Norwegian cod farmer Statt Torsk lost a total of 48,000 fish when it suffered an unexplained, sudden mortality event at one of its facilities last weekend.

The loss corresponds to a biomass of about 106 metric tons, or 24 percent of the fish that was in the facility.

It is still not clear what caused the mortality in two out of three pens at the company's Stokkeneset facility, but Statt Torsk officials believe it was caused by an “external happening.”