February 24, 2020
Residents in New Zealand’s North Island had quite a surprise when walking along the shore of Maunganui Bluff Beach last week. Indeed, about 500,000 mussels already dead were floating near and across the shore and in between rocks. The dead mussels were spotted by resident Brandon Ferguson of New Zealand’s North Island. He reported the incident by sharing a video on his Facebook page.
“It smelled like dead rotting seafood,” Ferguson told média. “Some of the mussels were empty, some of them were dead … Some were just floating around in the tide. There were well over 500,000 mussels and shells littering the coastline.”
New Zealand’s Rising Ocean Temperatures
Marine experts have linked the mussel’s death to climate change. Indeed, statistic shows that in New Zealand the temperature of the oceans surrounding the country has been increasing by 0.1 to 0.2 degrees Celsius every decade since 1981 and could be responsible for the massive mussel’s death. https://www.stats.govt.nz/indicators/sea-surface-temperature.
Marine scientist Andrew Jeffs of the University of Auckland said that the mussels might have died due to a condition known as heat stress, which could be triggered by mid-day low tides and hot weather. “The mussels die of heat stress. You imagine lying in the midday sun every day for four hours for the best part of a week. You’d be pretty sunburnt at the end of that,” he told the New Zealand Herald. Jeffs warned that if the temperatures if New Zealand’s oceans continue to increase, mussels and mollusks could soon disappear completely from the country.
Professor Chris Battershill, a marine ecologist at Waikato University, said there had been similar die-off in recent years involving tuatua cockles and clams. “The common denominators seem to be really hot conditions with lots of sunlight and unusually calm waters for an extended period,” he told AFP. “This leads to a combination of heat stress and the animals running out of oxygen because the water’s so still. They eventually succumb… they’re effectively cooked alive.” Battershill the extreme conditions were unusual. “Is it related to climate change” he said. “Mussels are hardy little animals, you think about when they’re harvested they survive in the supermarket with just a little water on them. “So it’s taken extreme conditions to kill them. And when you have many die-offs in recent years involving several species then you really need to sit up and take notice…”