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SeattleCityLightEnvironmentReport20145ContributingtoScienceCityLightunderstandsthattheessenceofsoundscalenvironmentalmanagementliesintheabilitytoembracescience-baseddecisionmaking.TolicenseallitshydroelectricprojectsCityLightdevelopedasetofenvironmentalmeasuresthatwerebasedonsciencresearch.ResearchtoinformouroperaonsandgaugethesuccessofenvironmentalstewardshipaconsconnuesatourSkagitRiverBoundaryandToltprojectsinpartnershipwithstateandfederalagenciestribesandnonprotorganizaons.FishResearchUnderstandingthelifehistoriesandabundanceoftheshspeciesoccurringintheSkagitPendOreilleToltandCedarriversisanimportantpartofconrmingwhethermeasurestakenbyCityLighttoprotectshareeecve.ResultsofsomeofourrecentsheriesstudiesincludeToltRiverSteelheadAtaggingstudyofjuvenilesummersteelheadthatliveaboveacanyonalongtheToltRiverprovideddataonhowlongtheshstayabovethecanyonwhentheyleavetheiresmatedageandhowfasttheyaregrowing.ArecentgenecstudyconrmedthatthesummersteelheadpopulaonfoundabovetheToltCanyonisdierentfromthewintersteelheadpopulaonfoundbelowthecanyon.SkagitRiverBullTroutGenecsAcomprehensivebulltroutgenecsstudyfoundthatpopulaonsofthisspeciesareextremelydiverseintheSkagitRiverdrainagewithgenecallyuniquepopulaonsBulltroutandthisDollyVardenarespeciesofnativechartrout-likeshinthesalmonfamily.Inthesummerof2013thersttwoadultsteelheadtaggedin2010returnedtothesouthforkoftheToltRiverontheirwayupstreamtotheToltCanyon.CityLightisaleaderinsponsoringgeneticresearchstudiestoimprovethemanagementofthreatenedshspeciesinthePacicNorthwest.presentinalmosteverymajorstream.MostimportantthebulltroutpresentinthethreeSkagitreservoirsaregenecallyverydierentfromthosefounddownstreamoftheSkagitRiverProjectandhavelikelybeenisolatedfromtheshinthelowerwatershedsincetheendofthelasticeage.SkagitRiverSteelheadHatcheryandWildSteelheadInteraconsThisstudywasconductedtoassesswhetherhatcherysteelheadhaveharmfulecologicalandorgenecimpactsonwildsteelheadpopulaonsintheSkagitwatershed.Itfoundecologicalimpactsfromhatchery-releasesteelheadonwildsteelheadpopulaons.SkagitRiverProjectNaveCharPopulaonsThisstudyfoundthatbulltroutpopulaonshaveincreasedalmost10-foldintheRossLakedrainageoverthepastdecadealikelyresultfromamajorchangeintheforagebasefortheseshoverthisperiod.ThisstudyalsodiscoveredthatDollyVardenarepresentalongwithbulltroutinallthreeSkagitreservoirswhichmaybetheonlylakesintheUnitedStateswherebothoftheseshspeciesarefoundtogether.