Old Saybrook — Plum Island is one of the ecological jewels of Long Island Sound that should be preserved rather than sold to the highest bidder for development, speakers at a public hearing said Wednesday.

“It is a beautiful, stunning place, and I don’t want to see that ever go away,” said Christopher Mitchell of Old Saybrook, the first of more than a dozen speakers at the General Services Administration hearing on the proposed sale of the 843-acre island, now home to the federal Plum Island Animal Disease Center. The 360 scientists and support staff who work there travel by ferries from Old Saybrook and Orient Point, N.Y.

An employee of the center’s marine division for 15 years, Mitchell said he regularly sees whales, porpoises, sea turtles, and seals, “and that’s just getting to work.”

About 75 people attended the hearing, including Sen. Richard Blumenthal, D-Conn., who said the GSA should recognize the federal government’s responsibility to be a steward of its own natural resources. A 2008 act of Congress requires that the island be sold if the animal disease lab is closed. The Department of Homeland Security, which oversees the lab, decided in 2009 to build a new, higher-security lab in Manhattan, Kan., But no funding is as yet in place for the new lab, which would cost an estimated $1.4 billion. The existing lab is expected to continue operations through at least 2021.

Before the hearing, Blumenthal was joined by U.S. Reps. Rosa DeLauro, D-3rd District, and Joe Courtney, D-2nd District, at a news conference announcing their support for preservation of the island, home to large colonies of endangered roseate and common terns, piping plovers and seals. They were joined by representatives of Audubon Connecticut, Save the Sound, the Citizens Campaign for the Environment, the Nature Conservancy and other groups.

“We already own it,” said David Sutherland, director of government relations for the Nature Conservancy. “We can’t squander this opportunity. This is our generation’s chance to make a big impact on Long Island Sound.”

Old Saybrook First Selectman Carl Fortuna and others at the news conference also lamented the local job losses that would result from the lab closure, and questioned the wisdom of the decision to close the Plum Island lab and build a new one in Kansas. They urged that the decision be reconsidered.

“It makes no sense,” said state Sen. Andrea Stillman, D-Waterford, adding that the existing lab should be modernized and expanded rather than closed. “The common sense solution to this is to leave it alone. What we have on that island now is an extraordinary research facility and an extraordinary wildlife habitat that live together.”

During the hearing, GSA representatives urged speakers to focus comments on the draft environmental impact statement for the proposed sale. The comments will be considered in the final version of the statement, which would be completed by the end of this year, and that will form the basis for the final decision on how to proceed, GSA officials said.

Because of wetlands, beach and dune areas, only about 195 acres of the island are suitable for development, said Josh Jenkins, project manager for AMEC Environment and Infrastructure Inc., the contractor hired by GSA to create the statement.

Moshe Gai, a physics professor at the University of Connecticut’s Avery Point campus in Groton, said it would be foolish to sell Plum Island for private development. Instead, it should be combined with other islands in the eastern Sound into a national park.

“What are you going to do? Sell America?” he asked, sparking applause among audience members. “This is ours. We own it.”

Zell Steever of Groton advocated that the island be turned into a federal research station to study the impact of climate change.

Charles Rothenberger, attorney with Save the Sound, said the draft environmental impact statement is deficient in several areas. A four-season biological survey should have been part of the study, he said. It also fails to address contaminated sites and groundwater that may be polluted, a legacy of the lab’s 58 years of operation.

The statement “does not provide a full and fair discussion of the impacts of the sale” and should be redone, he said.

j.benson@theday.com