2025 Midwest Fish & Wildlife Conference

AUTHORS: Devon C. Oliver, MNDNR; Loren Miller, MNDNR; Anthony Sindt, MNDNR; Cristian Hernandez, University of Minnesota

ABSTRACT: Redhorse species face a diverse array of impacts and conservation issues but often remain overlooked relative to their sportfish counterparts. Furthermore, they often lack constituency groups that advocate for their conservation. River Redhorse is a member of the Catostomidae family that have experienced reductions in abundance and range over the last century and are listed as critically imperiled in Kansas, New York, Louisiana, and Florida, imperiled in Wisconsin, Michigan, Virginia, and North Carolina, and vulnerable in Illinois, Indiana, West Virginia, Mississippi, and Georgia; additionally, they are listed as a species of special concern in Canada. Furthermore, like many potentially imperiled or vulnerable catostomid species, River Redhorse suffers from a paucity of demographic and life history information. Additionally, for River Redhorse, there is some ambiguity as to which morphological characteristics should be used to positively identify them relative to Shorthead and Greater Redhorse, which must be addressed first. Morphometrics and meristics used to determine species id can be highly variable, require harvest of the specimen, subjective, or are inconsistent in their determination across metrics both within and across different source material. To address this knowledge gap and to provide clarity in species identification for biologists and conservation hobbyists this study, 1) evaluated and compared morphometrics and meristics used to positively identify River Redhorse relative to Shorthead and Greater Redhorse, 2) determined useful morphometrics and meristics for identification of the three redhorse species within Minnesota based on genetically confirmed specimens.

AUTHORS: Drew Holloway, Muncie Bureau of Water Quality

ABSTRACT: Technology and standardization in electrofishing has come a long way over the years. For this presentation I will be using two of these technologies to help guide future sampling efforts for the Bureau of Water Quality in Muncie, IN. In 2022, we purchased the Smith-Root Apex electrofishing box to replace our outdated and heavily bandaged GPP Electofisher. Now, our historical monitoring stations could be GPS tracked and digitally recorded allowing us to see how yearly variation could affect our electrofishing results. Having previously recorded Side Scan Sonar (SSS) for these same historical sites it gave us the opportunity to not only see if habitats sampled are representative to the species found at each site but if a change in path also changed our fish community diversity. Three years of single pass electrofishing data will be presented from 10 randomly selected West Fork White River sites. The associated habitats will be represented based on SSS categories from previous works done by the Bureau of Water Quality.

AUTHORS: Kristen Bouska, U.S. Geological Survey, Upper Midwest Environmental Sciences Center; Levi Solomon, Illinois Natural History Survey, Illinois River Biological Station; Andy Bartels, Wisconsin Department of Natural Resources; Jim Lamer, Illinois Natural History Survey, Illinois River Biological Station; Hae Kim, Missouri State University; Quinton Phelps, Missouri State University

ABSTRACT: Vital rates (i.e., recruitment, growth, and mortality) are the processes responsible for changes in abundance and biomass of a population through time. Knowledge of vital rates and the factors that contribute to interannual variability in vital rates can provide critical information in determining why fish population abundances increase or decrease across time and space. Between 2018 and 2020, over 2,500 individual Bluegill were collected from five study reaches on the Upper Mississippi River and one study reach on the Illinois River. Together these study reaches span nearly 1500 river kilometers and 7 degrees of latitude and represent gradients such as temperature, discharge, and clarity. From the collected individuals, otoliths were extracted, and ages were estimated. Hierarchical growth models were used to estimate growth model parameters and mean-length-at-age for each species and study reach. Logistic regression was used to estimate average age and length at maturity. Study reach-specific age-length keys were created to assign ages to unaged fish collected during standardized sampling and used to estimate indices of recruitment, stock and annual mortality. We first investigated patterns in growth, maturity, recruitment, and mortality across study reaches. Next, we sought to understand the relative contribution of stock density, habitat availability, temperature gradients, and disturbance dynamics on population dynamics. With this presentation, we aim to improve our understanding of how and why bluegill populations vary across these two large rivers and plan to extend our analyses to several other species of interest.

