Seasonal movements of yellow-phase American eels ( Anguilla rostrata) in the Shenandoah River, West Virginia

American eels undergo extensive upstream migration in Atlantic coastal river systems. Few studies, however, have focused on movements of large yellow-phase American eels near dams in upper watersheds of Atlantic coastal rivers. We examined relationships between stream flow, water temperature, and lunar phase, and movements of radio-tagged yellow-phase American eels (518--810 mm TL) near Millville hydroelectric dam in the lower Shenandoah River, West. Movements of yellow-phase American eels differed among seasons. Water temperature and stream flow were associated with upstream migration during spring. Downstream movements during fall corresponded with decreasing water temperatures and darker nights near the new moon. Localized wandering (upstream and downstream movements) during summer occurred near dusk and dawn, and possibly reflected nocturnal foraging. In relation to hydroelectric facilities and eel passage within the Potomac River drainage, our data support a need for upstream passage during spring when water temperatures exceed 15°C