As far as I know this is the only research article that addresses plastic ingestion by salmon and steelhead in salt water. The data for this report was collected while examining stomach contents of ocean sampled fish for feeding and bioenergetics studies. I have been told that smolts that are collected in yearly coastal surveys often have plastic in their stomachs but it is not reported. Plastic ingestion has been observed in other species of marine food fish.

Big Fish Eat Plastic

One question that only recently has been addressed; are the pollutants concentrated on and in the plastic absorbed by fish when the plastic is ingested. The answer seems to be yes from the link below.

Plastic Ingestion

Studies that look at pollutants in fish are mos often addressing the danger of eating contaminated fish and not how the fish are harmed. There is a growing concern though of the impacts on reproductive success of fish exposed to pollutants. The link below is to a local example.

Puget Sound