Holyoke Dam fish elevators passed 470,407 American shad during the 2026 migration
With each new spring, there will be millions of gleaming silver scales below the surface of the Atlantic Ocean as American shad embark on a hard journey back home.
By instinct, these saltwater fish migrate towards the mouth of the Connecticut River, swimming upstream against strong currents in order to get back to their previous spawning areas.
When they reach Holyoke in Massachusetts, their path meets an impenetrable wall of industrial might, 30 feet high and 1,080 feet long, spanning across the fast-flowing river.
The migrating fish are led through tailrace channels by flowing water into submerged hoppers and lifted 30 feet in the air vertically and then let go upstream.
Why the shad need an elevator
For over a century, this artificial barrier channeled the natural flow of water to drive local machinery and severed the aquatic corridor entirely.
How such large numbers of migrating travelers manage to navigate this colossal barrier of granite and survive is one of the most impressive examples of ecological engineering on the American East Coast.
American shad are anadromous fishes who spend most of their adult life in coastal ocean waters but come back into the rivers for reproduction. These fishes migrate into the Connecticut River each year during the spring season, coming up in Holyoke around the end of April or beginning of May.
Human demands, however, became an obstacle to this movement.
This is because of the construction of the Holyoke Dam in its current granite structure in 1900 with the use of the adjustable rubber bladder system in storing the water that exerts enormous hydrostatic pressure through huge hydroelectric turbines.
Though the fall is designed to generate energy from natural sources, it becomes an insurmountable obstacle to this migration process.
Two lifts do the work
In order to overcome this steep vertical problem, engineers did not use the conventional method of fish ladders, which tire out the ocean fish traveling in the current.
Rather, the Holyoke Gas & Electric, the municipal utility company that operates there, came up with another solution called the Robert E. Barrett Fishway.
The system is the first fish lift ever built along the Atlantic coast.
It is based on two enormous industrial elevators.
The migrating fish are led through tailrace channels by flowing water into submerged hoppers and lifted 30 feet in the air vertically and then let go upstream.
In addition to transporting fish, the Robert E. Barrett Fishway is a biological counter station.
Fish biologists observe and count every single organism that swims up the Connecticut River.
The run climbed from two fish to 470,407
The above mechanical system was observed during the 2026 migratory season. The first two American shads of the season arrived in the hopper and migrated over the dam on April 15. As April progressed, the traffic kept increasing such that by April 30, 8,119 had been counted.
During the early parts of May, when the temperature of the river started rising, migratory behavior became intense.
As many as 42,407 shad migrated on May 5 alone. On May 20, 45,255 made their way up the elevator and raised the count for the season to 298,230.
By the end of May, there were 434,953 shad migrating through the elevators over the granite obstacle.
Migratory traffic decreased gradually through June and finally ended when only three fish migrated on June 30, thereby marking the end of the season with an unbelievable count of 470,407 fish.
Shad were not the only animals going up
The vertical elevators move all migratory species that need passage through the river. According to the 2026 HG&E statistics, there were 8,071 sea lamprey, 173 striped bass, 113 blueback herring, and 13 gizzard shad in addition to the main shad migration.
This river is home to organisms with highly diverse lifecycles.
Whereas shad, herring, and sea lamprey migrate from the ocean into the rivers to reproduce, American eels have exactly the opposite life cycle, migrating from fresh water into the Sargasso Sea over thousands of miles for reproduction.
The dam is right within the largest biological superhighway in America running along the entire coast of the eastern side.
The turbines and migration share the same river
The Holyoke Gas & Electric facility is still an important source of industrial energy.
The main station belonging to HG&E is the Hadley Falls station that has two hydroelectric generators that generate 33 megawatts of capacity, while the Holyoke Canal system generates another 17 megawatts of capacity with its other powerhouses.
The generation of clean energy and animal migration constitute the eternal problem of engineering each year.
The very dam erected for harnessing hydropower blocks a centuries-old biological route.
However, in 2026, nearly half a million American shads swam up to this 30-foot-high granite dam—and did not stop there but used the Robert E. Barrett Fishway to reach their destination.
Kelly is an experienced writer with 15 years of experience exploring the big stories that shape our world, from tech breakthroughs and space exploration to climate, energy, and the fascinating quirks of science. She has a talent for turning complex ideas into sharp, memorable insights that stay with readers long after they’ve finished reading.
