2025 Midwest Fish & Wildlife Conference

AUTHORS: *Seth Callahan, School of Natural Resources, University of Missouri, 302 Anheuser-Busch Natural Resources Building, Columbia, MO 65211, bscnh9@missouri.edu
*Presenting author

Jacob Westhoff, U.S. Geological Survey, Missouri Cooperative Fish and Wildlife Research Unit, School of Natural Resources, 302 Anheuser-Busch Natural Resources Building, The University of Missouri, Columbia, MO 65211, westhoffj@missouri.edu

Brett Perkins, The Nature Conservancy, Dunn Ranch Prairie, 16970 W 150th St, Hatfield, MO 64458, brett.perkins@tnc.org


ABSTRACT: Human-made structures such as box culverts and similar road crossings can cause habitat fragmentation within stream networks and require remediation for effective aquatic organism passage. There is increasing interest in restoring habitat connectivity and aquatic organism passage for conservation purposes, along with assessing project effectiveness. Two, low- gradient rock ramps were installed in the forks of Little Creek in Harrison County, Missouri in 2022 to protect existing infrastructure and restore natural aquatic organism passage to over eight kilometers of headwater stream. These first order prairie streams had been eroded by head cutting to the base of each of the box culverts resulting in greater than one meter of drop on the downstream side of each culvert. Installation of the rock ramps at a natural grade sought to restore stream connectivity and allow for aquatic organism passage. We tagged multiple fish species downstream of each rock ramp using passive integrated responder (PIT) and visual implanted elastomer (VIE) tags in the spring of 2024 and used submersible PIT antennas and seining to detect fish movement. We determined that both rock ramps have allowed for fish passage of multiple fish species, including an experimental population of Topeka Shiners. We detected 14.5% of all PIT tagged fish successfully using the rock ramps to move upstream in the first two months of data collection. Three VIE tagged fish were recaptured upstream of the box culverts with seine nets. Our preliminary results highlight effective methods for monitoring aquatic organism passage in prairie streams and the ecological benefits of restored stream connectivity in fragmented habitats.

AUTHORS: Matthew R. Acre, U.S. Geological Survey, Columbia Environmental Research Center; James J. Roberts, U.S. Geological Survey, Lake Erie Biological Station; Dustin W. Broaddus, U.S. Geological Survey, Columbia Environmental Research Center; Ryan J. Trimbath, U.S. National Parks Service, Cuyahoga Valley National Park; Curt P. Wagner, Ohio Department of Natural Resources, Division of Wildlife; Ramsey A. S. Langford, Summit Metro Parks; Eric Waits, U.S. Environmental Protection Agency, Office of Research and Development; Daniel J. Sullivan, U.S. Environmental Protection Agency, Office of Research and Development; Marc A. Mills, U.S. Environmental Protection Agency, Office of Research and Development; Nick Barkowski, U.S. Army Corps of Engineers; David M. Walters, U.S. Geological Survey, Columbia Environmental Research Center

ABSTRACT: Fragmented aquatic systems are ubiquitous across the globe. Dams and other water control structures represent significant barriers to fish passage. In many countries, these structures represent ageing infrastructure which no longer serve their original function prompting an accelerated dam removal period. In the U.S., nearly 1200 dams have been removed in the last two decades. Dam removals serve multiple functions such as securing public safety by removing failing infrastructure, defragmenting riverscapes, and restoring the natural aesthetics of the river. Additionally, removals offer an opportunity to inform conservation science and community recovery in reconnected systems. The Cuyahoga River, infamous for catching fire and one of the driving forces that established the Environmental Protection Agency, has undergone several dam removals since 2006. One of the last remaining dams, constructed in 1913, is slated to be fully removed by 2026. To empirically assess fish community response to current and future restoration efforts we established 12 sites on the Cuyahoga River. We electrofished each site four times annually from 2022 to 2024 following methods of the Ohio Environmental Protection Agency (OEPA). OEPA data was consistently collected on a 5- to 7-year cycle throughout the river and enabled us to directly compare historical assemblages (1987-2017) to more contemporary periods (2022-present). At the time of writing, we have collected over 20,000 fish and representing 60 species. We used ordination analyses, Bray-Curtis distances, and trajectory analyses to link disturbance events with community changes. The best predictor of community changes were dam removals followed by environmental variables such as river discharge. Other community metrics (diversity and richness) and trajectory analysis suggests communities downstream of the Gorge Dam, and with direct access to Lake Erie, are in a dynamic state. These baseline community data are critical to evaluate effectiveness of small and large restoration projects such as dam removals.

AUTHORS: Sophia M. Bonjour, U.S. Geological Survey; Cody G. Bowden, U.S. Geological Survey; Allison A. Pease, University of Missouri; Marc A. Mills, U.S. Environmental Protection Agency; David M. Walters, U.S. Geological Survey; Ryan J. Trimbath, U.S. National Parks Service; Curtis Wagner, Ohio Department of Natural Resources; Ramsey Langford, Summit Metro Parks; Matthew R. Acre, U.S. Geological Survey

ABSTRACT: Habitat fragmentation poses a significant threat to migratory species, particularly when compounded with additional environmental stressors. The Gorge Dam, located in the Cuyahoga River Area of Concern as designated by the U.S. Environmental Protection Agency, is scheduled for removal in the coming years. Dam and associated contaminated sediment removal is a part of ongoing restoration efforts aimed at improving water quality, enhancing fish habitat, and facilitating fish passage. These efforts follow the removal of five other dams along the Cuyahoga River. In this study, we used acoustic and radio telemetry to examine the seasonal movements of two migratory redhorse sucker species from 2023 to 2024). Silver Redhorse (Moxostoma anisurum) remained within the Cuyahoga River year-round, moving upstream an average of 28.8 km from March to April to an area between the historic Brecksville Dam (removed in 2020) and the Gorge Dam. In contrast, all seven Shorthead Redhorse (Moxostoma macrolepidotum) tagged in the river during 2023 migrated from the river into Lake Erie between May and July, moving a minimum of 60 km away from the river and averaging 19 km per day at emigration. Five Shorthead Redhorse returned to the Cuyahoga River between February and April 2024, with most fish moving more than 4 km upstream of the historic Brecksville Dam. Telemetry data provide support that fish are moving into areas reconnected by dam removals in the Cuyahoga River and reveal long-range migration patterns between the river and Lake Erie by Shorthead Redhorse.

