By now, we all know that our ocean waters are polluted. Garbage and waste created by humans gets dropped into the ocean every day, making life a lot tougher for marine plants and animals. One of the big parts of that garbage is plastic. 8 million additional tons of plastic are put into the ocean every year. We know that plastic can be destructive for the marine animals that ingest it. But could plastic also be coming back to hurt humans who eat those marine animals?
Plastic in the Oceans
There are a reported 50 species of marine fish that are known to snack on plastic particles that end up in the ocean. While researchers are still trying to discover why this is, the fact that it’s happening and that humans are in turn eating those same fish, is apparent.
The Problem of Plastic
Researchers from Ghent University in Belgium discovered that shellfish eaters ingest 11,000 plastic fragments through their seafood every year. This was of particular concern in Belgium where mussels are a large part of the Belgian diet. In the UK at Plymouth University, researchers discovered that plastic was found in a third of UK-caught fish such as cod, haddock and mackerel.
A study published in Science showed that young perch preferred to snack on polystyrene particles as opposed to the plankton they usually fed on. Plastic is usually found in the gut of a fish, since they are consuming it directly. When humans eat fish, we generally remove the guts and therefore, the plastic, or so we thought. Studies show that microplastics are able to transfer from the fish’ guts to the meat part that we ingest. In 2011, researchers found 83% of Dublin Bay prawns in the Clyde in Scotland had ingested microplastics. In addition, some smaller species of fish, like anchovies, are eaten whole by humans.
The Latest Study
A joint study between the University of California-Davis and Hasanuddin University in Indonesia was published in 2015. The study looked at 76 fish from Indonesian seafood markets and 64 fish from Californian seafood markets.
In the Indonesian fish, researchers found trash inside 28% of the individual fish and 55% of all the species tested. Similar results were seen in the Californian fish with man-made debris appearing in 25% of individual fish and in 67% of all species tested. The only difference lay in the type of trash they found.
Chelsea Rochman, the lead author on the study and an aquatic ecologist at the University of California-Davis said, “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.”
For the Indonesian fish, all of the waste found was plastic. But for the American fish, 80% was made of fibers. While plastic waste is a global issue, ocean gyres form large patches of plastic garbage throughout the water. In addition, garbage often lingers near its point of origin. As Indonesia deals with landfill scarcity, much of their plastic debris is left on the shores and washed into their waters. They also have a lack of pure drinking water, so they have to rely on bottled water which creates even more plastic waste.
A co-author on the study, Susan Williams, who works as a marine ecologist with Rochman, explained, “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. You have the best and the worst situation right in front of you in Indonesia.”
For the American fish, the fibers found inside their bodies have the potential to be just as dangerous as plastics. Researchers believe most of the fibers found were from clothing, usually originating from water in washing machines which catches tiny clothing fibers and brings them out to sea.