AUTHORS: Michael Louison, Mckendree University

ABSTRACT: Microplastics have emerged as a major contaminant of concern in a host of ecosystems, including freshwater systems. Previous work has documented the abundance of microplastics in the bodies of various organisms, finding that aspects of an animal’s niche (feeding habits, habitat choice, etc.) may influence exposure to microplastic contamination. To further our understanding of microplastic abundance in freshwater systems, we conducted a survey of freshwater fish taken from the lower Kaskaskia River in Southern Illinois, USA. The first sampling site (done via direct current boat electrofishing) was stationed directly below the Carlyle Lake dam (a heavily used recreational site with abundant pollution from litter) with two additional downstream sites also sampled. Five species of fish (flathead catfish Pylodictis olivaris, freshwater drum Aplodinotus grunniens, smallmouth buffalo Ictiobus bubalus, white crappie Pomoxis annularis, and gizzard shad Dorosoma cepedianum) of differing feeding ecologies were sampled, dissected, and subsequently examined for microplastics both visually (examinations of gills and stomach contents under microscope) and chemically (analysis of nanoplastic concentration in muscle tissue). Results revealed differences in microplastic load between fish species and between sites, as well as differences in measures of contamination using visual and chemical methods. Our results add to the present knowledge of microplastic abundance in organisms, and specifically how feeding type and proximity to sources of human pollution may impact microplastic abundance in freshwater fish.

AUTHORS: Ella Humphrey, University of Nebraska Lincoln; Jonathan Spurgeon, U.S. Geological Survey & Nebraska Cooperative Fish and Wildlife Research Unit; Sarah Sonsthagen, U.S. Geological Survey & Nebraska Cooperative Fish and Wildlife Research Unit

ABSTRACT: Climate change may impact the persistence of fish species based on their ability to adapt to changing environmental conditions, such as decreasing flows and rising temperatures. Fish rely on temperature regimes within their thermal tolerance to maintain metabolic processes. Thus, temperatures outside these tolerances will result in fish losing the ability to continue metabolic processes resulting in severe stress or death. Bigmouth shiner Hybopsis dorsalis is widespread throughout Nebraska and previous studies indicate that increasing temperatures may affect their range. Therefore, we evaluated the critical thermal maximum (CTmax) of H dorsalis and analyzed their expression of heat shock protein 70 (HSP-70) to quantify a thermal stress response over a gradient of temperatures (25-31°C). We found that HSP-70 expression was upregulated in response to temperatures >25°C, indicating a stress response. We then compared this thermal threshold to the yearly maximum temperatures from 42 rivers and streams in Nebraska to determine areas where H dorsalis may already be at risk for thermal stress within their range. About 88% of the sites surpassed 25°C at some point between May and September. This study provides evidence that H dorsalis may be experiencing thermal stress across Nebraska, which future climate scenarios may worsen.

AUTHORS: Ryan Skowronski, Eastern Illinois University; Eden Effert-Fanta, Eastern Illinois University; Dan Roth, Eastern Illinois University; Trent Thomas, Illinois Department of Natural Resources; Robert Colombo, Eastern Illinois University

ABSTRACT: The Midwestern landscape has been converted from forests and prairies into land used for urban development and agricultural practices over the past two centuries. This transformation in landscape composition has disrupted ecosystem function and reduced the stability of stream habitats by accelerating bank erosion, decreasing riparian buffers, and lowering water quality. These changes have led to the degradation of stream habitat heterogeneity, which is a key factor influencing the biotic integrity of fish assemblages. Habitat restoration is a common mitigation strategy for reversing stream degradation, though empirical research evaluating the effectiveness of habitat restoration is insufficient in the Midwestern United States. This study aims to investigate the temporal shifts in fish biotic integrity in four Illinois streams restored in the past 15 years using historical fish community data. We expect habitat enhancement to initially disrupt fish assemblages but show an overall increase in biotic integrity in restored sites over time with a rise in habitat specialist and intolerant fishes. Evaluating the outcomes of these restoration projects is critical to conserve fish communities in degraded streams and improve future restoration methods.

AUTHORS: Hannah Lenning, Iowa Department of Natural Resources/University of Nebraska at Kearney; Melissa Wuellner, University of Nebraska at Kearney; Seth Fopma, Iowa Department of Natural Resources; Keith Koupal, Nebraska Game and Parks Commission; Jayne Jonas-Bratten, University of Nebraska at Kearney

