Midwest Fish & Wildlife Conference 2016

AUTHORS: Marybeth Brey, U.S. Geological Survey, Upper Midwest Environmental Sciences Center, Brent Knights, U.S. Geological Survey, Upper Midwest Environmental Sciences Center

ABSTRACT: Minimizing propagule pressure is a key objective in minimizing the establishment of bighead carp and silver carp (Hypophthalmichthys nobilis and H. molitrix; hereafter, Asian carp (AC)) in the upper Illinois River and the Great Lakes. Currently, an electric dispersal barrier and contracted commercial fishing are the only measures in place to control fish movement. However, recent data suggest that characteristics of existing locks and dams on the river may also deter fish movement. Downstream of the electrical barrier are five “high-head” dams, including (from upstream to downstream) Lockport, Brandan Road, Dresden Island, Marseilles, and Starved Rock. Evidence in the form of continued low abundance of AC in the navigation pools above Starved Rock dam suggests that the high-head dams might be acting as deterrents to AC because of their design (i.e., gated, with relatively high head). The design of these dams might generally limit AC passage to times when gates are open (during high discharge events) or via lock chambers during spring or fall carp migrations. If the barrier characteristics of these high-head dams under various hydrologic conditions and seasons can be better understood and enhanced with low cost measures, then the number of AC present available to challenge the more comprehensive barriers would be reduced. To determine if these dams act as barriers and if barrier-characteristics of these dams can be enhanced, we used reach-specific hydrologic data, dam-specific design and operations data, and existing telemetry data (Southern Illinois University) on AC dam passage to assess under what conditions and how AC are passing through these dams. Alongside or following this assessment, we’ve begun to evaluate what combination of best management practices (including sound and CO2) at locks could best deter AC from entering or using a lock chamber.