Upstream migration of the American eel in the Shenandoah River, upper Potomac River drainage

Upstream migration and dam passage of American eels within the Shenandoah River were studied from 2003 to present.  Eel ladders were installed at three dams on the Shenandoah River; Millville, Warren, and Luray.  Data collected at eel ladders include eel counts, weights, total lengths, ages, and environmental variables associated with migration. Also, PIT tags have been used to monitor upstream movements. Over 10,000 eels have been counted at the Millville Dam eel ladder since 2003.  Eels using the ladder were typically between 200 and 550 mm in length, and range in age from 3 to 9 years.  Upstream movements of eels during spring, summer, and fall were associated with an increase in river flow and darker nights on or near a new moon. Monitoring of eel ladders at Millville, Warren, and Luray will continue, and additional ladders are planned for dams farther upstream within the watershed at Newport and Shenandoah, which will allow a more comprehensive study on eel movements within the Shenandoah River watershed.