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MAZINAIGANPAGE4FALL2013GLIFWCfsheriestechnicianNoahArbucklemarksaLakeMilleLacsspawningnorthernpikewithafn-punch.PhotobyEdWhiteINLANDFISHERIESOdanahWis.WhenwinterfinallyreleaseditsicygriponWisconsincededterritorylakeswalleyesraceduptowardstheprimespawningareasandGLIFWCsurveycrewswerenotfarbehind.Alateice-outin2013createdacondensedsur-veyseasonforGLIFWCandpartnersfromMoleLakeSt.CroixUSFWSandWDNR.Whentheicegoesoutlatethewalleyespawningperiodisshorterleav-inglesstimeforcrewstocompletepopulationestimates.Mark-recapturesurveysareconductedduringthespawningperiodwithfykenettingandelectrofishinggearandprovideestimatesofadultwalleyeabundance.In2013GLIFWCandpartnerswereabletocompleteestimateson18lakesintheWisconsincededter-ritoryincludingeightlong-termstudylakes.Asinmostyearscrewsencounteredawidevarietyofweatherconditionsrangingfromblindingsnowsquallstowarmspringthundershowers.Crewssur-veyedpopulationswithwiderangingadultdensitieswithsomepopulationsfoundtobequitehealthywhileotherswereweak.Tribalandstatebiologistswillmeetinmid-Augusttoevaluatethesurveyresults.Meanwhileinthe1837cededterritoryofMinnesotaGLIFWCUSFWSFondduLacandMNDNRwerecooperatingtocompletewalleyeandnorthernpikepopulationestimateson132500acreMilleLacsLake.Northernpikenettingstartedwellbeforeice-outinconnectedtributariesandcrewscombinedtotagover5000pike.Whentheicefinallystartedtoloosenaroundtheshorelinescrewsimmediatelybegantoelectrofishandfykenetforwalleye.Nearly7000walleyeweretaggedoverthecourseoflessthanaweek.JustasitwasinWisconsinthespawningperiodwasquitecondensedonMilleLacsLake.Shortlyafterthemarkingphaseendedandthewalleyeandnorthernpikehadachancetomixinthemainlakebasinandthenrecaptureeffortsbegan.Crewssetshort-termgillnetsoverafour-weekperiodandexaminedover3000walleyeand1000northernpikeformarks.BiologistsmetinearlyAugusttoexaminetheresultsofthesurveyandevaluatethenorthernpikeandwalleyepopulations.OdanahWis.WhenMinne-sotaDepartmentofNaturalResourcesMNDNRandGLIFWCbiologistsrantheirstockassessmentmodelsinordertodeterminetheharvestablesurpluslevelforthelakein2013theresultswerenotveryencouraging.Thepopulationmod-elsagreetheMilleLacsLakewalleyepopulationisatornearitslowestlevelsince1983.Theseresultswereconsis-tentwiththosefoundintheMNDNRfallgillnettingsurveywhichcaughtthelowestnumberofwalleyespernetliftinthelast40years.BiologistsareseekinganswersastowhythewalleyepopulationisindeclinesincerecentharvestsbytheStateandtheTribeshavebeenwellwithintheharvestablesurplussetat24ofthebiomassofwalleyeover14inches.Thecomplexlakeecosystemhasundergoneseveralchangesinthepastfewyearsandsinceeachpartofthesystemisin-terconnectedthecumulativeimpactsofthesechangesmaybelargerthaneachindividualchangewouldbeonitsown.SeveralaquaticinvasivespecieshavecolonizedMilleLacsLakeinclud-ingzebramusselsspinywaterfleasEurasianwatermilfoilandChinesemysterysnail.Ofthesezebramusselsandspinywaterfleasappeartobemostlikelytohaveamajorimpactonthefoodchainthatwalleyesdependonforsurvival.Zebramusselshavereachedadensityofover1200persquareme-terandfilternutrientsfromthewatercolumn.Spinywaterfleasareknownpredatorsofsmallerzooplanktonthatalsocomprisethebulkofthedietformanylarvalfishinthepelagicoropenwaterzoneofthelake.MilleLacsLakealsocurrentlycontainsalargenumberofpredatorfishotherthanwalleyes.Smallmouthbassnorthernpikeandmuskellungenumbersareatorneartheirall-timehighs.Asaresulttheforagebasehasbeenlowinrecentyearsandwalleyeofagivenlengthareweighinglessthaninthepast.Additionallydespitegoodnaturalreproductionandsurvivalofwalleyetotheirfirstfallrecruitmenttotheadultpopulationhasbeenlowinrecentyears.Biologistsandmanagersaretakingamulti-facetedapproachtobringthewalleyepopulationbacktomorenormalhistoriclevels.