[25 January/Stuff]

Marine farmers are “at the mercy of mother nature” as a looming heatwave threatens to lift water temperatures for a second successive year. National Institute of Water and Atmospheric Research (Niwa) are predicting temperatures to rise across the country over the coming week, impacting sea-surface temperatures. The warning comes after New Zealand King Salmon lost more than 1600 tonnes of fish last year, many of which overheated in warmer than usual Marlborough Sounds farms. Over a two week spell in early January, sea-surface temperatures in Marlborough peaked at 19 degrees Celsius, sitting 3 degrees above the long term average. King Salmon Chief Executive, Grant Rosewarne, said 20 per cent of the King Salmon stock did not survive last year. To put the loss in perspective, he explained in the wild situation, it’s generally 1 or 2 per cent which would survive … it’s a complete reverse situation. Mr Rosewarne said that in excess of 17 degrees water temperature, there’s some level of stress involved on the fish.