Midwest Fish & Wildlife Conference 2019

AUTHORS: Tyler Grabowski, University of Illinois; David Wahl, Illinois Natural History Survey; Joe Parkos, Illinois Natural History Survey; Dalon White, University of Illinois; Anthony Porreca, Illinois Natural History Survey

ABSTRACT: Global climate change is expected to exert selective pressures on behavioral phenotypes within freshwater ecosystems through environmental changes associated with chronic warming of water temperatures. We compared the behavioral profiles of bluegill sunfish (Lepomis macrochirus) from three power-plant cooling reservoirs to the behavioral tendencies of bluegill from three ambient reservoirs to investigate whether long-term exposure to increased water temperatures influences the expression of behavioral phenotypes. Power-plant cooling reservoirs were considered as model systems for global warming due to their year-round elevated water temperatures (~5°C) when compared to ambient reservoirs. We quantified activity, boldness, and exploration through 30-minute assays in a common laboratory setting that tested the spatial usage and response of individual fish to a suite of situations involving novel items and a predator, largemouth bass (Micropterus salmoides). For each assay, multiple measurements were recorded for each behavior, leading to the development of a principal component score (PCA) for activity, boldness, and exploration for each individual. PCA scores for each behavior were compared between groups (heated or ambient) and then used to determine how well behaviors correlated to one another within groups. Distinct behaviors did not differ between bluegill from heated and ambient lakes. However, we found significant directional changes between groups for the correlations of activity and exploration as well as for boldness and exploration. These results suggests that chronic exposure to warming can influence the expression of behaviors, providing insight for how the behavioral composition of bluegill populations may be modified in chronically warmed systems.

AUTHORS: Joseph D. Schmitt, Christopher S. Vandergoot, Richard T. Kraus – USGS Great Lakes Science Center, Lake Erie Biological Station

ABSTRACT: Populations of coldwater fishes such as burbot Lota lota, lake whitefish Coregonus clupeaformis, and lake trout Salvelinus namaycush have declined in Lake Erie, while cisco Coregonus artedi have been extirpated. Warming temperature regimes and the re-eutrophication of Lake Erie have increased the frequency of harmful algal blooms and hypoxic events, which can reduce oxythermal habitat availability. Using vertical profile data collected in the central basin from 2008-2017, we developed generalized additive models to explore spatial, seasonal, and interannual trends in oxythermal habitat availability for lake trout, cisco, lake whitefish, and burbot based on published oxythermal niche benchmarks. Habitat availability was usually temperature-limited rather than oxygen-limited, and significant (P<0.05) monthly and interannual variations in habitat availability were detected for most species. In general, oxythermal habitat was most limited during August and September; moreover, significant interannual trends in habitat availability were also detected, with 2016 having the most extreme habitat reduction for many species due to record high temperatures. Understanding the spatiotemporal dynamics of oxythermal habitat availability will be important for the conservation and restoration of these fishes in our changing climate. Moreover, these models can be integrated with climate predictions to better understand how warming temperatures will affect coldwater habitat in the future.

AUTHORS: Benjamin Winger, University of Michigan; Brian Weeks, University of Michigan; David Willard, The Field Museum

ABSTRACT: Global warming is hypothesized to cause reductions in animal body size. Migratory birds are particularly vulnerable to change because they breed at high latitudes where temperatures are changing most rapidly, their morphologies are constrained by the demands of migration, and they are dependent on fluctuating seasonal resources and climatic conditions throughout their annual cycles. We analyzed morphological change for 52 species of migratory birds from 1978-2016, using measurements of 70,000 specimens that died from building collisions during migratory passage through Chicago, IL. Across species, we found a consistent decline in body size and consistent increase in wing length. Body size declines are linked to increasing summer temperatures on the breeding grounds: years with high summer temperature yielded birds with smaller body size. Increases in wing length are driven by selection during the migratory period, which we hypothesize is due to compensatory selection for efficient flight to maintain migratory journeys in the face of shrinking body size. The species composition of the Chicago collision data we analyzed also yielded insights into the relevance of avian social behavior for understanding the negative impacts of artificial light on birds during nocturnal migration.

