Evaluation of fish passage for assessment of invasive carp deterrents at locks in the Upper Mississippi River

Invasive carp are established in the upper, middle, and lower Mississippi River and their expansion upstream threatens a variety of aquatic ecosystem services including fishing and recreational boating (U.S. Geological Survey, 2021). The physical and operational characteristics of Lock and Dam (LD) 19 restrict upstream movement of fishes because the only upstream fish passage route is through the lock chamber. This restriction might be hindering consistent reproduction and recruitment of Silver Carp Hypophthalmichthys molitrix and bighead carp H. nobilis (collectively referred to as bigheaded carp) enough to reduce their abundance upstream of LD 19. Locks and Dams 14 and 15 are infrequently in open-river condition (defined as the time when the adjustable spillway gates of the dam are raised out of the water, passing unobstructed water through the gates) and may also be limiting the continued upstream spread of invasive carp populations. Upstream passage of fishes at these locations would be limited to the lock chamber for the majority of the year (Wilcox et al., 2004; Bouska, 2021).