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IndependentPeerReviewoftheCommonThresherShark(Alopiasvulpinus)StockAssessment
IndependentPeerReviewReportfortheCenterforIndependentExperts(CIE)
RuiCoelho
June26-28,2017
SouthwestFisheriesScienceCenter8901LaJollaShoresDr.,LaJolla,CA92037
LaJolla,CA92037858-546-7000
September2017
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Contents
1.Executivesummary..................................................................................................................3
2.Background..............................................................................................................................4
2.1.Introduction.......................................................................................................................4
2.2.DescriptionofReviewersroles..........................................................................................5
3.SummaryfindingsforeachTOR...............................................................................................5
3.1.ToRsitem#1.....................................................................................................................5
3.1.1.Stockdefinition..........................................................................................................6
3.1.2.Catchhistorydata......................................................................................................6
3.1.3.CPUEstandardization.................................................................................................6
3.1.4.Biologicalinformation................................................................................................7
3.1.5.Lowfecunditystock-recruitmentfunction.................................................................8
3.1.6.Naturalmortality........................................................................................................9
3.2.ToRsitem#2...................................................................................................................10
3.3.ToRsitem#3...................................................................................................................11
3.4.ToRsitem#4...................................................................................................................11
3.5.ToRsitem#5...................................................................................................................13
Appendix1:Bibliographyofmaterialsprovidedforreview.......................................................15
Appendix2:CopyoftheStatementofWork.............................................................................16
Appendix3:Panelmembershiporotherpertinentinformation...............................................26
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1.Executivesummary
The Fisheries Resources Division (FRD) of the Southwest Fisheries Science Center (SWFSC)requested an independent review of the stock assessment of the common thresher shark(Alopias vulpinus) from the west coast of North America. The stock is described to rangebetweenthewestcoastsofMexico,USAandCanada.TherearenocurrentorhistoricalfisheriesalongthewestcoastofCanadaandininternationalwatersthattargetcommonthreshersharks.Bycatchfromotherfisheriesappeartoberare.Commonthreshersharkfisheries inboththeUSAandMexicohavedeclinedsubstantiallysincethestartofcommercialfisheriesinthe1970s,withtotalremovalsestimatedtobe<200tin2014.ThecurrentUSAfisherymanagementplanforthisstockincludesaharvestguidelineofamaximumof340tderivedfromtheoptimumyieldforvulnerablespecies(0.75*MSY).
TheStockAssessmentReviewPanelmetatNOAA’sSouthwestFisheriesScienceCenter inLaJolla,California,from26-28July2017toreviewastockassessmentofcommonthreshershark.
This is the first stock assessmentof common thresher sharks along thewest coast ofNorthAmericathatincorporatesinformationfromallfisheriesknowntobeexploitingthepopulation.TheStockSynthesis(SS)modelingplatformwasusedtoconducttheanalysis.Themodelbeganin1969,assumingthepopulationwasatequilibriumpriorto1969inanearun-fishedstate,andendedin2014,whichwasthelastyearthatdatawasavailable.
Themainuncertainty identified in thestockassessmentwasthereproductivebiologyof thisstock.Previousresearchsuggestedthatfemalesharkshadanageofmaturityof5yearsandanannualreproductivecycle.Thereviewscrutinizedtheevidenceforthisandfoundthatpotentialmisidentificationofpelagicwithcommonthreshersharksandproblemsindeterminingmaturitystageinsomeoftheoriginalstudies,pointedtoamorelikelyolderageofmaturity(age12)andpossiblyabiennialreproductivecycle.Thiswouldbeconsistentwithrecentstudiesforthesamespecies in theAtlantic.Additionally, anotherprevious study from the IndianOcean thatalsoshowedthatcommonthresherhasanageofmaturityof5yearsandanannualreproductivecycle was also analyzed during themeeting, and a similar problem in species identification(misidentification between pelagic and common threshers) was also found. On this issue, arecent IOTC (IndianOcean Tuna Commission)working paperwas provided by the reviewersaddressingpreciselythisissue.Therefore,thestockassessmentreviewagreedthattherewassufficientevidencetousethelateageatmaturitylifehistoryparameters.
Thosechangesinthereproductivebiologywerefoundtobethemajorsourceofuncertaintyinthemodels.Therefore,asensitivityanalysisusingthisfinalreproductiveschedulewascarriedout,mainlyinusingdifferentcombinationsofnaturalmortalityandparametersfromthestock-recruitmentfunction(Zfrac,fromtherelativelynewlow-fecunditystock-recruitmentfunction).In general, using those different combinations resulted in differences in the scale of theestimatedpopulations,butmostofthescenariosdeterminedconsistentlysimilarstockstatus,i.e.,thatthestockwasnotoverfishedandthatoverfishingwasnottakingplace.Therefore,thestockstatusdeterminationwasconsideredtoberobustlyestimated,withaconclusionthatthecurrent management harvest guideline of 340t seems to be adequate according to the USguidelinesforfisheriesmanagementofvulnerablespecies(0.75*MSY).
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Theotheraspectsoftheassessmentwereagreedtobebasedonthebestavailablescienceandcarriedoutinanun-biasedandcomprehensiveway.Theassessmentmodelconfiguration,catchassumptions,andinputparameters(e.g.,naturalmortality,spawner-recruitrelationship)werereasonable.Themodelswereappropriatelyconfigured,assumptionswerereasonablysatisfied,andprimarysourcesofuncertaintywerewellaccountedfor.
ThereviewprocesswaseffectiveinstructuringacriticalreviewoftheworkoftheSWFSCandinidentifying areas of concern and needs for additional work in future assessments. Someparticularrecommendationsforfutureworkwerelisted.Themainonewasregardingthemainaxis of uncertainty of the current assessment model, in particular the need for continuingbiologicalstudiestofurtherinvestigatethereproductivebiologyofthispopulation,especiallyintermsofthesizeatmaturity,ageatmaturity,andreproductivecycle/periodicity.
2.Background
2.1.Introduction
The Fisheries Resources Division (FRD) of the Southwest Fisheries Science Center (SWFSC)requestedanindependentpeerreviewofthestockassessmentforthecommonthreshershark(Alopias vulpinus) from the west coast of North America. The stock is described to rangebetweenthewestcoastsofMexico,USAandCanada.ThecommonthreshersharkfisheriesfromUSAandMexicoareindependentlymanagedbythePacificFisheryManagementcouncil(PFMC)andtheInstitutoNacionaldePesca(INAPESCA),respectively.TherearenocurrentorhistoricalfisheriesalongthewestcoastofCanadaorininternationalwatersthattargetcommonthreshersharks.Bycatchfromotherfisheriesappeartoberare.CommonthreshersharkfisheriesinboththeUSAandMexicohavedeclinedsubstantiallysincethestartofcommercialfisheriesinthe1970s,withtotalremovalsestimatedtobe<200tin2014.ThecurrentUSAfisherymanagementplanforthisstockofcommonthreshersharksincludesaharvestguidelineofamaximumof340tderivedfromtheoptimumyieldforvulnerablespecies(definedas0.75*MSY).
