There's trouble in paradise. Gibson Island, an exclusive bayside haven for Maryland's most genteel and wealthiest families, is being overrun by one of nature's gentlest creatures, the whitetail deer.

There are so many deer on the 1,000-acre island that the folks who occupy its 177 houses had planned to stage a one-day hunt with shotguns Saturday.

But that only stirred up more trouble when a Washington-based animal rights organization threatened legal action to stop the hunt and, if that was unsuccessful, pickets and a demonstration on Saturday.

By a special vote of the island's corporation on this Thanksgiving afternoon, the hunt was called off, John Quinn, master of the hunt, said tonight.

"The People for the Ethical Treatment of Animals threatened to get an injunction to stop the hunt based on the argument that the corporation had not exhausted all of the possible humane" solutions to the deer problem, Quinn said.

He denied the allegation, pointing out that the state Department of Natural Resources had outlined several possible approaches and determined that a one-day hunt was the best option. A meeting of the animal rights' group, DNR officials and island authorities is set for Tuesday, Quinn said.

Officials of the animal rights group could not be reached for comment tonight.

Although many of the island's self-proclaimed "conservatives and preservationists" were pained by the decision to stage a deer hunt, other residents said there wasn't much choice.

The deer are eating up their gardens and attacking their azaleas and other shrubs. The fear, supported by state Department of Natural Resources specialists, is that hunger and disease will cull the overpopulation if man doesn't.

"Not necessarily this year," said DNR deer specialist Bob Miller, who advised the islanders to schedule their first deer hunt, "but it's inevitable if they don't do something. They need to take some deer off that island and the longer they wait the worse it'll get."

"The DNR people said we could take half the existing herd and it wouldn't be detrimental," said Quinn.

Gibson Islanders, who fervidly shun publicity, tried to keep their hunt plans secret, but it an opponent tipped off newspapers.

Promptly half the nimrods in Anne Arundel County and quite a few from neighboring Baltimore inquired about getting onto the island to help residents thin the herd. "We've had a lot of calls," said Elmer Daubert, who runs Daubert's Sport Shop 1 1/2-miles up Mountain Road from the guarded causeway that is the only land access to the island, "and a lot of people came down looking to get on Gibson Island.

"But you can't. We just tell 'em it's a private island and it's not accessible."

Miller refused to guess how many deer are on Gibson. He said there is evidence of overpopulation in the woodlands, where the deer have browsed excessively, and in the animals' predilection for invading gardens and shrubbery.

Miller said the state regards populations of more than 40 deer per square mile as excessive. Gibson, 1 1/2-miles square, could have as many as 80 to 100 deer, according to some unofficial estimates.

Anne Schmeisser, an island resident for 24 years, said there were no deer around when she moved there and only in recent years have the animals created problems. She suggested that the "press of population" in booming Anne Arundel County forced the deer onto the woodsy island, but Miller said deer throughout the state have been moving into previously unused habitat as the herd expands.

Miller said the state deer herd has increased from a few thousand to about 100,000 in the last half-century as small farms reverted to second-growth woodlands, ideal deer habitat, and as the state encouraged deer expansion with transplanting programs and strict game-law enforcement. Miller said only 32 whitetail deer fell to Maryland hunters in 1931, while last year more than 18,000 were killed.

Quinn said three deer were killed by cars on the island this year, "and the speed limit here is 25 miles an hour." Another resident, who asked not to be named, said deer are in his garden "all the time," and he's seen as many as 10 or 12 deer at a time within 50 feet of his house.

Quinn agreed that the gentility of Gibson Islanders contributed to the problem, noting that if deer overpopulation occurred in other, less conservation-minded communities, the excess would quickly have been "harvested," as game managers put it, by local hunters.

"But the people here are very well grounded from a nature standpoint," he said. "They love to watch the ospreys, swans and geese. The island is a bird sanctuary. They banned DDT here long before Rachel Carson came along, and they don't spray for weeds and bugs here like they do elsewhere. The idea of hunting is very alien. Basically, they're against it."

Both Quinn and Miller denied a report that the drivers would push the deer to an open beach, where they would be "slaughtered." That report, which Miller said is preposterous to anyone familiar with whitetail deer's capacity to hide, sparked the worst of the residents' opposition, which since has quieted.

Some residents still oppose the hunt, said Schmeisser, "but it has grown to be the opinion that this must be done. We're a group of conservationists. We enjoy the deer. We just want to make sure they stay healthy, and under control."