A marine ecology researcher told a panel sponsored by the Western Pacific Regional Fishery Management Council on Wednesday that deep-sea mining will have a negative impact on Pacific fisheries, including in waters near the Big Island.
Douglas McCauley, a professor at the University of California at Santa Barbara, said seabed mining claims have been staked by nations and private contractors in the Clarion-Clipperton Zone.
The CCZ is a geologic fracture zone about the length of the continental United States from east to west — the western end of which is south of Hawaii Island.
“The first of these mining claim areas is just about 300 kilometers (south) of the border of the U.S. (Exclusive Economic Zone) near the Big Island,” McCauley told the panel. He added that mining could begin within two years, although he qualified that by saying such a prediction is complicated.
“They’re prospecting there to see what kind of resources are there,” McCauley said. “… Close to Hawaii, you have a number of claim areas that are from China, Russia — and then, all over the board as you march further to the east.”
McCauley, who also operates a website called Deep Sea Mining Watch, said the mining planned for the CCZ is for polymetallic nodules — also known as manganese nodules.
He said the noise from deep-sea mining, as well as the mining itself — which will dislodge sections of previously unexcavated ocean floor — will negatively affect fisheries.
“You have some sort of extractor … that grinds up material on the sea floor, sends it up through these riser pipes to the mother ship that’s operating at the surface,” McCauley said. “And on … these surface support ships, there’s not anything more happening than basic processing of taking out the ore — the resource that they want to take back to a shore-based facility to be refined — and ejection.
“As you can imagine, there’s a huge amount of wastewater and waste slurry that is then ejected back out. This is sort of a mobile or fluid version of the (waste) you would find in a (land-based) mining operation. There are two plumes that are created … on the sea floor where the mining actually occurs … and a plume that is formed where the wastewater is ejected … back into the area where the mining has occurred.”
According to McCauley, the wastewater plumes — which he said could contain copper, cadmium, iron, cobalt, chromium, nickel and zinc, “have more consequences for fisheries.”
He said computer modeling has been done by researchers from the University of Hawaii and Massachusetts Institute of Technology in an effort to determine how large those plumes will be, how far they will extend, and the impact they will have on fisheries.
“We won’t know until if mining were to start what would be the real spatial impact will be of these plumes,” he said. “… “U.S. fisheries, for the international fisheries that operate in the high seas, are some of the most impacted when you break it down by country level.”
He said the plumes could overlap into between 8% and 16% of U.S. fisheries.
“The CCZ is the area where there’s the highest level of catch overlap with these mining plume areas,” he said.
According to McCauley, projections about catch data based on the size of plume overlap into fisheries has been done for skipjack, yellowfin and bigeye tuna. With an overlap of 200 kilometers by the waste plumes, it’s projected there will be an encroachment of 11.3% into skipjack tuna fisheries.
“A number of 11% might be large, it might be small. But if mining was to be proposed in 11% of my own back yard or impact 11% of my family garden, I would be upset,” McCauley said. “It would not be a small number for me.”
Email John Burnett at jburnett@hawaiitribune-herald.com.