Grieg Seafood shares fall 5% as algae event hits 2026 harvest

Shares in Norwegian salmon farmer Grieg Seafood declined more than 5% on Monday following the company's reduction of its 2026 harvest forecast. The 2026 harvest is now expected to be 29,000 tonnes, a decrease from the initial forecast of 31,000 tonnes. Grieg attributes the decline to an algae event that damaged fish gills and increased mortality at one of its sites.

The company estimates the algae event resulted in a biomass loss of approximately 1,000 tonnes. To account for the reduced harvest volume and associated mortality costs, Grieg has raised its 2026 farming-cost forecast to NOK71 per kg, up from NOK67.5 per kg. Sea conditions were initially favorable through August, but an unforeseen algae event led to deteriorating conditions at the affected site.

Mortality rates increased gradually during September, prompting Grieg to temporarily halt harvesting at the site while it works to mitigate the impact. The suspension of harvesting is reflected in the revised full-year harvest forecast. Gried asserts that the mortality event is not anticipated to affect production in 2027. The company continues to evaluate the operational and financial implications of the algae event and will provide further details in its upcoming financial reports.