This is the first stock assessmentof common thresher sharks along thewest coast ofNorthAmerica that incorporates information fromall fisheriesexploiting thepopulation.TheStockSynthesis(SS)modelingplatformwasusedtoconducttheanalysis.Themodelbeganin1969,assumingthepopulationwasatequilibriumpriorto1969inanearun-fishedstate,andendedin2014,whichwasthelastyearthatdatawasavailable.Thestockassessmentconsideredthispopulationtobeasingle,well-mixed,trans-boundarystockandreliedheavilyondatafromboththeUSAandMexico.However,itisimportanttonotethattheanalystswhoreconstructedthecatchtimeseriesforMexico'sfisherieswerenotavailableforthepeerreviewmeeting.Akeyuncertainty highlighted in the stock assessment is the reproductive biology of this stock ofcommonthreshersharks.Previousresearchonthisstockofcommonthreshersharksuggestedthatfemalesharkshadanageofmaturityof5yearsofageandanannualreproductivecycle.However, a recent studyon the reproductivebiologyof thewesternNorthAtlantic stockofcommon thresher sharks demonstrated amuch oldermedian age ofmaturity (age-12) andlonger reproductive cycle (biennial or triennial cycle). Sensitivity model runs indicated thatchangingthematurityandperiodicity/fecundityschedulesresultedindifferencesinthetrend
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andscaleoftheestimatedpopulationdynamics,butisingeneraltobeusedfortheestimationofstockstatus.
ThestockassessmentprovidesthebasisforscientificadviceonthestatusofcommonthreshersharksalongthewestcoastofNorthAmerica.Anindependentpeerreviewoftheassessmentistherefore essential. The Terms of Reference (ToRs) of the peer review are given below.Supportingdocumentation for the common thresher shark assessmentwaspreparedby theSWFSC.
2.2.DescriptionofReviewersroles
TheStockAssessmentReviewPanelmetatNOAA’sSouthwestFisheriesScienceCenter inLaJolla,Californiafrom26-28July2017toreviewastockassessmentforCommonThresherShark(Alopiasvulpinus).
The Stock assessment work and presentations were provided by Steve Teo (SWFSC). OtherSWFSC scientists provided additional presentations and contributions, particularly SuzanneKohinonthereproductivebiology.OtherparticipantsfromtheSWFSCthatwerepresentandprovidedadditionalinputswereKevinHill,P.RCrone,Hui-HuaLee,HelenaAryafar,AntonellaPretiandHeidiDewar.
TheCIEReviewPanelwascomposedbyHenrikSparholt(Denmark,ReviewpanelChair),JosephPower (USA)andRuiCoelho (Portugal). Therewasno formal separationof the independentReviewersrolesasallcontributedtoallpointsoftheagendaandthediscussion.TheReviewPanel Chair coordinated the preparation of the summary report, and all other Reviewersprovidedcontributionsandrevisionstothefinalsummaryreport.
3.SummaryfindingsforeachTOR
3.1.ToRsitem#1
The item # 1 of the ToRs requested an "evaluation of the assessmentmodel configuration,assumptions, and input parameters (e.g., natural mortality, spawner-recruit relationship,reproductive biology) to determine if the data are properly used, input parameters arereasonable, models are appropriately configured, assumptions are reasonably satisfied, andprimarysourcesofuncertaintyareaccountedfor".
MostofthetimespentduringthemeetingwasonthispointoftheToRsandagenda.Themainitemsdiscussedwereintermsofmodelconfiguration,assumptionsandinputparameters.
Thosearedescribedindetailbellow:
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3.1.1.Stockdefinition
Thecurrentstockassessmentassumesthepopulationtobeasinglestock, relyingmainlyondatafromtheUSAandMexico.Thediscussiononthisissuewasrelativelylimitedasthecurrentevidenceseemstosupportthissinglestockhypothesis,includinggeneticsandtaggingdata.Thepanel agreed that there seems to be sufficient current information to assume this stockdefinitionaswasusedinthecurrentstockassessment.
3.1.2.Catchhistorydata
Itwasnotedthatseveralassumptionshadtobemadeonthecatchhistorytimeseries,especiallyas for the initial years there were very limited data and details in species-specific catchcomposition.Ingeneral,itseemsthattheworkthatwasdoneonthecatchreconstructionseemsadequate.
OnespecificcasethatwasnotedandraisedsomepossibleconcernswastheartisanalMexicanfishery(pangas).Thisfisheryiscomposedofverysmallboatsthatcanuseseveralartisanalgears,andthenumberofboatsoperatingisverylarge(around2000).Itwasnotedthatfromthose,onlyaminorityhavelicensestofishforsharks.Oneconcernfromthepanelatthemeetingwasthatthislargenumberofvesselswithoutsharklicensescouldalsobeby-catchingsharksthathadtobediscardedduetothevesselsnothavingspecificsharklicenses.Asthesharkdiscardandpost-releasemortality is likelyveryhigh,thiscouldbeavery importantsourceoffishingmortality not accounted for in the current catch history (as the catches are estimated fromlandings,butdonotaccountforpossiblediscardmortality).
Thisissuewasdiscussedatthemeeting,butunfortunatelytheanalystswhoreconstructedthecatchtimeseriesfromMexicowerenotavailabletobepresentatthemeeting.However,themodelersexplainedthattheMexicandataisactuallycomingalsofrommarketsamplingandnotnecessarilyonlyfromportsampling,andthereislikelyverylittlediscardinginthosefisheries.So,themarketsamplingshouldcoverwelltheoverallcatchandthereshouldn'tbetoomuchdiscarding in this fishery for this to be an issue. The panel understood this explanation andagreed that the catches used likely represent the best available information at this stage.However,itwasalsorecommendedtofurtherexplorethisissue,asthisfisherycouldrepresentsomeadditionalsourceofmortalitynotcurrentlyaccountedfor.
3.1.3.CPUEstandardization
The CPUE standardizationmethodwas briefly described and themainmethods and resultsshown.ThemethodusedwasthesameforallCPUEtimeseriesdata,specificallyGLMswithaDeltalognormalapproach(combinationofabinomialmodelformodelingtheprobabilityofasetbeingpositive,andalognormalmodelfortheexpectedCPUEconditionaltothesetbeingpositive). The panel agreed that this is a commonly used and widely accepted method incommercial fisheries CPUE data standardization. The method is particularly useful when acertainproportionofthedataiscomposedbyzeros.
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OnespecificcommentmadeontheCPUEstandardizationwasrelatedwiththedistributionused.Currently the data is being modeled in catch numbers (N, discrete distribution), thentransformed into a continuous variable (log (N)) to make it possible to use the lognormaldistribution (continuous distribution). It was suggested, in the future, to possibly test otherapproaches,forexample,tomodelthecatchdirectlyinnumbersusingadiscretedistribution(i.e.theNegativeBinomial,possiblywithzeroinflationifneeded).OtherpossiblealternativeistheTweediedistribution(generalizationoftheexponentialfamily)thatcanmodelthemassofzerosandthecontinuouscomponentforthepositivesetsinthesamemodel.ThosechangesareunlikelytohaveamajorimpactintheCPUEseriesbutitwouldbeinterestingtoalsotestforthosealternativeapproaches.
