Fraser Sockeye 2010 Findings of a Scientists Think Tank December 6, 2010

Transcription

1 Fraser Sockeye 2010 Findings of a Scientists Think Tank December 6, 2010 Steering Committee: Dr. Mark Angelo, Chair, Rivers Institute, British Columbia Institute of Technology Dr. Patricia Gallaugher, Director, Centre for Coastal Studies and Continuing Studies in Science, Simon Fraser University The Speaking for the Salmon Program at Simon Fraser University in partnership with the Pacific Salmon Foundation, the Rivers Institute at the British Columbia Institute for Technology, and Watershed Watch Salmon Society convened an independent think tank of scientists on December 2 3, 2010 to examine the 2010 Fraser River sockeye returns. The scientists addressed the following questions: Why was the return so large in 2010? Dr. Craig Orr, Executive Director, Watershed Watch Salmon Society How can you go from the worst to the best returns in one year? Dr. John Reynolds, Tom Buell Leadership Chair in Salmon Conservation, Simon Fraser University How do you manage for this kind of uncertainty? Dr. Brian Riddell, CEO, Pacific Salmon Foundation Mr. Ken Wilson, Member, Canadian Section of the Fraser Panel and Member, Integrated Harvest Planning Committee Bio sketches for the scientists and background materials are available on the website at: ( What follows is a statement of the findings. Sponsors: Faculty of Environment Faculty of Science Continuing Studies Centre for Coastal Studies 1

2 STATEMENTOFFINDINGS Whathappenedin2010? About29millionFraserRiversockeyesalmonreturnedtothecoastthisyear.Thiswasthe largestreturnsince1913,andwellabovethe11millionthathadbeenforecast.thishighreturn wasinstrongcontrasttothetrendsincetheearly1990sofdecliningproductivityinthefraser, culminatinginonly1.5millionfrasersockeyereturninglastyear.thissuddenreversalof fortuneshasledtoquestionsaboutscienceandmanagement,whichwerethesubjectofathink Tankinvolving23scientistshostedbySimonFraserUniversityonDecember2 nd and3 rd,2010. AlthoughtheaggregatereturnofFrasersockeyewasverylarge,whenconsideringtheindividual populationsthatcomprisethefrasercomplex,thepictureissomewhatmixed.whilereturns werehigherthanforecastsformoststocks,thestrongaggregatereturnwasdrivenlargelybyfish fromtheadamsriver,whichhashighrunseveryfouryears,including2010.therewerealso strongerthanaveragereturnsoffishtotheharrisonandchilkorivers,which,liketheadams, areinthelowertomiddlepartofthewatershed.incontrast,returnswerestillbelowaveragefor populationsintheupperwatershed,suchastheearlystuartcomplexthatspawnsinareas aroundtaklaandstuartlakesnorthwestofprincegeorge.thus,whiletheaggregatereturnsto thefraserwatershedwereindeedexceptionallyhigh,thiswasonlytrueforasubsetof tributaries.thefraserwatershedwasnotfulloffish. Mostofthefishthatreturnedthisyearwereproducedbyadultsthatspawnedin2006.Inthat year,continuinglowreturnshadledtoreductionsinthefisheryinordertoprotectthespawning population.thereducedfisheriesin2006succeededinallowingthe6 th largestnumberoffishto reachthespawninggroundssince1952andpossiblysincethehellsgateslidein1913.this largenumberofspawnersfouryearsagowasonereasonforthelargenumberoffishthat returnedin2010. Asecondcontributingfactorforthelargereturnsthisyearwasachangeincoastalocean conditionstowardcooltemperaturesinearly2008,whenthefishthatreturnedthisyearwere juvenilesenteringthesea.thesetemperaturesweresimilartothoseoccurringinthe1970s. Cooltemperaturessupportfoodwebs,includingenergy richzooplankton,thatarefavourableto growthandsurvivalofjuvenilesockeyesalmon. AthirdpossiblecontributingfactorwastheoccurrenceofamajorvolcaniceruptioninAlaska s AleutianIslandsinearlyAugustof2008,whichspreadashovermuchoftheoffshoreGulfof Alaska.ThisashfertilizedtheoceanandtriggeredanalgalbloomintheregionthattheFraser Riversockeyemigrateto.Thisalgalbloomwastoolateinthesummertotriggerapopulation increaseinzooplankton(foodforsalmon),butitmayhaveincreasedthecaloricvalueand availabilityofthosezooplanktonandenhancedover wintersurvival.supportforthevolcano theorytoexplainthelargereturnsin2010remainsequivocalatthisstage. Overall,2010representedareturntothehistoricalaverageofproductivity(returns/spawner) experiencedinthe1970s.itremainstobeseenwhetherthefavourableoceanconditionsarea one timeeventormarkareturntomorefavourableconditionsfromthepast.unfortunately,in theabsenceofadequateinformationonpathogensandparasitesonsalmonfarmsalongthe 2

