The company said that it may have to close one of its Marlborough farms for future summers after stock died from significantly warmer waters, reports RadioNewZealand.
Average water temperatures at the company's Waihinau Bay farm in the past few months have been some of the hottest on record for the area, averaging above the salmon's ideal growing conditions.
The company's Jemma McCowan said it could not say how many salmon had died for commercial reasons, but the cost was likely to be in the millions.
She said they would prefer not to farm Waihinau Bay in future summers and they were assessing whether infrastructure could be moved elsewhere.
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