SalMar, the world’s second-largest Atlantic salmon farmer, has culled 418,000 salmon fry at its Tjuin hatchery in Norway after a malfunction led to dangerously high pH levels in the water.
The issue arose on August 7 when a closed valve prevented sensors from monitoring the pH balance, causing the water’s pH to rise to 10.9—far above the neutral level of 6.2-6.8, according to Norwegian aquaculture news site, Kyst.
The hatchery’s liming system, designed to correct water acidity, ran for nearly eight hours without proper feedback, leading to irreversible damage to the fry.
For welfare reasons, SalMar decided to cull all affected fish on August 8. The company has reported the incident to the Norwegian Food Safety Authority and plans to investigate the cause to prevent future occurrences.