Fisheries management, Species status assessment

States

Maryland, Pennsylvania

There are four hydroelectric dams on the lower Susquehanna River that provide upstream fish passage fish passage
Fish passage is the ability of fish or other aquatic species to move freely throughout their life to find food, reproduce, and complete their natural migration cycles. Millions of barriers to fish passage across the country are fragmenting habitat and leading to species declines. The U.S. Fish and Wildlife Service's National Fish Passage Program is working to reconnect watersheds to benefit both wildlife and people.

Learn more about fish passage
. The fish passage facilities are owned and operated by the hydroelectric companies:

  • Conowingo Dam (Constellation Energy Corporation)
  • Holtwood Dam (Brookfield Renewable U.S.)
  • Safe Harbor Dam (Brookfield Renewable U.S.)
  • York Haven Dam (York Haven Power Company)

The fish passage facilities are operated in the spring months for the primary purpose of providing upstream passage to American shad, blueback herring and alewife (collectively known as river herring) to reach their spawning grounds in the middle and upper Susquehanna River.

Recently, several invasive fish species have become established in the lower Susquehanna River. Fish passage operations at the dams have been modified to help stop the spread of the invasive northern snakehead and blue catfish upstream into the Susquehanna River and reduce populations of flathead catfish that are already in the Susquehanna. At Conowingo Dam, all fish that are caught in the fish passage facilities are sorted. American shad and river herring are put in a truck and released in spawning habitats upstream of Safe Harbor or York Haven Dams. All invasive fish species are removed and used for research or provided to food shelves. All other fish are returned to the tailrace downstream of Conowingo Dam.

All fish are identified and counted at Conowingo Dam during the spring fish passage season. Preliminary weekly lift counts can be found below:

2024 Fish Counts at Conowingo Dam

ˆReleased Upstream of Safe Harbor or York Haven Dams | *Removed | ˇReleased downstream
Week StartingAmerican ShadˆAlewifeˆBlueback HerringˆNorthern Snakehead*Blue Catfish*Flathead Catfish*Gizzard ShadˇOther Speciesˇ
10 - Mar00000667,483177
17 - Mar000002918,096237
24 - Mar0000079,37352
31 - Mar0000038,511176
7 - Apr0000004,394621
14 - Apr0001112841,427853
21 - Apr56902620779,0482,067
28 - Apr86670649011278,5323,942
5 - May96023745301300,4821,721
12 - May7200115089238,7911,263
19 - May37011235339730,4681,451
Season Totals2,32419491,84343381,016,60512,560

2024 Fish Counts at York Haven Dam

The York Haven Fishway will open on April 1.  Fish counting will be started at a later date.
Week StartingAmerican ShadˆAlewifeˆBlueback HerringˆNorthern Snakehead*Blue Catfish*Flathead Catfish*Other Speciesˇ
0000000
Season Totals0000000

Annual American Shad Fish Counts

YearConowingo DamHoltwood DamSafe Harbor DamYork Haven Dam
199790,97128,06320,828-
199839,9048,2356,054-
199969,71234,70234,150-
2000153,54629,42121,0794,687
2001193,574109,97689,81616,200
2002108,00117,52211,7051,555
2003125,13525,25416,6462,536
2004109,3603,4282,109219
200568,92634,18925,4251,771
200656,89935,96824,9291,913
200725,46410,3387,215192
200819,9142,795125221
200929,27210,8967,994402
201037,75716,47212,706907
201120,571218-
201222,1434,2383,089224
201312,7332,5031,927202
201410,4252,5891,3368
20158,3415,2863,69043
201614,2766,6964,242178
201716,2653,1692,00762
20186,9921,458661-
20194,787570316-
2020485281-
2021*6,825--80
2022*4,597--2
2023*10,021--69

*Starting in 2021, all American Shad collected at Conowingo Dam were transported by truck and released upstream of Safe Harbor or York Haven Dams.  The fish passage facilities at Holtwood and Safe Harbor Dams have not operated since May 2020.

Facilities

Atlantic sturgeon swimming underwater
The Mid-Atlantic Fish and Wildlife Conservation Office works to protect the fish and water resources of the Susquehanna River and Delaware River basins. Our office represents the U.S. Fish and Wildlife Service on the Susquehanna River Basin Commission and the Delaware River Basin Commission.