Dam removals are bringing fish back across the northeastern United States

The removal of aging dams across the northeastern United States is sparking a dramatic resurgence of migratory fish, most notably herring, as waterways that have been blocked for decades are finally restored to their natural flow. In 2024, a wave of dam‑removal projects unfolded from Vermont’s Blake Higgins Dam to Maine’s Edes Falls Dam, New Hampshire’s Kimball Brook Dam, and a sweeping demolition of 27 obsolete barriers in Pennsylvania, none taller than about 20 feet. These efforts are part of a broader national trend in which more than 2,300 dams have been taken out since 1912, with the American Rivers nonprofit reporting that 2024 alone saw the reconnection of over 2,500 miles of fragmented streams. While the high‑profile dismantling of four hydroelectric dams on California’s Klamath River captured headlines for opening 400 miles of salmon habitat, the quieter, smaller‑scale projects in the East are now delivering comparable ecological dividends by re‑establishing spawning routes for a suite of diadromous species.

The ecological payoff of these removals is underscored by the sheer scale of fish habitat that remains blocked in the region: inventories indicate at least 35,000 dams still impede fish runs in the Northeast, including more than 3,000 in Massachusetts, 5,000 in Connecticut, and 9,000 in New York. Yet the recent spate of demolitions is already yielding measurable results. Nathan Furey, a fish biologist at the University of New Hampshire, describes the current “dam‑removal renaissance” as a period where barriers are disappearing faster than new ones are being built for the first time in history. In the Great Bay watershed, which feeds a tidal estuary through seven rivers, historic populations of Atlantic salmon, shad, sea lamprey, American eels, tomcod, sturgeon, alewives and blueback herring are beginning to recolonize. The revival echoes the 19th‑century struggle of Henry David Thoreau, who decried the Talbot Mills Dam on the Concord River for choking shad runs; today, that very dam may soon be dismantled, fulfilling a long‑standing ecological wish.

Looking ahead, the momentum generated by these projects is poised to reshape both riverine ecosystems and regional water management policies. As fish populations rebound, local fisheries, recreational anglers, and commercial harvesters stand to benefit from increased catches and healthier ecosystems. Moreover, the success of smaller, community‑driven removals is influencing state and federal agencies to prioritize barrier assessments and allocate funding for further demolitions, even as the remaining tens of thousands of dams present a formidable challenge. The renewed focus on restoring natural river connectivity also dovetails with broader climate‑adaptation strategies, as free‑flowing rivers can better accommodate shifting precipitation patterns and support biodiversity under warming conditions. In the coming years, the combined efforts of scientists like Furey, conservation nonprofits, and state governments are expected to accelerate the pace of dam removal, turning the once‑static landscape of the Northeast into a dynamic corridor for migratory fish and a model for river restoration nationwide.

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