AUTHORS: Don Pereira, HDR Inc.; Cory Gieseke, HDR Inc.; Joe Dvorak, HDR Inc.; Riley Adams, Calibre Engineering; Ben Nelson, City of Anoka; Chris Lord, Anoka Soil and Water Conservation District; Martin Weber, HDR Inc.


ABSTRACT: The Rum River in Minnesota is a tributary to the Mississippi River. It flows out of Mille Lacs Lake and joins the Mississippi River approximately 20 miles upstream of the Minneapolis/St. Paul metropolitan area. The Rum River is a significant coolwater ecosystem and is included in the State of Minnesota’s Wild, Scenic, and Recreational River Program. A wooden dam on the Rum River was initially constructed in 1853 to provide power for the early timber industry. After several modifications, the concrete dam today only provides for flood control and a summer recreational pool. The City of Anoka is now evaluating large scale reconstruction/modification and retrofitting to accommodate multiple uses and visions for the community. Candidate uses include hydroelectric power, a lock system for recreational boaters, a whitewater park, fish passage, and safety upgrades. We applied a water allocation model to determine the optimal combination of uses based on the amount of water available throughout the year. Our initial design work indicates that fish passage, a boat lock, and a whitewater park may be feasible. A comprehensive, multi-use system will serve many benefits, and a modernized, gentrified dam will be a key focal point for the local community.

AUTHORS: Jacob Zona, South Dakota State University; Tait Ronningen, US Fish & Wildlife Service; Christopher Cheek, South Dakota State University; Stephanie Webster, South Dakota State University

ABSTRACT: Habitat fragmentation is one of the most pressing issues in conservation biology. Restricting the movement of organisms can limit access to critical habitats during different life history stages, reduce population sizes, decrease genetic connectivity, and ultimately disrupt community structure. There has been a tremendous amount of research and management focused on the impact of large dams on aquatic ecosystems, particularly anadromous fishes. However, the removal or remediation of these structures is often socially unfeasible or financially restrictive. Work focusing on smaller, more abundant barriers to aquatic organism passage (e.g. culverts, low-head dams) has increased in recent years. Considering the wide geographic scope of this issue and the enormous number of potential barriers, careful consideration needs to be taken on where best to focus limited financial resources. As more stakeholders begin working in watershed connectivity, coordination between partners becomes increasingly important. Multiple resources available to managers have been recently developed to aid in this prioritization and coordination. We utilized the USFWS National Fish Passage Coordination Map and the SARP National Aquatic Barrier Inventory and Prioritization Tool to help us more effectively assess stream connectivity across the western Great Plains in partnership with the BLM. Using the NFPCM we prioritized 38 HUC10 watersheds across Eastern Montana based on percent BLM ownership, SGCN fish species richness, amount of stream habitat, and coverage by previous barrier survey projects. We also used the NFPCM combined with other GIS tools to identify, categorize, and prioritize potential barriers within each watershed prior to field surveys. Between July and September 2024, 329 potential barriers were assessed using the Stream Crossing Survey and the Dam and Diversions Survey through SARP. Each survey was uploaded to the NABI where managers can now use the prioritization tool to determine best candidates for remediation based on their specific connectivity goals.

AUTHORS: Mary Khoury, The Nature Conservancy; Erik Martin, The Nature Conservancy; Mark Anderson, The Nature Conservancy; Arlene Olivero, The Nature Conservancy; Analie Barnett, The Nature Conservancy.

ABSTRACT: Over the last century, the ecological integrity of most streams and lakes has declined, and now climate change is altering historic precipitation and temperature patterns, further impacting freshwater environments. In response, The Nature Conservancy’s (TNC) Center for Resilient Conservation Science engaged 60 colleagues over three years to assess river networks in the conterminous United States (CONUS) for resilience to climate change (Anderson et al. 2024). Freshwater resilience is the ability of a freshwater system to sustain biodiversity even as it responds to a changing climate. An integral component of freshwater resilience is aquatic connectivity. Large, diverse, and connected river networks in good ecological condition and with ample, unaltered water are expected to be more resilient because they provide many ways for freshwater species to adapt to changing conditions. TNC’s freshwater resilience analysis results are designed to assist practitioners working to protect or restore freshwater habitats. Available through the Resilient River Explorer (maps.tnc.org/resilientrivers), the two main products are: 1. Freshwater Resilience, a map and spatial database that scores every subwatershed in CONUS for climate resilience and provides users with the component values used to calculate resilience; and 2. the Freshwater Resilient and Connected Network (FRCN), which identifies a representative network of rivers, streams, and wetlands that, if conserved, could potentially sustain the freshwater diversity of CONUS under a changing climate. This presentation will highlight the key components of TNC’s freshwater resilience analysis, introduce the Resilient River Explorer (RRE) web tool and discuss its complementarity with the National Aquatic Barrier Inventory and Prioritization tool (https://aquaticbarriers.org/). While each web tool serves distinct purposes, the two can be used together to inform aquatic connectivity restoration activities that will increase the resilience of freshwater systems.

AUTHORS: Eric Rahm, Stream Biologist, Missouri Dept of Conservation

ABSTRACT: We will highlight the Missouri Stream Connectivity Partnership (MO SCP) and other conectivity teams throughout the Southeastern United States. We will share resourecs avaliable from American Rivers and the Southeast Aquatic Resource Partnership (SARP).

AUTHORS: Steven Bardin, Pro Lake Management/ Major League Fishing

ABSTRACT: Aquatic plant management is no longer exclusively targeted at reactive control. Instead, aquatic plants are considered beneficial habitats impacting the survival, recruitment, foraging success, and growth of fishes while sequestering excess nutrients. These emerging techniques are supported by anglers and strengthened with technological advances.

