Exclusive: ‘Fish sludge’ in coastal waters now has nutrient levels equivalent to those in untreated effluent of country the size of Australia, report finds

Norwegian fish farms are filling fjords and other coastal waters with nutrient pollution equivalent to the raw sewage of tens of millions of people each year, a report has found.

Norway is the largest farmed salmon producer in the world, and nutrients in fish feed are excreted directly into coastal waters. Analysis from the Sunstone Institute found that Norwegian aquaculture released 75,000 tonnes of nitrogen, 13,000 tonnes of phosphorus and 360,000 tonnes of organic carbon in 2025.