Midwest Fish & Wildlife Conference 2019

AUTHORS: Kirsten Vacura, Paul Venturelli – Ball State University

ABSTRACT: Human behavior is an important factor in natural resource management. Obtaining the public’s opinion – for example, through creel, mail, and phone surveys – can be time consuming and expensive. Analyzing the text that hunters and anglers contribute to online fora may be a faster and cheaper alternative. In this study, we used walleye (Sander vitreus) oriented online fora to compare and explain the “happiness” of walleye anglers among and within ten U.S. states. We used sentiment analysis to score text data from each state as positive, negative, or neutral, and then normalized these scores by expressing them relative to the baseline level of happiness in each state. We determined the extent to which fisheries management explained variation in “happiness” scores within and among states via statistical analyses that included such factors as regulation strictness and complexity, angler density, stocking programs, and transparency of the state's natural resource agency. Although we did not generate results in time for the abstract deadline, we are confident that we will explain some variation and have interesting things to report at the meeting.

AUTHORS: Susan Steffen, Kansas Department of Wildlife, Parks and Tourism

ABSTRACT: A 21-inch minimum length limit (MLL) on Walleye at Cedar Bluff Reservoir, Kansas, was implemented in 2018 to prevent recruitment overfishing by reducing exploitation of spawning-sized Walleye. Initially, anglers opposed the 21-inch MLL and voiced this through various outlets: on the 2013 Kansas Licensed Angler Survey, at commission meetings in 2017, and during the public meeting about the MLL in July of 2017. To better understand anglers’ feelings toward the MLL, I added supplemental questions at the end of the access point creel survey that was conducted from March to October 2018. Anglers that agreed to answer the additional questions were asked about the number of days they fished at Cedar Bluff Reservoir last year, their level of support for the 21-inch MLL on Walleye, and their confidence in KDWPT. Confidence in KDWPT was measured by four questions in a Likert scale format based on responses from 1 to 5 where 1 = strongly disagree and 5 = strongly agree. I was able to obtain useable responses from 200 anglers from March through early September 2018. The average age of anglers was 47 years old (SD = 16.13) and they fished on average 22 days (SD = 26.29) last year at Cedar Bluff Reservoir. The plurality, or 34%, of anglers interviewed supported the 21-inch MLL on Walleye. Confidence in KDWPT was high, with Likert scale means ranging from 3.95 to 4.10. Results from the remainder of anglers interviewed in September and October of 2018 will be presented as well. The creel survey and supplemental interview questions will continue through 2020 to determine if angler support for the Walleye regulation changes as the Walleye population responds to the regulation as well.

AUTHORS: Daniel Isermann, Lucas Koenig, Daniel Dembkowski – Wisconsin Cooperative Fishery Research Unit; Iyob Tsehaye, Wisconsin Department of Natural Resources; Wesley Larson, USGS-Wisconsin Cooperative Fishery Research Unit; Scott Hansen, Steve Hogler; Tammie Paoli – Wisconsin Department of Natural Resources; Troy Zorn, Michigan Department of Natural Resources

ABSTRACT: Green Bay supports important fisheries for walleyes, lake whitefish, and yellow perch and these species likely interact in a variety of ways. A better understanding of these interactions is needed to guide management decisions. Specifically, there are concerns that high walleye abundance could negatively influence abundance of yellow perch and lake whitefish, primarily through predation. However, the prevalence of round gobies within the ecosystem may provide a predation buffer for yellow perch and lake whitefish. Moreover, the lake whitefish population in and around Green Bay is comprised of multiple genetic stocks. Consequently, if walleye predation on lake whitefish varies across time and space, this predation could affect certain whitefish stocks to a greater degree than others. To help address some of these uncertainties, our research objectives are to determine if: 1) lake whitefish and yellow perch represent important prey for walleyes in Green Bay; 2) diets of these three species vary spatially and temporally and if diet overlap among species is evident; 3) the extent of walleye predation is sufficiently high to influence recruitment potential of lake whitefish and yellow perch and 4) extent of walleye predation varies among individual stocks of lake whitefish. We are integrating an intensive assessment of diet composition for all three species with bioenergetic modeling and genetic stock identification to address our objectives. We will discuss the innovative experimental framework we are using to address these objectives and provide preliminary results of our diet analyses.

AUTHORS: David G. Fielder, Michigan Department of Natural Resources

ABSTRACT: Walleye reached recovery targets in Saginaw Bay in 2009 and a management simulation model indicated that recreational fishing mortality could be increased by as much as 50% without exceeding reference points of sustainability. Recreational harvest regulations (daily possession limit and minimum length limits) were liberalized in 2015. Monitoring and evaluation has taken the form of creel survey and a fishery independent fish community netting survey. Besides indicators from those efforts, a stock assessment model is also used to gauge mortality rates and status relevant to sustainability thresholds. While walleye harvest has increased some, recreational effort has not changed greatly and that appears to limit the magnitude of the effect. The multiple survey and modeling approach to harvest regulation monitoring is effective, but costly and requires ongoing commitment to survey work and model updating.

