oil rig

Whales and dolphins under threat from deep-sea mining, study warns

Image credit: DT

Loud noises made during seabed mining in the deep ocean could have a negative impact on sea life, especially whales, scientists have warned.

Commercial-scale deep seabed mining in international waters could be permitted for the first time later this year.

Scientists from the University of Exeter and Greenpeace Research Laboratories believe the process could be a “significant risk to ocean ecosystems” with “long-lasting and irreversible” effects.

The study, which focuses on cetaceans such as whales, dolphins and porpoises, finds that urgent research is needed to assess potential impacts.

“Like many animals, cetaceans are already facing multiple stressors, including climate change,” said Dr Kirsten Thompson, of the University of 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.”

The sounds expected to be produced by mining operations, including from remotely operated vehicles on the seafloor, are likely to overlap with the frequencies at which cetaceans communicate, the researchers believe.

“We searched for data on how much noise such mining would cause, but no published assessment is available,” Dr Thompson added.

“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.

“Despite this lack of information, it appears industrial-scale mining could soon begin in one of the planet’s few remaining undisturbed environments.”

The Clarion-Clipperton Zone in the Pacific Ocean, which provides habitat for about 25 cetacean species including dolphins and sperm whales, is of particular interest to mining companies aiming to exploit polymetallic nodules.

In addition, mining companies are also looking to target seabed mineral resources in areas around seamounts and deep-sea hydrothermal vents, the researchers said.

“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 Dr Solène Derville, of 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.”

No commercial-scale seabed mining has yet occurred outside the exclusive economic zones of coastal nations, although 31 exploration permits have been issued for areas beyond national jurisdiction by the International Seabed Authority, a United Nations body.

In June 2021, the Pacific island of Nauru triggered the so-called “two-year rule” and informed the International Seabed Authority that it plans to mine the deep sea – meaning that mining could go ahead in June this year with whatever regulations the ISA has formulated by that time.

Nauru is working with a Canadian firm called The Metals Company (formerly DeepGreen Metals), which has already begun testing mining equipment in Pacific waters.

“Commercial-scale mining is expected to operate 24 hours a day, with multiple operations extracting minerals across an area of the seabed,” Dr Thompson said.

“We don’t know how this will affect cetaceans or the vast range of other marine species. What we do know is that it will be difficult to stop seabed mining once it has started.

“Given the imminent threat that the two-year rule presents to ocean conservation, we suggest there is no time to waste.”

Sign up to the E&T News e-mail to get great stories like this delivered to your inbox every day.

Recent articles