New Zealand’s largest king salmon farmer says it is closing some of its farms after global warming caused the massive death of fish, warning that it is a “canary in the coal mine” due to climate change.
New Zealand is the world’s largest producer of king salmon, or “chinook”, a highly valued breed that achieves a premium in the world market. The country’s farms account for about 85% of the world’s supply, said New Zealand King Salmon CEO Grant Rosewarne.
Now, the warmer summer seas are causing fish in some places to die en masse before they can reach maturity, causing farmers to dump thousands of tons of dead fish at local landfills.
“There should be alarm bells,” Rosewarne said. “When I joined this company, I never heard of the term ‘sea heat wave’ … Recently, there have been three.
“We thought we had more time,” Rosewarne said. “Climate change is a slow process but faster than many people think: certain industries are … canary in the coal mine.”
“We thought climate change was a really slow effect, detected for decades, and we possibly have it, two decades before it was even affected. Well, in a decade we were affected.”
It is considered common for a small percentage of farmed fish to die each year, but warming temperatures have significantly increased these deaths. In 2022, the King Salmon Company’s “biomass mortality rate” for fish was up to 42% in warm water areas where fish were not towed to cooler areas; compared to 17% in 2018. Even when fish were towed to cooler waters, many were dying: 37% in 2022, compared to only 10% in 2018.
During the summer months, the warmer temperatures of the water, warmed by the warm currents flowing down from the coral sea, had pushed some of the cultivated populations to the shore. “It simply came to our notice then [temperatures] “I don’t think that sounds like much to people, but a full degree is huge for our species,” he said. your hands “.
According to RNZ, trucks carrying dead fish from the area had dumped 1,269 tons of dead fish and debris in the Blenheim landfill during the summer, 632 tons in February alone, seven times last year and more than 194 tons. dumped in February 2020.
Now, New Zealand’s King Salmon will “leave” three of its farms in the warmer Pelorus sound zone, keeping only one open for testing. The company hopes to be allowed government permits for a water space where it can raise fish in cooler waters.