ABSTRACT: This research evaluates the impacts of restoring backwaters, a habitat type in large floodplain rivers that are essential for maintaining their high diversity of fauna. The restoration of backwaters has been an integral part of managing fish populations on the Upper Mississippi River since 1990 and is a major component of the Upper Mississippi River Restoration Program. This research looks at a 2013 restoration project that expanded on the traditional approach by restoring multiple backwaters in a single effort, resulting in 63 acres of backwater channels dredged within four backwaters, proximal in space (within 14-km reach) and time (2013-2017). Here, we evaluated whether benefits of restoration (increased catch or shifts in size structure) are observed beyond project boundaries and identified species that are indicators of backwater restoration, comparing two river reaches using a BACI approach. The river reach containing restored backwaters (Pool 12) is the Impact area, and a downstream river reach without restored backwaters (Pool 13) is the Control area. Historical, day electrofishing data was utilized, with the before period including sampling years prior to any construction (2006 – 2012) and the after period including years after construction concluded (2018 – 2024). For representative species, relative abundance was compared using the Kruskal-Wallis test. Nonmetric multidimensional scaling (NMDS) was conducted to visualize the similarities and differences between fish assemblages of each BACI group. Finally, indicator species analysis was conducted on each BACI group, which identified indicators of river reaches with and without this approach to backwater restoration. Understanding the scalar impact of Pool 12 restoration and its impact on fish assemblages informs the future planning of restoration projects to maximize program resources and efficiency.

AUTHORS: Tyler Hessler, Missouri Cooperative Fish and Wildlife Research Unit, School of Natural Resources, University of Missouri; Craig Paukert, U.S. Geological Survey, Missouri Cooperative Fish and Wildlife Research Unit, School of Natural Resources, University of Missouri; Yi Shang, Department of Electrical Engineering and Computer Science, University of Missouri; Zhenduo Zhai, Department of Electrical Engineering and Computer Science, University of Missouri; Shiqi Wang, Department of Electrical Engineering and Computer Science, University of Missouri; Jason Persinger, Missouri Department of Conservation

ABSTRACT: The use of side-scan sonar has seen a dramatic increase in use in a variety of studies including those with the aim to characterize fish habitat. Side-scan sonar has been used to quantify habitat for well over a decade now and has seen promise in a variety of aquatic systems from coastal reefs to backwater bayous. The use of UAS (also known as aerial drones) has also seen more frequent use in mapping features in aquatic systems. In our study, we propose the use of side-scan sonar and UAS to better standardize and streamline the collection of fish-relevant habitat data in non-wadeable, mid-sized rivers. Traditionally, identifying habitat from side-scan sonar and aerial imagery was a manual process that could take several hours to days to complete a site. The amount of data that can be quickly accumulated in riverine systems can be daunting, but the use of AI and other software may streamline the implementation of these data and provide another option for a manager’s toolbelt that can increase confidence associated with making informed decisions that rely on accurate habitat data. To date, we have conducted 25 side-scan surveys across 8 sites across the state of Missouri totaling over 80 river kilometers. In addition, we have conducted 30 UAS surveys across these 8 sites as well as another site just used for UAS imagery. Developing a standardized protocol using side-scan sonar and UAS with the power of AI modeling could significantly increase the quality of data collected in mid-sized rivers and also decrease the costs associated with collecting habitat data and delineating imagery manually.

AUTHORS: Tyler Ham, Missouri Department of Conservation; Shane Bush, Missouri Department of Conservation; Nathan Recktenwald, Missouri Department of Conservation; Christopher Brooke, Missouri Department of Conservation

ABSTRACT: As many reservoirs constructed throughout the USA continue to age, the quality of the fish habitat in these reservoirs has experienced a concomitant decline. Fish and wildlife agencies, nongovernmental organizations, and concerned anglers have all sought to supplement natural fish habitat by installing habitat structures to concentrate fish and improve angler catch rates. In Missouri reservoirs, these structures are primarily composed of submerged cedar, hardwood, or mixed cedar and hardwood trees. Being natural materials, these structures decay over time and require maintenance to provide adequate fish cover. To that end, there exists a paucity of knowledge on the physical longevity of these structures installed in Missouri reservoirs. The objectives of this study were to define the current condition and longevity of fish habitat structures in Missouri reservoirs and to provide management recommendations for the most efficient long-term maintenance and enhancement of habitat structures. Sonar imaging was employed on Table Rock Lake, Bull Shoals Lake, and Harry S. Truman Reservoir in Missouri to generate qualitative categorical condition scores for fish habitat structures. In each reservoir a spectrum of structure types was assessed that represented multiple year classes spanning over a decade. Condition scores were used to further categorize structures based on maintenance needs. We also examined the influence of depth, location, and material on structure longevity. This project focused on evaluating the controllable factors that can improve effectiveness and efficiency of fish habitat projects. Identifying the impact of these factors on fish habitat enhancement projects will have direct application to future decision making and benefit anglers using Missouri reservoirs.