SFS Annual Meeting

5/21/2019  |   14:00 - 14:15   |  250 CF

METALHEADS: WHAT CAN OTOLITHS REVEAL ABOUT SPORT FISH EXPOSURE TO ENVIRONMENTAL CONTAMINATION OVER TIME? Understanding when and where mobile aquatic consumers like fish accumulate contaminant loads from the environment is challenging because contaminants are typically extracted from pooled tissue (e.g., muscle), which provides little temporal or spatial information. Fish otoliths, which grow continuously and incorporate elements into their crystalline structure based on concentrations in the surrounding environment, may contain a ‘chemical history’ of individual exposure that can be linked to temporal landmarks (i.e., annuli). To understand timing of contaminant exposure, we compared concentrations of heavy metals (i.e., Hg, Cd, Cu, Pb) in muscle tissue and otoliths of two Lake Michigan species of economic importance – introduced Chinook salmon (Oncorhynchus tshawytscha) and native walleye (Sander vitreus). Walleye muscle was significantly higher in total Hg, Cd, and Pb than was salmon muscle. Despite higher concentrations of these metals in muscle, both species had similar concentrations of metals in the otolith edge (i.e., material reflecting most recent environmental conditions), suggesting that walleye exposure may have occurred earlier in life. Otolith microchemistry may provide a tool to assess heavy metal exposure of fishes over their life cycle, and to ultimately relate this exposure to environmental hotspots of contamination.

Katherine O'Reilly (Primary Presenter/Author), Illinois-Indiana Sea Grant, keo@illinois.edu;


Brandon Gerig (Co-Presenter/Co-Author), Northern Michigan University, bgerig@nmu.edu;


Gary Lamberti (Co-Presenter/Co-Author), University of Notre Dame, glambert@nd.edu;


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5/21/2019  |   14:15 - 14:30   |  250 CF

QUANTIFYING STREAM HABITAT VARIABLES TO IMPROVE SITE SELECTION FOR ENDANGERED DESERT FISH REINTRODUCTIONS Spikedace (Meda fulgida) and loach minnow (Rhinichthys cobitis) are two endangered fish native to the Southwestern United States. Once widespread within the Gila watershed, these species are now known to occur in only a handful of streams in Arizona and New Mexico. Repopulating stream reaches where these species are currently depleted or extirpated is crucial to their recovery, however relatively little is known about the habitat features of streams that promote spikedace and loach minnow persistence. We surveyed 19 stream reaches across the region in sites where the two species once existed, still exist, or where repatriations have occurred or may occur in the future. Streams occupied by spikedace and loach minnow clustered separately from unoccupied streams in multivariate habitat space, indicating an association of those species with particular habitat characteristics. Streams with loach minnow had smaller benthic substrates (gravels and cobbles), consistent with what we know about their life history and habitat preferences. Streams with spikedace shared a suite of habitat characteristics including a high proportion of run habitat.

Jack Torresdal (Primary Presenter/Author), Northern Arizona University, jtorresdal@gmail.com;


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5/21/2019  |   14:30 - 14:45   |  250 CF

FITNESS CONSEQUENCES OF LIFE-HISTORY VARIATION IN SPAWNING MIGRATIONS OF TWO INLAND SALMONIDS Life-history diversity can buffer populations against stochastic events by spreading risk and production over large geographic areas or across cohorts, stabilizing population productivity. The presence and timing of spawning migrations is an important life-history trait of inland salmonids. Otolith microchemistry analysis is increasingly used as a tool to trace fish migrations, yet few studies have traced migrations in small inland watersheds. Here, we evaluate the use of tributary habitat for spawning and describe and compare fluvial Brown Trout (Salmo trutta) and Rainbow Trout (Oncorhynchus mykiss) natal origin distribution, time spent in natal streams, and spawning site fidelity. 64% of Rainbow Trout and 56% of Brown Trout migrated after hatching. Brown Trout showed greater variation in time spent in natal tributaries suggesting that individuals are temporally distributing risk among offspring. By contrast, Rainbow Trout showed greater variation in natal origin, suggesting that individuals are spatially distributing risk among offspring. We also evaluated the fitness consequences of these migration strategies by examining growth rates. Our results indicate there is high inter and intra-specific migration variation in inland salmonid populations, but these are not linked to substantial variation in growth rates.

Annika Walters (Primary Presenter/Author), USGS Wyoming Coop Fish and Wildlife Unit, annika.walters@uwyo.edu;


Lindsy Ciepiela (Co-Presenter/Co-Author), USGS WY Coop Unit, lrciepie@gmail.com;


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5/21/2019  |   14:45 - 15:00   |  250 CF

INDIVIDUAL BASED MODELLING OF FISH MIGRATION IN A 2-D RIVER SYSTEM: MODEL DEVELOPMENT AND CASE STUDY Diadromous fish populations in the Pacific Northwest face interacting challenges along their migratory routes. These challenges include declining habitat quality, harvest, and barriers to longitudinal connectivity. These interacting factors influencing migration success make it challenging to assess management options for improving conditions for migratory fishes such as imperiled anadromous salmon and steelhead species along riverine migration corridors. We describe a migration corridor simulation model which integrates complex individual behavior, responds to variable habitat conditions over large areas, and is able to link migration corridor conditions to fish fitness outcomes. Our model, developed within HexSim, is built around a mechanistic behavioral decision tree that drives individual interactions with their spatially explicit simulated environment. Outcomes of the migration corridor simulation model include passage time, energy use, and survival, which can be used to evaluate trade-offs of behavioral thermoregulation on fish fitness. To demonstrate the potential utility of the simulation model, we describe the sequence of model events and basic model mechanisms. Then, we describe an application of the simulation model to a case study of salmon and steelhead adults in the Columbia River migration corridor.

