Jason Reynolds doesn’t have a million-dollar cruiser or a hopped-up engine in his booth at the New York National Boat Show, but that hasn’t tamped down his popularity. The professional bass fisherman leads freshwater-fishing demonstrations from a sawed-off boat tip that’s perched over a 41-foot-long, see-through fish tank. When he starts out he’ll usually be talking to a handful of people, but by the end of one of his high-charged talks he can look down to see he’s drawn more than a hundred onlookers.

Mr. Reynolds moves his rod gracefully and accurately while rattling off, at lightning speed, advice on casting, lures, and baits. He speaks in a down-home accent, playing up his small-town Oklahoma origins with lines like “Young lady, if you were a bass I’d have caught you!”

The program never really changes, and that includes the inevitable part at the end when Mr. Reynolds scans the crowd to realize that everybody is transfixed by the underwater scene, and nobody really cares what he has to say about freshwater-fishing techniques. Sometimes, if the lack of connection is especially palpable, he’ll come right out and ask: “Are you with me here? How many of you go bass fishing?” There will be no hands, maybe one.

“Okay,” he’ll say, suppressing a wince. “How many of you are interested in learning more about bass fishing?” A few more lazy hands will shoot up skyward.

Asked after a demonstration if this was the worst reception he’s ever encountered, Mr. Reynolds, 36, who looks like a ganglier and prettier Nicolas Cage, thought long and hard. “No,” he said, “but it’s in the top 10% of bad. Chicago was the worst. And Baltimore’s pretty bad, too.”

The problem Mr. Reynolds is experiencing doesn’t stem from a lack of interest in fishing: The metropolitan New York region is said to have an estimated 775,000 anglers. It’s the kind of fishing he preaches. Given New York City’s proximity to the ocean, more than 80% of fishing occurs in saltwater, which has nothing to do with freshwater fishing. The handful of New Yorkers who go freshwater fishing use Central Park, Prospect Park, or lakes at New Jersey or Long Island.

Saltwater-fishing aficionado Mehmet Guven, a Manhattan consultant who was at the show shopping for a boat, stopped by Mr. Reynolds’s tank and took a seat. He needed to rest his legs, he said. After the demonstration, Mr. Guven said he was less interested in learning fishing techniques than in observing the desperation with which the fish chased the bait. “I don’t think they fed those fish in a while,” he said.

Indeed, most of the people stopping at the tank just wanted to press their noses against the glass and absorb the hypnotizing view. Mr. Reynolds’s Kellygreen tank, with its panel windows and wheels underfoot, looks like a cross between an aquarium and a car of the Orient Express. The inside has been set up beautifully: Black crawfish, crappie, spotted Kentucky bass, and large- and small-mouth bass undulate through an arrangement of tree stumps, rocks, and ferns. “I set all this garbage up,” Mr. Reynolds said.

One reason Mr. Reynolds was invited to the event at the Jacob K. Javits Convention Center is that his loud and absorbing demonstration can always be counted on to please the boat-show crowd. According to Mr. Reynolds, President Bush even stopped by one time, back when he was governor of Texas.

Another reason is that in an effort last year to boost attendance, the New York National Boat Show started courting freshwater-fishing fans. At the 2004 show, three freshwater boat companies showed up. This year there are eight, as well as scheduled appearances by bass pros Larry Nixon, Jimmy Huston, and Kathy Magers, who all appear regularly on the Saturday morning ESPN bassfishing programs. The boat show’s manager, Michael Duffy, said: “It brings in freshwater fishermen who may have thought of the show as a saltwater show.”

The differences between freshwater and saltwater fishing go well beyond the salinity of the water. Saltwater fishing, which takes place on the ocean, is more expensive and fast paced, with bigger equipment and higher yields of bigger fish. The only downside: seasickness.

Purists gravitate toward freshwater fishing, which can be done in lakes, creeks, or ponds. It can be more cerebral, serene – and difficult, as the technique is more subtle.

A Long Island resident, Jeff Davis, said he goes saltwater fishing a hundred times for every time he goes freshwater fishing, but he prefers the latter. “You’re trying to outsmart an animal that has the brain of a pig and ends up outsmarting you,” the retired education administrator said. “I’d rather go one day in a canoe and catch just one fish. In saltwater you know something is going to come along. It’s not as interesting.”

A tournament bass fisherman, Mike Burkeen, who hails from Hot Springs, Ark., and works with Mr. Reynolds, put it this way: “I’m making them an offer. If I do it in a proper manner they’re going to accept it, but I have to make the bait enticing enough.”

While Mr. Reynolds may not be convinced that New York is a hotbed of freshwater-fishing enthusiasts, those who’ve already caught the bug insist it’s the next big thing, some even calling it the next Nascar.

“There was a stereotypical perception that freshwater fishing is all Southerners named Billy Bob or Joey Sue,” Rich Johnson, host of “The Fishing Line,” a television and radio show produced in Long Island, said. “But now it’s beginning to be recognized. The same 60-year-old corporate guys who were buying Harleys a few years ago are getting into it. They’re even getting into it in China and Japan.”

Helping matters is the success of the ESPN bass-fishing lineup, which has spawned action figures of pro bass fishermen available in toy stores.

Mike DeAvila, a Manhattan film director who runs the metro New York freshwater fishing Web sitenybass.com, said traffic has doubled in the past two years. Mr. DeAvila regularly fishes by the Central Park Boathouse.

“People look at you funny,” he said. “They think it’s New York City, it’s dirty. And there I am getting a big, healthy fish.”

For now, though, judging by Mr. Reynolds’s crowds, the ranks of New York freshwater fishermen could stand to swell. Following a presentation Wednesday afternoon, the cluster around Mr. Reynolds’s booth dissipated. His assistant took off to smoke a cigarette. There was nothing to do.

Jason Reynolds sat down and pulled a kazoo like duck-hunting gizmo out of his pocket. He blew into it, filling the convention hall with ludicrous duck noises.