Numeric Simulation Demonstrates That the Upstream Movement of Invasive Bigheaded Carp Can Be Blocked at Sets of Mississippi River Locks-and-Dams Using a Combination of Optimized Spillway Gate Operations, Lock Deterrents, and Carp Removal

Abstract

Invasive bigheaded carp are advancing up the Upper Mississippi River by passing through its locks-and-dams (LDs). Although these structures already impede fish passage, this role could be greatly enhanced by modifying how their spillway gates operate, adding deterrent systems to their locks, and removing carp. This study examined this possibility using numeric modeling and empirical data, which evaluated all three options on an annual basis in both single LDs and pairs under different river flow conditions. Over 100 scenarios were modeled. While all three approaches showed promise, ranging from 8 to 73% reductions in how many carp pass a single LD, when employed together at pairs of LDs, upstream movement rates of invasive carp could be reduced 98–99% from current levels. Although modifying spillway gate operation is the least expensive option, its efficacy drops at high flows, so lock deterrents and/or removal using fishing/trapping are required to move towards complete blockage. Improved deterrent efficacy could also offset the need for more efficient removal. This model could help prioritize research and management actions for containing carp.

Movements of a model fish, the common carp, through a generic Mississippi River lock and dam demonstrate how fish swimming performance, behavior, and discharge‐driven flow‐fields determine fish passage rates in ways that can be predicted and modified using fish passage models

“…The overall annual passage of common carp at LD8 was estimated using the S‐FPM (Zielinski & Sorensen, 2021). The S‐FPM used fish movement rates and route selection informed by field data and gated spillway FPI values from the FPM to estimate a total passage rate through LD8 across the study period.…”

“…Most recently, this modeling approach has been expanded (Gilmanov, Zielinski, Voller, & Sorensen, 2019) and FPM values have also been incorporated into a stochastic size‐structured fish passage model (S‐FPM) that creates estimates of fish passage rates across entire years and considers lock passage as well as fluctuating discharge (Zielinski & Sorensen, 2021). This model integrates output from the FPM on fish passage based on annual discharge, fish route choice (tendencies to swim up‐ or down‐stream through spillways or locks), and fish size to estimate overall passage rates through specific LDs.…”

Introduction to the Biology and Control of Invasive Fishes and a Special Issue on This Topic

“…[11]; enhanced/targeted fishing [4]; introduction of new predators or management of extant ones, especially predators for vulnerable young [3]; and introduction of novel pathogens [12]. Important abiotic approaches include the strategic use/development of new piscicides (fish poisons) [13], and the development of physical techniques to selectively block movement/migration of invasive fish into new areas where they might breed successfully [14,15]. It has been a major challenge to develop techniques that are simultaneously effective and highly specific, and also acceptable to the public.…”

“…In a study addressing bigheaded carps, Zielinski and Sorensen [15] focus on how the upstream of movement (i.e., invasion) of bigheaded carp through locks and dams in the Upper Mississippi River could be arrested. They show how the velocity of water passing through the locks and dams, which already divide this river into a series of pools, could be exploited to arrest carp movement upstream at a few specific locations (i.e., local conditions are very important) by adjusting dam spillway gate openings to increase water velocities and reduce carp passage.…”

“…Perhaps most importantly, Zielinski and Sorensen describe a strategy in which, in addition to adjusting lock and dam spillway gate openings, carp removal would also be conducted at key locations while deterrents such as CO 2 and sound could be added to their locks to affect a nearly complete (99%) block at low cost, even in the event of flooding. Zielinski and Sorensen [15] model over 100 scenarios in the Upper Mississippi River to show how this integrated multi-component control scheme could be immediately implemented at low cost at several key sites (pairs of locks and dams that rarely experience "open-river" conditions) without necessarily substantially affecting native fish populations in the river as a whole because particular species and locations can be targeted. Like McColl and Sunarto [13], real biological data are used, meaning that this strategy could be implemented and at low cost.…”