TheThe spawningspawning ecologyecology ofof brownbrown trouttrout inin aa nativenative cutthroatcutthroat trouttrout streamstream JeremiahJeremiah WoodWood PhaedraPhaedra BudyBudy GaryGary ThiedeThiede CutthroatCutthroat trouttrout Native to much of the western U.S. Significant decline in range and number Causes for decline include: - habitat loss - disease - nonnative species BrownBrown trouttrout Native to Europe, introduced in the late 1800 ’s Outcompete native fishes throughout introduced range, including cutthroat trout However, most local brown trout work has addressed adult fish, early life history information is lacking Current Brown Trout Distribution AltitudinalAltitudinal SpeciesSpecies ZonationZonation Distinct species ‘zones ’ 2400 formed after introduction Brown Red Banks Cutthroat 2000 Often temperature 1600 mediated 1200 Twin Bridges 800 However, adult brown trout 400 outcompete cutthroats in Third Dam 0 the Logan River regardless km) per (number Abundance 1400 1500 1600 1700 1800 1900 2000 2100 of temperature dfd of temperature Elevation (m) Need to investigate other causes OverallOverall GoalGoal UnderstandUnderstand whatwhat factorsfactors limitlimit brownbrown trouttrout populationpopulation distributiondistribution inin thethe LoganLogan River,River, UtahUtah ParticularParticular focusfocus onon earlyearly lifelife stagesstages STUDY AREA Logan River Flows some 50 km through northern Utah and joins the Bear River in Cache Valley Distinct environmental changes along elevational gradient Species distributions change along gradient StudyStudy ObjectivesObjectives 1)1) DocumentDocument brownbrown trouttrout spawningspawning inin thethe LoganLogan RiverRiver andand itsits tributariestributaries 2)2) InvestigateInvestigate factorsfactors affectingaffecting eggegg toto fryfry survivalsurvival ofof brownbrown trouttrout inin thethe LoganLogan RiverRiver 3)3) InvestigateInvestigate predatorypredatory potentialpotential ofof brownbrown trouttrout inin thethe LoganLogan RiverRiver Methods:Methods: DocumentDocument brownbrown trouttrout spawningspawning activityactivity VisualVisual habitathabitat surveyssurveys Identified suitable habitat ReddRedd countscounts Visited areas weekly Results Spawning took place between early November and early January Counted >1600 redds over 50 km area Brown trout spawned throughout the river, even where no adults are observed ResultsResults Low High ReddRedd Counts:Counts: LowerLower LoganLogan # of redds GISGIS slidesslides increasing Third Dam Very high redd densities Unique area just above Third Dam Lower Logan Other stretches are patchy, related to habitat ReddRedd Counts:Counts: TransitionTransition ZoneZone # of redds increasing Right Hand Fork Temple Fork Spawning habitat and intensity both patchy Right Hand Fk . nearly all resident Likely migratory component in Temple Fk . ion ect Dir Twin Bridges er Riv Redd Counts: Upper Logan # of redds increasing High gradient, very little spawning habitat Franklin Basin Few to no adult brown trout observed here Notice that we did observe brown trout redds here River Direction ConclusionsConclusions While variable in intensity, brown trout do spawn throughout the drainage, even where adults are not seen in summer surveys High degree of variability in redd density across sites (4 - 122/km) Parallels high range of adult densities Brown trout used nearly all habitat units designated as suitable for spawning However, little evidence of superimposition based on observation s Brown trout distribution could be limited by: winter conditions survival at another life stage FutureFuture Evaluate egg to fry survival across an altitudinal gradient Hold eggs in boxes in the gravel over winter Other work Compare redd physical features across sites Investigate brown trout predation on cutthroat trout AcknowledgementsAcknowledgements Funding Utah Division of Wildlife Resources Sport Fisheries Research U.S. Geological Survey - UCFWRU U.S. Forest Service – Brett Roper GIS / Mapping – Mike Ebinger USU Fish Ecology Lab Eriek Hansen, Kirk Dahle, Peter Mackinnon, Pete McHugh, Marc Weston, Robert Al - Chokachy , Kris Homel Questions?.