Trail of the whale: tracking grey whales with EarthWatch in British Columbia.

As we paddle our double kayak between GPS way-points, Jennifer Wladichuk readies her underwater recording apparatus. Wladichuk is a marine biology Ph.D. candidate studying grey whales and the ecosystems that sustain them, and she's about to measure the density of zoo-plantkton that serve as one of the great beasts' primary food sources. She and her scruffy yet enthusiastic group of grad students led by Canadian marine biologist William Megill, are out to discover why the grey whale has all but disappeared from the waters surrounding their remote wooded outpost on a small island off British Columbia's west coast, 300 miles straight north from Seattle.

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Just two years ago, Megill and crew couldn't eat dinner around the firepit without being interrupted by the sound of 20-ton grey whales surfacing for air between mouthfuls of zooplankton. But this summer and last, these great creatures have remained scarce, and Megill, a professor at the UK's University of Bath and founder of the nonprofit Coastal Ecosystems Research Foundation (CERF), can't understand why.

When I ask whether global warming may be to blame, Megill shakes his head. "The whales are thriving in other areas, so it appears this is a localized phenomenon," he says. Too bad for Megill, who chose the sparkling green and gray waters spread out before us more than a decade ago as his northern base of operations-due in large part to the abundance of grey whales fattening up for their fall migration down to their breeding grounds off Mexico's Baja peninsula.

Now Megill's team must travel upwards of 100 nautical miles in a diesel-spewing converted fishing boat to even catch a glimpse of the whales. The frustration in the air is palpable, although Megill smiles for a fresh crew of volunteers from EarthWatch Institute, the international nonprofit that enlists paying civilians to help various environmental scientists do their research around the globe.

EarthWatch Volunteers

Without the ongoing support of EarthWatch, Megill's grey whale research would likely have stopped years ago. But this summer he will host as many as 50 EarthWatch volunteers--some of whom have traveled from as far as Europe and Japan--in his coastal wilderness outpost. This fresh crop of volunteers are helping to gather ecosystem data, sort through thousands of photos, and launch unmanned research submarines.

Back on the water, Wladichuk lowers her hydrophone--two underwater microphones attached by a short cable to a digital sound recorder inside the kayak--into the chilly coastal waters in an effort to map mysids, the zooplankton favored by the whales. She doesn't hear them.

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"Maybe the whales ate themselves out of house and home two years ago," says Megill. His current hypothesis is that the once-thriving mysids need some time to recover before their chief predators can return. But Megill is the first to concede that other possibilities for the recent dearth of mysids--and whales--abound.

Although global warming is not the direct cause, it may be part of the bigger picture. "There could be larger changes going on due to global warming or any number of other factors," Megill says, adding that shifting ocean currents have profound effects on marine ecosystems. To solve the mystery of the missing whales, he will need a lot more data. And that's where EarthWatch comes in.

"EarthWatch makes our project possible," Megill says. EarthWatch volunteers not only magnify the amount of data he can collect, but also fund the ongoing research by paying for their spots on the team. One of the most innovative environmental groups in the world, EarthWatch puts its members to use, enabling them to get out into the field alongside environmental scientists. Generally, the work itself isn't too bad, especially when it consists of kayaking around the remote, pristine coastline of British Columbia.

With night falling, Megill steers the boat out of the cove that has served as home for the past week. He dears a narrow passage between islands and hits the open water, and much to our pleasure a group of white-sided dolphins fringed by surreal bioluminescence joins us, riding the wake off file boat's bow.

CONTACTS: CERF, http://cerf.bc.ca; EarthWatch Institute, [phone], www.earthwatch.org.

RODDY SCHEER contributes regularly to E.