Anotherspecificcommentwasmadeonthefactthattheindexfromthemainfishery(USDGN)hadtobebrokeninto3separatetimeseriesduetochangesinregulations,withaperiodinthemiddleofthetimeserieswithoutinformation.ThepanelrecognizedandacceptedthatthishadtobedonebecauseofthedifficultyofmodelingthosechangesinregulationsintheGLMmodels,as there is no overlap of the different regulations in time and therefore themodel cannotestimateparametersforthoseeffects.However,byhavingtobreakthetimeseriesfromthemain fishery in 3 different sections, the overall contribution of those time series to theassessmentmodelwasalsolower(exceptforS2thatstillcontributedsignificantly),andlikelyincreased the variabilitywithin each section. Thepanel suggested that, in the future, a newattemptcouldbetriedfortheentiretimeseriescombined,tryingtoaccountforthechangesinmanagementregulations(mainlyseasonalandspatialclosures)asdetailedspatialandseasonaleffectsintheGLM.
Finally,thegroupdiscussedtheuseofproxiesfortargetingvariablesinthemodels,inthiscasebasedontherankingsofswordfishcatchwithineachyear(usedascategoricalvariablesasaproxyfortargetingswordfishversussharks).Onepossibleissuethatwasraisedregardingthismethod is that ifwithin specific years there is consistently the same targeting for the samespecies (e.g., swordfish), there will still be categorization and ranking within each year notnecessarilyconsistentwiththeoverallvariations inthetargetingofthefleet(inter-annually).Thismeansthatthetargetingvariablewouldnolongerbecomparablebetweendifferentyears.Onepossiblesuggestionbythepaneltoaddressthisissueinthefuturewouldbetotestandconsiderinteractionsbetweenyearandtargetingeffects.
3.1.4.Biologicalinformation
Biology, especially the reproductive biology,was agreedby the panel to be likely themajorsourceofuncertainty in the stockassessment.Theoriginal stockassessment considered thehypothesis of a more productive biology based on a smaller size at maturity and annualfecundity.However,sincethen,therehavebeenconcernsabouttheoriginalbiologicalstudiesinthePacific,withthenewhypothesisthatsizeatmaturitycouldbelarger(moresimilartotheonedescribedfortheAtlantic)andperiodicitycouldbebiennial.
The main issues identified with the original biological studies can be related with eventualspeciesmisidentificationinthreshers(betweencommonandpelagicthresher),anissuethatis
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now also suspected in some of the original studies in the tropical Indian Ocean. As pelagicthresher is a much smaller species, the size at maturity is also smaller and if there ismisidentificationthiswillhaveagreatimpactintheestimationofthesizeatmaturity.Theremayhavealsobeensomeissueswiththeoriginalmeasurementsfromtheobservers.
ItshouldbenotedthatanexpertonsharkbiologyfromtheIndianOceanwascontactedbye-mailduringthemeeting(E.Romanov)thatwasalsoinvolvedinsomeoftheoriginalbiologicalstudiesinthatOcean.ThisexpertconfirmedthattheoriginalstudiesinthetropicalIndianOceanwerealsolikelymisidentifyingcommonandpelagicthresher,andthereforethecalculationofthesizeatmaturityislikelyalsoincorrect.
ThepanelthereforefullyagreedwiththisnewhypothesisofthebiologythatisnowposedbytheSWFSCscientistsofalargersizeatmaturity(alsocorroboratedfortheIndianOcean)andpossiblyabiennialreproductivecycle.However,usingthisnewbiologycreatedsomeadditionalconvergenceproblemsinsomeofthemodelsthat ingeneralneededlowervaluesofnaturalmortality(M)toconverge.ThisissuewasexploredatgreatlengthduringthemeetingwiththeSWFSCmodelerexploringmultiplescenarios(especiallycombinationsofMandZfracfromthestock-recruitfunction)toinvestigatewhichcombinationshadproblemsofconvergence,likelycaused by conflicts in the data (CPUE, size data and biology). The panel agreed that theuncertainties in the reproductive biology of the common thresher shark in the Pacific are asourceofmajoruncertaintyinthestockassessmentmodelandshouldbefurtherstudied.
Anotherminordetailnoted is that thecurrentmodel isusingageat lengthdatatoestimategrowthparametersinsidetheactualstockassessmentmodel.Anotheroptionposedwouldbetousetheparametersfromanexternallyfittedgrowthmodel(usingthesamedata)asfixedparametersintheSSmodel.ThemodelersexplainedthatbyallowingthestockassessmentSSmodeltoalsoestimategrowthprovidedmoreflexibilitytothebiologyandresultedinoverallbetterfits.ItwasalsonotedthattheparametersestimatedintheSSwereverysimilartotheexternallyobtainedgrowthparameters,sothisisnotlikelyamajorissueintermsofthestockassessmentmodel.
3.1.5.Lowfecunditystock-recruitmentfunction
Thestockrecruitmentfunctionusedinthefinalassessmentwastheonedevelopedrecentlyforlowfecundityspecieslikesharks.Withinthisfunction,theparameterZfracdefinestheslopeofthestock-recruitmentcurveattheorigin,i.e.,themaximumrecruitmentrateproducedwhenstock sizes approach very low values. This is conceptually very similar to the steepness (h)parameter of the Beverton-Holt stock-recruitment function, more commonly used in stockassessments.
The main issue discussed is that similarly to the steepness (h) parameter when using theBeverton-Holt function, there is usually also very little information in the data to actuallyestimateZfrac.And,therefore,inasimilarwaytoh,thevaluesofZfracoftenhavetobefixed(notestimated)andtendtobeveryinfluentialinthestockassessments.Thisissuewasexplored
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atgreatlengthwiththeuseofsensitivityanalyseswithvarioushypothesisandcombinationsofvalues.
Ingeneral,theuseofthisnewlowfecundityrelationseemstobeadequateforsharks.Butitwasalsonotedbythepanelthatanyotherformofthestock-recruitmentfunctionthathaverapiddeclinesattheorigin(i.e.,lowstocksize)shouldalsobeadequateforsharks,especiallyspecies like threshers that have very low productivity, mainly because of their very lowfecundity. Some suggestions of other stock-recruitment functions with those characteristicsweremade,asforexampleasimplehockeystickwiththerecruitmentconstantoverstocksizeuntilitreachesathresholdatwhichitdeclineslinearlytotheorigin.
The panel agreed that this function and others with these same characteristics (i.e., steepdeclineat lowstock size)would likelyhaveproducedsimilar results in the stockassessmentresults.AnditshouldbefurthernotedthatalternativeBeverton-Holtfunctionswereusedassensitivityanalysis(withthecorrespondinghvalue)andshowedverysimilarresultstotheuseof this new low fecundity stock-recruitment function. Therefore, the panel agreed that thepopulationdynamicsandstockstatusofthecommonthresherislikelyrobusttothefunctionused,aslongasitmaintainsthesetypesofcharacteristicsatalowstocksize.However,thepanelalsorecommendedthatfurthertestingwiththisfunctionshouldbecarriedoutinthefuture.
