Basket star with anemone on top of a boulder off Cape Arago, Oregon. (Photo courtesy of Oceana.) See complete pop-up photo gallery.

Off the coast of San Juan Island, greenlings doze on ledges 400 feet down. Sculpins snuggle into reefs scattered with scallops. Crabs camouflaged with feathery hydroids creep past crimson sea cucumbers.

It's a world invisible to us, at depths divers seldom venture.

But a series of expeditions mounted this summer by the environmental group Oceana is bringing some of these scenes into focus for what may be the first time.

"No one has ever seen what the sea floor looks like in some of these areas," said project leader Geoff Shester.

Working on the cheap, the team outfitted small ROVs (remotely-operated vehicles) with the type of video cameras skiers strap to their helmets. Operators guided the craft with joysticks and oohed and aahed as images flashed across their shipboard monitors.

"Most people think of colorful coral reefs in the tropics, but we have just as spectacular a sea floor, and even more diverse, right off the coast of Washington," Shester said. "We would go from eel grass beds to sandy bottoms with sharks cruising around to these amazing, rocky cliff walls -- all within a few hundred feet of each other."

The exploration around San Juan Island wrapped up last week. Earlier in the month, the team filmed in California's Monterrey Bay, and two sites off the Oregon Coast, near Coos Bay. Their deepest dives were 750 feet in an area called Coquille Bank, 20 miles off the Oregon town of Bandon.

Off Oregon's Cape Arago, they filmed basket stars with arms so curlicued they might have been drawn by Dr. Seuss. In the San Juans, rhinoceros auklets dived to feast on sandlance, and a minke whale swam past. Everywhere the underwater cameras looked, they saw living things -- encrusting the surfaces and crammed into nooks.

"The larger rocks were 100 percent covered with invertebrates -- sponges, anemones, bryozoans and hydroids," Shester said.

One of the group's goals was to simply begin cataloging the creatures that inhabit offshore shelves from Northern California to British Columbia. But there's a political motivation as well. Oceana campaigns against destructive trawl fishing, and images of thriving undersea ecosystems help build support.

"It's not just a bunch of mud and sand down there," Shester said. "There's a lot worth saving."

Oceana's Whit Sheard deploys the Mariscope ROV off San Juan island
Photo Courtesy of Oceana

On their Washington leg, the crew sailed from Port Angeles on a 45-foot, chartered catamaran called Gato Verde, or green cat. When they didn't have the sails up, they motored under biodiesel power.

Todd Schuster, captain of the Gate Verde, discusses dive locations.
Photo courtesy of Oceana

Now, the team is sorting through film and still images and recruiting expert biologists to help identify the species. "This is the early phase of what we hope will be a much broader and more comprehensive effort to map and characterize the coast," Shester said.

You can read expedition reports on Oceana's blog.

A crab perches on the edge of a living reef constructed by tube worms off San Juan island/Photo courtesy of Oceana