Midwest Fish & Wildlife Conference 2016

AUTHORS: Amanda Rosenberger, Missouri Cooperative Unit; Rory Mott*, University of Missouri

ABSTRACT: Water quality influences growth, development, and physiology of aquatic vertebrates. In particular, stable populations of the endangered Topeka shiner Notropis topeka have been linked to favorable water quality conditions. As is the case with many endangered fish, an assortment of biological and chemical factors are implicated in its decline, including stream channelization, sedimentation, pollution, and predation from nonnative stocked fishes. Current water quality assessments are based on lethal level experiments (e.g., LC50 tests), which are poorly suited for evaluating low level stressors. Conditions that test below threshold values may still impede growth and development; especially when considering the complex nature of compounding low level stressors. To aid The Missouri Department of Conservation (MDC) in the selection of reintroduction sites, our experiments will focus on exploring how sublethal water quality conditions influence the physiology and behavior of Topeka shiner. We will investigate the effects of dissolved oxygen, temperature, acclimation, nitrogenous waste, and chloride on Topeka shiner using non-lethal endpoints. To explore sublethal levels of selected parameters, our project objectives are twofold: (1) monitor Topeka shiner's behavioral responses to a gradual reduction in dissolved oxygen and (2) use critical swimming speed performance to determine thermal optima and sublethal effects of nitrogenous waste and chloride concentrations. We are incorporating preliminary data collected from the model species Cyprinella lutrensis to refine methodology and predict sublethal responses of Topeka shiner to common environmental stressors. This project will give insight to not only where Topeka shiners can persist, but also thrive; our focus on preference over tolerance allows selection of the most suitable reintroduction sites matching its physiological profile.

AUTHORS: Britney Mosey*, Affiliation: University of Minnesota; Jay Hatch, Affiliation: James Ford Bell Museum of Natural History, University of Minnesota; Jessica Kozarek, Affiliation: St. Anthony Falls Laboratory, University of Minnesota

ABSTRACT: The Topeka shiner Notropis topeka is a federally endangered fish species inhabiting the rapidly declining headwater prairie streams of the central US. When these streams intersect roadways, culverts create potential barriers to fish movement by physically impeding swimming (e.g. because of insufficient depth or excess velocity) or by behaviorally deterring movement (e.g. by reducing light levels). Barriers can limit fish migration to key seasonal habitats, such as spawning or nursery areas and off-channel pools and oxbows. They may also isolate small populations of fish further endangering their long-term survival. While some work has been done on swimming abilities and barriers of warm water fish species such as the Topeka shiner, little has been done to evaluate the effects of low light levels in culverts. We evaluated light levels and fish movement in three long box culverts and corresponding control stream reaches in critical Topeka shiner habitat in Southwestern Minnesota. Through a tag and recapture method using visible elastomer tags, more than 20,000 fish were tagged including 456 Topeka shiner, and over 2,000 were recaptured, including 54 Topeka shiner. We found many fishes, including Topeka shiners, passed through the three separate culverts, as well as through the natural stream reaches, under light levels typically experienced at twilight. Statistical analysis is being conducted to determine if fish movement through these long culverts is inhibited compared to the control reaches. Future plans include a laboratory study using surrogate species and pond-reared Topeka shiner to evaluate fish response to varying light levels in a controlled environment. Our research will determine if low light levels pose a barrier to fish movement and if light mitigation needs to be considered in long culverts.

AUTHORS: Andrew K. Schmucker*, Michigan State University; Nicholas S. Johnson, U.S. Geological Survey; Heather S. Galbraith, U.S. Geological Survey; Weiming Li, Michigan State University

ABSTRACT: American eels Anguilla rostrata have experienced staggering population declines in recent decades and are the focus of an international restoration effort. Previous studies have demonstrated that eels are attracted to conspecific washings, and that these cues may be useful for guiding migratory individuals around man-made river barriers. We built upon these studies by characterizing glass eel and elver dose-response relationships to conspecific cues, determining glass eel concentration preferences, and assessing cue responsiveness during late-stage glass eel metamorphosis into elvers; all important factors for gauging their potential utility for population restoration and understanding American eel chemical ecology. We hypothesized that American eels use conspecific cueing (habitat selection based on the quantity of conspecific odorants present), in part, to guide their migrations toward productive habitat, but that cue responses could differ by life stage. As such, we predicted that glass eels and elvers would have discernible dose response (attraction) relationships to glass eel and elver washings, respectively, that glass eels would consistently prefer the higher concentration washings if two were presented simultaneously, and attraction to glass eel washings would decrease during late-stage glass eel metamorphosis into elvers. In two-choice maze assays, glass eels were attracted to glass eel washings over a range of concentrations and the dose-response relationship best fit a logarithmic function. Elvers did not share the same relationships and no attraction was observed to elver washings. Glass eels still preferred undiluted washings when 1/16th and 1/100th dilution washings were also present. No discernible shift in response to undiluted glass eel washings occurred while metamorphosing into elvers. The conspecific cueing hypothesis was supported in some cases, indicating from a practical standpoint, that conspecific cues may be useful for guiding glass eels to passage around barriers if applied to passage devices at concentrations higher than present in the surrounding environment.

AUTHORS: Andrew T. Bueltmann*, Indiana Department of Natural Resources; Quinton E. Phelps, Missouri Department of Conservation

ABSTRACT: The U.S. Fish and Wildlife Service (USFWS) announced October 15th, 2015 that the American eel population is stable and endangered status was not warranted. Such a decision was based on information collected predominately from the east coast of North America with minimal information available from peripheral locations. Specifically, more information about American eels is needed throughout the Mississippi River Basin to fully understand the status of the panmictic American eel population. As such, our study aimed to garner further information about American eels and the interrelations to the potentially limited habitats occupied in the Mississippi River. To gain further knowledge we used data provided by the Long Term Resource Monitoring (1993 to 2015) to carry out Non Metric Multidimensional Scaling (NMDS) to identify habitat associations with American eel. Furthermore, a subsample of American eels was collected from 2011-2013 (via daily electrofishing) to identify timing of freshwater entrance into the Mississippi River via otolith microchemistry. From 1993 to 2015 a total of 154 American eels were collected which were most commonly located in habitats characterized by rocky substrate and low velocity (identified by NMDS results). From 2011-2013 a total of 40 American eels were collected for otolith microchemistry. Microchemistry results indicated American eels enter freshwater at approximately two years of age. With information provided by this study biologists may begin to understand residence duration of American eels in the Mississippi River and more specifically which habitats are important during that time period.