3.1.6.Naturalmortality
Asmentionedpreviously,oncethenewreproductivebiologywasdecided(basedonalargersizeatmaturityandpossiblebiennialcycle)thenaturalmortality(M)neededtobeadjusted.Thishappened because the low productivity by year per adult femalewould cause the stock tocollapseevenwithoutanyfishingeffort, ifMwasassumedhigherthan0.14.This isasimilarsituationtohavingvaluesoflambda(l)lowerthan1(inapopulationdynamicsmodelinthiscaseaLesliematrixmodel)thatwouldmeanacollapsingpopulationevenwithoutanyfishingmortality.Thiswasjudgedunrealisticinapopulationdynamicsperspective.
AmodelsensitivityrunwhereMwasallowedtobeestimated(notfixed)bythemodelgaveverylowvaluesofMofabout0.03,whichcorrespondstoaveryhighmaximumage.Mvaluesof0.04,0.06and0.08meanthat1%ofthestockincaseofnofishingwouldbeabout115,77and58yearsold,respectively.Basedonthemeta-analysisofM’srelationtoageatfirstmaturityandtomaximumage,thelower95%confidenceintervalwas0.06.RunswithMequal0.6and0.8(andZfracvaryingbetween0.6-0.9)madethemodelsabletoconvergeandnotdeviatemuchfromeachotherintermsofmodelperformance.Thepanelagreedthatamaximumageof58yearswasmorerealisticthan77yearsforthisspecies,andthereforetentativelydecidedonthatvalueforanewbaserun.
However, runswithM=0.08 and Zfrac=0.8 gave problemswith internal consistencies of themodelanddata(conflictsbetweenbiology,CPUEinformationandsizestructure).Therefore,Mhadtobefixedat0.04andZfractat0.5beforetheseinconsistenciesweresolved.After longdiscussions, itwas agreed touse this run as thebest descriptionof the stockdynamics andstatus,asthebaserun.ThisdecisionwasreachedknowingthatitmeantthatMwasoutsidethe
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rangeindicatedbythemetaanalysisofmaximumageandageofmaturity,meaningthattherewouldbeaverysubstantialnumberofveryoldfishintheplusgroup(25+).Whilethiscouldbepossible, at this stage it is unknown if that really is the case and where such part of thepopulation would be located (spatially, seasonally and possibly in terms of depth habitat).AnotherissuewasthatsuchalowMwouldresultinaveryhighmaximumageof115years.Still,andeventhoughtherewerethoseissuesthatremainedtobeaddressed,thisfinalscenariowasregardedasthebestcompromisebetweentheconflictingsignals in thedataandknowledgeaboutthereproductivebiologyandcorrespondingpopulationdynamicsofthispopulation.
3.2.ToRsitem#2
Theitem#2fortheToRsrequeststo"evaluatetheabilityofthemodel,combinedwithavailabledata,toassessthecurrentstatusandproductivityofcommonthreshersharksalongthewestcoastofNorthAmerica"
Itwas agreed that the final base casemodel at the end of themeeting, that combines thecurrently available data andmost likely hypothesis on the biology and population dynamics(largersize/ageatmaturityandpossiblyabiennialreproductivecycle),isabletocurrentlyandrobustlyassessthecurrentstockstatusofcommonthreshershark.Boththereviewpanelandmodelersagreedthatitwouldbebettertousethemostlikelybiologicalparameters(particularlythehighersize/ageatmaturitythatseemstobemorelikely)evenifthemodelfittingwasworseunderthosescenarios.Thereasoningwasthatthebestbiologicalinformationshouldbeusedto inform as correctly as possible the population dynamics of the stock, recognizing theconsequenceofaddeduncertaintiesinnaturalmortality,maturity,gestationandreproductivecycle.
Nevertheless,both the reviewpanelandmodelersat theendwereconfident that the stockstatusdeterminationwasrobusttothosescenarios,andthatthecurrentstocksizeisabovetheMSY-relatedlimitsestablishedintheUSmanagementsystem.Alltheuncertaintiesraisedanddetailedabove(point1oftheToRs)areimportant,butaftermultiplesensitivitymodelrunsitwas determined that, in general, the model was robust in terms of the stock statusdeterminationandproductivity.Thismeansthatevenwiththeuncertaintiesmentionedbefore,theconclusionsonthecurrentstockstatusisconsistent.Thetrajectoriesinbiomassandfishingeffortwereveryconsistentinshowingthatstocksizesdeclinedrapidlyintheearlyyearsduetohighfishingeffortandcatches.Whentheeffortandcatcheswerereduced,thestockstartedtorecover and is currently neither overexploited nor experiencing overexploitation. The maindifferenceinthevariousbiologicalhypothesisandlifehistoryparameterswasinthetimingandspeedoftherecovery.However,severalresearchrecommendationsweremadeforworkthatmightfurtherimprovethemodelinthefuture,thatarespecifiedindetailbelow(seeitem4oftheToRs,below).
Thepanelcautionedthattheuncertaintiesinlifehistory,especiallyreproductivebiology,andtheimplicationsforthestock-recruitmentrelationshiparelarge.Therefore,projectionsofstocksizeusingthecurrentassessmentandstock-recruitmentmodelwillbeextrapolatingbeyondthedataandwillalsobeveryuncertain.Therefore,andasaconclusion,whilethepanelisconfident
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thatthestockstatusisrobust(i.e.,stocknotcurrentlyoverfishednorundergoingoverfishing,accordingtotheMSY-relatedlimitsestablishedintheUSmanagementsystem)thepanelisalsolesscertainaboutfutureprojectionsandcatchstrategiesoreffort thatwouldberequiredtoachieveMSYrelatedtargets.IfmanagementweretopursueapolicyofMSYtargets,thentheability to precisely determine the strategy to achieve this would be severely limited byuncertainties in the basic biological information, as noted before. However, under currentcatches,thestockstatusseemstoberobust.
3.3.ToRsitem#3
Theitem#3fortheToRsrequeststo"evaluatetheadequacyofsensitivityanalysestorepresentthemainaxesofuncertaintyintheassessment".
Itwascleartoallthatthemainaxisofuncertaintyonthefinalagreedbasecasemodelwasthereproductive biology, and specifically the reproductive cycle/periodicity. In terms ofmanagementadvice,thesensitivitieswerethereforemainlyconcentratedonthisissue.Itwasagreedbyalltheparticipantsthatthisapproachwascorrect.
Currently thebasecasemodelassumesatwoyear reproductivecycle,andthis reproductiveperiodicityiscurrentlythemostuncertainparameterandthatisalsolikelycontributingtomostof the differences in the population dynamics of the species. Therefore, a strongrecommendationtofurthercontinueworkonthereproductivebiologyofthisspecieswasmade(see item4oftheToRs,below).Othercomponentsthatwerealsorecommendedforfurthertestingwerethestock-recruitmentfunctionandnaturalmortality(M).
