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 ofCalifornia’scoastline,andSanFranciscoBayinparticular,aregloballysignificanthotspotsof introductionscausedbyavarietyoftransfermechanisms(vectors)thathaveoperatedinthestateover centuries.Forthisreason,prudentandeffectivevectormanagementhasbeenapriorityforthestate anditisagloballyrecognizedleaderintherealmofcommercialshipvectormanagement.  Thereareadditionalvectorsthathavereceivedlittleresearchandmanagementattention,however,and theirroleinintroductionsandspreadofAISthroughoutCaliforniaislargelyunknown.Thisstudywas commissionedbyCalifornia’sOceanScienceTrusttocharacterizetheroleofonesuchvector– commercialfishingvessels.  Aim ThepurposeofthisstudywastoinvestigatefishingvesselsasvectorsofintroducedspeciesinCalifornia. ThestructureforcharacterizingthefishingvesselvectorfollowedascienceͲbasedvectormanagement frameworkinorderto:(a)evaluatetheinvasionhistoryofCaliforniaandvectorassociationsofspecies todeterminethepossibleroleoffishingvesselsintheinitialestablishmentandspreadofAISinthe state;(b)characterizethevector’scurrentstandingstockofvessels,theirrouteandtempopatterns,and thebiotaassociatedwithtransientcoastalvessels;(c)assesstheinvasionsimpactliteratureasitrelates toAISinCaliforniathathavefishingvesselsasapossiblevector;and(d)describethecriticalcontrol pointstodisruptthevector,toolsthatcanbeusedcanbetakenadvantageofthem,andthestatewide optionsforgeneratingvectormanagementactionbythefishingfleet.  Methods WeusedanextensivedatabaseofCalifornia’sAIShistorytoassesscurrentpatternsofAISdistribution, 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 endofthedistributionthattransferthousandsoforganismsandupto80speciesas‘floatingreefs’ 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%oftheAIScurrentlyestablishedonthestate’scoast.Theyalsonumberinthe thousands,makearrivalstoharborsannuallyinthetensofthousands,createstrongconnectionsamong harborsthatothervectorsdonot,travelthelengthofthestate’scoastandbeyond,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) fromallovertheworldandcontributestothebiotabeingtransferredaroundtheworld.This interchangeofbiotaintroducesnovelexoticspeciesintonativecommunitiesandhabitats,withthe effectofalteringtheecologyofthenearshoreenvironment.Becausemarinespeciesareintroduced intomaritimehubs,bioinvasionstendtooccurinbaysandestuarieswherehumanactivities,manͲmade infrastructure,andmultiplevectorsinteract.Thus,whenweconsiderthatspeciesinvasionsaffect biodiversityandenvironmentalquality–alongwithhabitatdestruction,overexploitation,pathogens, andpollution(Wilson1992;Wilcoveetal.,1998)Ͳitcanbenosurprisethatbaysandestuariesare amongthemostalteredanddegradedecosystemsintheworld(Carlton,1996).  California’sbaysandestuariesareageographicalfoundationforarichhistoryofbioinvasionstudies (Carlton,1979),theresultsofwhichhavebeenremarkable.SanFranciscoBaymaybethemostinvaded bayintheworld(Cohen&Carlton,1998)andthestateasawholehasaregionalrichnessofaquatic invasivespecies(AIS)towhichonlytwootherregionsoftheworldcancompare(HawaiiandtheEastern Mediterranean;Ruizetal.,2011a).Thenumberanddiversityofintroducedorganismsisafunctionof thecombinedvectorstrengthoftransfermechanismsthathaveoperatedinthestate.Theprolificacy andvarietyofthesevectors,alongwiththespatialandtemporalscalesoftheiroperation,have providedarichintroducedfloraandfaunathatthestate’swatersdidnotrepelandwithwhichitsnative biodiversitymustcoexist.  ThevectorsresponsibleformaritimeAISintroductions,toCaliforniaandelsewhere,arenumerous (Minchinetal.,2009).TheyincludeseveralsubͲvectorsofshippingandboating,canals,aquaculture transfers,fisheriesdevelopment,livebaitandseafoodimports,ornamentalspeciesimports,research activities,biologicalcontrolefforts,habitatmanagement,andmore.TheforemostvectorͲresearch focusgloballyhasbeenoncommercialshippingbecauseof(a)itsdominanceamongothervectorsin creatingbroadͲscalepatternsofAISdistributionsand(b)theavailabilityofextensive,detailed, centralizedrecordsofvesselactivitiesandroutes;certainlythefocusvariesamongregionswhereother vectors,likecanals,predominate(Gollaschetal.,2006)oronsmallerscalesinwhichshipsdonot operate(Wassonetal.,2001).Thisspotlightonshippinghasledtointernational,nationalandregional effortstoreducetheinvasionfootprintofships.Anequivalentmanagementattentiononothervectors hasyettoemerge.  TheFishingVesselasaVectorofAIS OnetransfermechanismthathasreceivedlittleattentioninCaliforniaandaroundtheworldisthe fishingͲvesselvector.Theprimarymeansofspeciestransfersbyfishingvesselsisbiofouling(i.e., organismsattachedandassociatedwithunderwatersurfaces),meaningthecauseoftransfersis inadvertent.Fishermenactivities,suchasthereleaseoflivebaitfrombaitwells,canalsoprovideAIS withadeliverymechanismtothemarineenvironment,thoughthisislargelythefinalstepinalivebait vectorprocessratherthanavesseltransfermechanism.Contaminatedfishinggearcanalsotransfer species,butweconsiderthistobealessersubͲvectoroffishingvessels(comparedtobiofouling)thatis associatedmorewiththelocalizedspreadofestablishedspecies(e.g.Relinietal.,2000).Ourfocusin thisstudywasonthevesselitselfasavector,butfurtherworkiswarrantedtodetermineifthereare anyspecialcasesofspeciestransfersassociatedwiththesesubͲvectorsinCalifornia. 