AUTHORS: Nate Long, Aquatic Control

ABSTRACT: Aquatic vegetation management challenges and opportunities and how we move forward. An overview of tools (herbicide) available for aquatic plant management to resource managers stressing the need for management in systems with an overabundance of plants. A look into challenges facing resource managers when deciding to manage either native or non native aquatic plants for fish populations. Lastly, what opportunities aquatic plant management can provide a fishery.

AUTHORS: Michael Hawkins, Iowa Department of Natural Resources

ABSTRACT: Lake restoration projects in Iowa focus on improved water quality, nutrient management, and habitat restoration. Many of the management actions taken during these projects focus on long-term improvements and stability, but some actions can produce an immediate impact, shifting a lake between turbid and clear water stable states. This shift can have dramatic impacts on aquatic plant densities and diversity. This shift in aquatic plant communities can then trigger a rapid shift in the fish community. These changes have positive ecological impacts and improve fishing opportunities, but this rapid shift in lake biology may present challenges for some users. The methods for lake restoration on three northwest Iowa natural lakes will be discussed along with the impacts on plant and fish communities. Challenges associated with public perception and invasive species will also be presented.

AUTHORS: Nick Kramer, Kansas Department of Wildlife and Parks

ABSTRACT: It is relatively easy to determine when aquatic vegetation should be removed from an impoundment or stream but when should managers consider establishing or maintaining an aquatic plant community? This presentation aims to answer that question by highlighting the many ecological benefits that aquatic vegetation can provide to our aquatic systems.

AUTHORS:  Ray Valley, President and Aquatic Biologist, BioBase LLC, St. Paul MN.

ABSTRACT:  It’s well understood that aquatic plants play a critical role in lake ecosystems at multiple levels. Aquatic plants control water quality and water quality controls aquatic plants. Aquatic plants shape fish communities, structure food webs and facilitate quality sport fisheries. Invasive species disrupt the ecological balance of lakes but are strangely friend or foe depending on what audience you find yourself in. As professionals, fisheries professionals, we get this. We also see that millions are spent in the US each year to control invasive aquatic plants. Despite the stakes, aquatic plant assessment and monitoring programs have generally been underfunded. If monitoring does occur, it is typically focused on frequency of occurrence of aquatic plant species and rarely abundance (biomass or biovolume). Although a great measure of species cover and diversity, frequency of occurrence is a poor measure of habitat as perceived by fish or the total biomass of plants that contribute to a lake’s nutrient budget. More recently, methods have been developed bringing species frequency surveys together with high definition abundance surveys. Now with the advent of Artificial Intelligence and continued innovation of consumer technology, we have the capability to precisely map the abundance of individual aquatic plant species. Investment will be needed to develop, scale, or repurpose technology developed for the consumer world for aquatic and fisheries management purposes.

AUTHORS:  Kara Tvedt, Missouri Department of Conservation; Frank Nelson, Missouri Department of Conservation

ABSTRACT:  Missouri has lost over 90% of its historic wetlands. Hence, many native aquatic and wetland plants have diminished over the last 200 years. At the same time the eutrophication of waterways and water bodies has increasingly led to more frequent harmful algal blooms across the state. One nature-based option for integrated watershed approaches is the strategic incorporation of reintroducing native wetland plants. In urban settings, where armored banklines and fluctuating water levels may prevent the opportunity of shoreline plantings, floating treatment wetlands may be considered. Although a growing number of cities in Europe and U.S. have been using this “green” solution to improve water quality, not all attempts are successful and can prevent the adoption and expansion of these strategies elsewhere. The Missouri Department of Conservation has been trouble-shooting potential hurdles, such as plant establishment and herbivory to increase success and implementation rates. The agency has also been experimenting with floating island designs that are plastic-free to account for the growing concern about plastic pollution and PFAS. This presentation will highlight our collaboration with partners and lessons learned from this pilot work.

AUTHORS:  Jeremy Risley, Arkansas Game and Fish Commission; Sean Lusk, Arkansas Game and Fish Commission; Eric Naas, Arkansas Game and Fish Commission


ABSTRACT:  Black bass anglers in Arkansas have long advocated for establishing aquatic vegetation in reservoirs with minimal macrophyte coverage to improve black bass populations in those systems. Despite facing various challenges along the way, the Arkansas Game and Fish Commission has remained dedicated to fulfilling these anglers' requests by introducing or restoring aquatic vegetation in those reservoirs. In the early 2000s, the AGFC tried introducing submerged aquatic vegetation in Bull Shoals Lake, a 19,504-hectare reservoir in north-central Arkansas. The approach involved planting vegetation in the substrate and protecting it with exclusion cages. Unfortunately, this endeavor was impeded by water fluctuations greater than 10 meters and turtle herbivory, which hindered the successful establishment of the vegetation. However, this failure led to potential successes. In the following years, the AGFC faced another vegetation-related challenge at DeGray Lake, a 5,585-hectare reservoir in west-central Arkansas. A decline in vegetation led to a noticeable reduction in the black bass population. This time, AGFC biologists took a different approach and created floating enclosures known as "Arkansas Floating Cubes" to aid in the spread of aquatic vegetation via wind and wave action and impeding herbivory. The deployment of these structures aided in the increase in vegetation density and subsequently improved the black bass populations over time. Encouraged by this success, the AGFC has expanded the use of the Arkansas Floating Cubes to two other highland reservoirs, Beaver and Greers Ferry Lakes, aiming to replicate the positive outcomes observed in DeGray Lake. The AGFC remains dedicated to employing innovative methods to establish or restore aquatic vegetation in reservoirs with little or no macrophyte coverage, ultimately benefiting sport fish populations like black bass and enhancing angler satisfaction in Arkansas.

