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Deep-sea mining poses unknown threats to whales

Commercial-scale deep seabed mining in international waters is set to begin for the first time in June 2023. However, according to a new study led by the University of Exeter and the Greenpeace Research Laboratories, the potential impacts of deep-sea mining on cetaceans (mammals such as whales, dolphins, or porpoises) is still unknown. The experts are calling for urgent research to assess the risks that such operations pose to ocean ecosystems.

“Like many animals, cetaceans are already facing multiple stressors including climate change,” said Kirsten Thompson, an expert in Ecology at Exeter. “Very little research has examined the impact that deep-sea minerals extraction would have on cetaceans. Cetaceans are highly sensitive to sound, so noise from mining is a particular concern.”

According to the scientists, the sounds expected to be produced by these large-scale mining operations – including those from remotely operated vehicles on the seafloor – are likely to overlap with the acoustic frequencies at which cetaceans communicate. 

“We searched for data on how much noise such mining would cause, but no published assessment is available. We know noise pollution in the ocean is already a problem for cetaceans and introducing another industry that is expected to operate 24/7 would inevitably add to existing anthropogenic noise were deep seabed mining to go ahead,” Thompson explained. “Despite this lack of information, it appears industrial-scale mining could soon begin in one of the planet’s few remaining undisturbed environments.”

The region in which the mining operations (led by the island of Nauru in order to exploit polymetallic nodules) will begin later this year – the Clarion-Clipperton Zone (CCZ) in the Pacific Ocean – is currently home to approximately 25 species of cetaceans, including dolphins and sperm whales.

 “Seamounts are now known as important offshore habitats for some cetacean populations that forage or regroup around them but we still lack basic knowledge of these fragile ecosystems,” said Solène Derville, a marine scientist at the Oregon State University. “In this context, it is very hard to assess the magnitude of the impacts of seamount seabed mining on the animals that live and feed around these structures.”

Further research is needed to assess how these large-scale operations will impact the local cetacean populations, and devise methods of protecting them these already endangered species.

The study is published in the journal Frontiers in Marine Science.


By Andrei Ionescu, Staff Writer

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