5  Giventhelongevityoffisheriesandtheextentoffishingfleetsaroundtheworld,itissomewhat surprisingthattherehasnotbeenmoreinterestinitsroleintransferringAIS.Thismaybeafunctionof thesizeofboatsandanassumptionoflimitedvoyagerangeoverwhichindividualfishingvesselstravel oritsdemotionunderthebehemothstatusofcommercialshippinginthisfield.However,itisalsolikely thattheoverridingissuesofresourceexploitationthatareinherentinfisheriesprovideenoughconflict withenvironmentalprotectionandsustainabilityastorenderbiofoulingtransfersanafterthought,orno thoughtatall.  TheexistingevaluationsorincidentalreportsoffishingvesselsasvectorstendtoemanatefromNew ZealandandAustraliainrecentyears.Hutchingsetal.,(2002)linkedfishingvesselsfromIndonesiato thearrivalofthebivalve,Mytilopsissallei,toDarwin,Australia.Inanotherreportedbivalveinvasion mediatedbyfishingvessels,Hayesetal.(2005)usedanexampleofanintroductiontoCairnsSeaportby Pernaviridisasatestcasetoevaluatescientificandcostconsiderationsfordetectionanderadicationof marinepests.  AnewsworthyvectoreventinvolvingaRussiansupertrawleroperatinginNewZealandwatersis infamousinthebiofoulingvectorliterature(Hay&Dodgshun,1997).ThevesselYefimGorbenko traveledtothesouthernHemisphereafteralonglayupintheBlackSeaanditwasdiscoveredtohave extraordinarylevelsofbiofouling,dominatedbymussels,onitshull.Thediscoveryresultedinan eventualdrydockingandremovalofanestimated90tonnesofbiofoulingforlandfill,aftermany monthsinNewZealand.Hay&Dodgshun(1997)reportedthatmaterialwasnotexaminedfullyby taxonomists,butitislikelythatmanynonnativespecieswerepresent.  ArecentcomprehensiveaccountoffishingvesselbiofoulingwasconductedbyPiola&Conwell(2010)in NewZealand.Theysampledthehullsofelevenfishingvesselsthathadarrivedfromoutsideofthe country’sterritorialwatersaspartofavectorprojectcommissionedbyBiosecurityNewZealand. Althoughthestudyfoundthatbiofoulinglevelsweregenerallylowamongboats,theyfoundbiofouling oneightoftheelevenvesselsand59morphoͲspecies.Amongthe37specimensidentifiedtospecies level,54%ofwerenonnativetoNewZealand.Furthermore,nineoftheAISarenotknowntobe establishedinNewZealand,andfourofthesespecieshadnotpreviouslybeenrecordedonother vectorsorasfailedintroductionsinNewZealand.Theoverallconclusionfromthisstudywasthat biomassonfishingvesselsthathadtraveledoverseas(notsolelydomesticboats)wasgenerallylow,but establishedandnovelAISwerestillapartofthebiofoulingcommunitiesbeingtransferred.  Accountsfromelsewherearelimited,althoughFarrapeiraetal.(2007&2011)didincludereportsof foulingsampledfromfishingboatsfromstudiesinBrazil.ThesevesselsrangedfromlaidͲupboats confinedtocertainports,throughlocalandregionallytransitingfishingboatsandweresampledin conjunctionwithothervesseltypes.Thedifferencesbetweenvesseltypeswerenotconsidered importantrelativetolayͲuphistoryandrangeofvoyageactivity.  WeknowofnoevaluationoffishingvesselsfromCaliforniaortheWestCoastofNorthAmerica.  CaliforniaCommercialFishing California’smarinefisheriesareanimportanteconomic,culturalandsocialcomponentofcoastallifein thestatedatingbackmillennia.Archaeologicalevidencesuggeststhishistoryextendsbackatleast8000 years,andsiteexcavationsprovideevidencenotonlyofsocialorganizationinpreͲhistoriccommunities, butthetypes(andspecies)offishexploited(Noah,1998).Theseincludedpelagicspecies,suchas sardines,anchovies,mackerel,andtunawhichsuggestsearlypeoplemayhavetraveledsomedistance

