Aquatic Invasive Species Vector Risk Assessments: 7KHUROHRIÀVKLQJYHVVHOVDVYHFWRUVIRUPDULQHDQG HVWXDULQHVSHFLHVLQ&DOLIRUQLD Final Report July 2012 Submitted to the California Ocean Science Trust Funded by the California Ocean Protection Council By: The Aquatic Bioinvasion Research & Policy Institute $3DUWQHUVKLSEHWZHHQ3RUWODQG6WDWH8QLYHUVLW\ WKH6PLWKVRQLDQ(QYLURQPHQWDO 5HVHDUFK&HQWHU Ian Davidson, Gail Ashton, Chela Zabin & Greg Ruiz TABLEOFCONTENTS 1.EXECUTIVESUMMARY...........................................................................................................................3 2.INTRODUCTION.....................................................................................................................................5 2.1Aims.....................................................................................................................................................7 3.METHODS............................................................................................................................................10 3.1InvasionHistory&VectorStrength..................................................................................................10 3.2VectorAnalysis..................................................................................................................................11 3.3ImpactsofCaliforniaAISwithfishingvesselbiofoulingasapossiblevector...................................13 3.4Vectordisruption..............................................................................................................................14 4.RESULTS...............................................................................................................................................14 4.1InvasionHistory&VectorStrength..................................................................................................14 4.2VectorAnalysis..................................................................................................................................21 4.3ImpactsofCaliforniaAISwithfishingvesselbiofoulingasapossiblevector...................................38 4.4Vectordisruption..............................................................................................................................40 5. DISCUSSION.........................................................................................................................................46 5.1MarineintroductionsinCaliforniaandtheroleoffishingvessels...................................................46 5.2Prospectsforstatewidefishingvesselvectormanagement............................................................49 6. ACKNOWLEDGEMENTS.......................................................................................................................53 7. REFERENCES........................................................................................................................................54 2 1. EXECUTIVESUMMARY Background Baysandestuariesareamongthemostdegradedandalteredecosystemsintheworld.Inconcertwith habitatloss,pollution,andoverͲexploitation,aquaticinvasivespecies(AIS)havehadaprofoundeffect onthefunctioningofnearshoresystemsthatresultinseriousecologicalandeconomiclosses.Thebays ofCaliforniascoastline,andSanFranciscoBayinparticular,aregloballysignificanthotspotsof introductionscausedbyavarietyoftransfermechanisms(vectors)thathaveoperatedinthestateover centuries.Forthisreason,prudentandeffectivevectormanagementhasbeenapriorityforthestate anditisagloballyrecognizedleaderintherealmofcommercialshipvectormanagement. Thereareadditionalvectorsthathavereceivedlittleresearchandmanagementattention,however,and theirroleinintroductionsandspreadofAISthroughoutCaliforniaislargelyunknown.Thisstudywas commissionedbyCaliforniasOceanScienceTrusttocharacterizetheroleofonesuchvector commercialfishingvessels. Aim ThepurposeofthisstudywastoinvestigatefishingvesselsasvectorsofintroducedspeciesinCalifornia. ThestructureforcharacterizingthefishingvesselvectorfollowedascienceͲbasedvectormanagement frameworkinorderto:(a)evaluatetheinvasionhistoryofCaliforniaandvectorassociationsofspecies todeterminethepossibleroleoffishingvesselsintheinitialestablishmentandspreadofAISinthe state;(b)characterizethevectorscurrentstandingstockofvessels,theirrouteandtempopatterns,and thebiotaassociatedwithtransientcoastalvessels;(c)assesstheinvasionsimpactliteratureasitrelates toAISinCaliforniathathavefishingvesselsasapossiblevector;and(d)describethecriticalcontrol pointstodisruptthevector,toolsthatcanbeusedcanbetakenadvantageofthem,andthestatewide optionsforgeneratingvectormanagementactionbythefishingfleet. Methods WeusedanextensivedatabaseofCaliforniasAIShistorytoassesscurrentpatternsofAISdistribution, timingofdetections,andvectorsresponsiblefortheintroductionandspread.Theprimaryfocuswason