The Bureau of Ocean Energy Management has released a final environmental impact statement that concludes seismic surveys for oil and gas exploration in the Gulf of Mexico would cause significant harm to marine mammals. The long-awaited review comes in response to a court-ordered settlement of a lawsuit brought by environmental groups. Its release comes as President Trump seeks to expand offshore drilling in federal waters. 

The analysis finds that as many as 31.9 million marine mammals in the Gulf of Mexico will be injured and harassed by oil and gas seismic surveys. This includes 80 percent of the Gulf’s endangered sperm whale population, estimated at 763 animals. Sperm whales will experience as many as 760,000 harassing exposures to airgun blasting over the next decade. 

“Oil industry airgun blasts harm whales and dolphins rather than giving them the protection they deserve. We can’t keep treating the Gulf of Mexico with such flagrant disregard,” said Miyoko Sakashita, ocean program director with the Center for Biological Diversity. “Trump’s promises to expand offshore drilling will amplify the damage we’re doing to whales and other marine animals.” 

The draft estimates that seismic blasting would cause as many as 588 injuries to the Gulf’s Bryde’s whales—of which only 33 individuals remain—or about 17 times for each member of this imperiled population.

“Seismic blasting harms everything in the water: whales, fish, even the zooplankton that are the foundation of life at sea,” said Michael Jasny, director of NRDC’s Marine Mammal Protection Project. “To permit seismic testing in view of these troubling findings would be to retreat from conservation.  It sends a message to the Gulf that, even after the Deepwater Horizon disaster, oil industry profits trump our coastal environment.”

Seismic exploration surveys use extensive arrays of high-powered airguns to search for oil. These generate the loudest human sounds in the ocean short of explosives. The blasts, which can effectively reach more than 250 decibels, can cause hearing loss in marine mammals, disturb essential behaviors such as feeding and breeding over vast distances, mask communications among whales and among dolphins, and reduce catch rates of commercial fish. 

“We were hopeful BOEM would opt for safeguarding our marine resources from damage associated with oil and gas development,” said Cynthia Sarthou, executive director of the Gulf Restoration Network. “Sadly, instead they have a once again put the interests of the oil industry ahead of environmental protection.” 

The report finally acknowledges what environmental groups have long warned: that these sonic blasts cause harm to marine mammals. The report estimates that oil and gas seismic surveys will harm whales and dolphins with as many as 4.3 million instances of injury, including permanent hearing loss.

“Flooding the ocean with noise from seismic surveys is a devastating one-two punch for the ocean,” said Steve Mashuda, an attorney with Earthjustice. “At a time when our oceans are already showing the stresses of climate change, it just doesn’t make sense to harm whales, dolphins, and other ocean wildlife in service of drilling for more oil we can’t afford to burn if we’re going to avoid the worst harms from climate change.”

Prior to the lawsuit, the oil and gas industry conducted seismic surveys for decades without the permits required by the Marine Mammal Protection Act and the Endangered Species Act. 

Today’s report outlines possible mitigation measures, including closure areas where seismic blasting would be banned, and reductions in the amount of activity permissible each year.

Plaintiffs in the lawsuit compelling the environmental review include NRDC, the Center for Biological Diversity, Gulf Restoration Network and Sierra Club, and are represented by Earthjustice.