A mass bleaching of more than 50 million sponges in New Zealand’s Fiordland was the largest of its kind ever recorded globally, scientists said on Wednesday. The 2022 mass bleaching was estimated to have cut the population by close to half, a study found. Lead author James Bell, a marine biologist at Te Herenga Waka—Victoria University of Wellington, said the bleaching occurred during an intense marine heatwave that lasted 259 days and pushed water temperatures to 4.4 degrees Celsius above average. The bleaching event occurred along 1,000 kilometres of coastline on the west coast of New Zealan…