AUTHORS: Scott Jones - University of Arkansas Pine Bluff

ABSTRACT: The Arkansas Game and Fish Commission initiated a vegetation re-establishment project on Lake DeGray in 2019 utilizing up to 22 stationary floating vegetation dispersion cages, termed “Arkansas Cubes,” loaded primarily with coontail (Ceratophyllum demersum). A concurrent project using commercially-available down and side-imaging sonar systems was implemented to track the expansion of naturally-rebounding and emerging colonies in sixteen sites featuring Arkansas Cubes and five sites without. Submerged aquatic vegetation was detected throughout lower Lake DeGray from 377 to 405 feet MSL, with coontail detected most frequently between 388 to 397 feet MSL. Coontail was observed in ten of sixteen ‘Cube sites. Eight of those sites had coontail directly underneath the ‘Cubes that did not exist before the ‘Cubes were installed. This is compelling evidence that the ‘Cubes have influenced the development of new coontail colonies. However, significant natural regrowth clouds the true impact of the ‘Cubes as coontail has also been observed in four of five ‘Cube-less sites. Insights on general colonization patterns observed in Lake DeGray will be discussed to help guide surveillance programs on other reservoirs selected for Arkansas Cube trials.

AUTHORS: Jason Euchner, Iowa Department of Natural Resources

ABSTRACT: When managing aquatic plants native or non-native an understanding of what species are present is critical for success. Many methods of plant sampling are used and this presentation will cover why and when the Iowa DNR uses different methods. These methods include presence/absence surveys, comprehensive transect surveys, and point intercept surveys.

AUTHORS: Jeremy Hartsock, Michigan State University, Department of Fisheries and Wildlife; Dan Hayes, Michigan State University, Department of Fisheries and Wildlife; Jo Latimore, Michigan State University, Department of Fisheries and Wildlife; Erick Elgin, Michigan State University Extension

ABSTRACT: Submersed macrophytes strongly influence the structure and function of inland lakes. However, quantitative data are broadly lacking on the distribution and abundance of aquatic macrophytes in northern Michigan. To fill these knowledge gaps, we performed macrophyte surveys at 75 inland lakes in the Northern Lake Huron and Eastern Lake Superior management units using a modified point-intercept survey approach whereby a double sided rake was tossed twice at each sampling point (~100 points sampled per lake). Among all lakes surveyed a total of 60 macrophyte species were observed. Chara sp. was the most frequently encountered macrophyte. The most species rich lake contained 32 species and the most species poor contained 3 species. Of note, we detected aquatic invasive species (AIS) in nearly half of the lakes surveyed. Invasive watermilfoil and starry stonewort were the most frequently observed AIS. An occupancy analysis revealed that a single rake toss approach underestimates the true occurrence of aquatic macrophytes due to incomplete detection probability. We also show that a single rake toss approach yields similar estimates of species richness but requires more points to be sampled than a two rake toss approach. Our experience is that approximately 100 points could be sampled per day with a two rake toss approach, yielding observed species richness close to predicted richness, and providing reasonable precision of estimates of coverage for common species. Future research will focus on comparing our modified PI survey to other macrophyte survey approaches.

AUTHORS:  Curtis Wagner, Ohio Division of Wildlife; Mark Warman, Cleveland Metroparks

ABSTRACT:  Historically, fisheries management has only superficially considered aquatic vegetation when engaging in fisheries assessment and actions. However, emerging invasive aquatic plants such as Hydrilla verticillate (Hydrilla) indicate the need to more fully integrate aquatic vegetation assessment and management with fisheries management. Hydrilla has become widely recognized as one of the world’s most aggressive invasive aquatic plants and is responsible for an array of environmental and fisheries disruptions when left unmanaged. The Ohio Department of Natural Resources, like many other state agencies, does not have a standardized aquatic vegetation assessment program nor a statewide rapid response plan for detected invasive aquatic plants; this deficiency has become most recognized through recent Hydrilla detections. Hydrilla was first detected in an Ohio reservoir in 2011, with multiple small impoundment detections soon thereafter. In recent years, new populations of Hydrilla have been discovered in large, public reservoirs, including one that links the Lake Erie and the Ohio River drainages. Here we will provide an overview of Hydrilla detections in Ohio to highlight the challenges, successes, setbacks, and lessons learned. These case studies highlight the importance of established partnerships, integrated funding, prevention strategies, and effective communication to address Hydrilla detections in a complicated management landscape. Perceptions vary widely among reservoir stakeholders concerning aquatic vegetation and invasive hydrilla; differences in opinions and understanding occur even among anglers. Fisheries managers are encouraged to consider incorporating aquatic vegetation assessments into fisheries management actions and to develop rapid response strategies with relevant partners for future invasive aquatic plant detections.

AUTHORS:  Authors: Augustus McAnally1, Taher Fletcher2, Jeremy Pritt3, Stephen Matter1, and Michael T. Booth4
1Department of Biological Sciences, University of Cincinnati
2U.S. Fish & Wildlife Service, Lake Champlain Fish & Wildlife Conservation Office
3Ohio Division of Wildlife
4U.S. Geological Survey, Michigan Cooperative Fish and Wildlife Research Unit

ABSTRACT:  Abstract: Understanding the effects of habitat on sportfish population characteristics in reservoirs is important for management, however, comprehensive habitat data are rarely available. More recent developments, using side-scan sonar, provide means to create high-resolution habitat data. Most habitat assessments occur within single systems; few have compared habitat metrics among reservoirs to determine the effects of habitat on sportfish populations. Applying a recently developed habitat assessment protocol, we used recreational side-scan sonar to quantify littoral aquatic habitat in sixteen inland reservoirs across Ohio. Aquatic vegetation, large woody debris, and substrate type were manually classified for the entire accessible littoral zone of each reservoir. Currently, we are performing analyses to understand whether reservoir-wide habitat metrics explain variation in catch rates and size structure of Largemouth Bass (Micropterus nigricans) collected during standard spring electrofishing surveys. The study aims to evaluate whether variation in the amount of habitat among reservoirs affects Largemouth Bass populations and determine if aquatic vegetation and other habitat features can be utilized to manage sport fish populations in reservoirs.

