As a teenager in Olney, Curt Lytle studied the tides of the Potomac River and the temperament of the finicky fish that would one day become his livelihood. Lytle's adolescent experience gave the professional fisherman an edge last week over hundreds of anglers accustomed to the stable lakes of Arkansas and Florida.

"Fishing tidal water? Oh my God, it was making me crazy!" said Judy Israel of Florida, another of the 376 anglers who competed in Charles County's Chevy Open, the pennant race of bass fishing.

Fast boats, long rides and quick, hurry-up fishing. A sport that longtime Potomac guide Ken Penrod calls the aquatic equivalent of a motorcycle gang.

Green-tinged largemouth bass are aggressive, antisocial, grumpy and territorial. Yet anglers came from as far as Japan and Australia to compete for their attention -- and a piece of the $1.25 million in prize money from the largest professional bass tournament to come to Maryland.

Each eight-hour day on the water is at times tranquil and frantic. At dawn, anglers stand in silence for a prayer and the national anthem on the wide platforms of their 22-foot boats that are bedecked with the logos of sponsors from dog food to cereal companies.

The high-tempo chase for the weightiest bass begins in waves about 13 miles west of La Plata at Smallwood State Park's marina. The armada charges at speeds of more than 70 mph with a morning sun the color of orange sherbet behind it.

Anglers scan murky grass beds, docks and the skeletons of shipwrecks where the predator fish lurk. High-tech gadgets help find the fish, but that doesn't guarantee a hook.

"It's worse than golf. One day you get five fish in 20 minutes. The next day, no fish," said Tom Toews, a Fredericksburg guide who helped pros scout the river early in the week for the "big ones" that anglers affectionately call hogs.

Artificial bait and a stash of a dozen rods in the rotation means constant casting. Lines whiz over the water, lures squeak on the surface and ospreys cry overhead.

Like a psychologist trying to assess a patient, an angler tries to decipher the desire of its catch, which changes with the tide. Do they want their bait fast, slow or stop-and-start?

Are they in the mood for a horny toad -- a gummy, frog-shaped lure that anglers pop along the top? Or a cigar-shaped one that cluck, cluck, clucks like a little fish smacking the water?

"When you set the hook and you feel something big on the end of the line, you've fooled that fish," amateur Charles King of Waldorf said with a chuckle.

Bass fishing has its roots in such southern states as Alabama and Florida. But since the Clean Water Act of 1972, the Potomac has emerged as a fish factory. Some 60,000 acres are loaded with two- to five-pounders.

For the four-day Forrest L. Wood Tour event that ended yesterday, the challenge was finding the fattest five fish on the first two days to land in the top 10 and continue competing. On Wednesday, the leader averaged four pounds per fish for at total of 20 pounds, 4 ounces. The final two days will be broadcast next month on Fox Sports Network.

Serious bass fishermen have close relationships with the creatures that drive their passion and provide a paycheck. Craig Powers, a 42-year-old pro from Tennessee, refuses to eat bass.

"It doesn't make sense to kill something you make your living from," said Powers, the side of his face near his eyes striped white from his ever-present sunglasses.

Derek Moyer, an amateur from Alexandria on leave from his day job at Booz Allen Hamilton, has sworn off eating all fish, insisting, "It's bad karma."

There are other superstitions. J.T. Kenney of Frostburg, Md., wears the same black University of Maryland sweat shirt on the first day of each competition and keeps a duck decoy onboard.

More than any lucky charm, timing is critical when it comes to the Potomac. On a lake, fish feed according to the time of day. On a tidal river, mealtime follows the water level, which can change by two to three feet, four times a day.

"For people who don't know tidal, it's a pain in the neck," said Lytle, who is 36 and lives near Norfolk. "Once you learn, it's very predictable."

Jim Moynagh and Warren Robertson net a bass on the Potomac River in their quest to win part of $1.25 million in prize money at the Chevy Open. Judy Israel holds a 5-pound 11-ounce catch from the first day.