the Utah AFS conference (March 15-17)

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Six of our undergraduate students (Chuck Carpenter, Levi Simmons, Thomas Hafen, Hunter Lucas, Emily Wright, and Justin Dorathy) and five graduate students (Ben Stout, Hayley Glassic, Bryan Maloney, Colton Finch, and Jamie Reynolds) gave presentations at the Utah AFS Conference held in Altamont Utah from 15-17 March 2016. Chuck Carpenter won the best student poster award and Colton Finch won the best student presentation award. Abstracts of their research are below:
  • A future of fire, floods, and fish 
Presenting Author: Colton Finch.
Contributing Authors: Colton Finch, Phaedra Budy – Department of Watershed Sciences and The Ecology Center, Utah State University/U.S. Geological Survey, Utah Cooperative Fish and Wildlife Research Unit, Department of Watershed Sciences, Utah State University, Patrick Belmont – Department of Watershed Sciences and Ecology Center USU
Abstract: Wildfire size and frequency are increasing and may be exceeding historic norms. Populations of native fishes may not be capable of recovering from unprecedented wildfires, especially where human activity has reduced habitat quality and connectivity. We used a population viability analysis to predict the probability of persistence of Bonneville cutthroat trout Oncorhynchus clarkii utah in steep watersheds of south-central Utah, USA. Treatment watersheds were burned in 2010 in the Twitchell wildfire, which was followedone year later by intense rainfall, large floods, and debris flows. Abrupt changes in channel morphology and water quality severely reduced or extirpated trout populations from entire watersheds. We represented a spatially-structured population of Bonneville cutthroat trout based on known habitat preferences, including the presence of natural and artificial waterfalls (fish barriers). Together with burn severity data, we used measurements of valley confinement, channel morphology, and distribution of debris flows (from high-resolution aerial lidar) to predict stream reaches where trout were extirpated after the Twitchell Fire. We combined these physical and biological habitat characteristics in a stochastic, stage-based matrix model to predict the probability that this spatially-structured fish population would persist after a suite of future wildfire scenarios. We demonstrate that fire occurring in synchrony across multiple watersheds forced Bonneville cutthroat trout populations past a quasi-extinction threshold in 45% of iterations; asynchronous fire caused extinctions in 0% of trials. Local extirpations occurred most frequently in confined valleys downstream of debris flows; fish barriers permanently reduced carrying capacity by preventing immigration to previously occupied reaches. Our results indicate spatial heterogeneity in fire severity and vital rates increase population viability; barriers and valley confinement decrease viability.
Deciphering the Pike Puzzle: Comparing invasive pike body condition and length-at-age to pike in their native range
Presenting Author: Chuck Carpenter. Contributing Authors: Jamie Reynolds and Dr. Jereme Gaeta – Department of Watershed Sciences and The Ecology Center, Utah State University.
Abstract: Invasive species are detrimental to native ecosystems through aggressive colonization, predation, and competition for resources. The introduction of an apex predator can alter the native trophic structure. Northern pike (Esox lucius; hereafter pike) have expanded their range across the USA. Anglers first observed nonnative pike in Utah Lake, Utah in 2010 after illegal introduction. The presence of pike is extremely concerning given potential predation on the lake’s endangered June sucker (Chasmistes liorus). A first step to evaluating the effect of this invader on endangered June sucker and the fish community is to understand the basic biology of northern pike in Utah Lake. In 2015, we collected 79 pike from state biologists, anglers, and commercial fishermen. We calculated pike body condition (Wr) and determined pike length-at-age using otoliths and cleithra. We developed a length-at-age model specific to Utah Lake pike and compared these observations to 209 adult pike from their native range in Green Bay, Wisconsin. Utah Lake pike lengths ranged from 82-846 mm, with a mean relative weight of 102, indicating a slightly better body condition than standard. Ages ranged from age-0 to age-7. We hope to expand our preliminary research by acquiring 300 more specimens during the 2016 field season. Our results can assist managers in assessing the potential impact of this invading predator.

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