Atlantic salmon recovery in Maine advances with Kennebec dam project

Biologists are reintroducing Atlantic salmon to the Sandy River using egg-planting and stocking, and a Nature Conservancy-led effort to buy and alter or remove four Kennebec River dams could reconnect habitat and allow fish to reach the Sandy River within about ten years.

Biologists and conservation groups are working to restore Atlantic salmon to the Sandy River watershed in Maine after the species was extirpated there in the 1800s when dams blocked passage. Field crews use an egg-planting technique that places fertilized eggs in stream gravel so juveniles hatch and grow in place. Most Maine salmon now depend on hatchery stocking, but natural reproduction and egg-planting have produced some returning adults in recent years. Key facts: - Field teams place fertilized salmon eggs into gravel cavities that mimic natural redds; the method was adapted from a prototype used in Alaska. - Christman and colleagues estimate the 495,000 eggs planted this year could lead to roughly 20 returning adults, and a single planting of 25,000 eggs might produce about 10,000 juveniles and potentially one returning adult in 2029 or 2030. - Juvenile salmon typically spend two to three years in freshwater, then two to three years at sea near Greenland before returning to Maine as adults. - A Nature Conservancy plan to buy four dams on the Kennebec River from Brookfield Renewable Partners seeks to free passage from the ocean to the Sandy River; the conservancy is raising $168 million to purchase the dams. - Project leaders estimate restoring free-flowing conditions could cost about $308 million and take up to ten years, and the plan may combine dam removal with other measures in coordination with local communities and businesses. - The proposal faces opposition from a paper mill that uses one dam for water supply, and the Federal Energy Regulatory Commission must approve the deal; opposition could delay or alter the project. Summary: If the dam purchase and subsequent modifications proceed, salmon could once again swim from the Gulf of Maine to Sandy River spawning grounds without being trucked around barriers, continuing a process of reconnecting the Kennebec that began with the 1999 Edwards Dam removal. The effort is gradual and uncertain, with fundraising, regulatory approval and local stakeholders cited as the next steps and possible points of delay.