6  fromthecoasttocatchfish(Noah,1998).Therewasnosuggestionthatpeopletraveledanygreat distancebyboattofishalongthecoast,however.  Theideaofhistoricfishingcommunitiesexploitingfisheriesatlocalsitesratherthantravelingalongthe coastisreinforcedbyNativeAmericanmaritimefishingdescribedbyArthurMcEvoy(1986).McEvoy reportedthatlifeforCaliforniahunterͲgathererIndianswas“sedentary”andthey“generallylivedand diedwithintentofifteenmilesoftheirbirthplaces.”Furthermore,their“economieswerefirstand foremosttheproductsoflocalresources.”Whilesalmonfishingwasbyfarthemostimportantofthe aboriginalfisheries,thereweretwomaritimecultures,theChumashandtheGabrielino,whichexploited marinefishesbetweenPointConception,SanPedroBay,andtheislandsoffshore(McEvoy,1986). AdditionalfeaturesofNativeAmericansocietythatpromotedsedentaryratherthantransientfishing communities,asreportedbyMcEvoy,wereadesiretounderͲexploitresourcestoensuretheirlongevity andtodesignaterightsoverresourcessuchthatoutsidersweredeniedaccess.Thislatterdevelopment playedaroleinthecommercializationoffisheriesovertimewhichendedthesustainableandsedentary natureofCalifornia’sfisheries.  Afterthestatewasformedin1850,therewasadiverseimmigrantfishingcommunitywithdifferent typesofvesselsexploitingavarietyoffishspecies,butremainingrelativelylocalinrange.This contrastedsomewhatwiththeextentoffishingontheEastCoastoftheU.S.,anditwasacausefor complaintamongsomeofficialsthattheWestCoastfishingindustryconsistedonlyofsalmonharvesting ontheColumbiaandSacramentoRiversandmarinefishingonlywithinclosevicinityofSanFrancisco (McEvoy,1986).Thischangedbytheturnofthecentury,whenthemostreadilycaughtinshorespecies (salmon,mammals,andabalone)declinedandtechnologicaladvancespromotedtheexplosivegrowth ofoceanfishing.Within15years,oceanicstocksofsalmon,sardinesandtunawerebeingdepleted (McEvoy,1986).  Thissynopsisunderscorestwoimportanthistoricalaspectsofcommercialfishingwithrespecttovector activityinCalifornia:1)fishingvesselswererelativelysedentaryandunlikelytohavehadamajorvector footprintuntilcirca1900,longaftertheageofexplorationhadbroughtshipsfromothercontinentsto thecoastofCalifornia;and2)thedevelopmentoffisheriesonthecoastofCaliforniaprovidedrich fodderforresearcherslikeArthurMcEvoyinterestedintheinteractionbetweenexploitationof ecologicalresourcesandtheirlegalprotection.  Inmoderntimes,theCaliforniaDepartmentofFish&Game(DF&G)managestheoceanfisheriesforthe state,includingregisteringandpermittingissuesrelatedtovessels,catchquotas,fishsizes,andseasonal andzonalmanagement(DF&G,2012).Therearerecordsdatingbackto1928onfishlandingsandthe listofspeciescaughtinthestateextendstoatleast336groups(speciesandotherdivisionsof commerciallandings;SouthwestFisheriesScienceCenter,2012).Thefishingfleetreportslandingsona perarrivalbasispervessel,andthesedata(definingthecurrentfleet)wereasourceforonecomponent ofthisvectoranalysis.  2.1Aims ThepurposeofthisstudywastoinvestigatefishingvesselsasvectorsofintroducedspeciesinCalifornia. Thisisthefirstsuchanalysisforfishingvesselsinthestate,toourknowledge,andonepartofabroader investigationintosixAISvectorscommissionedbytheCaliforniaOceanScienceTrust.Thestructurefor characterizingthefishingvesselvectorfollowedthescienceͲbasedvectormanagementframework outlinedbyRuiz&Carlton(2003).Thisframeworkincludesseveralcomponentsthatcontributeto

7  vectormanagementactionandsubsequentmonitoringoftheefficacyofthatmanagement.Thesteps takeninthisstudyincludedevaluationofvectorstrength,vectoranalysis,andvectordisruption.An additionalstepͲexaminationofreportedimpactsofAISalreadyestablishedinCaliforniaandassociated withfishingvessels–wasalsoundertakentodeterminetheconsequencesofintroductionslinkedto fishingvesselactivity.  InvasionHistory&VectorStrength Vectorstrengthisameasureofthenumberofintroductionsthathaveresultedfromavector.Because introductionsareusuallynotdetectedinrealtime,itisrarelypossibletodeterminetheexacttimeand location,orspecificsource(vesseloraction),foranAISbeingintroducedandbecomingestablished. Therefore,abroadlyacceptedmethodistoevaluatetheinvasionhistoryofanareaanddeducethe vectororvectorsresponsibleforincursions.Thismethodutilizestiming,location,andlifeͲhistory characteristicsofspeciestodeterminevectorassociationswitheachintroductionevent.Ourgoalwas tocharacterizeCalifornia’sinvasionhistorywithrespecttovectorpatternsandtherolefishingvessels mayhavecontributedtothesepatterns.Afterbrieflyoutliningthestateinvasionhistory,wehonedin onpossiblevectorassociationsoffishingvesselsasacomponentofbiofoulingandnonͲbiofouling transfersforthewholestate(firstrecordsandcurrentstandingstockofAIS,aswellasthedifferential patternsofvectorsascribedtoAISamongbays).ThiswasachievedusingdatafromtheNationalExotic MarineandEstuarineSpeciesInformationSystem(NEMESIS)forCalifornia(providedbytheMarine InvasionsLabattheSmithsonianEnvironmentalResearchCenter[SERC]).  VectorAnalysis Ourvectoranalysisofcurrentfishingvesseloperationsinthestateconsistedoftwocomponents:1)the spatialandtemporal(seasonal)patternsoffishingvesseltrafficand2)biotaassociatedwithsmallboats (ratherthancommercialships)andcoastallytransitingvesselsinCalifornia.Evaluationsofvesseltraffic andfluxintoandwithinCaliforniaprovideanunderstandingofwherevesselsarriveandhowfishing harbors(bays)areconnectedtoeachotherviatransientfishingvesselvoyages.ThevectorͲassociated biotacomponentprovidedinsightintothetypesoforganismsthathavebeenrecordedonthe submergedsurfacesofboats(usingaliteraturesearch)aswellasasampleofbiotacurrentlytransiting thestate’scoastasbiofoulingonboats(fromsamplingtransientboatsatCalifornianharbors).  ImpactsofCaliforniaAISassociatedwiththefishingvesselvector Carlton&Ruiz(2003)didnotincludeanimpactcomponentintheirframeworkforvectoranalysisand management,presumablybecauseoftheindirectnatureofsuchananalysis–speciescauseimpacts ratherthanvectors.Nonetheless,weconsidereditinstructivetoexaminetheAISimpactliteratureto determinethenumberandnatureofimpactstudiesamongspeciesassociatedwithfishingvessels.It wasnotpossibletoundertakeanimpactevaluationofallAIScurrentlyestablishedinCalifornia,sothis componentwasrestrictedtothreeAISrichgroupsͲalgae,molluscsandcrustaceans.  Vectordisruption Theprocessunderlyingthewayinwhichavectorworkscanbebrokendownintosubcomponentsthat mayprovidecluesastowheremanagementactivitiescouldbetargetedtointerruptthetransfersof species.Thegoalistoevaluatecriticalcontrolpointsinthevectorprocessandthetoolsthatcanbe usedtocloseoffthemovementofspecies.Weassessedthefishingvesselvectorprocessinthis manner,andevaluatedthecostsandbenefitstoimplementationofmanagementactionsatthevessel level.Wealsoreportedonstatelevelvectormanagementasitpertainstofishingvessels. 