AUTHORS:  Robert Davis, Center for Limnology, University of Wisconsin; Ellen Albright, Center for Limnology, University of Wisconsin; Katie Hein, Center for Limnology, University of Wisconsin; Michael Verhoeven, Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota- Twin Cities; Zach Feiner, Center for Limnology, University of Wisconsin & Office of Applied Science, Wisconsin Department of Natural Resources

ABSTRACT:  Aquatic macrophytes provide important habitat for fish at various life stages and can influence fish population characteristics such as growth and size structure. Even though aquatic plants are generally considered to be important to fish communities, the exact nature of the relationship is not well understood. Moreover, multiple factors (climate, aquatic invasive species, nutrient loads) are causing aquatic plant communities to shift through time. Walleye are a culturally and economically important species to the upper Midwest that are currently experiencing declines in recruitment success due to climate change and other factors. In this study, we seek to elucidate the role that aquatic vegetation plays in determining walleye recruitment success. Point-intercept aquatic plant surveys from Minnesota and Wisconsin were used to quantitatively describe plant communities in lakes spanning 2003 to 2018, and annual fall electrofishing recruitment surveys were used to quantify walleye recruitment during the same time period. Random forest models were used to understand the nature of the relationship of aquatic plant communities to walleye recruitment and any interactions that may exist between aquatic plant communities and other important environmental variables previously found to influence walleye recruitment success (e.g., growing degree days, lake surface area). Overall, we hope to determine pertinent interactions between Walleye recruitment success and aquatic macrophyte communities, which could inform habitat management strategies that may benefit Walleye fisheries throughout the region.

AUTHORS:  Zachary S. Feiner, Wisconsin Department of Natural Resources, University of Wisconsin-Madison Center for Limnology; Alexander Latzka, Wisconsin Department of Natural Resources; Allison Mikulyuk, University of Wisconsin-Madison Aquatic Science Center; Heidi Rantala, Minnesota Department of Natural Resources; Bethany Bethke, Minnesota Department of Natural Resources; Ellen Albright, University of Wisconsin-Madison Discovery Farms; Catherine Hein, University of Wisconsin-Madison Center for Limnology

ABSTRACT:  Aquatic vegetation provides critical habitat for fishes throughout life. However, aquatic vegetation is changing in many lakes due to increased lakeshore development, invasive species, and climate change. Underappreciated and poorly understood linkages between aquatic plants and fish could serve as an underutilized opportunity to support fisheries outcomes by considering management of plant and fish communities in concert. Researchers in the Upper Midwest are currently engaged in a broadscale effort to understand relationships between aquatic plant and fish communities in temperate lakes with the goal of better informing current management practices and developing new habitat management tools. In the process, it became clear that the large number of potential quantifiable predictors and responses (e.g., individual, population, and community-level metrics for both plants and fish) and broad range of possible management partners necessitated a clearer understanding of the major issues and priority questions surrounding current plant management practices. We held multiple workshops with state, federal, tribal, and local agencies, as well as public stakeholders, to seek input on aquatic plant and lake habitat management goals, barriers, and research questions. We discuss outcomes of these workshops, including identifying high-priority research needs and management questions, as well as similarities and differences in perspectives among groups. This feedback provided tangible objectives for performing applicable science around aquatic plant management, while also providing important information for lake decision-makers on an important but previously rarely considered issue in fisheries management.

AUTHORS:  Daniel Isermann, USGS-Wisconsin Cooperative Fishery Research Unit; Ryan Bohen, Wisconsin Cooperative Fishery Research Unit; Daniel Dembkowski, Wisconsin Cooperative Fishery Research Unit; Alexander Latzka, Wisconsin Department of Natural Resources; Joseph Hennessy, Wisconsin Department of Natural Resources

ABSTRACT:  Bigmouth buffalo Ictiobus cyprinellus and smallmouth buffalo Ictiobus bubalus (herein buffalo) are native, non-game fishes that rarely receive management attention. Increased participation in bowfishing has prompted efforts to better understand the population dynamics of buffalo and other native fish to determine their resiliency to harvest. Buffalo are native to many water bodies in Wisconsin, but little information exists regarding their population dynamics and contribution to bowfishing harvest. Consequently, our research objectives were to: 1) describe age composition, reproductive traits, and population dynamics for buffalo populations in Wisconsin; 2) assess their resiliency to harvest, and 3) determine the contribution of buffalo to harvest at bowfishing tournaments. We collected buffalo from 14 Wisconsin waterbodies with the help of the Wisconsin Department of Natural Resources and Wisconsin Bowfishing Association (WBA). Fish were selected for age estimation using a modified age-length key approach. Lapillus and asteriscus otoliths were used for age estimation. Age structure of buffalo populations varied considerably among populations, with maximum ages ranging between 15 and 70 years. Maturation schedules also varied, with age at 50% maturity ranging between 2.0 and 6.5 years and length at 50% maturity ranging between 382 and 505 mm. Three populations were oversampled (100≤ fish) to determine the minimum number of fish in a subsample needed to fully represent age composition in the population. Bowfishing harvest was recorded at each WBA tournament in 2023 and will be recorded again in 2024. All fish brought to the weigh-in were enumerated and identified to species or species group. Contribution of buffalo to tournament harvest peaked at 70.9% at the first tournament and was lower at the next four tournaments at 10.7%, 6.0%, 0.3% and 3.5%, respectively. Our research provides fishery managers with landscape-level population information on buffalo in Wisconsin and that may help inform future management decisions.

