Evaluation of Alternative Escapement Goals

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  • AnalysisofEscapementGoalsforBristolBaySockeyeSalmontakingintoAccountBiologicaland

    EconomicFactors

    FinalDraftReport

    March10,2015

  • AnalysisofEscapementGoalsforBristolBaySockeyeSalmontakingintoAccountBiologicalandEconomicFactors

    FinalDraftReport

    Preparedby:

    CurryJ.Cunningham,JocelynWang,RayHilborn,andChrisAnderson

    SchoolofFisheriesandAquaticSciencesUniversityofWashington

    Box355020,Seattle,WA981955020

    and

    MichaelR.Link

    LGLAlaskaResearchAssociates,Inc.2000W.InternationalAirportRd,SuiteC1

    Anchorage,AK99502

    Preparedfor:

    BristolBayScienceandResearchInstitutePOBox1464,Dillingham,Alaska99576

    BristolBayRegionalSeafoodDevelopmentAssociation800E.DimondBlvd,Suite3131#158

    AnchorageAK995152028

    TheAlaskaBoardofFisheriesJuneau,AK

    March10,2015

  • i

    ExecutiveSummary

    AtanAlaskaBoardofFisheriesmeetinginDecember2012,theAlaskaDepartmentofFishandGame(ADF&G)proposedincreasingsockeyeescapementgoalsforseveralriversystemsinBristolBay.AfteramovementbyindustrytogettheBoardofFisheriestoadoptoptimumescapementgoals(OEGs)atthethencurrentescapementgoallevels,ADF&Gagreedtopostponeimplementingtheproposedescapementgoalsuntilindustrycouldstudythebiologicalandeconomicimplicationsofchangestoexistingescapementgoals.TheindustrywastoworkwithADF&G,fishermenandprocessorsandtoreportbacktotheBoardofFisheriesintwoyears,andpriortothe2015fishingseason.

    AstudywasledbytheBristolBayScienceandResearchInstitute(BBSRI)withfinancialsupportfromBBEDCandtheBristolBayRegionalSeafoodDevelopmentAssociation.Overthelast18months,fisheryscientistsandeconomistsfromtheUniversityofWashingtonandBBSRIexaminedthebiologicalandeconomicimpactsoffouralternativeescapementgoalpolicies,includingthecurrentescapementgoals.Aspartofthestudy,anAdvisoryPanel(AP)wasassembledwithrepresentativesoffishermen(setanddriftnet),processors,anindependenteconomist,andanADF&Gmanager.TheAPmetfivetimesoverthelastyeartoreviewmethodsandprovidefeedbackonhowtobestquantifytheimpactsofdifferentescapementgoalpolicies.

    Thisreportisthesecondoftworeportscompletedbythestudyteam.Inthefirstreport,weexaminedtheprocessofsettingescapementgoalsbelievedtomaximizecatches(alsoknownasBEGsorBiologicalEscapementGoals)byexploringsomeapproachesdifferentfromthoseusedbyADF&G.

    StudyApproach

    Weusedcomputermodelstosimulatethefisheryandtheindividualsalmonstocksonadailybasisunderalternateharvestpoliciestounderstanddifferencesinkeyvariablessuchascatch,valueofharvesttofishermenandprocessors,andtheinterannualvariabilityinthese.ComputermodelswereconstructedthatmimictheBayssockeyestocks,managementrules(whentoopenandclosethefishery),harvestingandprocessingrevenues,andtheeffectsofescapementlevelsonsubsequentreturns.Themodelwasrunfor100yearsimulations,andthesesimulationswererepeated100timesforeachescapementgoalalternativetocharacterizedifferencesamongpolicies.Wecharacterizedtheeconomicperformance(i.e.,revenuetoharvestersandprocessors)acrossallescapementgoalsexamined.Allthealternativeswelookedatwouldqualifyaseithersustainableescapementgoals(SEGs)orBEGs,andassuch,couldbeimplementedbyADF&GwithoutBoardofFisheriesinvolvement.

    AlternativeEscapementGoalsExamined

    1. Currentescapementgoals(SEGs;inusethrough2014)2. ADF&GproposedSEGsandBEGs(thoseproposedinDecember2012)3. BEGsdevelopedbyADF&Gexpectedtoprovidemaximumsustainedyield(BEGs)

  • ii

    4. Escapementgoalsthatvarywiththesizeoftheannualreturn(totalreturnorTRbasedescapementgoals).

    KeyFindings

    Generally,movingtohigherescapementgoalswillproducelargerandmorevariablerunsandescapementsacrossBristolBay,butthisisnotexpectedtotranslateintolargerharvestsorrevenuetoharvestersandprocessors.Insomecases,harvestswillbesmallerunderhigherescapementgoals.

    Weexpectarelativelyflatplateauofcatchandvalueofcatchacrossawiderangeofescapementlevels;narrowlydefinedescapementgoalsdonotseemwarrantedand,thisalsohasimplicationsforhowtodefineforegoneharvest.

    CurrentandproposedSEGsareeconomicallyrobust.Ingeneral,thecurrentandtheADF&Gproposedescapementgoalsperformedwellintermsofharvestandrevenuetotheharvestingandprocessingsectors,relativetoBEGs.

