Light Trapping Reveals Multiple Bigheaded Carp Spawns Upstream of Lock and Dam 19 in the Upper Mississippi River.

This article focuses on the reproduction and larval recruitment of invasive Bighead Carp (Hypophthalmichthys nobilis) and Silver Carp (Hypophthalmichthys molitrix), collectively known as bigheaded carp, upstream of Lock and Dam 19 (LD19) on the upper Mississippi River. Using quadrafoil light traps deployed from 2016 to 2018 in Pools 17–19, researchers documented advanced larval and postlarval bigheaded carp only in Pool 19, confirming successful spawning and recruitment past the yolk sac stage in this critical management zone. Genetic analyses verified the presence of both Silver Carp and Bighead Carp larvae, with evidence of multiple spawning events in 2016 and fewer in subsequent years, suggesting variable recruitment success influenced by environmental conditions. The study highlights the importance of monitoring larval retention and recruitment upstream of LD19 to inform management strategies aimed at limiting the spread of these invasive species.