Atlantic Seismic Tests for Oil: Marine Animals at Risk?

U.S. environmental review paves the way for first air-gun surveys in 26 years off the East Coast.

The Obama administration has paved the way for the first seismic oil and gas exploration in 26 years off the U.S. Atlantic coast, with an environmental review that concludes the air-gun blasts will have “moderate” impacts on marine mammals and sea turtles.

The final Environmental Impact Statement (EIS), released Thursday by the U.S. Department of Interior’s Bureau of Ocean Energy Management (BOEM), outlines measures for minimizing the impact on wildlife that are especially sensitive to the intense sound impulses used to prospect for energy resources beneath the seafloor. (See related, “Study: Planning Can Protect Whales in Seismic Surveys.”)

The document was three years in the making, and the Obama administration was urged to advance the plan by Southern governors, who say offshore drilling could bring new jobs to their states. But environmental groups argue that proposed mitigation measures will be insufficient to protect the rich sea life in the survey area, a large swath of the Atlantic coast, stretching from Delaware to Florida and encompassing an area twice the size of California.

“Imagine dynamite going off in your living room or in your backyard every ten seconds for days to weeks at a time,” said Matthew Huelsenbeck, a marine scientist at Oceana, one of the environmental groups opposing the plan. (See related, "Offshore Energy Clash Over Undersea Sound.")

The government’s estimates of the undiscovered oil and gas resources beneath the U.S. Atlantic outer continental shelf range from 1.3 to 5.58 billion barrels—a drop in the bucket compared with the Gulf of Mexico’s undiscovered stores, which government assessors estimate at 38.8 to 59.2 billion barrels. But energy industry officials say the figures could be understated, because the last energy exploration of the offshore Atlantic occurred in 1988, with equipment that is now outdated. Modern 3-D seismic equipment has uncovered huge oil reservoirs hidden beneath salt deposits in the Gulf of Mexico. The energy industry says similar potential discoveries might lurk in the depths of the Atlantic, but that they could be uncovered only by seismic surveys—towing air guns behind vessels and blasting extremely loud sounds down to the seabed to detect the size and location of hydrocarbon deposits. (See related graphic: “The Noisy Ocean.”)

Drilling in the Atlantic could add “1.3 million barrels equivalent per day to domestic energy production, which is about 70 percent of the current output from the Gulf of Mexico, and raise $51 billion in new revenue for government,” said Erik Milito, director of upstream and industry operations for the American Petroleum Institute (API) at a news conference Thursday after the release of the EIS.

BOEM Director Tommy Beaudreau said in a statement that the agency is “employing a comprehensive adaptive management strategy” that takes into account the fact that scientific knowledge about the Atlantic Ocean is constantly changing and building. “New information and analyses will continue to be developed over time,” he said.

"The Department and BOEM have been steadfast in our commitment to balancing the need for understanding offshore energy resources with the protection of the human and marine environment using the best available science as the basis of this environmental review," Beaudreau said.

The EIS concludes that there would be “minor to negligible” impact to most wildlife, with the exception of marine mammals and turtles, for which impact could be “moderate.” The review estimates that about 138,000 marine animals could be injured in some way, and perhaps 13.6 million could have their migration, feeding, or other behavioral patterns disrupted by the seismic surveys. (Read also "Giant Squid Killed by Sound?")

Here is a rundown of the main Atlantic ocean species likely to be affected:

North Atlantic Right Whales

Hunted almost to extinction partly because their docile nature and habit of swimming near the surface made them easy targets and the “right” whales to hunt, the North Atlantic right whales have recovered only marginally even though they have been protected from commercial hunting by international agreement since 1986.

Fewer than 500 of these whales are alive today, and the proposed region for air-gun surveys coincides with the main range of the remnants of the species.

“It’s the rarest of the large whales,” Huelsenbeck said. “You can consider it the American bison of the sea.”

These stocky black whales grow to 40 or 50 feet (12-15 meters) and are easy to spot because of the white patterns on their heads known as callosities made from infestations of whale lice.

To help protect these whales, BOEM proposes that during a key period when larger numbers are present, between November and April, the air-gun surveys would be banned close to the coast. The limitation essentially would put a narrow strip of the survey area off limits during the winter and early spring months, preventing seismic testing up to 20 nautical miles (37 km) from shore.

Environmentalists argue that such measures are unlikely to offer full protection to the whales because new research shows that they swim much farther offshore. Cornell University researchers placed listening stations off the coast and heard right whale calls at least 65 nautical miles (120 kilometers) out to sea. (See related, "Bubble Curtains: Can They Dampen Offshore Energy Sound for Whales?")

Humpback Whales

Many other large cetaceans live in the proposed survey area, including humpback whales, killer whales, sperm whales, and short-finned pilot whales, which use low frequency sounds in their daily lives in many ways.