AUTHORS:  Joe Spooner, Nebraska Game and Parks Commission; Kali Boroughs, Nebraska Game and Parks Commission; Thad Huenemann, Nebraska Game and Parks Commission

ABSTRACT:  Multiple options exist to tag freshwater fish including batch marks (Visible Implant Elastomer-VIE or fin clips) and individual marks (P-Chip Microtransponders or Passive Integrated Transponder-PIT tags). Few options exist for individually marking small-bodied fish (i.e., < 100 mm TL) where upon recapture individual identification can be obtained without mortality. Nebraska is home to 26 at-risk listed fish species including many that are small-bodied. There is a lack of information on demographic rates across Nebraska on our small-bodied at-risk. To determine demographic rates through mark-recapture methods, marking techniques are required that enable individual identification, do not modify behavior or mortality of individuals, and remain readable during the duration of the study. In some cases, multiple size options are available with varying results from previous studies on post tagging fish survival and retention rates. New technology also becomes available that have minimal testing results promting the need to test multiple tag options. The objective of this study was to determine post tagging survival and tag retention for four tag types including three PIT tags (8 mm Biomark, 8 mm Voda IQ, 7 mm Voda IQ) and a newly released tag (FRyID) on Bigmouth Shiners Notropis dorsalis in a laboratory setting. Results indicated that fish survival did not differ between any of the tag types and control fish. However, tag retention was significantly lower for FRyID than PIT tags. The results of this study will provide options for use on small-bodied at-risk fish in Nebraska to monitor population demographic rates over time. Some studies may include estimating movement rates, survival, or population size. This will help managers determine their status in the state and may inform if intervention is needed.

AUTHORS:  Lily Thompson, University of Missouri; Gregory Jacobs, Cornell University; Brandon Gerig, University of Wisconsin-Madison; Allison Pease, University of Missouri

ABSTRACT:  Species introductions and biodiversity loss can result in the global change phenomenon of biotic homogenization, or the process of ecological community assemblages becoming more similar to each other over time. Freshwater fish communities are understood to be particularly at risk for biotic homogenization and shifts in fish community composition can jeopardize the distinctiveness of native communities and the ecosystem services they provide. The US National Parks Service (NPS) is tasked with preserving unimpaired natural and cultural resources, including fish community assemblages. Therefore, there is a clear interest in understanding levels of biotic homogenization in the fish communities within NPS properties. We evaluated changes in fish community assemblages in midwestern National Parks using data from the NPS Heartland Inventory and Monitoring Network in two time periods: 2006–2008 and 2021–2023. Our goals were to characterize variation in fish assemblage structure among Parks, to test whether biotic homogenization has occurred over the approximately 15 years between sampling periods, and evaluate whether some Parks have shifted assemblage structure more than others. We explored both taxonomic and functional changes in local contributions to beta diversity of these sites to understand the potential for loss of unique species identities and ecosystem functions, respectively. We compared Park specific estimates of beta diversity change and assessed whether these differences could be explained by associated environmental variation. Overall, we found evidence for both homogenization and differentiation among these midwestern National Parks depending on whether taxonomic or functional homogenization metrics were used. This suggests that ecosystem function may be maintained in these locations even if the species’ identities in the fish assemblages change.

AUTHORS:  Robert Mapes, University of Toledo; Christine Mayer, University of Toledo; Song Qian, University of Toledo; Robert Hunter, US Geological Survey; Matt Acre, US Geological Survey; James Roberts, US Geological Survey; Ryan Young, US Fish and Wildlife Service; Ryan Brown, Michigan Department of Natural Resources; Lucas Nathan, Michigan Department of Natural Resources; Eric Weimer, Ohio Department of Natural Resources; John Dettmers, Great Lakes Fishery Commission

ABSTRACT:  Grass carp (Ctenopharyngodon idella) control efforts in the Great Lakes follow an adaptive management framework to continually improve removal efficiency. Initial planned action events suggested a combination of electrofishing toward trammel nets (combination method) was the most effective method to herd fish for capture. However, these initial attempts had low catches and were focused on locations with low apparent grass carp densities. Following substantial project expansion and increased effort in areas with higher apparent densities of grass carp, field crews began to experiment with other methods. A second post-hoc method comparison found electrofishing without the trammel nets to be at least >2.8 times more efficient than the combination method. The project adapted and began focusing on electrofishing while continuing to explore ways to improve efficiency by leveraging telemetry information and experimenting with other capture methods. Field crews tested passive overnight gill net sets in locations informed by telemetry and previously high capture rates. These efforts collected more grass carp in one night than the previous month of electrofishing. Expanding gill net use has contributed to more grass carp being captured during 2024 than in any other year since control efforts began in 2018. Designing a project to capture novel species with limited information is challenging and therefore an adaptive approach that analyzes data in real time is vital to invasive species control. A multi-disciplinary team with diverse skills, enables near real time incorporation of information to inform ongoing removal efforts. Although adapting to new gears has resulted in increased captures, changing methods creates challenges evaluating the effectiveness of the program through statistical models. The adaptive management framework allows for Great Lakes Grass Carp practitioners to quickly leverage data as it is collected and make concurrent changes in the field, which is invaluable to control the spread of invasive carp.

AUTHORS:  Aaron Muehler, Ball State University; Amy Kinsley, University of Minnesota-Twin Cities; Nicholas Phelps, University of Minnesota-Twin Cities; Paul Venturelli, Ball State University



ABSTRACT:  Recreational anglers and boaters can be a major vector of the spread of aquatic invasive species (AIS), but movement patterns are oftentimes poorly understood due to the difficulties of collecting data. Currently, Minnesota collects movement data through statewide watercraft inspection stations. In the past these data have been leveraged to predict movement patterns of anglers and boaters. As such, these data are the current gold standard, but there may be another option. A potentially innovative and economical solution is to obtain movement data from smartphone applications (apps) in the form of angler recorded catch times and locations. Aggregate forms of these data can then be used to describe and predict the relative popularity of lakes, and the flow of traffic among them. The goal of this study was to gain insight into the ways that big data can improve predictors of pathways of AIS spread. To that end, we employed predictive modeling previously used to build a movement network with watercraft inspection data and applied it to data from a popular fishing app, Fishbrain. We found that these two networks were comparable and displayed a high level of connectivity among Minnesota waterbodies, potentially furthering the spread of AIS. Although similar, differences present likely stemmed from biases in which group of anglers were surveyed within each collection method. Simply, watercraft inspections only targeted watercraft users, while Fishbrain provided data for both shore and private access anglers, along with boaters. These insights are essential to the design and optimization of prevention, detection, and monitoring efforts for Minnesota and may allow for enhanced resource allocation. These results also provide insight into how this approach can be expanded to inform larger efforts (e.g., the Great Lakes Region, contiguous U.S.), and set the stage for future work.