    PursuingtheoreticalmaximumyieldthroughtraditionalBEGsinBristolBaywilllikelyleadtolessaverageyieldandmorevariableyieldthanthecurrentandproposedSEGs,andaTRbasedescapementgoalpolicy.ManagementforBEGsalsoposesthegreatestchanceofsmallBaywideannualharvest.Escapementgoalsthatweexaminedthatincreasedforlargerruns(TRbasedescapementgoals)providedtheleastvariableharvestsandlowestprobabilityofsmallannualBaywideharvests.

    GiventhedynamicsoftheBristolBaysockeyesalmonpopulationsandthefishingindustry,thetheoreticalmaximumyield(MSY)isnotthepracticalmaximumyield.Thefisherycannottakefulladvantageofoccasionallylargereturnstoincreaseexpectedcatchabovealternativepoliciesacrossmanyyears.Asaresult,thecurrentandproposedSEGscouldbecalledBEGs,inamorebroadlydefinedversionofthetermMSY.

    EscapementgoalpoliciesshouldprovideforflexibilitytomanagersgiventhevariableanduncertainfishandfisherydynamicswithinandacrossfishingdistrictsintheBay.

    RecommendationsfromtheStudysAdvisoryPanel

    TheAPsrecommendationbuiltupontheresultspresentedhereand,essentially,hybridizedthreeoftheescapementpoliciesweexamined:thelowerboundofthecurrentSEGs,theupperboundsoftheproposedSEGs,andlanguageinmanagementplansthatcapturethespiritoftheTRbasedpolicy.TheeffectwouldbetohavewiderstockspecificescapementgoalrangesthaneitherthecurrentorproposedSEGs,andprovideguidelinestomanagerstoachievelowerrangeescapementsinsmallrunyearsandhigherrangeescapementsinlargerrunyears.TheAPbelievedthatifADF&GcouldadoptatheserevisedSEGs,andtheBoardofFisheriesamendmanagementplans,implementationofOEGsbytheBoardofFisherieswouldnotbenecessary.

  • iii

    TableofContents

    ExecutiveSummary..........................................................................................................................i

    Introduction....................................................................................................................................1

    StudyObjectives.............................................................................................................................1

    StudyApproach...............................................................................................................................2

    AlternativeEscapementGoalsExamined.......................................................................................3

    OrganizationofthisReport.............................................................................................................4

    BackgroundandPreviousWork......................................................................................................5

    TheStudysAdvisoryPanel.............................................................................................................6

    Acknowledgements.........................................................................................................................7

    References .....................................................................................................................................7

    Chapter1:BiologicalandManagementModelsUsedtoSimulateRiverandDistrictspecificAnnualReturns,Catches,andEscapementunderFourEscapementGoalPoliciesintheBristolBaySalmonFishery.....................................................................................................................11

    Chapter2:EconomicModelingtoEstimateHarvesterandProcessorRevenuesunderFourEscapementGoalPoliciesforBristolBaySockeyeSalmon.........................................................21

    Chapter3:ConclusionsfromanAnalysisofAlternativeEscapementGoalPoliciesforBristolBaySalmon........................................................................................................................................31

    Appendices...................................................................................................................................A1

  • I1

    Introduction

    InDecember2012theAlaskaBoardofFisheries(BoF)struckacommittee1tooverseetheanalysisofoptimumescapementgoals(OEGs)2forBristolBaysockeyesalmon.TheBoFactionwasinresponsetoproposedrevisionstoBristolBaysockeyesalmonescapementgoalsbytheAlaskaDepartmentofFishandGame(ADF&G;Fairetal.2012).ThisreportistheoutcomeofananalysisofescapementgoalsforBristolBaysockeyesalmonthattakeintoaccountbiologicalfactors,managementuncertainty,andeconomicfactors.

    TheBristolBayEconomicDevelopmentCorporation(BBEDC)committedtoleadingananalysisofalternativeescapementgoalsthroughitsnonprofitsubsidiary,theBristolBayScienceandResearchInstitute(BBSRI).BBSRIretainedfisheriesscientistsandeconomistsfromtheUniversityofWashingtontoconducttheanalyses.SalmonprocessorsinBristolBayandthedriftnetfleetsRegionalSeafoodDevelopmentAssociation(RSDA)pledgedlogisticaland/orfinancialsupporttotheanalysis.ADF&GagreedtopostponetheimplementationofrecommendedSustainableandBiologicalEscapementGoals(SEGsandBEGs)forsixsockeyestocksuntilthe2015season,pendingtheresultsfromtheanalysis,whichwasexpectedpriortothe2015season.

    StudyObjectives

    1. Examinealternativeapproachestoestimatingmaximumsustainedyield(MSY)escapementgoalsforBristolBaysockeyesalmonstocks,andcomparetothosefromFairetal.(2012).

    2. Buildabiologicalmodelofthepopulationdynamicsof9BristolBaysockeyestocksandsimulatesdailyreturnstofourofthefiveBristolBayfishingdistricts(Figure1)basedonpreviousescapementlevels.

    3. BuildamodelofthedailymanagementdecisionstomimicfisherymanagerbehaviorinBristolBay.

    4. BuildamodelthatcaptureskeyeconomicfactorsaffectingthevalueofthecatchfromtheBristolBaysalmonfishery.

    5. Conductamanagementstrategyevaluationbysimulatingthedailymanagement,harv