8  Inthediscussion,weevaluatedalloftheseelementstogetherandprovideanoutlineofvector managementstrategiesthatcouldbepursuedforthisvector.

9   3.METHODS  3.1InvasionHistory&VectorStrength  California’scoastalmarineandestuarineinvasionhistory AdatabaseofAISforCaliforniawascreatedfromtheNationalExoticMarineandEstuarineSpecies InformationSystem(NEMESIS)providedbytheMarineInvasionsLabatSERC.Thedatabasehasbeen compiledovermanyyearsandcontainsinformationontheidentity,locations,populationstatus (whetherconsideredtohaveanestablishedpopulation),timingoffirstdetection,andotherdetails(lifeͲ historyandimpactsummaries).Thedatasetalsocontainsinformationonsalinitytoleranceofspecies andallfreshwatertaxawereremovedforthisanalysis.Speciesofuncertainorigin(mayormaynotbe nativetoCalifornia)werealsoexcludedsothatonlyknownnonͲnativespecieswereincluded.  Importantly,theinvasionͲhistorydatasetalsocontainsvectorinformationthatusesthetiming,location andlifeͲhistoryofeachintroductiontoascribeavectororvectorsconsideredresponsiblefor transferringthespeciestoitsnewnonͲnativelocation.Thisapproachisabroadlyacceptedonethat underpinsseveralimportantanalysesofinvasionhistoriesfromdifferentregionsaroundtheworld (Carlton1979;CohenandCarlton1995;Ruizetal.,2000;Hewittetal,2004).However,thevector informationinthisdatasetdidnotincludedifferentiationofbiofoulingvectors(commercialshipping versusrecreationalboatingversusfishingvessel)untiltheinitiationofthisproject.Thesedesignations wereaddedtothedatasetforCalifornia.  SeveralanalyseswereconductedtocharacterizetheinvasionhistoryofCaliforniaandthepossible associationswithfishingvesselvectors.ThestatewidetaxonomicbreakdownofAISandthetemporal trendofAISdetectionsandaccumulationwereplottedtoprovideabriefoverviewoftheextentofthe data.Vectorsassignedtospeciesfirstrecords(initialintroductions)werethenplottedtoevaluatethe roleofbiofoulingasavectorinthestate.Additionalpartitioningofthedatabyvectorwasusedto evaluatethedegreetowhichthecurrentstandingstockofAISinthestatecanbeassociatedwithfishing vessels.Wealsoanalyzedthedurationbetweenfirstandmostrecentrecordsasafunctionofvessel vectors(whichprovidessomeinsightaboutspreadofspeciesalongthecoast).Finally,weevaluatedthe numberofAISperbaywithrespecttofishingvesselharborsandvectorassociations.  Forthislastcomparison,itisimportanttonotethatthespatialdesignationsintheinvasionhistory (NEMESIS)databasedidnotaligncompletelywithfishingvesselharborsbecausethedatabaseincludes areasthatarenotfishingvesselharborsandbecauseNEMESISusedawatershedspatialnetworkof locationsinCalifornia.Therefore,thebaysusedforanalysesincludeddataforAISandfishingarrivals thatoverlappedexactly(e.g.SanFranciscoBay),datathatoverlappedbutforwhichNEMESISincluded additionalspaceoutsideoftherelevantbay(e.g.SantaBarbara),dataforwhichtwoorthreedistinct fishingharborswereincludedinonewatershed,andNEMESISlocationsinwhichnofishingharborwas present.Thisresultedin32baydesignationsfromTijuanaestuaryinthesouthtoCrescentCityinthe north.ThesedesignationswereusedforallamongͲbaycomparisonsofAIS.     

10  3.2VectorAnalysis  Fishingvesseltrafficpatterns PatternsoffishingvesselmovementsinCaliforniawereassessedusingadatasetprovidedbythePacific StatesMarineFisheriesCommission(PSMFC).ThedatawereobtainedthroughthePacificFisheries InformationNetwork(PacFIN)andrepresentsafourͲyearintervaloffishingvesselarrivals(January2005 –December2008).Thedatawerecompiledfromfishtickets,whichistherequireddocumentationfrom eachvesselarrivaltoreportthetypeandnumber(orweight)offishlandedaftereveryarrival. Therefore,eachentryinthedatasetrepresentsavesselarrivalthatlandedfish;itshouldbenotedthat additionalarrivalsbyvesselswhentheydidnotlandfishwouldnotbecapturedinthesedata. Nonetheless,thisisthemostcompletedatasetofmaritimefishingvesseltravelhistoryforthestateand itprovidesaconservative(orminimum)estimateofconnectivityamongbays.  PacFINidentifiesanddescribesatleast136differenttypesofvesselandgearcombinations (http://pacfin.psmfc.org/pacfin_pub/data_rpts_pub/code_lists/agency_gears_grid.txt),whichinclude manysubͲtypesofdredgevessels,linefishingvessel(e.g.longliners),nettingvessels(e.g.gillnets, seiners),trollers,trawlers,andothertypes(e.g.diverfisheryvessels).Wedidnothavedataonvessel typesforourtrafficanalyses.Whilevesseltypeandgearsmayplayaroleinvesselbehaviorsthataffect speciestransfers,thedatawegatheredonvesselmovementswassufficientforouranalysesinthis report.  Eachentryinthedatasetincludedthelocation,date,andananonymousvesselidentifierforeach arrival.TheanonymousidentifierwasconsistentacrosslocationsandtimessuchthatvesselfluxͲ arrivalsamongdifferentportsbythesamevesselͲcouldbeevaluated(e.g.Vessel1thatarrivedin CrescentCityin2005wasthesameVessel1thatarrivedtoSanFranciscoBayin2008).Thereweretwo exceptions:PacFINusesoneidentifierforcertainarrivals,termedzzzvessels,whichresultinmany differentboatsbeingassignedthesamevesselidentifier.Thetwocodesinthisdatasetassignedtozzz vesselarrivalswerenotincludedinanalysesbeyondtheinitialsummarystatisticsofstatewidespatial andtemporaltrends(becausetheycouldnotbeisolateddowntoindividualvessels).Thesezzzarrivals accountedfor0.01%ofthetotalarrivalsinthedataset.  Ouranalysesofthesedatafocusedoncharacterizingthespatialandtemporalpatternsoffishingvessel arrivalsacrossthestate.First,weexaminedthestatewidedistributionofarrivalsandthetemporal patternofthosearrivals.ThePacFINrecordingsystemuses58differentharborcodesaslanding (arrival)locationsandweaggregatedsome(e.g.allharborswithinSanFranciscoBay)toalignstatewide spatialarrivalpatternswithbaysandwithouranalysesofAISinvasionhistorydata.Weassessedthe patternofmonthlyarrivalsstatewideandformajorfocalharbors.Then,weseparatedthevesselsthat reportedmorethanonelocationofarrival(transientboats)fromthosethatreportedonlyonelocation ofarrivalfortheentirefouryears(solelyresidentboats).Thesolelyresidentboatsdonotcarryavector risk,atleastinthecontextofthisdataset,becausetheyhavenotreportedapossibilityoftransferring biotafromoneharbortoanother.Thetransientboats,however,hadthepotentialtodeliverorganisms amongdifferentports.Weexaminedthefluxofboatsamongharbors,portconnectivity,themost transientvesselsinthedataset,andlinksbetweenCaliforniaharborsandharborsinthePacific Northwest(Oregon&Washington).  Vectorbiota1:organismsassociatedwithboatfouling

