Scientists call for moratorium on ocean mining, fearing impact on Pacific tuna fishery

Around 500 scientists from 44 countries have signed a letter urging a moratorium on ocean mining, an activity that researchers say could be adversely affect fisheries, in particular deep-sea catches like tuna.

Scientists made the plea recently after an ocean-mining company and its host country, the Pacific island nation of Nauru, touched off a two-year rule with the International Seabed Authority (ISA), headquartered in Kingston, Jamaica. The two-year rule – triggered by Nauru on behalf of Vancouver, Canada-based Nauru Natural Ocean Resources Inc. – means that time is short for the ISA to set a code on the specifics of seafloor mining.

But researchers like Douglas McCauley, a professor of ocean science at the University of California Santa Barbara, told SeafoodSource that not enough is known about the impacts of seafloor mining on marine life.

“There has just been a lot of concern about this. We have 500 scientists saying we simply cannot activate this ocean mining, that we need to put a pause to it until we understand it’s impacts on the ocean and on fisheries, and we simply don’t have that science in hand,” McCauley told SeafoodSource. “Scientists never agree on anything, so it’s especially interesting to see 500 scientists signing on to the statement.”

If the process is not stalled, McCauley said that the policy developed in the next few months will shape the next century of ocean mining. Fisheries, he said, could be drastically altered. In seafloor mining, heavy equipment chews up the floor of the ocean. After the minerals are extracted, sediment-heavy wastewater is pumped back into the ocean via large tubes. Sediment from these plumes, researchers say, could end up in seafood and could smother the fragile forage base for fisheries.

Jesse van der Grient, a researcher from the University of Hawaii who is studying the potential effects of wastewater plumes on the fisheries, told SeafoodSource the effects of the plumes are still not well-understood by the scientific community.

“One of the problems that we have is that we need to know how far these sediment plumes will spread out from the ships they are discharged from. Right now, we don’t actually have good numerical models about how these sediment plumes are going to spread across the ocean,” van der Grient told SeafoodSource.

Van der Grient and her colleagues have assessed different plume sizes, and concluded that U.S. commercial fleets stand to have the most overlap with seafloor mining, in particular in the Clarion Clipperton Fracture Zone in the central Pacific. There, miners hope to dig up rich stores of nickel and cobalt – minerals used in the construction of lithium-ion batteries – but the area is also home to valuable tuna fisheries. A recent University of Hawaii paper concluded that mining plumes could overlap into 8 to 16 percent of current fishing grounds.

“I suppose on one hand, 16 percent of catch overlap doesn't sound like much. However, I would just say that if folks had been given permission to mine on 16 percent of my land, I would care,” McCauley said.

It is not just the U.S. that could see adverse impacts. Studies have shown that fisheries in China, Mexico, Venezuela, Spain, the Philippines, as well as small island-nations could suffer from seafloor mining. Despite this, McCauley said there has been a notable absence of fisheries representatives in the discussions on ocean mining.

“There are representatives from a diversity of different ocean industries that could be affected by ocean mining present already in the negotiations on if and how to start commercial ocean mining at the International Seabed Authority meeting - ranging from the subsea cable industry to underwater munitions industry,” McCauley said. “But I have never met a fisheries representative sharing perspectives on what ocean mining would mean to the seafood industry at the ISA.”

McCauley said he does not know if regional fisheries management organizations are planning to weigh in on the seafloor mining debate.

“The only fisheries industry group that I am aware of engaging on the subject is the E.U.'s Long-Distance Advisory Council, which called for a moratorium on commercial seabed mining,” McCauley said.

Earlier this summer, the U.S. state of Washington banned offshore mining, and Pacific island nations Fiji and Papua New Guinea have shown an interest in an ocean-mining moratorium. Several major companies, including Samsung, BMW, and Google, have pledged not to use minerals from deep-sea mining in their supply chains.  

Photo courtesy of Yana Mavlyutova/Shutterstock