Professional angler Robert Hinds Jr. knew exactly what he'd hooked Friday as he fished Little Hunting Creek in Fairfax County.

Still, it took a while to convince the state wildlife officials that sitting in the bottom of Hinds's 21-foot bass boat was a northern snakehead, an Asian predator known for its uncanny ability to breathe air, travel short distances on land and obliterate native species with its hearty appetite.

"I was skeptical," said John Odenkirk, a biologist with the Virginia Department of Game and Inland Fisheries, who has been dispatched several times for alleged sightings since 2002 when snakeheads were found breeding in a pond in Crofton. The species resurfaced again two weeks ago in Wheaton.

Hinds's catch, snagged not in a pond but in a tributary of the Potomac River near Mount Vernon, marks the first time a snakehead has been reported found in Virginia's waterways, officials said yesterday.

The snakehead was placed on the state's list of predatory and undesirable exotic species in 2002. That same year, federal regulations were put in place prohibiting interstate transport and importation of the fish. Virginia officials said they have been watchful since the snakehead turned up in Maryland, where it has proved capable of running wildlife officials ragged.

Just two weeks ago, authorities were forced to drain a lake in Wheaton Regional Park after an angler hooked a 19-inch snakehead. The search of Pine Lake turned up no other snakeheads or snakehead eggs.

Hinds, who makes his living participating in fishing tournaments, was scoping out a canal off Little Hunting Creek, a day before a local bass-fishing contest, when he discovered that he had made a most unusual catch.

"I thought as soon as I caught it, 'That's a snakehead,' " said Hinds, noting the fish's jagged tail and what he said was its resemblance to a copperhead snake. "People didn't want to believe me. They kept saying it was a bowfin. But it wasn't. I knew."

And eventually, so did state officials, who sent a team of fisheries biologists to the creek to "electrofish" the water -- a procedure that allows biologists to stun the fish temporarily while they study the underwater habitat. What they discovered were about 24 species living in the creek, including a host of exotics, among them some liberated pet goldfish, but no snakeheads. And no eggs.

The snakehead "was probably a pet that wasn't wanted anymore," Odenkirk speculated. "Or maybe after the attention of the Maryland case, someone got scared" and dumped it. "They should have just killed it and eaten it or put it in their garden."

Yesterday, the foot-long fish was still sitting in a cooler in the back of Odenkirk's truck. Soon he'll give it a closer exam, opening it up to determine its sex. Officials estimate that it was 2 years old. Snakeheads have been known to grow as long as 33 inches.

Asked if he's concerned about the species' apparent journey toward the Potomac, Odenkirk was very matter-of-fact.

"Of course, you're concerned about it," he said, "but it's one fish, and whether or not it finds a mate and can spawn -- I'm not going to lay awake at night worrying about it."

In the meantime, the state is asking anglers to continue to keep watch. They're also using the discovery to renew their plea to aquarium owners to resist dumping nonnative fish into Virginia's lakes and rivers.

"If there were a pair [of snakehead] and they were able to repopulate, we would have a situation on our hands," said Julia Dixon Smith, a spokeswoman for the Virginia Department of Game and Inland Fisheries. "It was encouraging news not to find any others. That doesn't mean we won't be steadfast in watching the situation."

Officials with the Virginia Bass Federation say its members will be vigilant.

"We're on the lookout," said Bill Haire, a director for the group's Northern Virginia region, adding that snakeheads "can devastate a fishing population in any body of water."

Hinds, who moved from Chesterfield to Louisiana in February, didn't do too well in Saturday's bass tournament. And although he didn't fly home a winner, he left Virginia with something no other angler can claim.

"I got a great fish story," he said.

The snakehead was caught in this canal off Little Hunting Creek, a tributary of the Potomac, near Mount Vernon."I was skeptical," said John Odenkirk, a biologist with the state fisheries department, about the snakehead story.The northern snakehead is an Asian predator known for its ability to breathe air, travel short distances on land and devour native species. One was recently caught in Wheaton.