11  WesurveyedthepeerͲreviewedandgrayliteratureforrecordsofspeciesattachedtoorotherwise transportedbyboats(anywhereintheworld).Theseboatsincludedfishingandrecreationalvessels, butnotcommercialships,bargesorotherplatforms(rigsetc).Ourinitialgoalhadbeentodifferentiate amongfishingandrecreationalboats,butforthemostpartthisdistinctionwasnotmadeinthe literaturealthoughrecreationalboatsgenerallyoutnumberedfishingboats.Weevaluatedallboatdata tomaximizethedatasetandreportgeneralpatternsofbiotafromboats.  ForthepeerͲreviewedliteratureweusedthesearchterms“invasi*”AND“boat*”,“nonͲnative”AND “boat*”and“fouling”AND“boat”forallyearsintheBIOSISsearchengine(ThomsonReuters).Papers thatincludedrecordsofnamedorganisms(usuallyspecieslevel)sampledfrombiofoulingofboatswere identifiedandthespeciesdatawithinthementeredintoadatabase.Additionalrecordsweregathered fromasearchofthereferencesectionsoftheinitialpapers.Furtherrecordsweregleanedfromgray literatureincludingunpublishedreports,theses,andnotesprovidedbycolleagues.Whenpossible,we includedrecordsaftercorrespondingwithauthorstogetfurtherinformationaboutspeciessampled fromboatsbutwhichwerenotreportedinthepapersorreports.  Afterexhaustingoursearchforpapersandreports,weenteredintoadatabaseasmuchofthefollowing informationthatwasavailableforeachspeciessampled:reference,speciesname(ortaxon),locationof sampling,dateofsampling,lifeͲstage,whetherthespecieswassampledonresidentorjustarrived transientboats,andwhethertheauthorsprovidedinformationonwhetherspecieswerenativeornonͲ nativetotheregionwhereitwasrecorded.Weusedthreeinternetsitestoassistwiththesetaxonomic classifications:AlgaeBase(http://www.algaebase.org/),IntegratedTaxonomicInformationSystem (http://www.itis.gov/),andtheWorldRegisterofMarineSpecies(www.marinespecies.org/).Where therewasdisagreementbetweenthesesystems,weusedAlgaeBaseastheauthorityforthealgae,and forinvertebratesAbbottetal.1997(tunicates)andCarlton(2007).HigherͲleveltaxonomicclassification wasbasedonPearseetal.(1987).  Thisdatasetprovidedalistofspeciesthathavebeenrecordedfromsmallboatsengagedinrecreational travelorfishing.Therecordscomefromallovertheworldandwereusedtoassessthebroad taxonomicpatternsofspeciesassociatedwithbiofouling.  VectorBiota2:SpeciessampledonsubmergedsurfacesoftransientboatsinCalifornia WesampledtransientboatsuponarrivalatdockatSanDiegopolicedockandSantaBarbaraHarbor. Ouraimduringsamplingexcursionswastosamplerecreationalandfishingboatsequally,butdespite conversationswithdozensoffishermenattheirboats,wesimplywerenotgivenpermissiontosample manyfishingboats.Thevastmajorityoffishermenthatwehavespokentoduringthisandother projectspolitelydeclinetoansweraquestionnaire,andgenerallyruleoutanypossibilityofproviding permissiontosampletheundersidesoftheirvessels.TheyoftenciteoverͲregulationoftheirlivelihood asareasontodeclineparticipationinoursurveys.WedidhavetheopportunitytosampletouristdeepͲ seafishingvesselsinSanDiegoandfoundsometobeheavilyfouled.However,wedeclinedtocollect andprocesssamplesbecausethesevesselstravelonlyoutͲandͲbacktothesameharborinSanDiego. Assuch,itwasnotusefultospendtimeandresourcesonsampleprocessinghavingdiscoveredthis voyageinformation,becausethespeciesarenottransferredtoadifferentharborandothertransient boatsamplingtookprecedence.AdditionaldataforfishingvesselswasgatheredfromMontereyHarbor foratotalof53boatswithvectorbiotadata(49recreationalvesselsandfourfishingvessels).  Vesselsweresampledafterabriefquestionnairewiththevesselownerandpermissionwasgrantedto conductaninͲwatersurveyandcollectionoftheboat.Thequestionnairewasusedtogatherthree