3.4.ToRsitem#4
The item # 4 for the ToRs requests for "recommendations for future research priorities andfurtherimprovementstotheassessmentmodel".
Therewasgeneralagreementbetweenthereviewpanelandstockassessmentscientistsontherecommendationsforfutureresearch.Specificrecommendationsforfutureresearchwere:
• Juvenilesharksurveys:Thesurveydesignandprotocolsof theUSA juvenile threshersharksurveyshouldbereexaminedandimproved.Suchsurveyscouldbringimportantadditionalinformationtofuturestockassessmentmodels.Inthiscase,whiletherewasdatafromthejuvenilesurveyandaCPUEstandardizationprocedure,thestandardizedCPUEfromthissurveywasnotactuallyusedintheassessment.Thereasonspresentedforthisarethatthelocationandtimingofthesetsweredeterminedbythecaptain,withsomeoftheinitialsetsusedaslearningsets,inawaysomewhatsimilartocommercialfisheriesoperations.Therewerealsoissueswithnon-standardizedsoakingtimes,thatwas later tried to be taken into account as part of the effort in the standardizationprocedure.With the information and limited local knowledge I have on this specificsurvey,Icannotprovideveryspecificdetailsonhowtopossiblyimprovethesurvey.But
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thegeneralidea,andinorderforsuchsurveytobemorerepresentativeofthejuvenilethreshersharkabundance,itwouldbeimportanttobedesignedinasmuchafishery-independentapproachaspossible,withsometypeofrandomizedsamplinglocations,possiblydepthandseasonallystratified,andusingconsistentoperationsandmethodsthroughtime.ThelocalNOAAresearchersinvolvedinsuchsurveyandfamiliarwiththespecific conditions and logistics are the ones better suited to improve the specificmethodsinthisparticularcase;
• Catch and catch-at-size data: Both catch and catch-at-size estimates from USA andMexicofisheriesshouldbeimproved.ThemainprioritieswouldbetheMexicofisheriesandalso theUSArecreational fishery.Thecatchhistoryofbycatchspecies, includingmostsharkspecies, isusuallyoneofthemajoruncertaintysourceswhenconductingstockassessments.Often,this isanunknownandunaccountedsourceofuncertaintythat is not considered, given that historical catches are usually point values givenwithoutanyassociateduncertainties.Eveniftherearenowbetterestablishedprogramstorecordcatch,effortandsizedistributionsofthefisheries,thehistoricalcatchesarestillusuallyverypoorlyknowforthebycatchspecies.Insuchcases,thereistheneedtoreconstructthehistoricalcatchestosomedegree.Thereareanumberofwaystodothisincluding,forexample,statisticalmethods(e.g.,GLMorGAMmodelstoestimatepast catches based on a series of covariates) or methods based on ratios oftarget/bycatchspecies.Insuchbycatchspecieswithlimitedhistoricalcatchinformation,it is usually recommended to try to reconstruct the catches based on varioushypotheses,andthentestthosewithinsensitivitymodelruns;
• Sizedata/samples:sizesamplesseemedadequate fromsomefisheries (e.g.,USDGN)butvery limited inothers,especially for theUSrecreational (USREC)andtheMexicofisheries (MXDGNandMXLL).Especially inthosecaseswithvery limited information,therewastheneedtoassumesimilarsizestructure(i.e.,similarselectivity)tosomeofthe other fisheries with more information. This might be an important source ofuncertaintyinthecurrentmodelandassuchitwasrecommendedformoreefforttobeputincollectingsizedatafromthosefisheries,preferablywithsex-specificinformation.The improvement in the size/sex samples could be accomplished by a variety ofmethods,allwithdifferentcharacteristicsandcaveatsthatneedconsideration.Thebestway to improve data collection is specific to each fishery and fleet, and the localresearchersfamiliarwiththefleetsarebettersuitedtoknowwhicharethepreferredmethods.Sometraditionalapproachesforconsiderationare:
o Scientificonboardobservers:Thisisusuallythepreferredmethodandtheonemost likely to capture the entire size distribution of the catches fromeachfleet. The drawbacks are usually high costs, and possible logistics issues ofhavingobserversinsmallervesselswithlimitedspaceandconditions;
o Port sampling: this is usually a cost-effective way to sample the sizedistributionof the landings. Themaindrawback is that it is notpossible tosample discards, both in terms of discarded species and discarded sizes.Threfore, great care needs to be used when using only port-samplinginformationtostudythespeciescompositionandsizedistributionofafishery;
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o Self-samplingprograms:thoseareprogramswherefishingskippersandcrewsare trained tovoluntary record thesizedistributionof thecatchduring thefishingoperations.Ifproperlyestablished,thoseprogramscanusuallyprovideagoodcoverageofthesizedistribution,thatcan includebothretainedanddiscards,atleastforthemaintargetedspecies.Establishingandmaintainingthequalityofsuchprogramsimpliesastrongrelationbetweentheresearcherswiththefisheriessector;
• Low fecundity stock-recruitment relationship: The use of the relatively new low
fecunditystockrecruitmentrelationshipseemsappropriateforsharksingeneral,andparticularly for Lamniformes as the common thresher that have someof the lowestfecundities even within sharks. However, this low fecundity stock recruitmentrelationship is relativelynewandhasnot yetbeen fully tested, and requires furtherresearch.Thestockstatusofcommonthresherseemedtoberobusttothis issue(astestedwith sensitivityanalysis),but itwouldbe recommended to testotheroptions(e.g.,ahockeystickmodeloranyotherfunctionthatallowsforrapiddropsatverylowstocksizes);
• Reproductivebiology:Thecurrentlackofknowledgeanduncertaintiesassociatedwiththereproductivebiologyislikelythemaincauseofuncertaintyinthestockassessmentmodel.Whilemostcasesandsensitivities testedwith thevarioushypothesesdonotaffectthestockstatus,insomecasesthereareproblemsofdataconflictsinthemodelthat needs further exploration. As such, it is highly recommended to continue thebiological studies to further investigate the reproductive biology of this population,especially in terms of the size at maturity, age at maturity, and reproductivecycle/periodicity. It isalsonoted,however,thatwhileparameterssuchassize/ageatmaturity should be relatively simple and feasible to study, the reproductive cycle(periodicity)will likelybemuchmoredifficult to fully studydue to theneed tohaveaccesstolargenumberofsamples(matureandpregnantfemales)overallseasonsandwithdetailedreproductivedata;
• CPUEstandardization:WhiletheoverallCPUEstandardizationprocessseemedtofollowthecurrentpracticesinfisheries,especiallywithlargepelagics,thereweresomeissuesthatcouldbethefocusforfutureworkandresearch.Specifically,itwasrecommendedtotestsomealternativedistributions(e.g.,NegativeBinomialforcountdataorTweedieforcontinuousdatawithamassofzeros),considerandtesttheinclusionofinteractions,testthepossibilityofmodelingtheUSDGNasasingletimeseries(usingdetailedspatialandseasonaleffectstotrytoaccountforspatial/seasonalchangesinmanagement),andconsider using vessel effects as a random variable to add variability associatedwithdifferentvesselsofthefleet.