Marcia Snyder (Primary Presenter/Author), US Environmental Protection Agency, snyder.marcia@epa.gov;


Nathan Schumaker (Co-Presenter/Co-Author), US EPA, schumaker.nathan@epa.gov;


Joe Ebersole (Co-Presenter/Co-Author), US EPA, Western Ecology Division, Corvallis, OR, ebersole.joe@epa.gov;


Jason Dunham (Co-Presenter/Co-Author), U. S. Geological Survey, jdunham@usgs.gov;


Randy Comeleo (Co-Presenter/Co-Author), US Environmental Protection Agency, comeleo.randy@epa.gov;


Matthew Keefer (Co-Presenter/Co-Author), University of Idaho, mkeefer@uidaho.edu;


Peter Leinenbach (Co-Presenter/Co-Author), US EPA, leinenbach.peter@epa.gov;


Allen Brookes (Co-Presenter/Co-Author), US EPA, brookes.allen@epa.gov;


John Palmer (Co-Presenter/Co-Author), US Environmental Protection Agency, Region 10, palmer.john@epa.gov;


Dru Keenan (Co-Presenter/Co-Author), US Environmental Protection Agency, keenan.dru@epa.gov;


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5/21/2019  |   15:00 - 15:15   |  250 CF

DO DRIER CONDITIONS INFLUENCE STATE TRANSITIONS IN STREAM FISHES? A CASE STUDY WITH MINNOWS IN A SOUTHEASTERN US RIVER BASIN In a changing world, tools for predicting population responses to shifting environmental conditions will be useful. As freshwater ecologists, we recognize the influence of flow on lotic communities, but approaches for predicting temporal state changes due to hydrologic variation remain underdeveloped. Here, we use a dynamic model of stream fish abundance states (absent, present, abundant) to evaluate the hypothesis that drier hydrologic conditions influence the probabilities of state transitions in a group of 20 minnows. Fish data were collected from 40 sites throughout the Apalachicola-Chattahoochee-Flint River Basin between 2011 and 2017, and we used a spatially distributed, deterministic, physically-based hydrologic model to generate site-specific median flow values. Preliminary model results suggest that drier conditions may limit the resilience of stream fish communities, as the probability of colonization decreased when median flows diminished. Additionally, results indicated that the probability of minnows remaining abundant also decreased during drier conditions. Interestingly, drier conditions did not appear to exert as much influence on the probability of extirpation. Dynamic modeling approaches offer great promise for generating empirically-driven estimates of state changes over time, thereby facilitating evaluation of hypothesized links between environmental changes and population responses.

Kit Wheeler (Primary Presenter/Author), TN Tech University, kitwheeler@gmail.com;


Mary Freeman (Co-Presenter/Co-Author), US Geological Survey, mcfreeman@usgs.gov;


Seth Wenger (Co-Presenter/Co-Author), Odum School of Ecology, University of Georgia, swenger@uga.edu;


Jessica Davis (Co-Presenter/Co-Author), University of Georgia, Athens, JessicaLdavis17@gmail.com;


Jacob LaFontaine (Co-Presenter/Co-Author), USGS, jlafonta@usgs.gov;


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5/21/2019  |   15:15 - 15:30   |  250 CF

INTERACTIONS BETWEEN PREDATOR TRAITS AND PRODUCER STRUCTURE: THE ECOLOGY AND EVOLUTION OF FINDING FOOD IN COMPLEX AQUATIC HABITATS Evolutionary diversification in the traits of predatory fish has consequences for a wide range of ecosystem functions, including the composition of primary producers. At the same time, the structure of producer communities shapes the diversity and availability of prey resources, which constrains the potential niche differentiation of predators. To investigate the interactions between diversity in predator traits and diversity in producer structure, we used a large-scale mesocosm experiment with threespine stickleback fish from lake and stream ecotypes in central Switzerland. We manipulated the presence of aquatic macrophytes and found that they increased the abundance and diversity of benthic invertebrates, which in turn increased the survival of divergent juvenile stickleback phenotypes competing for food. Using stable isotopes and body condition, we found that habitat complexity and fish density interactively affected the potential strength of selection on fish feeding morphology. Because fish feeding niche is both a cause and a consequence of habitat structure, this work demonstrates a potential eco-evolutionary feedback between the ecology of aquatic habitats and food webs and the evolution of predator strategies for detecting and consuming prey.

Rebecca Best (Primary Presenter/Author), Northern Arizona University, rebecca.best@nau.edu;


Miguel Leal (Co-Presenter/Co-Author), EAWAG, Switzerland, miguelcleal@gmail.com;


Moritz Lürig (Co-Presenter/Co-Author), EAWAG, Switzerland, Moritz.Luerig@eawag.ch;


Marek Svitok (Co-Presenter/Co-Author), Technical University in Zvolen, Slovakia, svitok@tuzvo.sk;


Philine Feulner (Co-Presenter/Co-Author), EAWAG, Switzerland, Philine.Feulner@eawag.ch;


Ole Seehausen (Co-Presenter/Co-Author), EAWAG, Switzerland, Ole.Seehausen@eawag.ch;


Blake Matthews (Co-Presenter/Co-Author), EAWAG, Switzerland, Blake.Matthews@eawag.ch;


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