MILLINOCKET, Maine — The Town Council has joined a small but growing list of opponents to a $50 million project to buy and decommission three Penobscot River dams to restore upstream passage for sea-run fish, officials said Tuesday.

Councilors approve of the Penobscot River Restoration Trust’s goal — creating an influx of Atlantic salmon, sturgeon, alewives and other fish in the Penobscot — but they fear that invasive species, such as the Northern pike, also would get into the river and destroy the Katahdin region’s native fisheries.

The PRRT is working to remove the Veazie and Great Works dams and install a fish bypass at the Howland dam. Permits are being reviewed. No timeline has been set.

Laura Rose Day, the river restoration trust’s executive director, said the trust shares the councilors’ concerns. Pike have been in the Pushaw Lake area of the lower Penobscot since at least 2003, state biologists said.

“We have been aware that pike are in the drainage of the river, and that’s why we had a team of experts that looked at that issue,” Day said Tuesday. “There is a risk, but it’s one factor among many.”

The council also objects to the loss of hydroelectric capacity from the Veazie and Howland dams, although the PRRT’s agreement with dam owner PPL Corp. allows for the restoration through other dams of all but 10 percent of the electricity lost.

“At a time when energy independence is front and center on the American agenda and hydropower is a renewable, nonpolluting energy source, it is unconscionable to allow two operating facilities to be rendered inoperative, especially for the dubious purpose of fish restoration that has demonstrated extremely low rates of success over the past several decades in Maine,” council chairman Wallace Paul wrote in a letter to the Federal Energy Regulatory Commission.

FERC is among the agencies that must approve the project.

The council’s disapproval, which culminated in a 6-0 vote Thursday in favor of a resolve and the letter, follows a similar letter sent earlier this month to FERC by the Millinocket Fin & Feather Club. Some former state biologists also have complained about the PRRT’s plan.

“The dams would be removed to meet some altruistic dream of environmental groups who ultimately would like to take out every dam in the world, especially dams in Maine,” Town Manager Eugene Conlogue said Tuesday. “This is not good public policy. It has not been properly put before the public. It is being improperly rushed behind the scenes before people know what it is.”

The trust’s actions occurred in conjunction with many public agencies, with several public hearings, and occurred over several years after a great deal of study, Day said.

And the issue is far from settled, said Richard Dill, regional fisheries biologist for Maine Department of Inland Fisheries and Wildlife based in Enfield. Biologists lack conclusive data that Northern pike, which is among the illegal species most predatory to salmon, are in the main stem of the Penobscot.

Only unconfirmed reports say so, Dill said.

Pike and other predatory species can possibly swim from the Penobscot to Piscataquis rivers, to the east branch of the Pleasant River, then cross over to Upper Jo-Mary Lake and into the West Branch of the Penobscot River, Dill said.

But biologists have not determined whether the connective waters — Upper Ebeemee Lake, Wangan Brook and Sanborn Pond — are deep enough to allow that, Dill said. Their studies are ongoing.

“It could occur,” Dill said of the feared migration of predators. “The likelihood of pike or other predatory fish getting into the watershed there now, or 100 years from now, is hard to tell. I hate to put a timeline on it because it could happen tomorrow.”

Another problem: Pike fisheries usually are created by fishermen, not swimming fish, Dill said. Adult pike have been found in other states to travel 25 miles during a single spawning season, but typically get into waterways when fishermen put them there.

Installing a fish sorting device at Howland was examined, said Dana Murch, a dam and hydropower supervisor for Maine Department of Environmental Protection, but that proved to be very difficult, expensive and not very practical.