Springtime brings hundreds of thousands of fish to a place that was meant for no such thing.
The Holyoke Dam spans the Connecticut River (and generates hydropower) between Holyoke and South Hadley, Massachusetts.
The dam stands across the route fish use to reach their spawning grounds.
American shad must find a way safely past the dam.
Each year, American shad migrate upstream from the Atlantic Ocean to where their lives began.
In 2026, more than 470,000 American shad did just that.
The obstacle standing across the route
Although the dam is a significant obstruction to migratory fish, the Holyoke Dam sits about 30 feet above the water level and diverts water through its hydroelectric facilities and canal system.
Without aid, many migratory fish will fail to pass the dam.
To overcome this problem, there is the Robert E. Barrett Fishway.
Instead of using traditional “fish ladders”, the fishway utilizes two fish lifts (or elevators).
The lifts collect fish entering areas immediately beneath the dam.
Those collected fish are then elevated over the dam prior to release further upstream.
Once released, the fish may continue their migration toward their spawning grounds.
Since construction, the fishway has operated for decades and remains one of the most successful fish lift systems on the Atlantic coast.
Fish passing through each of the two lifts are monitored and tallied throughout the entire duration of their migrations.
How nearly half a million shad passed
As per Holyoke Gas & Electric, a total of 470,407 American shad migrated through the fishway in 2026.
Migrations occur between April and June.
The first American shad of 2026 arrived via the fishway on April 15th.
By mid-May, things picked up remarkably quickly.
On May 5th, a single day saw more than 42,000 shad pass through the lifts.
An even larger number, 45,255, passed through on May 20th.
Additional days later in May produced daily totals exceeding 20,000 shad.
By the last week of May, cumulative totals had exceeded 434,000 American shad.
Only a small handful of additional fish entered the totals in late June.
Ultimately, the annual tally stood at 470,407 American shad.
Visitors can watch portions of the migration through underwater viewing windows at the Robert E. Barrett Fishway during the operating season.
The remaining tally consisted of 8,071 Sea Lamprey; 173 Striped Bass; 113 Blueback Herring; and 13 Gizzard Shad.
The return to their spawning grounds each spring
American shad migrate to the ocean as juveniles, mature there, and typically return to freshwater to spawn for the first time at about age 4 or 5.
As adults, every spring, they return to the original freshwater rivers and streams where their life cycles started in order to reproduce.
The Robert E. Barrett Fishway provides a mechanism for migrating fish to pass by the dam and continue their migration upstream.
Holyoke Gas & Electric has taken numerous actions to enhance fish passage since obtaining operation of the Holyoke Hydro System in 2001.
Amongst those activities were structural modifications made to increase the capacity of both the fishway and provide improved methods for safe movement of fish downstream and upstream.
What nearly half a million fish revealed
The successes experienced during the 2026 migration illustrate how these enhanced systems work at large scales.
Over a period of three months, the fishway moved nearly half a million American shad past a structure created exclusively for regulating water flow and generating electricity.
The dam is still firmly intact today along the river.
Yet so too is the natural migration route today.
Each spring, when the fish lifts begin operating and the fish arrive again, yet another generation begins their own journey upstream through one of the largest fish passes along the Atlantic coast.
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