Over 300 tonnes of microplastics a year from Norwegian salmon farms
There are many indications that plastic pipes transporting salmon feed pellets under pressure can be a significant source of pollution. The Norwegian Society for Nature Conservation believes that more than three hundred tonnes of microplastics each year go straight to the sea through wear and tear on feed pipes at Norwegian fish farms, and have asked their Government that a survey of these plastics emissions be initiated.
They compared scrapped and less worn plastic pipes for use in feeding farmed fish. The pipes are used to transport abrasive fish feed pellets under pressure. This wears the wall on the inside of the pipe. They found that the weight difference on slightly worn and very worn pipes was on average half a kilo per meter of pipe, and on this basis estimated that the feed pipes at Norwegian fish farms generate more than 325 tonnes of microplastics in a year.
What happens to micro - or nanoplastic particles from the feeding tubes has not been investigated. How fish - and people - are affected by plastic is a whole new field for researchers. There are two large projects in the EU looking at whether plastic eaten by fish can have health effects on the fish, and can possibly end up on the food plate for people.