Total number (N), mean (±1 SE), minimum, and maximum total length (mm) and weight (kg) of Grass Carp Ctenopharyngodon idella captured upstream and downstream of Lock and Dam 19 (LD19) from April to October 2014 and 2015 using boat electrofishing. Located near Keokuk, Iowa, USA, LD19 represents the farthest downstream lock and dam where fish movement upstream is restricted to the navigation locks, creating a semipermanent barrier to upstream movement. Mean Grass Carp length and weight represent mean values across both 2014 and 2015.