Major New Zealand salmon producer shuts farms as warming waters cause mass die-offs

New Zealand’s biggest king salmon farmer is shutting some farms as warming seas cause mass fish die-offs. Photograph: Murdo Macleod/The Guardian

New Zealand’s biggest king salmon farmer says it is shutting some of its farms after warming seas prompted mass die-offs of fish, warning that it is a “canary in the coalmine” for climate change.

New Zealand is the world’s largest producer of king, or “chinook” salmon, a highly valued breed which fetches a premium on the world market. The country’s farms account for about 85% of global supply, New Zealand King Salmon chief executive Grant Rosewarne said.