Whales Are Being Killed by Noise Pollution

Scientists examine the carcass of a gray whale before performing a necropsy to determine how it died. Natalie Fobes/Science Faction/Corbis

After a Eubalaena glacialis whale dies, it floats. Moby-Dick-era whalers knew this and gave the species—treasured for its high blubber content—its common name: They're the "right whale" to hunt. Now, with only around 500 of them left in the wild, North Atlantic right whales are the most endangered whale species in the world.

Harpoons are no longer their enemy. Eight out of 10 right whales bear the scars left behind by accidental encounters with fishing rope, one Georgia wildlife official told Newsweek. These thick lines can wrap so tightly around the whales that they die from lacerations. Right whales are also uniquely disposed to collisions with ships. By nature, they swim toward boat noises, which often leads to gruesome accidents.

Worse yet, as the oil and gas industry lobbies for permission to drill offshore, scientists say the deafening noise from seismic oil exploration could spawn devastating consequences. Extreme noise pollution has been known to kill hundreds of whales and dolphins at a time. In the worst case, they say it could someday lead to an extinction right before our eyes. "We're filling their ocean with noise," says Christopher W. Clark, a senior scientist at Cornell University. He tells Newsweek that, "their whole social network is dependent on calling back and forth." It's how they find food and stick together. He believes the constant groan of ship engines has already contributed to slow reproduction of the large, aquatic mammals.

There's evidence that jarringly loud noises could also lead to a surge in mass strandings, the deadly phenomena in which droves of marine mammals flop ashore. Scientists know these groundings have happened for millions of years. In 2010, for example, archaeologists investigated the fossils of 40 whales mysteriously beached 5 million years ago in Chile. The cause of such ancient strandings may never be proved, but one recent study attributed their deaths to toxic algae.

There is no single cause, and most mass strandings go unexplained. Increasing evidence, however, suggests man-made sound might be driving up their occurrences. Beaked whales are perhaps the most sensitive to sound. Under normal circumstances, they're known to safely dive thousands of feet in search of food. But when they hear loud noises, they dive recklessly—sometimes to the point where they die from the bends.

Research also suggests that noises may lead to strandings. In a 2009 study, "Beaked Whale Strandings and Naval Exercises," American scientists reported that there were 136 documented mass strandings of beaked whales between 1874 and 2004. All but 10 happened after the advent of high-powered military sonar in 1950. Some investigations have expressly linked strandings to sonar.

The instruments used by the oil and gas industry could be equally destructive. Seismic surveys use sound waves to paint 3-D images of what's under the sea floor. Based on these images, scientists can determine the best places to drill test wells. That's great for the bottom line, but not so good for nearby wildlife. A mass stranding of around 100 melon-headed whales in Madagascar in 2008 prompted an international investigation, and the International Whaling Commission determined seismic surveys for ExxonMobil to be the cause.

The surveys involve loud air guns blasted every 16 seconds. A government protocol requires that no animals be exposed to noise greater than 180 decibels. By comparison, standing a stone's throw from a jet engine sounds like 140 decibels. But it's worse underwater, where sound carries much farther than it does through air. There's evidence, for example, of behavior changes among humpback whales more than 120 miles away from loud noise sources, Scott Kraus, vice president of research at the New England Aquarium, tells Newsweek.

In February, the Interior Department released a highly anticipated report endorsing the environmental safety of nine proposals from oil and gas companies to conduct seismic surveys off the coast between Florida and Delaware. It said that most of the harmful effects of sound can be mitigated and clears the way for drilling once the Obama administration's temporary ban, enacted after the Deepwater Horizon disaster, is lifted in 2017.

The Interior Department acknowledged the possibility of wildlife deaths because of excessive noise, but it's not easy to calculate an exact number. For example, among bottlenose dolphins (like Flipper) the number of deaths and injuries could be 2,091 annually, or it could be 11,748. Causes that are cited range from collisions with survey vessels to the bends to direct injury from concussive sound waves.

Marine biologists mostly worry about long-term effects. They believe that because noise and other obstructions are making it difficult for North Atlantic right whales to find food, they have had a hard time keeping birth rates ahead of mortality rates. In good conditions, the whales alert one another when, for example, one finds a nice patch of plankton, but amid the drone of ships these alerts are difficult to hear. One 2012 study co-authored by Kraus found that right whales suffer from chronic stress; ships have them constantly on edge.

In response to an interview request, the American Petroleum Institute pointed to its previous statements on the environmental impact of these surveys. "Like all offshore operations, seismic surveys are highly regulated, and surveyors follow strict guidelines to protect marine life," said Erik Milito, a director at the institute, at a recent press conference.

Those guidelines involve a slow ramp-up of audio levels, meant to give animals time to clear out. Then during the seismic surveying, two government-certified third-party contractors constantly scan the area with binoculars. If something wanders into the area, they stop the work until the animal leaves.

Milito says offshore drilling between 2017 and 2035 could create 280,000 jobs, extract 1.3 million barrels of oil per day and generate $51 billion in tax revenue—if seismic surveys are allowed to go forward. The oil and gas industry is confident environmental safeguards are effective, and ultimately the Obama administration agrees. The environmental study "analyzes the best available scientific information, which indicates that the potential for seismic airgun noise to physically injure endangered whales is very limited and would only occur if an animal was in very close proximity (meters) of a large airgun source," says Caren Madsen, a spokeswoman for the Interior Department's Bureau of Ocean Energy Management.

Kraus and others do believe humans and whales can share the ocean. "Quieter vessels and seismic approaches, gear modifications for aquaculture and fishing gear...seem feasible and would help immensely," he says.

Already, new laws requiring ships to go slower off the coast have reduced collisions, the National Oceanic and Atmospheric Administration says. And some lobstermen have recently switched from sturdy lines for their lobster pots to a newer type of safety rope, which breaks away from the buoy when something heavy enough hits it. "I don't want to get a whale in any of my gear," says David Casoni, a lobsterman with the Massachusetts Lobstermen's Association.

But whales are still getting stuck. In February, wildlife officials in Florida and Georgia rescued an entangled baby off the coast of Jacksonville, Fla. A 300-foot, lead-weighted fishing rope was tied up in its baleen, the hairlike filters some whales have in place of teeth. The rescue team cut the rope short and watched the whale swim away.

Clay George, of the Georgia Department of Natural Resources, told Newsweek this one was lucky: "Some likely just die before anybody gets to them."