President Donald Trump listens to Japan's Prime Minister Shinzo Abe speak during their meeting, Friday, Nov. 30, 2018 in Buenos Aires, Argentina. Credit: Pablo Martinez Monsivais | AP

The Trump administration on Friday paved the way for a first-in-decades sonic search for oil and gas under Atlantic waters with companies using loud air gun blasts that conservationists say threaten to harm whales, dolphins and other animals.

The National Marine Fisheries Service issued “incidental harassment authorizations” permitting seismic surveys proposed by five companies to disturb marine mammals that are otherwise protected by federal law. The approvals allow the companies to incidentally — but not intentionally — harass marine mammals in conducting the geophysical surveys.

The firms, including TGS-NOPEC Geophysical Co. Asa, Schlumberger Ltd. subsidiary WesternGeco Ltd., and a unit of ION Geophysical Corp., still must win individual permits from the Interior Department’s Bureau of Ocean Energy Management before they can conduct the work, but those are widely expected under President Donald Trump, who has made “energy dominance” a signature goal.

The seismic surveys would be used to help identify oil and gas reserves in Atlantic Ocean waters along the U.S. East Coast, from Delaware to central Florida.

The geophysical studies involve periodic blasts from large compressed air guns, which send out sound waves that penetrate the sea floor. When the sound waves bounce back, they are captured by sensors towed behind seismic vessels. The resulting data is used to produce detailed maps of underground geological features.

Conservationists say the blasts are so loud they jeopardize the hearing of dolphins, cause whales to beach themselves and disrupt animals’ mating and feeding habits. Scientists have warned that the surveys could cause long-lasting damage to marine animals.

The authorizations lay out steps the geophysical companies must take to mitigate damage to animals, including limitations meant to protect the critically endangered North Atlantic right whale. There are fewer than 500 remaining North Atlantic right whales, which travel each winter from their feeding grounds near Canada and New England to warmer waters off South Carolina, Georgia and Florida.

“Scientists warn that seismic activity alone could drive the endangered North American right whale to extinction,” said Michael Jasny, director of the Marine Mammal Protection Project at the Natural Resources Defense Council.

“The seismic air guns are firing blasts that are so loud, they create one of the loudest man-made sounds in the ocean,” said Diane Hoskins, a campaign director with the conservation group Oceana. “The blasts are repeated every 10 to 12 seconds, weeks or months at a time, and the sound travels extremely far in the ocean — the distance of a flight from New York to Las Vegas.”

Under the authorizations, the companies must use observers and listening equipment to monitor for marine life, and shut down operations when some sensitive species are detected. The companies also are required to gradually increase activity, rather than immediately starting with intense blasts, giving a chance for animals in the area to flee operations as they escalate and potentially reducing their noise exposure.

Supporters stress that similar seismic surveys are already being conducted for scientific research and help find sites for wind turbines off the East Coast. Despite extensive use of the technology, there has been “no known detrimental impact to marine animal populations or to commercial fishing,” the Interior Department asserted in 2014.

Advocates also stress that when used to identify potential oil and gas resources, seismic surveys can help energy companies better target later drilling and decrease the odds of sinking more so-called “dry wells” that end up being a bust.

“These activities are exploration activities,” said Nikki Martin, president of the International Association of Geophysical Contractors. “The assessment of the resource is critical; it’s critical knowledge for the states and critical knowledge for the federal government in determining future decisions regarding offshore exploration and development.”

It has been decades since the last seismic surveys for oil and gas along the East Coast — and those only touched a sliver of the territory the Trump administration is considering for energy development. The Interior Department is developing a proposal for selling offshore drilling rights over the next five years, after putting almost all U.S. coastal waters — including the Atlantic — on the table for leasing in a draft plan last January.

If ultimately permitted, the seismic surveys would mark another Trump administration reversal of an Obama-era decision in the name of prioritizing domestic energy development.

The Obama administration denied pending seismic applications in January 2017. But Trump sought to streamline government permitting of seismic surveys in an April 2017 executive order. And within days, Interior Secretary Ryan Zinke had issued an order resuming evaluation of the seismic permit applications that had been rejected.

The other companies winning incidental harassment authorizations are CGG Services US Inc. and Spectrum Geo Inc.