12  categoriesofinformationfromtheboaterorfisherman,followingthebroadoutlineofquestionsasked inpriorbiofoulingstudies(e.g.Floerl&Inglis,2005;Davidsonetal.,2010):[1]vesselinformation(type, lengthandhomemarina);[2]hullmaintenancepractices;and[3]timingandlocationsoftransits. Additionalquestionsforfishermenonactivitieswithbaitandgearwereplannedbutwewereunableto developtheconversationstothispointsimplybecausetheypreferrednottoengagewithusinmuch detailonthebiofoulingissue.SamplingwascarriedoutusingSCUBA,wherebytwoorthreedivers surveyedtheentirelengthandbreadthofthevessel’ssubmergedsurfaces,payingparticularattention toheterogeneousnicheareas(rudders,intakes,propellers,struts,thrusters).  Duringthesurveys,onedivertookphotographs,videoimagesandnotestodocumenttheextentof foulingandrecordwholeͲvesselcategoricalabundance.ThesixcategorieswerebasedonalogͲscale estimateofabundancerangingfrom1Ͳ10organismsthroughto>100,000organisms(individualsor colonies).Aseventhcategoryofzerobiotawasalsoincluded.Thisdiveralsotookanimageofeach nicheareawhichwasusedtomeasurepercentcoverofbiofoulingpernichearea.SeveralphotoͲ quadratsofhullsurfaceswerealsotaken,fiveofwhichwereselectedatrandomtogenerateameasure ofpercentcoverofthehull.HullquadratimageswereprocessedusingapointͲcountmethodof100 dotssuperimposedontheimage.  Theotherdiver(s)collectedbiotasamplesbycarefullyscrapingandpickingbiotafromthehullandniche areasandplacingtheminzippedplasticbags.Foramajorityofvessels,itwaspossibletocollectall organismsencounteredbecausebiofoulingwasnotsoextensiveastoexcludethisapproach.Incases wherebiofoulingwasveryextensive,biotawerecollectedfromeachhulllocationensuringallvisibly uniquemorphologicalformswereincluded.SampleswereinitiallysortedintomorphoͲtaxashortlyafter collectionandpreservedforfurtherprocessingtospecieslevel(orlowesttaxapossible).Certaingroups weresenttoexperttaxonomistsforidentificationorconfirmation.  Becauseofthedisparitybetweensamplingoffishingandrecreationalvessels,dataforthefewfishing vesselsispresentedinthetextforeachvesselwhilerecreationalboatswereanalyzedinaggregate.The overalldataprovidesasampleofthespeciesbeingtransportedonvesselsonCalifornia’scoastline(to thebaysinwhichsamplingwasconductedandotherbaysthatformedtheitineraryofeachtransient vessel).Weexaminedthetaxonomicbreakdownofspeciesrecordedonboats,thespeciesrichness amongvessels,theabundanceoffoulinganditsrelationshipwithpercentcoverofhulls,and comparisonsofboaterreportedhullmaintenanceandbiofouling.  3.3ImpactsofCaliforniaAISwithfishingvesselbiofoulingasapossiblevector Weconductedareviewofreportedimpactsonallspeciesofcrustacean,molluscandalgaereportedas establishedintheNEMESISdataforCalifornia.Thesethreetaxaarespeciesrichgroupsinthestate. AlgaeandmolluscdatawerecompiledbytheUCDavisvectorteam(studyingtwodifferentvectors)and weprovidedcrustaceandata.Astandardizedstepwisesearchwasdesignedcollaborativelyamong groupsusingtheBIOSISacademicsearchengine.  1. WeusedthefollowingsearchtermsinBIOSIStoprovidethe‘firstcut’ofimpactliterature: Topic=(AdventiveORAlien*ORBioinvasi*ORBiosecur*ORExotic*ORForeignORIntroduc*OR Incursion*ORInvad*ORInvasi*ORNonendemic*ORNonendemic*ORNonindigenousOR NonindigenousORNonnative*ORNuisance*ORPest*ORPest) AND Topic=(speciesnameinquotes,e.g."Ficopomatusenigmaticus")

13  AND Timespan=1926Ͳ2011. ThistimespancorrespondedtotheearliestrecordsinBIOSIStothelastfullyearofdata.Searches forspeciessynonymswerealsoconductedandthenumberofpapersreturnedforeachspecieswas recordedasmetaͲcontent.  2. Thetitlesofpaperswereexaminedforrelevancetoimpactsandallirrelevantpaperswereremoved. TheremainingnumberofpaperswasnotedinmetaͲdata.  3. Fortheremainingstudiesthatwereretained,abstractswereexaminedforrelevanceandthose deemedtocontainimpactsdataweredownloaded.Thenumberofarticleswithimpactdatawas notedinmetaͲcontent.  4. Dataforpaperswereenteredintoaformattedspreadsheet.Dataincludedreferenceinformation, thenonͲnativespeciesname,thenameoftheimpactedentity(species,habitat,processinvolved), thetypeofimpact,andthewayimpactsweremeasured(fieldstudies,experiments,monitoring dataetc).  Thesedatawereusedtosummarizeexistingdataonimpactsforspeciesrelevanttofishingvessel vectors.  3.4Vectordisruption  Weexaminedthevectorprocessforfishingvesselfouling(andnonͲfouling)toidentifypotentialpoints thatareconducivetovectorinterruptionactions.Inadditiontothisprocessanalysis,wesummarized theapproachesandstrategiesthatcanbeusedtocausevectordisruptionandutilizecriticalcontrol pointsintheprocess.Finally,weevaluatedstatewidevectorcontrolprogramsforvessels.Theoverall goalwastoincludeanoverviewofmanagementoptionsavailabletoreduceorpreventspeciestransfers byfishingvessels(atthevesselandstatescales).  4.RESULTS  4.1InvasionHistory&VectorStrength  California’scoastalmarineandestuarineinvasionhistory ThedatasetofCaliforniamarineandestuarineAISconsistedofrecordsfor300species(withrecords datingfrom1853to2009).Twoofthesespecies,thealgaeCaulerpataxifoliaandthepolychaeteworm Terebrasabellaheterouncinata,areconsideredextinctfromthestateafterapparentlysuccessful eradicationefforts(Culver&Kuris,2000;Ansderson,2005).Afurther20specieswereconsideredtobe failedintroductionstothestate.Thisresultedin278extantAISinCalifornia.Thestatusesofthese278 speciesinthestateincludedconfirmedestablishedspecies(basedonrepeatedrecords)andunknown populationstatus.Speciespopulationsdesignatedasunknownmaybeestablished,buttheresimply haven’tbeenfollowuprecordstoprovideconfidencethattheypersist.TheseunconfirmedͲstatus specieswereincludedinanalyses(n=278). 

