A report by the Sunstone Institute has found that Norwegian fish farms discharged 75,000 tonnes of nitrogen, 13,000 tonnes of phosphorus, and 360,000 tonnes of organic carbon into coastal waters in 2025 — levels equivalent to the untreated sewage of up to 30 million people, far exceeding the country's actual population of 5.5 million. The pollution, which stems from fish excrement and uneaten feed released through open-net cages, raises fears of destructive algal blooms that strip oxygen from the water; fjords (semi-enclosed coastal inlets particularly vulnerable to nutrient accumulation) such as the Sognefjord and Hardangerfjord are already recording declining oxygen levels in their deep waters. Norway is the world's largest farmed salmon producer, and while regional officials have begun rejecting new farm licences in affected areas, the Norwegian Seafood Federation maintains that current production remains within nature's carrying capacity and that the industry is working to reduce its environmental footprint.