3.5.ToRsitem#5
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The item # 5 for the ToRs requests for a "brief description on panel review proceedingshighlightingpertinentdiscussions,issues,effectiveness,andrecommendations".
Itisveryimportanttonotethattheentiremeetingwasveryproductiveandalwayscarriedoutinamuchpositiveatmosphere.
The SWFSC scientists, especially themodeler Steve Teo, was very supportive and skillful inprovidingthepanelwithseveralextraassessmentmodelrunsandplotsofselecteddiagnosticsinaspeedyandveryefficientwayduringthemeetingandintheeveningsbetweenthemeetingdays.Thepanelappreciatedandthankedallthesupportandpositiveatmosphere,aswellastheimmediatewillingnessofthemodelerstotestandconsiderallthealternativeapproachesandscenarioshypothesized.
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Appendix1:Bibliographyofmaterialsprovidedforreview
Documentsprovidedforreviewpriortothemeeting
Aryafar,H.,Preti,A.,Dewar,H.,Kohin,S.2017.Re-examinationofthereproductivebiologyofcommonthreshersharksalongthewestcoastofNorthAmerica.FisheriesResourcesDivision,Southwest Fisheries ScienceCenter,NationalMarineFisheries Service,NationalOceanic andAtmosphericAdministration,8901LaJollaShoresDrive,LaJolla,CA92037,USA.
Teo,S.L.H.;Rodriguez,E.G.,Sosa-Nishizaki,O.2016.Statusofcommonthreshersharks,Alopiasvulpinus,alongthewestcoastofNorthAmerica.NOAA-TM-NMFS-SWFSC-557.
StockSynthesismodelfilesandotherrelatedassessmentinformationpublishedintheinterimthatwereprovidedbytheSWFSCProjectContact(SteveTeo).
Additional documents provided during the meeting both by the review panel and stockassessmentanalysis
Anon.2017.FAQs:WestCoastdriftgillnet(DGN)fishery&protectedspecies.U.S.Departmentof Commerce, National Oceanic & Atmospheric Administration, National Marine FisheriesService,WestCoastRegion.
Romanov, E. 2015.Do common thresher sharksAlopias vulpinus occur in the tropical IndianOcean?IOTCWorkingPartyonEcosystemsandBycatch(WPEB).Olhão,Portugal.
Taylor,I.G.,Gertseva,V.,Methot,R.D.,Maunder,M.N.2013.Astock-recruitmentrelationshipbased on pre-recruit survival, illustrated with application to spiny dogfish shark. FisheriesResearch,142:15-21.
Teo,S.L.H.2017.PopulationdynamicsofcommonthreshersharksalongtheWestCoastofNorthAmerica,assumingalternativereproductivebiologyandnaturalmortalityparameters.FisheriesResources Division, Southwest Fisheries Science Center, National Marine Fisheries Service,NationalOceanicandAtmosphericAdministration,8901LaJollaShoresDrive,LaJolla,CA92037,USA.
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Appendix2:CopyoftheStatementofWork
StatementofWork
NationalOceanicandAtmosphericAdministration(NOAA)
NationalMarineFisheriesService(NMFS)
CenterforIndependentExperts(CIE)Program
ExternalIndependentPeerReview
StatusofCommonThresherSharks,Alopiasvulpinus,
alongtheWestCoastofNorthAmerica
Background
TheNationalMarineFisheriesService(NMFS)ismandatedbytheMagnuson-StevensFisheryConservationandManagementAct,EndangeredSpeciesAct,andMarineMammalProtectionActtoconserve,protect,andmanageournation’smarinelivingresourcesbaseduponthebest scientificinformationavailable(BSIA).NMFSscienceproducts,includingscientificadvice,areoftencontroversialandmayrequiretimelyscientificpeerreviewsthatarestrictlyindependentofalloutsideinfluences.Aformalexternalprocessfor independentexpertreviewsoftheagency'sscientificproductsandprogramsensurestheircredibility. Therefore,externalscientificpeerreviewshavebeenandcontinuetobeessentialtostrengtheningscientificqualityassuranceforfisheryconservationandmanagementactions.Scientificpeerreviewisdefinedastheorganizedreviewprocesswhereoneormorequalifiedexpertsreviewscientificinformationtoensurequalityand credibility.Theseexpert(s)mustconducttheirpeer reviewimpartially,objectively,andwithoutconflictsofinterest.Eachreviewermustalsobeindependentfromthedevelopmentofthescience,withoutinfluencefromanypositionthattheagencyorconstituentgroupsmayhave.Furthermore,theOfficeofManagementandBudget(OMB),authorizedbytheInformationQualityAct,requiresallfederalagenciestoconductpeerreviewsofhighlyinfluentialandcontroversial sciencebeforedissemination,andthatpeerreviewersmustbedeemedqualifiedbasedontheOMBPeerReviewBulletinstandards.(http://www.cio.noaa.gov/services_programs/pdfs/OMB_Peer_Review_Bulletin_m05-03.pdf).FurtherinformationontheCIEprogrammaybeobtainedfromwww.ciereviews.org.
Scope
TheFisheriesResourcesDivision(FRD)ofSouthwestFisheriesScienceCenter(SWFSC)requestsanindependentreviewofthebenchmarkstockassessmentdevelopedforthecommonthreshersharkstockalongthewestcoastofNorthAmerica.Thebiologicalrangeofthestock
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spansthewestcoastsofMexico,theUnitedStatesofAmerica(USA),andCanada.ThecommonthreshersharkfisheriesoftheUSAandMexicoareindependentlymanagedbythePacificFisheryManagementcouncil(PFMC)andtheInstitutoNacionaldePesca(INAPESCA),respectively.However,therearenocurrentnorhistoricalfisheriesalongthewestcoastofCanadaandininternationalwatersthattargetcommonthreshersharksandbycatchappearstoberare.CommonthreshersharkfisheriesinboththeUSAandMexicohavedeclinedsubstantiallysincethestartofcommercialfisheriesforthisstockinthelate1970s,withtotalremovalsestimatedtobe<200tin2014.ThecurrentUSAfisherymanagementplanforthisstockofcommonthreshersharksincludesaharvestguidelineof340tbasedonanunpublishedanalysisofUSAdataandisderivedfromtheoptimumyieldforvulnerablespecies,whichisdefinedas0.75*MSY(orreasonableproxy).