AUTHORS: L. Zoe Almeida, Ohio State University; Matthew D. Faust, Ohio Department of Natural Resources, Division of Wildlife; Stuart A. Ludsin, Ohio State University; Elizabeth A. Marschall, Ohio State University

ABSTRACT: Growth rates of animals are often assumed to be a response to recent environmental conditions; however, there is increasing evidence from numerous organisms that growth in one year may also be reflective of environmental conditions experienced earlier in life. Therefore, large-scale stressors, such as eutrophication and climate change may affect individuals immediately and latently, which is rarely considered in the management of exploited populations. Herein, we examined the factors that may influence growth rates of Lake Erie walleye (Sander vitreus), a system exposed to eutrophication and climate change. We used data from annual fall gillnet surveys (1978-2015) to characterize median size-at-age of individual annual cohorts in response to changes in physical conditions (e.g., temperature) and the food web (e.g., prey availability) during early life (= age-2), which may have arisen due to eutrophication and climate change (i.e., warming and increased precipitation). We hypothesized that environmental conditions in the current year, growth rates during early-life (as a reflection of early-life environmental conditions), and growth rates in the previous year (as a reflection of recent growth) would affect age-specific annual growth rates. We performed preliminary linear mixed model analyses with the median size within cohorts at age-2 representing early life growth, median growth rate in the previous year, and annual average temperatures. Using a model selection approach, no combination of these factors was better able to predict growth rates than the null model. However, we still need to test for effects of age-0 growth on growth rates later in life and for other environmental effects on growth, including annual cumulative degree days, prey-fish availability, and walleye population size. Our analyses will assist Lake Erie fisheries managers by assessing the relative importance of early-life versus contemporary growth conditions on recent growth performance.

AUTHORS: David Dippold, The Ohio State University; Grant Adams, University of Washington; Stuart Ludsin, The Ohio State University

ABSTRACT: Both density-dependent and density-independent factors can affect the harvest of exploited fish populations. For instance, inter-annual variation in temperature could modify the timing and spatial extent of fish migrations, and in turn, fishery catches. However, this relationship could be mediated by density-dependent factors, if for example, high fish abundance leads to widespread habitat use that reduces the effects of temperature on migration and subsequent harvest. Toward understanding the relative influence of these factors on fishery harvest, we quantified the relationship among temperature, population size, and the temporal and spatial distribution of walleye (Sander vitreus) recreational harvest in Lake Erie during 1990-2015. Knowing that adult walleye migrate eastward from the western basin during spring and summer towards cooler temperatures, we hypothesized that: 1) years with higher spring and summer temperatures would be accompanied by reduced catches in the western basin relative to the deeper, cooler central and east basins; 2) walleye catches in the central and eastern basins would occur earlier during the spring/summer in warmer (relative to cooler) years; and 3) these relationships would be more apparent in years of low population size because in years of high abundance, walleye (especially young adults) would continue to reside in the west basin throughout the summer. To test our hypotheses, we constructed and compared variable coefficient generalized additive models, which used spatially-explicit (10x10 min grids) recreational catch and effort information, as well as temperature, bathymetric, and lake-wide abundance data. Beyond discussing the role of temperature and total abundance in driving spatiotemporal patterns in walleye harvest, we discuss the implications for fisheries management under a changing climate.

AUTHORS: Andrew Carlson, Minnesota Department of Natural Resources

ABSTRACT: The science of evaluating species distributions against environmental conditions has advanced tremendously in the past decade following technological improvements in tagging and monitoring systems. Using data collected from acoustically tagged adult Walleye, generalized linear mixed models were developed to predict the probability of occurrence at depth given temperature and oxygen within stratified lakes. Following, using data from a survey-specific temperature and oxygen profile, the relative odds of occurrence for Walleye was calculated throughout the water column and at the depths of the gillnet sites. Comparisons between modeled probability of occurrence and observed catch rates at specific sites were made to evaluate the degree to which site-level patterns can be explained by the habitat sampled. Integrating and accounting for known measures of environmental variability that systematically influence catch statistics will improve the quality and subsequent interpretation fisheries data to support management decisions.

