Last spring, Don Powers steered his government-issue pickup down Highway 1, the thin ribbon of blacktop that hugs California's North Coast. The sun shone bright, the scent of salt hung on the wind, and the world felt rapturous. In fact, a crackpot preacher  Harold Camping had prophesied that the Rapture would actually take place then -- May 21, 2011 -- and that it would kick off God's 153-day plan to destroy the entire universe. The announcement lent a certain frisson to the moment.

All down the coast, cars were parked haphazardly along the highway's shoulder. Powers, who is 32, grew up in nearby Fort Bragg, and knows the area -- and its water -- intimately. Just south of Mendocino, he pulled to the side of the road and parked near a chained wooden gate. He pulled a camouflage jacket over his bulletproof vest and extracted a pair of binoculars from behind the shotgun and the M-14 rifle mounted next to the driver's seat. Then he squeezed through the gate into the yard of a multimillion-dollar seaside home.

Powers raised the hood of his jacket to mask the shape of his head and scrambled into the branches of a dwarfish, wind-tortured pine that clung to the edge of a cliff above a rocky cove. Two hundred feet directly below him, waves exploded on the rocks. The inlet, fringed by wind-sculpted cypress trees, cradled a murky, turbulent world alive with energy. And Powers -- a warden with the California Department of Fish and Game -- leaned so far out over the edge that it seemed he might rocket straight onto the rocks below. Binoculars jammed to his eyes, he watched as two young men in blue-and-gray camouflage wetsuits swam out into the middle of the cove and then disappeared underwater.

The coves along the coast here are full of abalone, a marine snail that is surely one of oddest creatures ever to fire the mind -- and appetite -- of humankind. Blindly peering out from beneath shells that look like flattened potatoes, abalone spend their lives grazing on the ocean's thick forests of kelp. The animals keep a vise-like grip on the stony seabed, and can be levered off only with special pry bars. But, fresh from the water, they are a delicately flavored embodiment of the rocky coves in which they dwell.

For more than a century, California had a thriving commercial abalone trade. But with increasing pressure on abalone populations, the fishery is now one of the most tightly regulated in the state. The commercial fishery was shut down in 1997. While abalone used to be caught all the way down to the Mexican border, today they can only be gathered north of the Golden Gate Bridge. Scuba tanks are prohibited; divers must hold their breath and free-dive, sometimes to depths beyond 30 feet. Each diver can take no more than three abalone per day, or 24 per year. And while abalone can be "gifted" to friends, it is absolutely illegal to sell them.

Which isn't to say there's not a thriving black market. Roughly 130 species of abalone are scattered around the world. But the huge California red -- which can grow up to 11 inches in length and yield six pounds of meat -- is the king. A single specimen, in high demand in stateside Chinatowns and in Asia, can bring $100 to $150. For an unscrupulous diver, the temptation to poach can be huge. "You go down there," Powers said as he watched the divers in the water, "and they're like hundred-dollar bills, just lying on the bottom."

That's why Powers spends his days hunkered eyeball-deep in poison oak, gathering evidence against poachers. Most are simply scofflaws, garden-variety opportunists who grab an ab or two when no one seems to be looking. But others are hardcore rustlers for whom diving is a full-time job. And for someone like Powers, who grew up diving for abalone, chasing down poachers can become an intensely personal pursuit.

"Somebody new is always popping up," he said. And when that happens, he added: "I'm gonna be all over them like a rat on a Cheeto."