BAR HARBOR – The more than 92,000 cruise ship passengers who disembarked this season at the summer resort community are a driving force of the economy, local officials say, but as ships and their attendant tour buses grow ever larger, some wonder when enough will be enough.

“We absolutely see the value in cruise ship visitation, but the sky is not the limit,” Costas Christ, executive director of the Bar Harbor Chamber of Commerce, said Thursday. “We do not want to mortgage the integrity of our community … for any business interest, including cruise ships.”

Mount Desert Island’s natural beauty, abundant opportunities for “soft-adventure” activities and picturesque communities are all draws for the tourists who booked passage on one of the 84 ships that docked here this season – which now stretches from mid-May to the end of October. Though precise dollar figures of what passengers spend on their daylong visits to the island are not available, it’s a significant amount, Christ said.

“There is absolutely no question in Bar Harbor’s case that cruise ships are making an important economic contribution to our community,” he said. “No doubt about it.”

Numbers of ships and passengers have rapidly increased over the last 15 years. There were 16 in 1987, 39 in 1999 and 87 in 2004, which deposited a total of 92,460 passengers on the town’s narrow, bustling streets.

Not only are more ships dropping anchor in Frenchman Bay in recent years, the ships are carrying far more people. The average ship these days carries around 2,000 passengers. Between 1989 and 1999 the typical cruise ship carried fewer than 1,000 passengers.

Some local business owners look at the big ships with their larger payload of passengers with a concerned eye. They see issues of sidewalk and road congestion as a downside to the probability that the tourists will open their wallets for a lobster dinner or tourist knickknack.

“We are definitely in favor of cruise ships coming to the island,” Julie Veilleux, owner of three downtown Window Panes retail shops, said recently. “We would like to monitor the numbers of cruise ships that come. We’re for quality over quantity.”

One issue that has been troubling residents lately is whether streets have reached their limit when it comes to the size and quantity of the large tour buses that pick up ship passengers for tours of Acadia National Park and other local destinations.

“There is growing concern about the impact of cruise ship buses on the community,” Dana Reed, Bar Harbor town manager, said. “The buses have just grown so large – we’re not talking about tiny little tour buses … they take up a lot of space.”

Glenn Tucker of Coastal Kayaking is a local tour bus owner-operator who got into the business five years ago and generally provides two bus tours to the cruise ships.

“Cruise ships are an integral part of our business,” he said. “I do think cruise ships are valuable to Bar Harbor. They pump a lot of revenue into the economy here.”

The trend among tour-bus operators is to use 46- or 56-passenger luxury motor coaches with air conditioning and restrooms. A suggestion made at an October town council meeting to encourage bus owner-operators to replace large motor coaches with smaller, propane-fueled buses similar to the Island Explorer buses wouldn’t be realistic, Tucker said.

“Island Explorer buses don’t have bathrooms,” he said wryly.

Not everyone in town is convinced that Bar Harbor needs cruise ships, according to the town manager.

“Depending on who you talk to, the cruise ships are of varying value to the town,” Reed said. “Right now, I’m not hearing from the people who love them.”

Higher-end stores and stores that carry more portable items generally do better from the ships’ visits, he said.

“A jewelry store owner told me they do great on cruise ship days,” Reed said. “Cruise ship passengers, I am told, tend to be higher income than our everyday visitor … If the hardbacks are going out, there’s a cruise ship in.”

That isn’t always obvious to the store owners and managers who ring up their purchases and sometimes give back change from a dollar.

“It’s amazing how many people come in and spend 27 cents,” Laura Dowling, employee at Sherman’s Bookstore, said. “Coffee table books, picture stuff, those are the ones that sell. That and postcards.”

Dowling, who is from Ellsworth, was philosophical as she described how foot traffic and tour bus congestion can make it difficult to get to work or anywhere in town.

“Bar Harbor is a tourist town. There’s nothing we’re going to do to change that,” she said. “That’s how a lot of these businesses survive, but sometimes it gets a little much.”

Two well-heeled couples from California braved the chill winds on a bright, brisk day in late October. They were passengers on a weeklong cruise on the Seven Seas Navigator and had declined the proffered bus tours for a little exploring on their own.

“Being from California, these communities here in Maine look so different,” Hugh Loftus of Walnut, Calif., said while looking for a good place to eat the state’s favorite crustacean. “It’s different enough for us to be interesting in and of itself.”

Christ of the Chamber of Commerce said that Bar Harbor needs to work hard to protect that difference.

“We have what the market wants, and it’s ours to lose if we don’t take care of the resources we have now,” he said. “In Bar Harbor we would like this town to be a model of what we call ‘destination stewardship,’ so that we can find the right balance for our tourism economy and for our local, cherished way of life.”

If limits aren’t put in place, Bar Harbor runs the risk of losing what makes it special, much as has happened to the crowded tourist ports of Cancun, Mexico, and St. Thomas in the U.S. Virgin Islands, he said.

“What was once a beautiful island to go visit has become a cruise port,” he said of St. Thomas. “That’s its identity.”