ThisisthefirststockassessmentofcommonthreshersharksalongthewestcoastofNorthAmericathatincorporatesinformationfromallfisheriesexploitingthepopulation.TheStockSynthesis(SS)modelingplatformwasusedtoconducttheanalysis.Themodelbeganin1969,assumingthepopulationwasatequilibriumpriorto1969inanearunfishedstate,andendedin2014,whichwasthelastyearthatdatawasavailable.Thestockassessmentconsideredthispopulationtobeasingle,well-mixed,trans-boundarystockandreliedheavilyondatafromboththeUSAandMexico.However,itisimportanttonotethattheanalystswhoreconstructedthecatchtimeseriesforMexico'sfisherieswillnotbeavailableforthepeerreview.Akeyuncertaintyhighlightedinthestockassessmentisthereproductivebiologyofthisstockofcommonthreshersharks.Previousresearchonthisstockofcommonthreshersharksuggestedthatfemalesharkshadanageofmaturityof5yearsofageandanannualreproductivecycle.However,arecentstudyonthereproductivebiologyofthewesternNorthAtlanticstockofcommonthreshersharksdemonstratedamucholdermedianageofmaturity(age-12)andlongerreproductivecycle(biennialortriennialcycle).Sensitivitymodelrunsindicatedthatchangingthematurityandfecundityschedulesresultedinsubstantialdifferencesinthetrendandscaleoftheestimatedpopulationdynamics.ThestockassessmentprovidesthebasisforscientificadviceonthestatusofcommonthreshersharksalongthewestcoastofNorthAmerica.Anindependentpeerreviewoftheassessmentisthereforeessential.TheTermsofReference(ToRs)ofthepeerreviewandthetentativeagendaofthemeetingarebelow.
Requirements
NMFSrequiresareviewchairwhohasaworkingknowledgeandrecentexperienceintheapplicationoffisheriesstockassessmentprocessesandtwo(2)reviewerstoconductanimpartialandindependentpeerreviewinaccordancewiththeSoW,OMBguidelines,andtheToRsbelow.TheChairwouldensurethatreviewersunderstandtheimportanceofthepeerreviewprocessinaccordancewiththeSoW,OMBGuidelines,andToRs.Inaddition,thechairwillbeselectedbythecontractorandberesponsibleforfacilitatingthemeeting.TheCIEchairshallserveasanexternalexperttochairthepanelreviewandhaveexcellentoralandwrittencommunicationskills.Inaddition,thechairshallahaveworkingknowledge,recentexperienceintheapplicationoffisheriesstockassessmentprocesses,andresults,including
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populationdynamics,integratedstatisticalage-structuredmodelslikeStockSynthesismodelsandsharkbiology(reproductionandgrowth).Thechairshouldalsohaveexperienceconductingstockassessmentsforfisheriesmanagement.Thereviewersshallalsohaveworkingknowledge,recentexperienceintheapplicationoffisheriesstockassessmentprocesses,andresults,includingpopulationdynamics,integratedstatisticalage-structuredmodelslikeStockSynthesismodelsandsharkbiology(reproductionandgrowth).Theyshouldalsohaveexperienceconductingstockassessmentsforfisheriesmanagement.Itisdesirableforatleastoneofthereviewerstobefamiliarwithsharkstockassessments.
Tasksforreviewers
1)Reviewthefollowingbackgroundmaterialsandreportspriortothereviewmeeting;
Teo,S.L.H.,E.G.Rodriguez,andO.Sosa-Nishizaki.2016.Statusofcommonthreshersharks,Alopiasvulpinus,alongthewestcoastofNorthAmerica.NOAATechnicalMemorandum.NOAA-TM-NMFS-SWFSC-557.196pp.
Aryafar,H.,A.Preti,H.Dewar,andS.Kohin.ReproductivebiologyparametersforcommonthreshersharksalongthewestcoastofNorthAmerica.Documenttobedeveloped.
StockSynthesismodelfilesandotherrelatedassessmentinformationpublishedintheinterimthatisprovidedbytheSWFSCProjectContact.
2)Attendandparticipateinthepanelreviewmeeting.ThemeetingwillconsistofpresentationsbyNOAAandotherscientists,stockassessmentauthorsandotherstofacilitatethereview,toansweranyquestionsfromthereviewers,andtoprovideanyadditionalinformationrequiredbythereviewers.
3)Afterthereviewmeeting,reviewersshallconductanindependentpeerreviewreportinaccordancewiththerequirementsspecifiedinthisSoW,OMBguidelines,andToRs,inadherencewiththerequiredformattingandcontentguidelines;reviewersarenotrequiredtoreachaconsensus.
4)EachreviewershouldassisttheChairofthemeetingwithcontributionstothesummaryreport.
5)DelivertheirreportstotheGovernmentaccordingtothespecifiedmilestonesdates.
SpecificTasksforCIEChair:
ThefollowingchronologicallistoftasksshallbecompletedinatimelymannerasspecifiedintheScheduleofMilestonesandDeliverables.
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1)Conductnecessarypre-reviewpreparations,includingthereviewofbackgroundmaterialandreportsinadvanceofthepeerreview;
2)ParticipateasthechairduringtheJune26-28,2017panelreviewmeetingattheSouthwestFisheriesScienceCenterinLaJolla,California,andfacilitatethepanelreviewmaintainingthefocusofthepeerreviewinaccordancewiththeToRs;
3)ProduceaSummaryReportoftheproceedings.Thesummaryreportshallnotbeaconsensusreport.TheindependentCIEreviewersshouldhaveanopportunitytoreviewandprovidecommentsorelaborationonanypointsraisedinthesummaryreportthattheyfeelmightrequirefurtherclarification.
ForeignNationalSecurityClearance
Whenreviewersparticipateduringapanelreviewmeetingatagovernmentfacility,theNMFSProjectContactisresponsibleforobtainingtheForeignNationalSecurityClearanceapprovalforreviewerswhoarenon-UScitizens.Forthisreason,thereviewersshallproviderequestedinformation(e.g.,firstandlastname,contactinformation,gender,birthdate,passportnumber,countryofpassport,traveldates,countryofcitizenship,countryofcurrentresidence,andhomecountry)totheNMFSProjectContactforthepurposeoftheirsecurityclearance,andthisinformationshallbesubmittedatleast30daysbeforethepeerreviewinaccordancewiththeNOAADeemedExportTechnologyControlProgramNAO207-12regulationsavailableattheDeemedExportsNAOwebsite:http://deemedexports.noaa.gov/andhttp://deemedexports.noaa.gov/compliance_access_control_procedures/noaa-foreign-national-registration-system.html.ThecontractorisrequiredtouseallappropriatemethodstosafeguardPersonallyIdentifiableInformation(PII).
PlaceofPerformance
Theplaceofperformanceshallbeatthecontractor'sfacilities,andattheSouthwestFisheriesScienceCenterinLaJolla,California,USA.
SouthwestFisheriesScienceCenterPacificRoom8901LaJollaShoresDriveLaJolla,CA92037USA
PeriodofPerformance
TheperiodofperformanceshallbefromthetimeofawardthroughAugust18,2017.TheCIEchairandeachreviewer’sdutiesshallnotexceed14daystocompleteallrequiredtasks.
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ScheduleofMilestonesandDeliverables:Thecontractorshallcompletethetasksanddeliverablesinaccordancewiththefollowingschedule.