AUTHORS: Chelsey L. Nieman, Suzanne M. Gray – The Ohio State University

ABSTRACT: Increasing anthropogenic turbidity changes underwater visual environments, leading to altered perception of visual cues. This alteration may have a variety of consequences, such as movement to other localities, a shift in diet or preferred prey, and reduced consumption of prey items. Lures are known to be perceived by fish as a potential prey item, therefore lure color/type can be utilized as a relative proxy for prey items that fish are capable of visually perceiving in turbid water. The objective of this study was to understand how shifts in visual environments may influence predatory success of Walleye (Sander vitreus) in Lake Erie using both local knowledge of altered fishing practices as well as lure success. Charter boat captains on Lake Erie are experienced in fishing in and around algal blooms and as such their knowledge and real-time lure success data allowed us to monitor color of lures that were successful in attracting Walleye under differing conditions. A survey of Lake Erie charter captains (N=37, 38% response rate) was used to determine how altered water quality (i.e. algal blooms) affected fishing practices and lure usage over the long term, with results indicating that lure color success changed in highly turbid water. Additionally, a mobile phone application, Walleye Tracker, was used by 19 charter captains over two years to gather real time data on lure successes. The use of photographs of lures and water conditions allowed for quantitative, in situ, analysis of lure successes in differing water clarity conditions. The results of this study indicate that increases in both sedimentary and algal turbidity that are altering the underwater visual environment are not only changing visual perceptions of Walleye, but also indicate that this is likely to have long-term consequences, not only for the ecosystem, but also for recreational anglers within these altered systems.

AUTHORS: Christopher Vandergoot, US Geological Survey; Matthew Faust*, Ohio Department of Natural Resources; Jason Robinson, New York State Department of Environmental Conservation; Andy Cook, Ontario Ministry of Natural Resources and Forestry; Tom MacDougall, Ontario Ministry of Natural Resources and Forestry; Charles Krueger, Michigan State University

ABSTRACT: Walleye support important commercial and recreational fisheries throughout Lake Erie.  To manage this fishery sustainably, a thorough understanding of the underlying biological and ecological processes regulating population dynamics is essential.  Recently, numerous acoustic telemetry studies have been undertaken to address key management uncertainties associated with movement patterns, spawning ecology and phenology, stock contributions, habitat use, and population dynamics. While these studies have resulted in an unprecedented amount of information, challenges ranging from determining best tagging practices, maintaining receiver networks, managing and analyzing large datasets, and communicating research findings to managers and constituents have occurred along the way.  This presentation will provide an overview of past and current Lake Erie walleye acoustic telemetry projects and summarize management uncertainties addressed to date.  Additionally, how results from completed and ongoing studies could be incorporated into current stock assessment practices will be presented.  Lastly, we’ll discuss how biologists and researchers communicate these scientific findings to a diversity of audiences, from fishery managers to resource users.

AUTHORS: Richard T. Kraus, US Geological Survey - Lake Erie Biological Station; Michael J. Hansen, US Geological Survey - Hammond Bay Biological Station; Matthew D. Faust, Ohio Department of Natural Resources - Division of Wildlife; Graham D. Raby, University of Windsor; Christopher S. Vandergoot, US Geological Survey - Lake Erie Biological Station; Charles C. Krueger, Michigan State University

ABSTRACT: Migratory fish movement can be classified as partial or differential migration, contingent behaviors, or other types of alternative migratory tactics. Growing evidence suggests that multiple variables, including metabolic and growth trajectories, risk-reward tradeoffs, personality, social interactions, and current physiological state underpin such modalities. We combined acoustic telemetry with sclerochronology to investigate if and how growth was associated with seasonal habitat use of a migratory freshwater fish, Lake Erie Walleye Sander vitreum. Non-linear mixed-effects modeling of back-calculated length-at-age from fin spines revealed individual growth trajectories that varied among spawning locations. Further, logistic principal components analysis of acoustic telemetry detections revealed stock-specific patterns in seasonal habitat use. Our results highlighted that individuals and groups of individuals within a stock are likely subjected to varying levels of fishing mortality based upon their migration pattern. For managers, differences in growth associated with spatial modalities in movement may translate into overexploitation of population segments.

AUTHORS: Nick Kramer, Kansas Department of Wildlife, Parks, and Tourism

ABSTRACT: Gill nets are one of the most popular gears implemented to assess fish populations in North America. Ease of construction and low maintenance has led to their success and widespread implementation in the field of fisheries management. The characteristics of a gill net, along with the size and shape of the fish affect how capture occurs (i.e., wedging, gilling, tangling, or a combination). Many studies have been completed on selectivity of various sizes of mesh. Despite the importance of mesh size, the shape of the mesh can also be altered by modifying the hanging ratio which in turn will affect the catchability of fishes with differing body shapes. Additional studies have demonstrated the effectiveness of hobbling or tying down gill nets. This creates more of a “baggy” net which studies have shown to capture a wider size range of fish and may increase catches of species that could easily become tangled due to external protrusions (e.g., Channel Catfish or Paddlefish). In recent years, Kansas Department of Wildlife, Parks, and Tourism biologists have become interested in managing Blue and Flathead Catfish and have placed an increased priority on sampling these species; however, the biologists currently have little insight into fully representative population parameters due to standardized sampling gear that does not capture larger individuals. Thus, the objective of this study is to evaluate the effectiveness of various gill net designs to sample fish populations in Kansas impoundments with special consideration given to species of interest for biologists (e.g., Blue Catfish, Flathead Catfish). Year one of this study found differences in catch rates for some commonly assessed species. These differences were further examined in year two of the study by expanding the sample size; in both number of sets and number of reservoirs.