AUTHORS: Richard R. Budnik, Ohio Department of Natural Resources, Division of Wildlife, Inland Fisheries Research Unit; Geoffrey B. Steinhart, The Ohio State University, Department of Evolution, Ecology and Organismal Biology, Aquatic Ecology Laboratory; Joseph D. Conroy, Ohio Department of Natural Resources, Division of Wildlife, Inland Fisheries Research Unit; Richard D. Zweifel, Ohio Department of Natural Resources, Division of Wildlife; Stuart A. Ludsin, The Ohio State University, Department of Evolution, Ecology and Organismal Biology, Aquatic Ecology Laboratory

ABSTRACT: Increased temperatures due to climate change will likely decrease the quality and quantity of habitat available to reservoir sport fish, although the extent of the effect will likely be variable by species. We developed bioenergetics models to estimate growth rate potential (GRP), a metric of habitat quality, for Largemouth Bass, saugeye, and White Crappie during a 13-year span (2005–2016) in three Ohio reservoirs that varied in productivity (summer 2012–2014 concentrations: chlorophyll a 7–55 µg/L; total phosphorus 21–106 µg/L). We contrasted these baseline measures of habitat quality with projected future changes in GRP and high-quality habitat (HQH; GRP > 0) availability under stabilizing (RCP 4.5) and increasing (RCP 8.5) carbon emission scenarios which estimate air temperatures will increase 2.5 and 4.8 degrees C by 2099. Our simulations predicted Largemouth Bass, saugeye, and White Crappie GRP would decrease an average of 0.001 g/g/day, 0.003 g/g/day, and 0.007 g/g/day, respectively, under RCP 4.5, and 0.005 g/g/day, 0.004 g/g/day, and 0.013 g/g/day under RCP 8.5. The average reduction of HQH was greatest for saugeye (20% loss) under RCP 4.5 and for White Crappie (45% loss) under RCP 8.5. Largemouth Bass HQH was the least affected with an average reduction of < 9% under both scenarios in all reservoirs. Temperature increases in the highest productivity reservoir led to the greatest reduction in habitat quality and quantity among reservoirs. These outcomes, as shaped by temperature changes, have the potential to influence not only the performance of individual fish but also will affect population dynamics, trophic interactions, and fish community structure.

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: Hisham Abdelrahman, James Stoeckel – School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University; Jacob Westhoff, Missouri Department of Conservation

ABSTRACT: Previous researchers have shown that extraregional invasive crayfish possess certain life-history and ecological traits that facilitate their ability to successfully invade large areas in distant regions, whereas extralimital invaders tend to remain localized and occupy smaller ranges.  Physiological traits may provide additional explanatory power for realized and potential range of crayfish species. In this study, we tested for thermal performance differences related to respiratory physiology among multiple crayfish species with narrow to broad native and invasive ranges. We hypothesized that species with broad ranges would be thermal generalists relative to species confined to limited ranges. To test this hypothesis, we generated thermal performance curves of respiratory enzymes in the electron transport system (ETS) for 12 individuals from each of five species. Optimal thermal range was defined as the temperature range within which ETS enzyme activity was within 10% of the maximum observed value.  Contrary to our original hypothesis, optimal thermal range of respiratory enzymes was not correlated with geographic range, but was lowest in the most widespread species (Procambarus clarkii) which was also the only species with a strong propensity to burrow.  We also found that the two extraregional invaders (Faxonius virilis and P. clarkii) had significantly lower enzymatic activity levels at optimal temperatures than did the extralimital invader (F. neglectus) or the two native species with restricted ranges (F. eupunctus and F. marchandi).  Results thus far suggest that enzymatic thermal breadth may be more closely tied to habitat plasticity whereas enzyme activity level may be a more useful predictor of geographic range. Additional species are currently being analyzed to better assess the robustness of these conclusions.