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ue to COVID-19, monitoring of shad passages will not be done in 2020. The hydro companies on the Susquehanna are taking precautions to ensure plant operators and essential maintenance staff stay healthy and safe.

Shad activity for 2019 began April 1 at Conowingo, the first American Shad passage occurred on April 9. The last day of operations was June 6. Weekly reports are listed below.

YTD Passages


First day of operation in 2019 - April 1
First American Shad passage - April 9
Last day of operation in 2019 - May 31

Reports (week ending): 4/13=6, 4/20=19, 4/27=32, 5/4=1,890, 5/11=3,343, 5/18=3,620, 5/25=4,293, 6/1=4,787


First day of operation in 2019 - April 1
First American Shad passage - May 1
Last day of operation in 2019 - June 5

Reports (week ending): 4/13=0, 4/20=0, 4/27=0, 5/4=227, 5/11=512, 5/18=531, 5/25=539, 6/1=569, 6/8=570

Safe Harbor

First day of operation in 2019 - May 3
First American Shad passage - May 3
Last day of operation in 2019 - June 6

Reports (week ending): 5/4=15, 5/11=296, 5/18=306, 5/25=314, 6/1=316, 6/8=316

York Haven

No operations in 2019*

Susquehanna River Hydroelectric DamsThere are fish passage facilities (fish-ways) at each of the four Hydroelectric Dams on the lower Susquehanna River. Conowingo, Holtwood and Safe Harbor Dams, the first three moving upriver, have fish lifts or elevators. York Haven Dam, the fourth dam, has a vertical slot fish ladder. Fish lifts work by using water currents to attract the migrating fish into a channel. Crowder gates close to crowd the fish over the hopper bucket, and the bucket is lifted vertically to the level of the reservoir upstream. The water and fish in the bucket are then dumped into an exit trough which leads the fish to the reservoir. All of the fish-ways were constructed with viewing windows where biologists count the migrating fish.

Further upstream, the Fabri-Dam at Sunbury is scheduled to have a fish ladder built when state funds become available. Hepburn Street Dam in Williamsport has a ladder in place, which will be upgraded in the near future.

Fish passage operations typically begin at Conowingo on April 1, or when water temperature reaches 50° Farenheit. Fish passage operations upstream are triggered by counts of migrating fish at the next dam downstream. Reports of fish-way activity, numbers and species of fish passed are provided by the dam operators to the Fish and Boat Commission on a weekly basis and are updated regularly and reported on this web page. Very high flow events can disrupt normal fish passage schedules and operations, however, by following updates, observers can get a feel for the beginning, peak, and end of the run. Fish-way operations cease mid-June to coincide with the apparent ending of the run. Declining numbers of fish counted and temperatures increasing to ranges above that of spawning shad trigger the closing of the fish-ways. Dam operators, the U. S. Fish and Wildlife Service and the Pennsylvania Fish and Boat Commission work together to determine fish-way schedules.


​YearConowingo​Holtwood​​Safe Harbor​York Haven​

* The East Channel fishway at York Haven Dam is typically operated April 1 through mid-December but observation of shad and fish passage at the fishway will not occur until 1,000 American Shad are passed at the Safe Harbor Dam fishway. Once manned-observation is initiated (typically, within four days of the 1,000 shad milestone) it will continue until natural resource agencies determine an end date. Factors such as daily shad passage counts at all Susquehanna River fishways, condition of shad passing those fishways, river temperatures and river flows all contribute to determining the end date.