GOULDSBORO — Citing “unprecedented scale, unproven technology” and pollution risk, Frenchman Bay Conservancy last month sent a letter to Gov. Janet Mills opposing American Aquafarms’ proposed salmon farm in Frenchman Bay and requesting the project be denied.

Twenty-one additional organizations signed the letter, including the Downeast Salmon Federation, Natural Resources Council of Maine, Friends of Acadia and College of the Atlantic President Darron Collins.

“Very rarely, if ever, does the broad spectrum of environmental, economic and cultural interests represented by the 22 organizations that signed this letter come together with such a clear, single voice,” said Paul Parshley, president of the conservancy’s board of directors. The American Aquafarms “project is not just a small local issue, it is an ill-advised development proposal with ramifications far beyond Frenchman Bay.”

American Aquafarms pushed back this week against the concerns outlined in the letter.

“The yield and economic benefit per acre to the state and local communities from each of these sites will far exceed any comparable alternative use of this area,” according to a response provided Monday, Dec. 6, by American Aquafarms CEO Keith Decker.

“The introduction of clean closed pen technology with waste collection ensures the minimal environmental impact of the operation. Compared to traditional fish farming without waste collection, the impact to the bay is minimal.”

The Norwegian-backed company proposes to raise salmon at two 60-acre sites northwest of Long Porcupine Island and northeast of Bald Rock Ledge in Frenchman Bay. The company notes that it is only seeking 10 acres of each site for exclusive rights to place fish pens (15 at each site). For the remaining acreage, the company seeks “non-exclusive rights for moorings, where lobstering and other activities can and should continue as before,” Decker said.

The company says the project “will have minimal impact on existing fisheries.” Opponents, including local fishermen who joined a “Save the Bay Flotilla” this past summer, disagree given the rich fishing grounds in the area.

The conservancy’s letter questions the technology planned for the site and says it has never before been deployed at this scale. “Their 30 semi-closed pens would allow the daily discharge of an estimated four billion gallons of rinse water containing nitrogen, phosphates, and other dissolved chemicals,” according to the letter. The conservation groups also raise concerns about the potential for fish escape, disease, dissolved contaminants, veterinary pharmaceuticals and “longer-term uncharacterized impacts on the Bay’s floor.”

American Aquafarms countered that closed pen technology has been in use since the 1980s in Norway. “The volume of water circulated through the pens is not a discharge but instead is natural, clean water in which the fish thrive and grow.” Plans for removing fish feces from the water before its release into the bay are detailed in the company’s pending discharge application with the state Department of Environmental Protection.

The American Aquafarms CEO said that use of antibiotics or chemicals are not part of planned operations but may be used in a limited capacity if necessary.

Opponents say the company’s models do not accurately simulate the risk posed to the bay by water released from the pens.

The environmental impact of fossil fuel usage is also at issue. Opponents point to the fuel that will be used to power ten 500kW diesel generators at the pens as well as emissions generated from trucking salmon from the processing plant in Gouldsboro to markets elsewhere.

American Aquafarms said opponents’ calculations of the operation’s fuel usage were “grossly exaggerated.” Decker said average usage would be much lower than installed capacity and the company was exploring other options to power its equipment, including biofuel, wind, solar and electric battery packs. Raising salmon in the U.S., as opposed to air shipping fish from overseas, will substantially reduce CO2 emissions, he said.

As for the project’s ability to adapt to climate change, that’s part of the plan, Decker said. “Closed pens already provide stable water flow and temperature that insulate fish from dangerous conditions already noticeable as climate change impacts offshore waters.”

The company’s reassurances are unlikely to sway opponents, who are deeply concerned about the health of the bay and the wildlife and industries that rely on it.

As the two sides polish their talking points, the conversation is only beginning. American Aquafarms’ two lease applications to the Department of Marine Resources have yet to be accepted as complete. The company has yet to file an application for its proposed land-based operations, including a hatchery and processing facility, at the former Maine Fair Trade plant in Gouldsboro. That town recently enacted a six-month moratorium to assess and possibly update local regulations to cover finfish aquaculture applications.

On May 17, the conservancy requested that the U.S. Army Corps of Engineers conduct an Environmental Impact Statement under the National Environmental Policy Act on the American Aquafarms project. Regulatory review of the company’s application has not progressed yet to the federal level and the Environmental Impact Statement decision is pending.