3 3 migrationroute,theroleofthispotentialfactorinboththerecentdeclinesinmarinesurvivaland intheremarkableturnaroundin2010cannotbeassessed. Mortalityoffishduringtheirupstreammigrationandpriortospawninghasbeenanongoing concerninthefraser.thiscanbeexacerbatedbyatendencysince1996offishthatcomprisethe late run complex,includingthosefromtheloweradamsriver,tomigrateup riverearlierthan usual,therebyencounteringmuchhighertemperaturesthanaverageduringtheirmigration. Thisearlymigrationofasegmentoflate runfishoccurredagainin2010.whilethetemperatures in2010werenotasextremeashasbeenseeninseveralofthepast15years,temperaturesinthe lowerfraserriverexceeded18 0 Cfora30 dayperiodinmidsummer,athermaldurationknown toreducesurvivalofmigratingadults.thesetemperaturesserveasareminderofthegrowing challengesthatfrasersalmonwillcontinuetofaceasaresultofclimatechange. Whatcanwelearnfrom2010aboutscienceandmanagement? Onelessonfrom2010isthatconservationeffortstoallowfishfromtheparentalgenerationto reachthespawninggroundscanwork.whilethisiscertainlyencouraging,wewerealsolucky, duetothereversalofoceanicconditionstocoolertemperaturesnotseensincethe1970s. Second,thehighreturnsof2010alsounderscorehowdifficultitistotrack(andforecast)a movingtarget,wherebysalmonliveordieaccordingtoanenormousnumberofinteracting variablesduringboththefreshwaterandmarinephasesoftheirlifecycles.weshouldexpect surprisesbecauseofthecomplexityofecologicalinteractionsandtheinherentunpredictability oftheweatherandoceanconditionsthatdrivethem. Third,thehighreturnremindedushowimportantitisformanagerstohaveaccesstoaccurate in seasoninformationasthesalmonarereturningtothecoast,giventheinherentuncertainties inforecasts. Movingforward Canada swildsalmonpolicysetsclearprioritiesformanagementofsalmon.however, implementationofthispolicyhasbeenslow.thedepartmentoffisheriesandoceansneedsto demonstratethewilltoconverttheadmirableintentionsofthepolicyintomeaningful managementaction.therewillbeimportanttradeoffsbetweenobjectivessuchascommercialscaleexploitationofstrongstocksandprotectionofweakstocks.implementationofthepolicy shouldbeaccompaniedbytransparentanalysesofthemagnitudesofsuchfisheriestradeoffs, andconsiderationofthefullersetofvaluesincludedinthepolicy,includingfirstnationscatches, ecosystem basedmanagement,protectionofadiversityofpopulations,andsocialvalues. Thelargeunresolveduncertaintiesaboutwhatcausedthecatastrophicreturnin2009andthe unprecedentedhighreturnin2010highlightourcollectiveuncertaintyabouttherelativerolesof climatechange,aquaculture,andfisheriesmanagementindeterminingsalmonreturns.efforts shouldbemadetodevelopacoordinatedmulti disciplinaryresearchprogramtoaddressthese issues.partnershipsshouldharnessexistingresourcesandstudies,augmentedbyimproved monitoring.therearefewcomprehensiveyear round,annualecologicalstudiesoflakeecology inrelationtosalmon.weneedtobetterunderstandecologicalinteractionsinlakes,including anydelayedcompetitiveeffectsthatmayoccurbetweenyoungfromsuccessivecohorts.

