Portland’s Historic Preservation Board recommended that House Island be designated as a historic district on Wednesday following a lengthy debate between those hoping to strengthen protections and critics who viewed the effort as a last-ditch attempt to prevent improvements of a private island.

Situated between Peaks Island and South Portland, House Island occupies a prominent location in the city’s harbor and an important place in Portland history.

Fort Scammel on the island’s southern tip is the only fort along Maine’s coast to see action during the War of 1812, when the fort exchanged fire with a British privateer. For centuries fishermen used the island for curing fish and processing lobster. And in the early 1900s, House Island became Maine’s version of Ellis Island and served as a federal immigration station and quarantine facility.

The board’s recommendation will go to the Portland Planning Board and then to the City Council for consideration.

Michael Scarks, a Portland developer who has restored several properties in the city, purchased House Island this spring with plans to build several new houses on the island while preserving Fort Scammel. The nonprofit Greater Portland Landmarks requested that the island be designated a historic district this summer, and several Preservation Board members agreed to consider the proposal.

Designation does not prohibit development, but means new structures would be subject to additional review by the city’s Historic Preservation Board or planning staff. Additionally, changes to historic structures on the property would have to be approved in a process that board members described as cooperative, not confrontational.

“The board’s intent . . . is to collaborate with developers and property owners,” member Penny Pollard said.

On Wednesday, Scarks announced that he had sold the northern half of the island to a couple, Christina and Vincent “Cap” Mona, who plan to restore three existing buildings that date to 1907 and were once part of the immigration station.

The Monas, both of whom have worked on historic preservation in the Washington, D.C., area, said they are committed to spending the large sums needed to revive the historic structures on House Island and bringing them up to code, but expressed concerns about a historic district designation.

“We are ready to go,” Cap Mona told the board. “We just don’t want anybody to hold us up.”

The House Island proposal highlighted the growing tensions between economic development and historic preservation in Portland as the city becomes a hot real estate market.

Kenneth Thompson, an author and historian of Maine’s forts who supported the designation, said House Island is a rare, still-existing example of a style of fort built just before the War of 1812. Although the fort was subsequently expanded during the Civil War, much of the original Fort Scammel is still buried on the site.

Arthur Fink, a former board member who lives on Peaks Island, said historic district designation is appropriate and will help guide – not impede – development on the island.

“Where else in Maine or in Portland can we encounter so much history in one place?” Fink said.

But others questioned the timing of the designation nomination, coming only after Scarks purchased a property that had been on the market for years.

“I would be appalled if I purchased property like that and, all of a sudden, out of left field comes forward a letter saying this property should be designated as a historic district,” said Harry McCann, a local business owner and tenant of a Scarks property.

Harold Cushing, whose family owned the island for decades until he sold it to Scarks this year, was among those who questioned why the historic district request popped up only recently. Cushing said both the city of Portland and the state declined his offers to sell the island for $1. And he asked why if the island was so historic he could never attract city schools to bring students there?

Cushing also pointed out that almost none of the windows, paint, porches, stairs, roofs or other features of the buildings are original.

“Everybody thinks it hasn’t changed, but it has changed quite a bit,” Cushing said. “And everyone wants it to stay the same.”