14  ThetaxonomicbreakdownofstatewideAISrevealedarangeoforganismsfrombacteriatovertebrates, havebeenintroducedandcurrentlyexistinCaliforniacoastalwaters(Fig.1).Crustaceanshaveplayeda dominantroleintheinvasionhistoryofthestate.Therewere82introducedspeciesofcrustaceans, representingalmost30%ofthestate’stotalAIS,andamphipods,isopods,andcopepodswerethe dominantsubͲgroups(Fig.1B).Molluscswerethesecondlargestgroupinthestate,consistingof27 gastropodsand19bivalves.Afurtherseventaxagroupscontributedbetweentenandthirtyspeciesto thestateAISpool,whilefivegroupscontributedfiveorfewerspecies.Includedintheseminorgroups wasthebacteria,Xenohaliotiscaliforniensis,apestofabaloneestablishedinNorthernCaliforniaandthe muskrat,Ondatrazibethicus,whichisintroducedfromtheeasternU.S. 

shrimp B 80 A crabs crayfish amphipods California  60 in  tanaids AIS

 isopods

of polychaetes  cumaceans 40 leeches bivalves anthozoans oligochaetes gastropods mysids scyphozoans leptostracans

number hydrozoans 20 barnacles copepods ostracods 0 051015202530 numberofspecies(crustaceans)

 Figure1.TaxonomicbreakdownofAISinCalifornia.The278marineandestuarineAISbelongedto14different taxonomicgroups(A).Thistaxonomicbreakdownisinformal–thesamehierarchyoftaxonomicunitsarenot consistentacrosstaxa.TherichnessoffourofthegroupswerefurthersubͲdividedtheseareindicatedinthe plotforcnidarians,annelids,andmolluscs.ThecrustaceansweretherichestgroupofAISwith82different speciesandthesubͲdivisionofthistaxonisshowninpanelB,whichshowsamphipodstobetherichestofthe nonͲnativecrustaceansinthestate.  Theyearsoffirstdetection,orrecordingofanintroduction,forthe278CaliforniaAISrangedfrom1853 to2007.Theearliestrecordisforthebarnacle,Amphibalanusimprovisus,collectedfromSanFrancisco Bay,whilethemostrecentisforactenophore,Valliculamultiformis,inSanDiegoBay.Although introductionsearlierthan1853arelikely,suchspeciesmaycurrentlybeclassifiedascryptogenic (unknownorigin)andrequirefurtherworktoreconstructtheirinvasionhistory.Thedatasetalso includedfirstrecordsforspeciesincertainbaysafter2007(themostrecentin2009),buttheserecent recordswereforspeciesthathadalreadyestablishedpopulationselsewhereinthestate.Therehave doubtlessbeennewinvasionstothestatesince2007thathaveyettobereportedorconfirmed.  TherateofnewAISintroductionshasbeengrowingexponentiallysincethe1850s,undergirdingan exponentialaccumulationofAISinthestate(Fig.2).Themostrecent25Ͳyearperiodhasseenprolific numbersofnewAISenterthestate,comparedtopriortimeintervals,withalmost40%ofthestate’s totalAISbeingdetectedsince1983(themostrecentintervalinFig.2).Theoveralltrendof introductionsisdrivenbyaswatheofanthropogenicvectorsthathavebeenoperatinginthestatefor centuriesandprovidesthefoundationfortheoverallinvasionhistoryofthebroaderNEPacificregion (Ruizetal.,2011a).

15   300

250

200 AIS  of  150

100 number 50

0

timeperiod  Figure2.TemporalpatternofAISintroductionstoCalifornia.Theplotshowsfirstdetectionsorreportingof newAIS(blackdiamonds,solidline,r2=0.98,p<0.01)andtheaccumulationofAIS(greycircles,dashedline, r2=0.98,p<0.01)forCalifornia.Nearly40%ofthestate’sAIShavebeendetectedsince1983.(n=274speciesfor thisplotbecauseofabsenttemporaldataforfourAIS).  VesselvectorsofCalifornia’sAIS ToevaluatetheroleofvectorsincreatingCalifornia’sAIShistory,wefirstexaminedthevector associationsforfirstrecordsofspeciestothestate.This‘firstcut’ofvectorstrengthanalysisfocusedon biofoulingofalltypesofvessels(Fig.3).For274speciesforwhichtherewereyear×vectordata,54AIS wereattributedexclusivelytovesselbiofouling.Afurther106AISwereassociatedwithvessel biofoulingincombinationwithothervectorpossibilities,whichmeantthatthebiofoulingvectorcould belinkedtobetween20%and59%ofthestate’sinitialAISincursions.TheremainingnonͲbiofouling transferredspeciesincluded28(10%)thatmaybeassociatedwithfishingvesselactivity(e.g.relatedto transfersofbaitbyfishermenonboats)and86(31%)thatwereneitherlinkedtobiofoulingofvessels noranysortoffishingvesselactivity. 