Withintwoweeksofaward ContractorselectsandconfirmsCIEChairandreviewers
NolaterthanJune5,2017 Contractorprovidesthepre-reviewdocumentstotheCIEChairandreviewers
June26-28,2017 Panelreviewmeeting
NolaterthanJuly7,2017
TheCIEChairsubmitsadraftSummaryReporttothecontractorforeachoftheindependentreviewerstoreviewandcomment
July17,2017 ContractorreceivesdraftindependentpeerreviewreportsaswellastherevieweddraftSummaryReport
July31,2017 ContractorsubmitsfinalreportstotheGovernment
ApplicablePerformanceStandards
Theacceptanceofthecontractdeliverablesshallbebasedonthreeperformancestandards:
(1)Thereportsshallbecompletedinaccordancewiththerequiredformattingandcontent(2)ThereportsshalladdresseachTORasspecified(3)Thereportsshallbedeliveredasspecifiedinthescheduleofmilestonesanddeliverables.
Travel
AlltravelexpensesshallbereimbursableinaccordancewithFederalTravelRegulations(http://www.gsa.gov/portal/content/104790).Internationaltravelisauthorizedforthiscontract.Travelisnottoexceed$10,000.
RestrictedorLimitedUseofData
Thecontractorsmayberequiredtosignandadheretoanon-disclosureagreement.
NMFSProjectContact:
DaleSweetnam
[email protected],FisheriesResourcesDivisionSouthwestFisheriesScienceCenter
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NationalMarineFisheriesService8901LaJollaShoresDriveLaJolla,CA92037(858)546-7170
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PeerReviewReportRequirements
1.ThereportmustbeprefacedwithanExecutiveSummaryprovidingaconcisesummaryofthefindingsandrecommendations,andspecifywhetherthesciencereviewedisthebestscientificinformationavailable.
2.Thereportmustcontainabackgroundsection,descriptionoftheindividualreviewers’rolesinthereviewactivities,summaryoffindingsforeachTORinwhichtheweaknessesandstrengthsaredescribed,andconclusionsandrecommendationsinaccordancewiththeTORs.
a.Reviewersmustdescribeintheirownwordsthereviewactivitiescompletedduringthepanelreviewmeeting,includingabriefsummaryoffindings,ofthescience,conclusions,andrecommendations.
b.ReviewersshoulddiscusstheirindependentviewsoneachTORevenifthesewereconsistentwiththoseofotherpanelists,butespeciallywherethereweredivergentviews.
c.Reviewersshouldelaborateonanypointsraisedinthesummaryreportthattheybelievemightrequirefurtherclarification.
d.ReviewersshallprovideacritiqueoftheNMFSreviewprocess,includingsuggestionsforimprovementsofbothprocessandproducts.
e.Thereportshallbeastand-alonedocumentforotherstounderstandtheweaknessesandstrengthsofthesciencereviewed,regardlessofwhetherornottheyreadthesummaryreport.ThereportshallrepresentthepeerreviewofeachTOR,andshallnotsimplyrepeatthecontentsofthesummaryreport.
3.Thereportshallincludethefollowingappendices:
Appendix1:Bibliographyofmaterialsprovidedforreview
Appendix2:AcopyofthisStatementofWork
Appendix3:Panelmembershiporotherpertinentinformationfromthepanelreviewmeeting.
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TermsofReferenceforthePeerReviewStatusofcommonthreshersharks,Alopiasvulpinus,alongthewestcoastofNorthAmerica
1. Evaluatetheassessmentmodelconfiguration,assumptions,andinputparameters(e.g.,naturalmortality,spawner-recruitrelationship,reproductivebiology)todetermineifthedataareproperlyused,inputparametersarereasonable,modelsareappropriatelyconfigured,assumptionsarereasonablysatisfied,andprimarysourcesofuncertaintyareaccountedfor.
2. Evaluatetheabilityofthemodel,combinedwithavailabledata,toassessthecurrentstatusandproductivityofcommonthreshersharksalongthewestcoastofNorthAmerica.
3. Evaluatetheadequacyofsensitivityanalysestorepresentthemainaxesofuncertaintyintheassessment.
4. Recommendationsforfutureresearchprioritiesandfurtherimprovementstotheassessmentmodel.
5. Briefdescriptiononpanelreviewproceedingshighlightingpertinentdiscussions,issues,effectiveness,andrecommendations.
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TentativeAGENDA2017CommonThresherShark(Alopiasvulpinus)
StockAssessmentReview
SouthwestFisheriesScienceCenter8901LaJollaShoresDr.,LaJolla,CA92037
LaJolla,CA92037858-546-7000
Thisisapublicmeeting,andtimeforpubliccommentmaybeprovidedatthediscretionofthemeetingChair.ThisisaworksessionfortheprimarypurposeofreviewingthecurrentCommonThresherstockassessment,undertheCenterforIndependentExpertstermsofreference(ToR).
TheStockAssessmentReviewPanelwillreviewtheassessmentandproduceindependentreportsandinconjunctionwiththeChair.TheStockAssessmentTeam(STAT)willprovide
presentationsandallappropriatebackgroundinformationneededforthereview.
MONDAY,JUNE26,2017A. CalltoOrder,Introductions,ApprovalofAgenda Chair (10a.m.,15minutes)B. TermsofReferenceforStockAssessmentReviewProcess DaleSweetnam (10:15a.m.,15minutes)C. CommonThresherStockAssessment SteveTeo,STAT (10:30a.m.,1.5hours)LUNCHD. CommonThresherStockAssessment(Continued) SteveTeo,STAT (1p.m.,2hours) BREAKE. DiscussionandRequests Panel (3:30p.m.,1hour)F.PublicComment (4:30p.m.,0.5hours)TUESDAY,JUNE27,2017G. ResponsetoRequests SteveTeo,STAT (8:00a.m.,2hours)BREAKH. InitialReportWritingandSTATWorkSession Panel (10a.m.,2hours)LUNCHI. DiscussionandRequests (1:30p.m.,1hour)
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J. PublicComment (2:30p.m.,0.5hours)BREAKK. ReportWritingandSTATWorkSession Panel (3:30p.m.,2hours)WEDNESDAY,JUNE28,2017L. ResponsetoRequests SteveTeo,STAT (8a.m.,2hours)BREAKM. DiscussionandRequests Panel (10:30a.m.,1.5hours) LUNCHN. ResponsetoRequests SteveTeo,STAT (1p.m.,1hour)O. PublicComment (2p.m.,0.5hours)BREAKP. Discussion–NextStepsandDeadlines (3p.m.,1hours)Q. FinalizeReportAssignments Chair (4p.m.,1hours)R. WorkSessionasNecessaryandMeetingWrapUp Chair (5p.m.)ADJOURN
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Appendix3:Panelmembershiporotherpertinentinformation.
ThefollowingtableprovidesthepanelmembershipincludingtheCIEreviewersandSWFSCscientiststhatcarriedouttheassessmentandmadethepresentations:
Name Organization CountryHenrikSparholt(Chair) CIE DenmarkJosephPowers CIE USARuiCoelho CIE PortugalSuzanneKohin SWFSC USAKevinHill SWFSC USAP.R.Crone SWFSC USAHeidiDewar SWFSC USAHui-HuaLee SWFSC USAStevenTeo SWFSC USA