AUTHORS:  Nicholas Iacaruso, University of Illinois Urbana-Champaign, Illinois Natural History Survey; Joel Corush, Illinois Natural History Survey; Mark Davis,University of Illinois Urbana-Champaign, Illinois Natural History Survey

ABSTRACT:  Aquatic invasive mollusks (gastropods and bivalves) are among the most ecologically and economically impactful groups of non-native species to the Midwest United States. They can achieve hyper-abundance in freshwater ecosystems, negatively impacting native mollusk biodiversity, damaging infrastructure, altering ecosystem characteristics, and facilitating other invaders. Early detection of new populations before they become hyper-abundant can be an effective strategy for mitigating their worst impacts. However, their small size and cryptic life history often make new invasions difficult to identify. Here, we deploy environmental DNA (eDNA) metabarcoding to detect aquatic invasive mollusks across the Illinois River waterway, an aquatic highway connecting the Mississippi River to the Great Lakes. We focused on six focal species with varying levels of establishment and distribution throughout the Illinois River. We sampled the Illinois River and 24 tributaries over two years to estimate the relative distribution of each invasive mollusk. We also performed eDNA metabarcoding to detect the native mollusk and fish communities in each tributary. We intend to find correlations between the presence of the invasive mollusks and the physical habitat measurements, land-use metrics, or native mollusks and fishes that may inform the current heterogeneous distribution of aquatic invasive mollusks. Our study will also serve as a model for studying the fine-scale spatial distribution of aquatic mollusk eDNA and aid in understanding why some tributaries are more heavily invaded than others.

AUTHORS:  Adam C. Jones, US Geological Survey; Jesse R. Fischer, US Geological Survey; Josey L. Ridgway, US Geological Survey.

ABSTRACT:  There are over 40,000 dams in the Mississippi River Basin, and concentrations of invasive Silver Carp (Hypophthalmichthys molitrix) below them are well documented as populations attempt to migrate, reproduce, and establish in upstream ecosystems. Consumer-grade sonar and image analysis techniques provide an efficient and cost-effective approach to evaluate and monitor the density of invasive carp populations in these unique and intensely managed areas of interest. Current automated image analysis tools are reliable and used throughout the Mississippi River Basin to count, measure, and understand the behavior of invasive carp populations in a diversity of habitats. However, these tools are ineffective in quantifying targets within high density groups (i.e., schools), prompting the need for additional image analysis techniques and an improved understanding of the three-dimensional distributions of invasive carp individuals and concentrations. Overall, our objective is to evaluate fine-scale and reach-wide abundance dynamics through time (i.e., day, night, and season) and environmental conditions (i.e., water discharge, velocity, temperature). We conducted repeated sonar surveys using side-scan and down-imaging sonar in the Kentucky Lake and Lake Barkley tailwaters (Tennessee River and Cumberland River respectively) throughout 2023 and 2024. Four parallel transects were conducted for each 5-km reach downstream of each dam. Surveys began at the dams and moved downstream at ~8 km/h to ensure consistent images. Current data processing involves the manual identification of fish groups (i.e., area) within side-scan sonar images and the use of simultaneously recorded down-imaging sonar images to quantify depth distributions of high-density schools to estimate volumetric abundances of invasive carp. Manual processing will be used to train machine learning models similar to approaches being used to estimate individual fish targets. These results will inform future research objectives to improve survey design as well as management efforts, such as deterrence and removal actions in these critical bottleneck habitats.

AUTHORS:  Christina M Mackey, US Geological Survey, Missouri Cooperative Fish and Wildlife Research Unit; Craig Paukert, US Geological Survey, Missouri Cooperative Fish and Wildlife Research Unit; Mark L. Wildhaber, US Geological Survey - Columbia Environmental Research Center; Allison A Pease, School of Natural Resources - University of Missouri; Jacob D Faulkner, US Geological Survey - Columbia Environmental Research Center; Robin D Calfee, US Geological Survey - Columbia Environmental Research Center

ABSTRACT:  In the Mississippi River Basin and Great Lakes of the USA, behavioral deterrents that utilize acoustic stimuli are being considered for deployment in rivers to deter movement of invasive carps. Grass Carp Ctenopharyngodon idella are ostariophysans that possess an inner ear connection to the swim bladder allowing them to detect a broader range of frequencies compared to non-ostariophysans. This provides the potential for a greater range of response to acoustic stimuli. Previous research demonstrated the ability of Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix to avoid acoustic stimuli in the laboratory. Prior to this study, limited data were available to support avoidance of acoustic stimuli by Grass Carp. We evaluated acoustic stimuli as a deterrent for Grass Carp by exposing two naïve juvenile carp together to a recording of one of three acoustic stimuli—a 10 second chirp (0.3 – 5 kHz), continuous 100 horsepower boat motor (0.6 – 10 kHz), and 3-6 beats/second percussion (0.375 – 23.5 kHz). Trials were conducted in a 720-liter indoor tank and Grass Carp behaviors (swimming velocity, proximity among individuals, time near stimulus) were measured for 10 minutes prior to (baseline behavior) and during the presentation of the stimulus (response). Grass Carp swimming velocity was statistically similar among stimuli, though carp in percussion trials appeared to show a slight increase. Compared to baseline behavior, Grass Carp spent more in close proximity when exposed to chirp stimulus and farther apart during exposures of boat motor stimulus. All three acoustic stimuli appeared to increase the time Grass Carp spent near the stimulus source, although responses varied among trials. Preliminary results suggest that Grass Carp response to acoustic stimuli presented in this study is complex and of relatively modest magnitude. The immediate value of acoustic stimuli as a deterrent is unclear from these results and warrants further study.

