Superchilled water confirmed as cause of Nova Scotia fish deaths

Nova Scotia's fisheries minister says recent fish deaths at several aquaculture sites in the province, caused by extreme cold weather, is a rare event that couldn't have been prevented.

The province says coastal waters typically remain above freezing during the winter.

But shallow ocean water can drop below 0.7 C, which is the temperature at which fish blood freezes.

The government said in two cases, net pens were damaged and dead fish were released, but the nets have been repaired and there is no evidence that live fish escaped.

Fisheries and Aquaculture Minister Keith Colwell says it's still not known exactly how many fish died, but the dead fish have been properly disposed of.

He says at least one pen suffered a total loss.

New Brunswick's Cooke Aquaculture operates three of the sites at Shelburne Harbour, Jordan Bay and Port Wade where salmon fish deaths were confirmed.

Colwell says the cold also killed wild mackerel in Bras d'Or Lake in Cape Breton and trout at another fish farm.