For thousands of years, the annual fish runs on Maine rivers like the Kennebec were a sight to behold. Atlantic salmon, some weighing as much as 15 pounds, migrated thousands of miles from waters off Greenland to reach their traditional Maine spawning grounds come May. Alewives, blueback herring, and shad joined them. Swimming against the current, the fish would leap above the river’s waterfalls. The yearly rite was a reassuring sign of a healthy ecosystem and a thriving salmon population, a critical resource for the original inhabitants of Wabanaki, Maine.
Then, the fish stopped coming. Beginning in the late 1700s, hydropower-hungry industry began to dam Maine’s major rivers. Populations of alewives, blueback herring, and shad fell. And the numbers of Atlantic salmon declined, too, sinking so low that, by the year 2000, the species landed on the endangered species list.
“When dams prevented Atlantic salmon from returning to their native waters, it meant the near extinction of the fish from U.S. waters,” says Sean Mahoney, CLF vice president for Maine. “It also harmed the people, communities, and wildlife that depended on those fish for food.”
The Dam Problem
The Kennebec River is emblematic of the damage dams can do to healthy rivers. For decades, dams blocked fish passage in Maine, causing a series of cascading problems. Dams alter water flow and temperature, reducing habitat diversity and causing sedimentation changes. Dams also stagnate water, raising water temperatures and killing off species requiring cooler conditions. Changes in water flow and temperature can also kill off insects, a vital food source for fish.
“Over time, people began to see all the downsides to interrupting the natural flow of water,” says Mahoney. “After Congress passed the Clean Water Act, water quality improved, and more people started calling to remove the dams blocking Atlantic salmon’s annual migration.”
A Revitalization and Vindication
For the next few decades, authorities began to act with a renewed understanding of the importance of free-flowing rivers. In 1999, Maine removed the Edwards Dam on the Kennebec River in Augusta. It was the first major dam to be removed in the United States.
With that dam gone, the lower Kennebec roared back to life. Migrating fish, like alewives, blueback herring, and shad returned. So did the eagles, egrets, and ermine that feed on them. Atlantic salmon once again began to venture up the Kennebec, although not in the prodigious numbers of the past.
“It’s not rocket science,” says Mahoney. “If you improve water quality and access, the fish will come back. And once they come back, the rest of the ecosystem has a chance to rebuild.”
Although Atlantic salmon are back, all is still not well. Salmon swim the river in relatively small numbers. That’s because four dams owned by Brookfield Renewable Partners, an international multi-billion-dollar energy giant, continue to block passage to salmon spawning grounds in the Sandy River. The four dams – the Lockwood, Hydro-Kennebec, Shawmut, and Weston – are still generating power (unlike thousands of small dams across New England blocking fish passage). CLF has worked with the Natural Resources Council of Maine, the Atlantic Salmon Federation, Maine Rivers, and Trout Unlimited to sue Brookfield for violating the Endangered Species Act by allowing its dams to kill large numbers of Atlantic salmon. We also oppose the company’s efforts to secure a new federal license to operate their dams for another 40 years.
“The value of the power generated by the dams is questionable considering their negative impact on the endangered Atlantic salmon and Maine’s ecosystem,” says Mahoney.
Working to Restore Maine Ecosystems
As more residents grasp the importance of restoring Maine’s river ecosystems, the state continues to make progress. Maine has removed more than 50 dams over the last four decades, and CLF has played a role in those efforts.
In 2007, CLF began working to revive the alewife fish population on the St. Croix River. In the 1980s, the river boasted a population of 2.5 million alewives, but by 2002, thanks to dams, that number had plunged to barely 900. Working with our partners, we reopened fish ladders where dam removal was not possible, and today, alewife numbers have surged nearly to levels last seen four decades ago.
We also pushed to remove portions of the Saccarappa Dam on the Presumpscot River. When the dam was taken down in 2019, alewives and blueback herring, and in smaller numbers, American shad, returned.
More Work to Free Rivers
Today, we have seen the proof that dam removal can dramatically improve river health. We continue to press on, and our efforts are paying off. Last year, a federal court reasserted Maine’s role in relicensing the Shawmut Dam along the Kennebec, allowing the state to weigh in on fish passage and water quality.
Letting rivers run free is critical to bringing millions of sea-run fish back to Maine. It will help us preserve valuable state fisheries and improve the vitality of the Gulf of Maine. Balancing the need for a healthy ecosystem with the benefits of dams requires careful management, but it is possible. At CLF, we are dedicated to finding this delicate balance. With persistence, the annual fish run on the Kennebec may return to the spectacle it once was.