It appeared to be a typical mayoral race in Chesapeake Beach. By 3:30 p.m. Wednesday, the only declared candidate was Gerald W. Donovan, the five-term mayor, who has not faced an election challenge since 1988.

Then, with less than an hour to go before the 4:30 p.m. filing deadline, Joseph W. Johnson strode into Town Hall and filed papers to challenge Donovan, whose father and grandfather also were mayors of the Calvert County town.

Johnson, 61, who moved to the Chesapeake waterfront town of 3,000 four years ago from Prince George's County, called Donovan a part-time mayor who places his economic interests over those of the community.

Donovan owns several business in the town, including the 72-room Chesapeake Beach Hotel and the Rod 'N' Reel restaurant.

"He's running his own little fiefdom down here," said Johnson, a retired Naval Research Laboratory analyst who was active in Prince George's civic causes.

Donovan was on vacation in California, town officials said, and could not be reached for comment last week. But the incumbent mayor's supporters said he has never used his office to improperly benefit his businesses.

"I bet you he spends half his time during the week doing town business. That costs him money," said James L. Parent, who ran unsuccessfully for Town Council on Donovan's slate in 2000 and is running again this year.

"I think he's doing a heck of a job," he said.

If elected, Johnson said, he would develop a strong adequate-public-facilities ordinance to slow development. He said such a law, which is designed to prevent growth from outpacing public services and infrastructure, is not in Donovan's financial interest.

"He wants to develop as much as he can develop," Johnson said.

Johnson, who opposes gambling, also said he believes Donovan hopes to create a casino at his hotel.

Parent, however, said gambling is unlikely to return to Chesapeake Beach. He said the issue is being raised only to damage Donovan politically.

Cleaning up the Chesapeake Bay is another goal that Johnson said he plans to pursue as mayor. Johnson said his experience as a civic activist in Prince George's would help him lobby successfully for funding to clean up the bay.

"If I do nothing else in my life but raise hell about this bay, that's enough," Johnson said.

Johnson said he decided to run after neighbors repeatedly asked him to challenge Donovan, whom some have called a polarizing figure.

Even though Donovan was the lone mayoral candidate in the 2000 town election, only 655 of the 967 town voters that year cast their ballots for him, said Michelle Jenkins, the town clerk.

To Johnson, the 2000 results indicate that many voters disapprove of his opponent's performance.

Johnson said that discontent might bring him more votes than his stands on local issues.

"I think I will draw a lot of votes just because people don't like Donovan," he said.