Microplastics

Plastics in general are a serious and increasing pollution problem in our oceans, both large items (mesoplastics) like drink bottles and fish nets and floats, and microplastics (particles less than 5 mm in length).

There has not yet been sufficient research to establish whether the hazard of microplastics is a risk to human health (1). According to the current state of knowledge on the toxicity of microplastics, the risk associated with the consumption of fishery and aquaculture products contaminated with microplastics is negligible (2). Much more research is urgently needed.

Microplastics have been found in pretty well all parts of the human body, including the reproductive system (3), and may exacerbate inflammation in some chronic human illnesses (4).

World wide, commercial fishing is one of the main source of marine plastic pollution (5). Open net pen salmon farms contribute to plastics and microplastics pollution, by mesoplastics in marine debris (6), and microplastics from feed pipe contamination (7).

Farmed salmon in industrial feedlots can ingest microplastics from their industrial surroundings, and also from microplastics present in their commercial feed (8). Studies have found microplastics present in farmed salmon, particularly in their gills and gastrointestinal tracts. While one study by the World's largest salmon farmer Mowi (9) found no microplastics in salmon fillets, the presence of microplastics in other parts of the fish is concerning.

Microplastics may cause problems for the salmon.

Microplastics can absorb and concentrate pollutants from the surrounding environment. When fish ingest these contaminated microplastics, the pollutants may transfer to their tissues. This could potentially increase human exposure to these contaminants when consuming the fish. (10)
Research on yellow perch exposed to microplastics showed lower amounts of protein and minerals in exposed fish, altered liver function and changes in gut microorganism communities (11). Some types of microplastics have been shown to increase stress and compromise fish immune systems (12).
Research has shown that the presence of microplastics can increase the severity of viral diseases in fish. This could potentially lead to increased use of antibiotics in aquaculture, contributing to antibiotic resistance issues that affect human health (13).

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