin University in Indonesia tested 76 fish from markets in Makassar, Indonesia, and 64 from Half Moon Bay and Princeton in California.
In Indonesia, all of the particles found in the fish were plastic, whereas in California, 80 percent of the debris was fibrous material. “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,” lead author Chelsea Rochman, a postdoctoral fellow at UC Davis, told Phys.org. “We think the type of debris in the fish is driven by differences in local waste management.”
There is very little in the way of garbage collection or waste management in Indonesia, so plastic bags, bottles, and other waste is dumped on beaches or into the ocean. “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 at UC Davis.
In contrast, while California has widespread systems for collecting waste, most residents use washing machines. The waste water from those machines ends up in water treatment plants offshore California. The researchers’ theorized that clothing fibers from this waste water end up in the ocean and are ingested by fish in the area.
Because the debris was found in the fishes’ guts, it is unlikely to be eaten by humans unless the fish is eaten whole, as is common in Indonesia and with small fish such as sardines and anchovies.