In a quirk of politics that is startling even by Empire State standards, a band of irate fishermen who live almost 300 miles from New York City may play a pivotal role in determining the fate of the state Senate.

Normally, a local dispute over fishing rights on a 16-mile river running through Oswego County would not have significant political repercussions much beyond the blizzard-prone region on the eastern shore of Lake Ontario.

But such a scenario is unfolding in New York’s North Country, the site of a special Senate election taking place next week that has the chance to reduce the Republicans’ hold on the chamber to one slim vote.

At the onset of the race, which was triggered by the retirement of a Republican senator, few in Albany expected it to be close. The district is one of the few in the state in which Republicans outnumber Democrats by a wide margin.

The Democratic challenger, Assemblyman Darrel Aubertine, has defied expectations and moved within striking distance of his Republican opponent, Assemblyman William Barclay, according to a local poll released this week.

Democratic campaign aides say Mr. Aubertine, a former dairy farmer and insurance salesman from Jefferson County, has boosted his support in large part by tapping into a long-simmering resentment over a $30 fee that the Barclay family requires fishermen to pay to drop their lines in a section of the Salmon River that it controls.

“All of a sudden it became an issue after several years only because the Aubertine camp needed an issue,” the chairman of the Republican Party of Oswego County, George Williams, said.

“They want to talk about fish, and I’m very strenuously making the point that it ain’t an issue,” a spokesman for the Barclay campaign, Christopher McKenna, said.

The dispute, which is dominating local press coverage of the race, centers around a two-decade old battle between fishermen in the area and Mr. Barclay’s family, which owns hundreds of acres of land, called Douglaston Manor, that encompasses a one-mile section of the river.

Twenty years ago, Mr. Barclay’s father, Hugh Douglas Barclay, a former state senator and ambassador to El Salvador and one of the richest residents in the county, began charging fishermen a small fee to fish in his section of the river, home to some of the largest freshwater salmon in North America.

The one-mile section of river managed by the Barclays is downstream from where the fish enter during spawning season from the still-water estuary that empties into Lake Ontario.

At the top of the river is a hatchery that was financed by public grants secured by the elder Barclay when he was a state senator.
In the 1990s, after several fishing guides refused to pay the fee and were caught fishing along the private stretch, the elder Barclay sued them for trespassing.

The family eventually won the case after the Court of Appeals ruled in 1997 that while the public had the right to navigate the river, the easement of passage did not displace property rights accompanying the private ownership of the riverbed, including exclusive fishery. In other words, fishermen could float along the river but could not drop a line without permission from the Barclays.

Years later, the battle over the river lingers in the minds of many local residents.

“I haven’t paid Barclay, and I never will,” said Robert Jordan, a part-time fishing guide who said he’s been catching salmon and trout in the river on a McKenzie-style drift boat since the late 1970s.

“I don’t believe I should have to pay what I have already paid for with my license dollars and tax dollars. The water doesn’t belong to anybody yet he controls the water,” Mr. Jordan, a registered Republican and a respondent in the lawsuit, said.

“It’s like the Gestapo down there,” a 62-year-old fishing guide outside Pulaski, Richard Redsicker, said.

Mr. Redsicker said he also refuses to fish in what he dubbed “Barclay kingdom,” a boycott that has taken a toll on his business. Last fall, he said, few salmon made it past the gauntlet of hooks in the shallower Barclay section, which drew hundreds of fishermen a day despite the fee.

The Aubertine campaign reignited the debate earlier this month by airing a campaign ad featuring a voice-over from an unnamed young man who wistfully recalls the time as a child when he used to be able to fish in the river for free.

“Me and my granddad never fished on the Salmon River again,” the narrator says over a hazy image of a solitary blue drift boat floating on the river.

The ad, which instantly became the talk of Pulaski, infuriated the Barclay campaign, which quickly discovered that the man behind the voice was a 25-year-old named Justin Winkle, who subsequently apologized to the Barclay family and admitted to reporters that he had never fished in the river with his grandfather, but only as an adult.

A spokesman for the Aubertine campaign said Mr. Winkle’s narration in the commercial, which was produced by the same ad team used by Governor Spitzer, was not supposed to be taken literally but to represent the experiences of fishermen in the area.

The Aubertine campaign has questioned the circumstances behind Mr. Winkle’s apology.

The day before he recanted, two friends of Mr. Barclay’s, a Republican county legislator and a former schoolmate, visited Mr. Winkle’s home to talk with him about the ad.

Later that evening, they drove to a bar and bought Mr. Winkle at least one drink. At 11:30 p.m., the county legislator Shawn Doyle said, Mr. Winkle drove off to go to a party that was miles away. Near dawn, state police arrested him and charged him with driving while intoxicated. The next day, he offered his apology to reporters.

Mr. Doyle said he had nothing more than a friendly conversation with Mr. Winkle and accused the Aubertine campaign of trying to smear him. “The Aubertine people are trying to ruin me,” he said.

Allies of Mr. Barclay say the pay-to-fish operation has helped to clean up a river they say was treated shabbily by the local fishermen.

Mr. Williams, the Republican chairman of Oswego, said that before the family charged boaters, people would leave salmon carcasses on the Barclay property.

“If you have smelled the innards of a salmon, it is almost toxic,” Mr. Williams said.