Invasive carp pose a serious risk to the upper mississippi and missouri river basins

We havedeveloped four projects to better understand the spread, population dynamics, and effects of invasive carp in these systems. First, hybridization between silver carp and bighead carp in the mississippi river basin has been identified from distinctive hybrid gill morphology, but the genetic and ecological mechanisms underlying hybridization remain elusive. Further, the extent of bigheaded carp hybridization could be changing through time but has not been assessed. This work is important as hybridization may dampen population growth if hybrids contribute fewer offspring to the next generation relative to the parental species. Therefore, we will assess the extent introgressive hybridization varies temporally in portions of the UMR, examine potential environmental drivers of hybridization, and potential effects to fitness linked characteristics such as body condition.next, invasive carp are expanding upstream in the mississippi river basin. However, our understanding of the full impacts of bigheaded carp invasions to river ecosystems at different densities is incomplete which hampers our ability to control their populations through early detection, barrier management, and removal. Previous research focused on trophic competition between bigheaded carp and native planktivores and found high diet overlap. However, potential food web consequences of invasive carp on other fishes are unknown. Gradients of bigheaded carp abundance range from absent upstream of tributary dams to dominant in downstream reaches of southern tributaries. This establishes a spatially replicated gradient of carp abundance across the region and presents a timely opportunity to acquire information about how invasive species abundance may influence food webs dynamics. Third, the upper mississippi river invasive carp partnership has identified the area from LD 15 downstream to LD 19 as the intensive management zone (IMZ) for bighead carp and silver carp. Contracted removal efforts have been implemented in this zone since 2016, but the impacts of those efforts are largely unknown. Furthermore, additional contract removals in pools 20-22 began in FY21, and various levels of independent commercial fishing for invasive carp also occur, primarily below LD 19. A robust stock assessment program is needed to more directly evaluate how populations of invasive carps may be affected by current contract removals and control efforts, and to forecast their future response to alternative control strategies. Finally, invasive carp are well-established throughout the missouri river and tributaries downstream of gavins point DAM. Knowing when and under what environmental conditions adult bighead and silver carp are moving into the tributaries will help inform when to monitor the population as well as implement management actions. Understanding the movement range of bighead and silver carp in the missouri river basin, the environmental conditions associated with movements, and the conditions associated with congregations at deterrent barriers currently present in the missouri river basin will allow for the identification of locations where deterrence technologies, concentrated removal efforts, physical barriers, or other emerging technologies can be utilized for containment and control. Identification and evaluation of containment opportunities can facilitate the implementation of deterrent and or removal systems that may limit dispersal, reproduction, or recruitment of invasive carp. A better understanding of the movement and behavior of invasive carp in tributaries and in association with barriers is critical to devising strategies for successful containment.