“The mid- and south Atlantic is very special,” said Huelsenbeck of Oceana. “It’s home to an abundance and diversity of marine mammals that’s almost unparalleled throughout the world.”

The National Marine Fisheries Service (NMFS), a division of NOAA, is in the final stages of a 15-year research program gathering expert advice on how marine mammals are disturbed and damaged by sound.

Last week, a group of more than 100 scientists wrote to Obama urging him not to finalize the EIS until the latest marine mammal acoustic guidance is available. Without the NMFS advice, the EIS will, they said, “be scientifically deficient and quickly outdated.” (See related story: "Chilean Wind Farm Faces Turbulence Over Whales.")


Large populations of many smaller cetaceans live in the proposed survey area, including dolphins such as Atlantic spotted, bottlenose, and Risso’s dolphins. These animals are especially sensitive to the higher frequency sounds produced when the air guns blast.

“The air guns operate in broadband,” said Huelsenbeck, producing a large range of frequencies, both high and low.

The higher pitched sounds don’t provide useful information to the surveyors, but they can damage dolphins’ hearing and disrupt their behavior. Alternative survey technologies are being developed that are likely to be less harmful. Marine vibroseis, for example, would emit vibrations instead of bursts of intense sound.

In its report, the BOEM states that as marine vibroseis technologies are developed the agency would consider requiring and/or incentivizing their use, but that this would not be a wholesale replacement for air guns.

BOEM also proposes spacing air-gun surveys at least 25 miles (40 kilometers) apart to reduce their cummulative impact.

Huelsenbeck points out that sounds in the ocean can travel much greater distances. The sound of air guns, he said, “can disturb marine mammal behavior over 100 miles [170 kilometers] away.”

BOEM’s recommendations also will require survey vessels to use passive acoustic monitoring systems to listen for marine mammals’ calling in the test areas, although the agency said the approach may not be entirely effective.

“If they detect sensitive marine life in the vicinity, then all operations stop immediately and are restarted only when the area is clear,” said API’s Milito.

Loggerhead Turtles

Florida beaches are home to 90 percent of the world’s loggerhead turtle nesting sites. Midway between Jacksonville and Miami, Brevard County alone has about 33,800 nests. Other species of threatened or endangered sea turtle live in the region as well, including hawksbill, Kemp’s ridley, and green turtles.

Like the plan to close an area in Virginia to protect the right whale, BOEM proposes cordoning off near-coastal waters off Brevard County during the turtle nesting season. No air-gun surveys would be allowed in the area from May to October.

With chunky heads and heart-shaped shells that can grow to about 3 feet (1 meter), loggerheads are the second largest sea turtles after gigantic leatherbacks. Females spend years roaming the oceans, munching shellfish as they go, before returning to the beach they were born on to lay their own eggs.

Little is known about the impact of noise on turtles but it is likely that juveniles might be especially vulnerable. After they hatch, they swim straight out to sea, through areas where air-gun surveys would still be permitted.

Commercial Fish

Air-gun surveys could also scare fish away from commercially important fishing grounds along the coast.

“Seismic testing has disrupted fisheries around the world,” said Oceana marine biologist Matthew Huelsenbeck.

Seismic surveying off the southwest coast of Africa in recent years has been linked to the disruption of migrating tuna and consequently a dramatic decline in catches off the coast of Namibia.

Many species fished in the mid- and south Atlantic—including wahoo, swordfish, and billfishes—embark on long-distance migrations. This means that any impacts of air-gun surveys are likely to spread beyond the survey area itself.

BOEM’s report offers no measures to specifically deal with the impact on fish species, although it suggests that slowly ramping up sound levels during surveys could be effective.

“The process begins with a soft start, a technique that gradually increases sound levels, allowing animals that may be sensitive to the sound to leave the area,” said API’s Milito.

But fish eggs and larvae can be killed by intense sound, and the the growth of young scallops is also affected.

The final EIS will be available for public comment until April 7. The schedule after that could move quickly.

“We would hope the government could begin approving permits in the coming months,” said Milito.

Miliko said that seismic surveys have been conducted safely for decades in the Gulf of Mexico and other areas off the U.S. coast and around the world. “Like all offshore operations, seismic surveys are highly regulated, and surveyors follow strict guidelines to protect marine life,” he said.

But environmental groups expect to submit formal objections during the public comment in the weeks ahead. “We don’t believe we need to turn the Atlantic into a blast zone to fulfill our energy needs,” Huelsenbeck said.

Read This Next

Can science help personalize your diet?
Hogs are running wild in the U.S.—and spreading disease
Salman Rushdie on the timeless beauty of the Taj Mahal

Go Further

Subscriber Exclusive Content

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet