Plastic in fish: A problem for the environment and people

Here are six kinds of fish and shrimp that are economically or culturally important in Oregon (clockwise from top left): Chinook salmon, lingcod, black rockfish, pink shrimp, Pacific herring, and Pacific lamprey (NOAA Fisheries, Oregon Department of Fish & Wildlife, North Carolina Wildlife Resource Commission).

(JANUARY 24, 2025) New research from Portland State University (PSU) shows that tiny plastic particles from clothing, packaging, and other products are ending up in fish that people eat. 

What was the research?

PSU scientists studied small plastic pieces, called microplastics, in seafood. They focused on fish and shrimp commonly eaten in Oregon, such as black rockfish, lingcod, Chinook salmon, Pacific herring, Pacific lamprey, and pink shrimp. These small plastics were found in the edible parts of the seafood.

The study showed that pink shrimp, which feed near the surface of the water, had the most plastic particles in their tissues. Chinook salmon had the least. Smaller animals like shrimp and herring eat tiny organisms called zooplankton, which often collect plastic particles.

Here are some details from the research:

• Researchers found tiny plastic fibers, fragments, and films in most of the 182 seafood samples.

• Washing fish fillets and shrimp removed some of the surface plastic contamination.

• Microplastics are not just in fish but are also found in other foods like bottled water, beer, honey, beef, chicken, and tofu.

Why does it matter?

These tiny plastic pieces can move from the stomach of the fish into the muscles, which are the parts people eat. This could have health effects for animals and humans. 

What happens next?

The researchers are working on solutions to reduce plastic pollution. Some of their projects include:

• Developing filters for washing machines and dishwashers to catch plastic fibers.

• Testing filters in storm drains to stop plastic from entering waterways.

Professor Elise Granek, one of the study leaders, says it’s important to find ways to prevent microplastics from reaching the environment. “What we put into the environment ends up on our plates,” she explains.

This research is helping scientists and policymakers understand the problem of microplastics and find ways to keep our food and oceans safe.