Wild Atlantic salmon, known as the “King of Fish” for their sporting qualities, are on the brink of extinction in the United States. Once numbering as many as a half million in U.S. rivers, Atlantic salmon dwindled to as low as 450 in recent years. The National Marine Fisheries Service has a once-in-a-generation opportunity to help restore this iconic species by insisting on conservation measures to the Kennebec River in Maine. The Kennebec was one of the most productive rivers in the country for salmon and other freshwater-marine fish. Four hydropower projects, owned by the energy conglomerate Brookfield Renewable Partners, prevent Atlantic salmon, American shad, river herring and other species from migrating to and from the ocean in a safe and timely manner and to rebuild sadly diminished populations. These dams account for only 0.4 percent of Maine’s total power generation.
The Kennebec River, along with the Penobscot, are the only two large rivers in the U.S. with extant populations of Atlantic salmon. Salmon in both are endangered, but the Kennebec’s is particularly vulnerable because most of its high-quality spawning habitat is in the tributary Sandy River, upstream of the four Brookfield dams.The small number of returning adult salmon that enter the fishway at the first dam on the river, the Lockwood Dam, cannot get to the Sandy River their own — they must be captured and trucked there. Brookfield’s proposed measures for upstream and downstream fish passage at each of its four dams will not pass Atlantic salmon and other sea-run species in sufficient numbers to restore viable, self-sustaining populations. Not only do these dams impede upriver migrations but their impoundments expose migratory fish to high temperatures, disorient them by reducing river flow speeds, and provide an environment in which predator species thrive. Restoration of these fish is not possible without dam removal.
Shawmut Dam, the third dam on the Kennebec, is currently undergoing Federal Energy Regulatory Commission (FERC) relicensing. As part of that process the Fisheries Service must issue a “biological opinion” that will evaluate the cumulative impact of continued operation of all four Brookfield dams on endangered Atlantic salmon and other sea-run fish. In the past, successful restoration of migratory fish on the Kennebec has only occurred as part of relicensing processes in which federal agencies took bold steps. This led to removals of the Edwards and Fort Halifax dams, which brought dramatic increases in sea-run fish populations; the river herring run in one tributary went from zero over the century and a half before dam removals, to 6 million in only a few years following. Not only are river herring important ecologically as estuarine and marine prey species but commercial fishermen travel far from Maine’s coast to net these fish for scarce lobster bait.
Progress on the Kennebec River has stalled at the Lockwood Dam, and neither Brookfield nor previous dam owners have installed effective fish passage there in the 24 years since the Edwards Dam removal. The National Marine Fisheries Service holds the fate of Atlantic salmon in its hands. The decisions the agency makes in its upcoming biological opinion will help determine whether Atlantic salmon survive or go extinct in the United States. The federal government has shown interest in removing multiple dams on the Snake and Klamath Rivers in the West. The Kennebec is a similarly critical resource in the East, and the Fisheries Service must not condemn it to the same fate as the other great East Coast salmon rivers, the Connecticut and the Merrimack. These rivers have modern engineered fish passage systems that were supposed to restore populations of salmon and other freshwater-marine fish, and they have failed spectacularly. Salmon have disappeared from these rivers.
Maine gets most of its hydropower from a scant number of dams; about nine out of more than 120 generating dams provide more than half of the state’s hydroelectricity. Each of these dams are larger than Brookfield’s four lower Kennebec damsand tend to be higher in watersheds where they do not destroy migratory fish populations. In 2021 alone, Maine installed more solar electric capacity than Brookfield’s four lower Kennebec dams provide, even accounting for the fact that hydroelectric facilities operate more of the time than solar generators. Over the next five years, Maine is likely to install solar capacity greater than five times these dams’ capacity. Maine also has ambitious plans to add thousands of megawatts of offshore wind power to its grid. Brookfield’s lower Kennebec dams are increasingly insignificant as a renewable energy resource.
Society has not done a good job balancing hydropower with sea-run fish resources. The great fish migrations that used to feed much of the country have collapsed, largely due to dams. Engineered fish passage systems have failed to bring these populations back. The National Marine Fisheries Service, the agency most responsible for protecting coastal fisheries resources, needs to take a hard look at the imbalance between using rivers for hydropower and restoring native fish runs. The agency’s upcoming Kennebec biological opinion must start to remedy this imbalance. Endangered Atlantic salmon and the other migratory fish species are not compatible with the continued existence of the four lower Kennebec dams.
John Waldman, Ph.D., is a professor of biology at Queens College, City University of New York. His focus is on aquatic conservation, particularly of freshwater-marine migratory fishes. Waldman is author of “Running Silver: Restoring Atlantic Rivers and their Great Fish Migrations.”