Firstforthe2013fishingyeartheStateandtheTribesagreedtosettheharvestablesurplusat250000whichisexactlyhalfoftheharvestablesurplusfor2012.Thisincludesaquotareductionforbothfisheries.TheTribesdidnottaketheirfullallocationinspring2013harvesting15138lbs.outofthequotaof71250lbs.StateharvestasofJune30was70904lbs.outofaquotaof178750lbs.Inadditiontothereducedharvestlevelsbothfisherieschangedregulationstoprotectsomeofthelessabundantsmallwalleyes.Thestateanglingregulationfor2013allowstheharvestoftwowalleyesperdaybuttheymustbebetween18and20inches.TheTribesremovedtheirspearingsizelimitinitiallyinplacetoprotectlargerfemalewalleyesthepre-viousspearingsizelimitwasonefishperpermitofanysizeandonebetween20and24inches.TheStateandTribesalsoagreedtoattempttoreducethenorthernpikepopulationbyincreasingthenorthernpikecapsharedequallybetweenbothfisheriesfrom30000lbs.in2012to50000lbs.in2013.Northernpikemayeatyoungwalleyeandcompetewitholderwalleyeforavailableforage.AdditionallytheStatesmallmouthbassregulationshavebeenrelaxed.Biologistsarealsoundertakingavarietyofstudiestoincreaseunder-standingofthewalleyepopulationandevaluatefuturemanagementoptions.Inspringof2013MNDNRFondduLacUSFWSandGLIFWCfieldcrewsundertookmark-recapturepopulationestimatestudiestomeasuretheabun-danceofwalleyeandnorthernpikeinMilleLacsLake.Thesestudieswillbeusedtoanchorthepopulationmodelsandimproveunderstandingofthefallgillnetassessmentresultsconductedyearly.Additionallybiologistsarecon-ductingananalysisoflong-termtrade-offsbetweenyieldandspawnerbiomassunderavarietyofmanagementoptions.Modelprojectionsarebeingruntoex-amineoutcomesofregulationsoptionsintheshortandlong-term.Studiesareongoingtoevaluateanglingspear-ingandnettingharvestpatternsandtheircombinedimpactsonthewalleyepopulation.Finallyasuspendedgillnetstudyisbeingconductedinconjunctionwiththeregularfallassessmentstotestwhetherwalleyearemovinghigherinthewatercolumnduringtheassessmentinsomeyears.MilleLacsLakewalleyenumberslowbiologistsseeksolutionsByMarkLuehringGLIFWCInlandFisheriesBiologistGarrisonMinn.FisheriesbiologistsareanalyzingdatacollectedfromspawningnorthernpikeatLakeMilleLacs.Alongwithanongoingwalleyestudythatrunsintoautumnthepikemark-and-recapturesurveyispartofabroadefforttogetabetterhandleontheoverallfishery.ConductingthenorthernpikeassessmentinconjunctionwiththewalleyeassessmenthelpsusunderstandmoreaboutthepredatorbiomassinthelakesaidMarkLuehringGLIFWCinlandfisheriesbiologist.Italsoprovidesananchorinourmodelfordeterminingoverallnorthernpikepopulationsizeandestablishingfutureharvestlevels.AsopenwateremergedlastspringfisheriesstafffromtheFondduLacTribeGLIFWCandDepartmentofNaturalResourcesinstalledfykenetswhereMilleLacstributarystreamsmeetthebiglakecapturingnorthernsheadeduprivertospawn.Techniciansdeterminedthesexofeachfishaswellasrecordedlengthbeforeapplyingamarktoeithertheanaldorsalorcaudilfinintheformofhole-punch.GLIFWCfisheriesstaffprimarilyworkednearthemouthsoftheRumRiverSe-guchieCreekGarrisonCreekandWhitefishCreekalongMilleLacswestshore.BeginninginlateMayandthroughJuneinteragencyfisherystaffbrieflysoakedgillnetsfrom22surveyzonesaroundthelakeinsearchoffishinclud-ingwalleyethathadbeenpunch-marked.Luehringsaidthatsuitablenumbersofnorthernswerenettedintherecapturephaseoftheassessmenttohelpresearchersestimatethelakewidepopulation.Northernpikeareamongtheearliestspawners.Theiradhesiveeggssticktosubmergedvegetationforaroundtwoweeksbeforehatching.Adultnorthernsarelargeaggressivefeedersandbiologistsarestudyinghowmuchimpacttheyhaveonwalleyenumbers.PikesurveykeyelementofMilleLacsassessmentByCharlieOttoRasmussenStaffWriterGLIFWCassessmentcrewssurvey18lakesinWisconsinMilleLacsLakeinMinnesotaByMarkLuehringGLIFWCInlandFisheriesBiologistEssentialOjibwemowinogaawalleye