4 Monitoringshouldproceedfromlakestothesea:therehavebeenfewcomprehensivestudiesof out migratingfrasersockeyesmoltssincethe1960s,yetrecentresearchsuggeststhattheremay behighermortalityoffishatthisphaseoftheirlifecyclethanhadbeenpreviouslythought.this programshouldincludeaninvestigationofsurvivorshipasfaralongthecoastalmigrationroutes asisfeasible.theprogramshouldincludefactorsthatcaninfluencesurvival,suchasdiseases, foodavailability,predators,andcontaminants.thisshouldincludeuseofnewtechnological innovationsinelectronictaggingoffishandsensoryapparatustomonitoroftheirenvironment. Thismonitoringshouldbeintegratedwithassessmentsofthehealthoffishinsalmonfarms, includingretroactiveandongoingfullpublicdisclosureofcomprehensiveandrigorous monitoringprogramsforpathogensandparasitesinfishfarms.finally,weneedtomaintainand improvein seasonstockassessmentsthroughtestfisheriesandothermeans,inordertogauge thestrengthofrunsofreturningfishearlierintheseasonthaniscurrentlypossible,inorderto givemanagersandthefishingindustrymoretimetoopenfisherieswhenwarranted. ScientistswhoparticipatedintheThinkTankfeltstronglythattheenhancedmonitoring programsrecommendedabovewillgreatlyimproveourabilitytosustainpopulationsoffraser Riversockeyeinachangingworld. Catch and escapement of Fraser sockeye Millions Escapement Catch 5 0 Year ThesedatawereprovidedbythePacificSalmonCommission(PSC).Spawningescapementsin 2010arepreliminaryestimatesgeneratedbytheThinkTankofscientists,usingdatafromthe Missionhydroacousticsite.Theestimatesofescapementfor2010willundoubtedlychange whenthedepartmentoffisheriesandoceansgeneratesfinalnumbersinearly

5 Thefigureaboveshowsreturnsperspawner,whichisthetotalnumberofadultsproducedby eachspawner.thisincludescatch,in rivermortality,andfishthatsurvivetospawn.the productivityfigurepresentedinthestatementofthescientists ThinkTankfrom2009usedfouryearaveragedrunningproductivity,tosmoothoutspikescausedbyannualvariationin productivitybysomestronglycyclicalstocks.thefigurepresentedaboveshowsactualyear byyearvalues,withoutthefour yearaveraging. Thefigureabovepresentsfour yearrunningaverageproductivitycomparabletothefigurethat wasproducedbythe2009scientists ThinkTank.Althoughthereturnsperspawnerin2010 werenearaverage,thevalueisbroughtdownbythethreeprecedingyearsoflowproductivity. 5

6 6 ThinkTankofScientists ListofParticipants (biosketchesavailableathttp:// December2010 Dr.MarkAngelo Chair,RiversInstitute, BritishColumbiaInstituteofTechnology Dr.SoniaBatten PacificCPRProjectCoordinator,SirAlisterHardy FoundationforOceanScience Dr.DougEggers ChiefFisheriesScientist, AlaskaDepartmentofFishandGame Dr.IanFleming Professor,OceanSciencesCentre, MemorialUniversityofNewfoundland Dr.PatriciaGallaugher Director,ContinuingStudiesinScienceandthe CentreforCoastalStudies;andAdjunctProfessor, Biosciences,SimonFraserUniversity Dr.KeesGroot ScientistEmertius,DFOandConsultant,Yellow PointBio Research Dr.ScottHinch FisheriesScientist,ForestSciencesandCentrefor AppliedConservationResearch, UniversityofBritishColumbia Dr.NathanMantua AssociateProfessor,SchoolofAquaticandFishery Sciences,UniversityofWashington;andResearch Scientist,PNWStation,USForestService Dr.CatherineMichielsens QuantitativeFisheriesBiologist, PacificSalmonCommission Dr.JonathanMoore AssistantProfessorandLiberEroChairofCoastal Studies,SimonFraserUniversity(January2011) Dr.AlexandraMorton Director,SalmonCoastFieldStation Dr.CraigOrr ExecutiveDirector, WatershedWatchSalmonSociety Dr.RandallM.Peterman Professor,SchoolofResourceandEnvironmental Management,SimonFraserUniversity Dr.JohnReynolds Professor,BiologicalSciencesandTomBuellBC LeadershipChairinSalmonConservationand Management,SimonFraserUniversity Dr.BrianRiddell CEOandPresident,PacificSalmonFoundation Dr.MarvinRosenau Instructor,Fish,WildlifeandRecreationProgram, BritishColumbiaInstituteofTechnology Dr.RickRoutledge Professor,StatisticsandActuarialSciencesandCo Director,HakaiNetworkforCoastalPeople, EcosystemsandManagement, SimonFraserUniversity MichaelStaley SeniorBiologist,FraserRiverAboriginalFisheries SecretariatandMember,FraserRiverPanel TechnicalCommittee Dr.JackStanford JessieM.BiermanProfessorofEcologyandDirector, FlatheadLakeBiologicalStation, UniversityofMontana Dr.CarlWalters Professor,FisheriesCentre, UniversityofBritishColumbia Dr.DavidWelch President,KintamaResearchCorporation KenWilson Member,MarineConservationCaucus,Integrated HarvestPlanningCommittee;andMember, CanadianCaucusoftheFraserPanel,Pacific SalmonCommission Dr.AndrewWright DirectorofActenum,Zymeworks,andPharos Capitalandaco founderofaegismobility