AUTHORS:  Cade Roach, University of Missouri; Matthew R. Acre, US Geological Survey; Allison A. Pease, University of Missouri

ABSTRACT:  Efficient methods for estimating species abundance are critical for assessing the status of Silver Carp (Hypophthalmichthys molitrix) in the Mississippi River basin, given the ecological and economic threat this invasive species poses to water resources. Measuring Silver Carp abundance helps to characterize range expansion dynamics and evaluate management strategies. Recreational-grade side-scan sonar (SSS) offers a novel approach to monitoring fish abundance, yielding estimates comparable to traditional mark-recapture methods but at a much lower cost. Regardless of the approach used to estimate abundance, imperfect detection resulting from factors such as survey method, observer subjectivity, environmental conditions, and species behavior can lead to inaccurate estimates. N-mixture models, a suite of hierarchical regression techniques, simultaneously estimate abundance and detection probability from spatially and temporally replicated count data, addressing the issue of imperfect detection. Our study aimed to estimate the abundance of Silver Carp before, between, and after mechanical removal efforts to determine the efficacy of successive removals and characterize the ensuing population dynamics. We conducted SSS surveys in the Lamine River, a tributary of the Missouri River, before and after each of two removal efforts carried out by the Missouri Department of Conservation and the U.S. Fish and Wildlife Service in September 2024. We georectified the SSS images, used semiautomated image processing to extract counts of Silver Carp, and fit N-mixture models in frequentist and Bayesian frameworks to estimate abundance and detection probability. Here, we compare abundance estimates between different stages of the removal efforts to quantify removal success and identify trends in population dynamics. We also compare the estimates of abundance and detection, computational intensity, and measures of fit between the frequentist and Bayesian approaches. Finally, we discuss potential methods to improve the differentiation of Silver Carp from other species with similar morphology in SSS imagery.

AUTHORS:  Lindsey A.P. LaBrie: Graduate Research Assistant (Ph.D.), Arkansas Cooperative Fish & Wildlife Research Unit, University of Arkansas, Department of Biological Sciences, Fayetteville, AR, 72703. Email: llabrie@uark.edu

Caleb P. Roberts: Unit Leader, U.S. Geological Survey, Arkansas Cooperative Fish & Wildlife Research Unit, University of Arkansas, Department of Biological Sciences, Fayetteville, AR, 72703. Email: cr065@uark.edu

ABSTRACT:  Preventing new invasions from occurring is the most effective way to avoid the negative ecological, economic, and societal impacts of invasive species. Two established and highly related methods for preventing new invasions are horizon scans and risk screening. Horizon scans use expert consultation and consensus building to conduct rapid risk screening. Arkansas, like the rest of the U.S., is experiencing negative impacts of invasive species, and thus, there is a critical need to prevent new invasions and thereby avoid new negative impacts. Here, we met this need through three objectives: we 1) extracted risk screening results for fish in trade from the U.S. Geological Survey’s Horizon Scan of Vertebrates in Trade and adapted these results to Arkansas, 2) used the fish species screened in the USGS Horizon Scan to determine how climate matching scores shifted under future climate scenarios, and 3) developed a standardized workflow for risk screening for aquatic nuisance species in the United States that incorporates risk of establishment under future climate scenarios. To accomplish the first objective, we pulled risk screening scores (comprised of risk of establishment, invasion history and pathways, and potential negative impacts) for the 319 fish species identified in the USGS Horizon Scan. For the second objective, we used all fish species identified and screened in the USGS Horizon Scan. Then, using future climate models (Shared Socioeconomic Pathways models) for the years 2040, 2070, and 2100, we calculated climate matching scores between potential fish invaders’ native ranges and the climate in the U.S. For the third objective, we created a future risk factor scoring protocol for risk of establishment under future climate scenarios and applied the scoring to all fish species from Objective #2. Under current and future climates, only Prochilodus lineatus and Chondrostoma nasus received high risk scores in Arkansas. However, 11 species moved from low to medium risk under future climates, reflecting increased establishment potential. Most of the species that moved from low to medium risk are known invaders outside the U.S. and are known to have strongly negative ecological impacts in their introduced ranges, such as Clarias gariepinus, Abramis brama, and Hemichromis lifalili. Although climate change is increasing the potential for invasive species to establish in Arkansas, we show that prioritizing invasive species for prevention and watchlists is still feasible as the climate changes. Species identified as medium and high risk in this project are strong candidates for in-depth risk screening summaries and adding to an invasive species watchlist for Arkansas.

AUTHORS:  Braden Whisler, Eastern Illinois University; Robert Colombo, Eastern Illinois University; Daniel Roth, Eastern Illinois University; Eden Effert-Fanta, Eastern Illinois University

ABSTRACT: 
Bighead Carp (Hypophtalmichtys nobilis) and Silver Carp (H. molitrix), often referred to as bigheaded carps (BHC), have invaded many rivers throughout North America and the Mississippi River drainage. With their niche occupation and feeding habits, evidence suggests the degradation of native fish assemblages through competition. Although there are spawning populations located throughout the BHC invasion, few studies have focused on visualizing the timing and location of spawning events. The aim of this study is to examine how spawning BHC utilize tributary versus mainstem river sites throughout the year and in varying environmental conditions. From April to September of 2021-2024, BHC ichthyoplankton were collected from mainstem and tributary sites in the La Grange Pool of the Illinois River throughout an array of different environmental conditions (flood, high/low stream velocity, temperature). Consistent with previous studies, flood pulses, higher water velocities, and temperature thresholds triggered spawning events, contributing to higher densities of BHC ichthyoplankton drifting in the current. High-water years also facilitated the movement of BHC into tributary systems, contributing to spawning events and larger BHC ichthyoplankton catches in the tributaries. This study demonstrates the importance of continued monitoring of spawning conditions and timing in areas where BHC are already established. By developing predictive models for BHC spawning events in both mainstem and tributary habitats, resource managers can implement targeted removal strategies for spawning adults at invasion fronts or areas of special concern, such as the Laurentian Great Lakes. These proactive measures have the potential to significantly reduce year class sizes and mitigate the ecological impact of BHC invasions.