biofouling,whichistheprimarymechanismofspeciestransfersbyfishingboats.Thenweevaluatedthe arrivalpatterns,voyageroutes,seasonaltrends,andharborconnectivityoftheexistingfishingfleetin thestate.Wealsoexaminedliteraturerecordsofspeciesassociatedwithtransfersonboatsand sampledcoastallytransientboatsinCaliforniatodescribetheboatvectorbiota.Ourreviewofimpact literaturefocusedonthreespeciesͲrichAIStaxainCalifornia(crustaceans,molluscs,andalgae)to provideinformationaboutknownorpotentialimpactsbyspeciesinthestate.Finally,weconducteda vectorprocessanalysistodeterminethecriticalcontrolpoints(similartoHazardAnalysisandCritical ControlPoints[HACCP]approach)thatexistforfishingvesselAIStransfersandevaluatedthevessel scaleandstateͲscaleapproachesthatmaybeutilizedforeffectivevectormanagement. Findings Fishingvesselsareapossiblevectorfor74%ofthe278AISknowntobeestablishedinCalifornia.The acceleratinginvasionandspreadrateinthestateandthediversityoforganismsthatcanbelinkedto vesselsplayimportantrolesinthishighvectorassociation.However,historicalandcurrentvoyage routessuggestthattransoceanicandinteroceanicintroductionstothestateareunlikelytohave occurredviafishingvessels.Inaddition,alloftheAISthatcanbeassociatedwithfishingvesseltransfers 3 arepolyvectic(possiblymultiplevectors),withextensiveoverlapamongcommercialships,recreational boatsandfishingvessels.Nonetheless,87%ofthemostrecentdecadeofnewintroductionsandnew recordsofspread(133AISand26bays)havefishingvesselsasapossibletransfermechanism.Also, whilethereishighvariationinthenumbersofAISoccurringamongbays,fishingvesselscanbelinkedto anaverageof85%(±10%)forbayswithacurrentstandingstockoftwentyormorespecies. ThecontemporaryfishingfleetinCaliforniaconsistsofmorethan2400vesselsthatmakeatleast50,000 arrivalstoharborsannually.Althoughaslightmajorityofthesevessels(52%)areresidentboats (reportingarrivalstojustoneharbor),theproportionofvesselsthatarrivedtoeachharboroverafour yearperiodwashigherfortransientvesselsthansoleͲportvessels.Seasonalvariationinthearrivals patternswaspronouncedinsomebays(e.g.SanDiego),butincontrasttorecreationalvessels,thestate widemonthlypatternofarrivalswasnotseasonallypronounced.Portconnectivitywashighestamong subsetsofadjacentbaysandtherewerealsotransientvesselsthatvoyagedtheentirelengthofthe stateduringthedataperiod(Jan2005toDec2008).Bayconnectivityforfishingvesselsincludesoverlap withothervesseltypes,butalsodifferencesinpairͲwiselinkagesandinintensityofconnections(e.g. creatinglinksbetweenshippingandnonͲshippingbays).Inaddition,therewere356boatsthatreported arrivalsinCaliforniaandPacificNorthwestStates.Vesselsamplingrevealedawiderangeofbiofouling richnessandextentamongboats(n=53)butweweresurprisedbytheproportionofvesselsattheupper endofthedistributionthattransferthousandsoforganismsandupto80speciesasfloatingreefs associatedwiththeirsubmergedsurfaces. Theimpactsliteraturereviewhighlightedthepaucityofimpactsliteraturethatexistsandthe unevennessofeffortamongspecies.Thereweredatafor22AISwithfishingvesselbiofoulingasa possiblevector,butfewofthesestudieshavebeencarriedoutinCalifornia.Thereareotherhighly impactingAISinCaliforniawithfishingvesselsasapossiblevector,butthisreviewdidnotcapturethe fullscaleoftheseelusivedata. Finally,weidentifiedthreecriticalcontrolpointsinthevectorprocess(colonizationprevention,transfer disruption,andreleasecontainment)forfishingvesselbiofoulingandthetoolsthatcanbeemployedon avesselͲscaletotakeadvantageofthese.Wealsoassessedtherangeofoptions(andtheirlikelyissues andoutcomes)thatthestatecanpursuetoapplyacommercialfishingvectormanagementpolicyinthe state,fromretainingthestatusquotofullregulationandenforcement. Conclusions FishingvesselsareanimportantmaritimevectorinCaliforniabecausetheymaybeassociatedwith transfersof74%oftheAIScurrentlyestablishedonthestatescoast.Theyalsonumberinthe thousands,makearrivalstoharborsannuallyinthetensofthousands,createstrongconnectionsamong harborsthatothervectorsdonot,travelthelengthofthestatescoastandbeyond,mayplayarolein AISspreadbyfishinggear,andmayactasanimportantfinalstepinthecauseofbaitAISintroductions. Inshort,theyareapartofthevectorratchetingeffectthatoccurswhenmultiplevectorsandAIS populationsinteractinspaceandtime. Ourrecommendationforastatepolicywouldincludescientificallypolledoutreachofthecommercial fishingcommunitytoevaluate(a)vectorawareness,(b)uptakeofvectormanagement,and(c)changes overtimeinthesetwometrics(aandb)afterintensiveoutreach.Thevalueofsuchanapproachisthat itisdatadriven,providinginsightonthehumanpopulationengagedinthevectoractivity,thespecies transfersthatoccurafterinitiationofthepolicy,andanevaluationovertimeofwhethervectorstrength (invasionscausedbythevector)hasdiminished. 4 2. INTRODUCTION Californiareceivesmarineandestuarineorganismsviaanthropogenictransfermechanisms(vectors)