Whales hunting uses theodolite

The odd underwater noise, an upsweeping "whoop," will start as quietly as conversation, rise as loud as traffic and peak at the din of a rock concert, all within one second.

Chances are, whales will listen. And without doubt, scientists will watch.

All of it is part of an experiment that Oregon State University marine researchers plan early next year during gray whale migrations. They hope to learn whether low-power acoustic devices -- this one emitting a single "whoop," then a rising "whoop-whoop-whoop," -- can prevent whales from approaching wave-energy platforms and cables that might one day occupy waters off Oregon and elsewhere.

But results could reach much farther, leading to help for marine mammals in peril worldwide.

"There are no tools of this nature in existence," says Bruce Mate, the director of the OSU's Marine Mammal Institute.

But first things first.

The $410,000 pilot project, paid for by the U.S. Energy Department, is a first step toward reducing potential risk to marine mammals by wave-energy technology.

Little is known about whether or how such technology might affect marine life. But some people worry about whales' potential to become entangled in underwater cables or debris attached to them, or to hurt themselves by ramming into platforms holding wave-energy gear.

"We're not saying wave energy devices have been shown to cause a problem" says Barb Lagerquist, an OSU senior faculty research assistant working with Mate on the project. "We're just saying it would be prudent to have something on the shelf."

Oregon hopes to become a leader in wave-energy technology. In 2007, OSU launched a test run of a wave-energy buoy. In 2008, the university won a five-year, $6.25 million grant to establish an ocean energy research center in Newport. At least one test device is expected to be anchored to the sea floor near Reedsport before the end of this year.

Mate and his crew applied for permits from the National Marine Fisheries Service to test acoustic devices. They expect to earn approval, in part because they plan to keep the noise to a level that carries no possibility of injuring the animals, simply of altering their behavior ever-so-slightly, Lagerquist says.

The entire population of eastern North Pacific gray whales -- an estimated 18,000 animals -- migrates past Oregon twice a year, heading south to breed and calve off Baja, Mexico, in winter, and returning north to feed in spring. In a 2008 study, Mate and his colleague, Joel Ortega, found that 61 percent of migrating gray whales spotted off the coast passed within three nautical miles of shore.

In proposals for wave energy, devices would be placed in that same slice of ocean.

Next year's study will run Jan. 1 through mid-April, ending before mothers and calves migrate north in May. Scientists will moor a sound device about the size of a carry-on suitcase a little shy of three miles offshore, due west of Yaquina Head. They plan to program the device so it emits the whoop sound three times a minute during a six-hour stretch each day. Otherwise, it will be silent.

On shore, observers will be equipped with binoculars and an instrument called a theodolite, which will allow them to scan the horizon and calculate distance to the whales, and the whales' latitude and longitude. They'll map the animals locations, determine their traveling speed, then compare how differently whales move when noise is being emitted, versus when the device is silent.

"Ideally," Mate says, "we'd like to see the whales respond to these pings by moving about 500 meters around the device, which adds just a tiny bit -- one 100th of 1 percent -- to their migration distance.

Acoustics have been used for many years to prevent entanglements in fishing nets, to reduce bycatch of dolphins and other marine mammals. And wildlife managers routinely use acoustic harassment to keep seals and sea lions away from aquaculture facilities or prime recreational salmon runs.

In 1985, after a humpback whale dubbed Humphrey wandered into San Francisco Bay and up the Sacramento River, numerous attempts to coax him back into salt water failed. He appeared to be dying when an acoustic specialist offered recordings he'd made of humpback feeding vocalizations, hoping it would lure the whale back to sea. The U.S. Navy provided the required underwater sound device.

After it was lowered into the river and the sounds filled the water, Humphrey surfaced, followed the boat carrying the device many miles back to the bay and finally, under the Golden Gate Bridge and into the Pacific, where he belonged.