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Whales beach seismic research

On Sept. 25, five vacationing marine biologists sailing in Mexico’s Gulf of California came across two recently beached Cuvier’s beaked whales. Surprised by the find, the biologists wanted to contact a Mexican colleague to perform necropsies to determine why the whales had died — but the radio on the sailboat was not strong enough to reach the researcher, 40 miles away. The biologists hailed a nearby ship, hoping to use its satellite phone.

The ship was the Maurice Ewing operated by Columbia University’s Lamont-Doherty Earth Observatory. The biologists quickly learned that the ship, funded by the National Science Foundation (NSF), had been pulsing the ocean with high-powered sound waves to map the lithosphere beneath the ocean floor. Aware of recent correlations between Navy sonar exercises and beaked whale deaths, the biologists immediately suspected the sound waves had fatally disoriented the whales.

Environmental lawyers got wind of the incident and took the issue to court. On Oct. 30, the Northern California District Court issued a temporary restraining order halting the surveys. The Court found that it was likely that both the acoustic blasts were irreparably harming marine mammals and that NSF had violated U.S. environmental laws — criteria strong enough to grant a temporary stop. While important legal questions remain, the restraining order shut the door on a major research initiative more than 10 years in the making.

A recent court order stopped the Maurice Ewing from conducting seismic surveys in the Gulf of California on the grounds that the survey’s loud acoustic pulses may have been harming marine mammals. Photo courtesy of Lamont-Doherty Earth Observatory, Division of Marine Affairs.

“It was a huge blow,” explains geophysicist Steven Holbrook, from the University of Wyoming, who was one of the four primary investigators on board the Ewing at the time of the strandings.

The geophysicists were working in the Gulf of California because it is one of the two best places in the world to study a complete rift complex that is actively driving continents apart, explains Michael Purdy, director of the Lamont-Doherty Earth Observatory. Understanding rifting is a major scientific objective within the NSF-funded MARGINS program that supported the Ewing cruise. The other prime candidate for studying rifting is the Red Sea, but no cruises to that location have been funded.

The powerful air guns on the Ewing generate high-resolution images of the lithosphere that read like deep roadcuts into Earth, detailing the shapes and distributions of rock layers five miles or more below the ocean floor. “This is a methodology that has evolved over several decades, and we use it because it is the best,” Purdy says.

The marine biologists initially suspected that the Ewing was to blame because the strandings fit a pattern, explains John Hildebrand, a whale and acoustics specialist at the Scripps Institution of Oceanography. Beaked whale strandings in Greece in 1996 and again in the Bahamas in 2000 occurred at the same time that NATO and the U.S. Navy, respectively, were using high-powered sonar in nearby waters. “If you look at all the recent strandings incidents, about half a dozen, you see a good correspondence between a ship track and the timing of the strandings. And it is consistently beaked whales that is the species most affected,” Hildebrand says.

When researchers on the Ewing first heard of the strandings, they halted all air gun activity. But as evidence came in, it looked unlikely that the Ewing caused the beachings, and so they resumed, Holbrook explains. Spurred by the Bahamas incident, the Navy has done tests concluding that sounds below 180 decibels do not damage marine mammals; intensities above 180 can damage lungs and tissues. The intensity of sound generated by the Ewing air guns falls steeply with distance so that it goes below 180 decibels at 3.2 kilometers from the ship. According to Holbrook, the Ewing was at least 80 kilometers from the whales when they beached, casting doubt on a causal link. When the researchers did resume the seismic profiling, they took several steps to minimize the possibility of harming marine mammals. They reduced sound levels, increased efforts to spot whales and stopped working at night. These steps complemented the Ewing’s standard procedure of slowly ramping up the intensity of the air guns when beginning a seismic survey — allowing any marine mammals in the immediate vicinity to leave before being exposed to dangerous levels of sound.

The additional mitigation efforts limited productivity, explains Holbrook. “From the actual restraining order, we lost six days of work outright. But there was a much greater impact from the voluntary measures we undertook.” The research crew ended up completing little over half of the four transects across the rift that they had intended.

Yet those voluntary measures were not enough, explains Hildebrand, who had informally asked the Marine Mammal Commission to review the planned cruise before it left, after he had discovered that air guns would be used. “The problem is that from visual surveys you only see about 20 percent of these animals because they are deep diving,” he says. That means many whales could be within 3.2 kilometers of the Ewing — the danger zone — without researchers knowing it.

Hildebrand and colleagues presented their concerns at the annual meeting of the Marine Mammal Commission in San Diego, which happened to be scheduled soon after the strandings. Brendan Cummings, an attorney for the California-based Center for Biological Diversity who attended the meeting, quickly saw a need for action. “It was clear to me that the scientists wished the government would do something, but the agency people were not sure they had the right jurisdiction. It was also clear to me that indecision would mean nothing would happen.”

After some digging, Cummings and colleagues found that the National Science Foundation had not applied for permits under the Marine Mammal Protection Act (MMPA) to do their research. Nor had NSF gone through the environmental assessment procedure required by the National Environmental Policy Act (NEPA). These alleged violations became the crux of the Center’s law suit.

NSF contended that no evidence connected the Ewing to the beached whales. Furthermore, the Ewing was operating in Mexican waters and therefore was not subject to the U.S. environmental laws. In a letter to the Center for Biological Diversity, Anita Eisenstadt, Assistant General Counsel to NSF, wrote, “Before the cruise began, we obtained all required permissions from the Mexican government because the vessel is operating in Mexican waters.”

While the court decision sided with the environmental lawyers, the restraining order is temporary and does not set a precedent for future cases. It will stay in effect until a more extensive court trial, which will likely happen within the year, determines whether to make the order permanent. The judge may decide that the point is moot, because the temporary restraining order has already stopped the research, and the Ewing has no plans within the foreseeable future to return to the Gulf of California.

Several key questions remain unresolved that will likely come up if another hearing is held. Each side has a different interpretation of the exact timing of the beachings and how close the Ewing was to the whales when they beached. A second question is whether the strandings linked to Navy sonar provide any guide for interpreting the cause of the strandings in this case. The air guns from the Ewing produce acoustic pulses that, at their source, are more intense than the Navy’s sonar. However, whales respond to specific frequencies of disturbance, as well as magnitude, and the air guns operate at a much lower frequency (about 100 hertz) than the Navy sonar (several kilohertz), Holbrook says. Also, the Navy sonar continuously sweeps the ocean with sound waves, while the air guns only fire short acoustic pulses once every 20 to 60 seconds.

A larger question is over the jurisdiction of U.S. environmental laws — do they apply to federally funded ships operating in the waters of other countries? “There is a horrible dearth of legal certainty on this matter,” says Curt Suplee, director of the Office of Legislative and Public Affairs at NSF. “If you are in the Gulf of California, where every cubic inch of water is in territorial waters or the Exclusive Economic Zone (EEZ) of Mexico, do these laws apply? The Center for Biological Diversity has the perfect right to seek a different interpretation.” One reason that question has not been fully resolved is that EEZs were established after the NEPA and MMPA laws.

A final court ruling could help resolve these scientific and jurisidictional questions. In the meantime, this case has put the spotlight on NSF, Purdy says. “It is clear that this case has brought the issue into the public scrutiny, and it is clear that we are going to be scrutinized very carefully in the future, and we need to continue to show that we are operating legally and responsibly.”

Greg Peterson


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