16  60 biofoulingalone 50

biofoulingw/other

AIS 40  vectors of  30 notbiofouling 20 number

10

0 preͲ 1878 1879Ͳ1904 1905Ͳ1930 1931Ͳ1956 1957Ͳ1982 1983Ͳ2007 timeperiod  Figure3.BiofoulingvectorassociationswithinitialrecordsofAISinCalifornia.Theplotshowstheextentto whichbiofouling,themainvectorforfishingvessels,isassociatedwithCaliforniaAIS.Thesedataareforfirst recordsonly(n=274species).Thelegendisincludedinthisplotandbarsrepresent1)speciesconsideredtohave beenintroducedviabiofoulingalone,2)biofoulingasapossiblevectorincombinationwithothervectors,3) speciesnotassociatedwithbiofoulingͲmediatedintroduction.ThehighnumberofnonͲbiofoulingspeciessince 1983islargelyaresultofinitialincursionsviaballastandaquaculture.  Itisdifficultafterthisfirstclassificationofspecies×vectordatatodirectlyassociatebiofoulingwith differentcategoriesofvessels(commercial,recreational,fishing,military,rigs/platforms).Thisisnot surprisingsincethereisalreadysignificantoverlapbetweenbiofoulingandnonͲbiofoulingvectorsthat createsarangeofpossiblevectorstrengths.Fromthefirstrecordsforthestate,speciesthatwere introducedfromafar(transoceanicorinteroceanic)viabiofoulingareveryunlikelytohavebeenbrought tothestatebyactive(inͲservice)fishingvesselsbecauseCalifornia’sfishingindustryisdomestic.In moderntimes,nationalorinternationalfishingboatsarenotarrivingfromoutsideofadjacentcoastal areas,andamajorityoperateswithinstatewatersonly(seebelow).Similarly,historicalaccountsof marinefishingonthecoastdonothighlightanylongͲdistancearrivalsoffishingboatstothestate,or evendescribeextendedcoastwisevoyagesbyfishingvessels.FishingcommunitiesinCaliforniatended todevelopalongthecoastratherthanoutsiderstransitinglongerdistances(byboat)toexploitfisheries. Therefore,initialintroductionstothestatefromfishingvesselsappearlikelytoberareincaseswhere thespeciesisafirstrecordfortheNEPacific.OnlycasesofcoastwisesourceͲtoͲdestination introductionsmaybecommonforfishingboats.  Toillustratethis,considerthecaseofAmphibalanusimprovisus.ThisbarnaclewasrecordedinSan FranciscoBayin1853andistheinitialrecordfornotonlythestate,buttheentireNEPacificregion.Our reviewdatasetstatesthatitisthoughttohavearrivedfromitsnativerangeinthenorthAtlanticas foulingonships’hulls.Itisalmostcertainthatfishingvesselswerenotimplicatedinthisinitial biofoulingͲmediatedarrivalbecauseofthetimingandprobabledistancefromthesourcepopulation. Subsequently,ithaspersistedforwelloveracenturyinthestateandbeenrecordedinfiveother locations,mostrecentlyElkhornSloughandTijuanaEstuary(1998and2003,respectively).Afterits initialincursion,itislikelytobeassociatedwithcoastwisefishingvesselbiofoulingtransfers.However, theexampleinSanFranciscoBaycannotbeincludedinfishingvessels’vectorstrengthmeasurements, eventhoughthespeciesisnowlinkedtothefishingvesselvectorinthestate. 

17  Ofcourse,thisistrueofmanyspeciesthatcaninteractwithvectorsotherthantheonethatwas responsiblefortheirinitialincursion.Thus,whenweconsidervectorsforthe278AISacrossallbaysin thestate,207ofthe278wereassociatedwithfishingvessels,including175linkedtobiofoulinganda further32linkedtofishingvesselactivitybutnotbiofouling(Table1).Thesenumbersrefertothe currentstandingstockofAISinthestateandnotjustfirstrecords(i.e.A.improvisusisincludedonthe basisthatdetectionssubsequenttoitsfirstmayhaveinvolvedfishingvesseltransfers).Allofthe specieswithfishingvesselsaspossiblevectorscanbeconsideredpolyvecticwithothervectors, particularlyotherbiofoulingtransfermechanisms.  Table1.NumbersofCaliforniaAISassociatedwithfishingvesselvectors.Thetableshowsfivewaysof categorizingspecies(n=278),withthetopthreelinkedtofishingvesselsandthefourthonenotassociatedwith fishingboats.Incomparisontoinitialincursions(Fig.3),therewasanoverallincreaseinthenumbersofAISthat couldbelinkedtofishingvesselsbecause15of86firstrecordsofnonͲfishingvesselspeciescouldsubsequently becoupledwithfishingvesselvectorsaftertheirinitialincursiontothestate.Intotal,fishingvesselscanbe implicatedintransferring74%ofthestandingstockofCaliforniaAIS(maximumpossible),althoughallofthese speciescanalsobelinkedtoothervesseltypesand/orothernonͲvesseltransfermechanisms.See Supplementarymaterialfordetails(Appendix1).  Vectorassociation NumberofAIS(all staterecords) Biofoulingalone 46 Biofoulingwithothervectors 129 NonͲfoulingfishingvesselwithothervectors 32 Notassociatedwithbiofoulingorfishingvessel 71 Numberofspeciesassociatedwithfishingboats 207     ForthestandingstockofAISinthestate,thefishingvesselvectorisassociatedwithallmajortaxonomic groups(Fig.4).Fishingvesselscanbelinkedto100%ofthealgae,cnidarian,bryozoan,andascidian species(78speciescombined).Biofoulingasasolevector(includingfishingvessels)orincombination withothernonͲfoulingvectorsplaysanimportantroleintransferringthesefourtaxa.Thevectorwas notlinkedtoasignificantproportionofplatyhelminthspecies,manyofwhichareparasiticoffish, althoughthenonͲfoulingcomponentoffishingvectoractivitywaslinkedto50%ofthesespecies.The onlytaxonomicgroupthatdidnothaveonerepresentativetransferredbybiofoulingalonewasthe annelids,butfishingvesselswerestillassociatedwithtransfersof92%ofthesepolyvecticspecies (specieswithmorethanonepossiblevector). 

18  18 13 21 20 25 82 46 18 21 14 100% notbiofouling&not fishingvessel 80% nonͲfoulingfishing  vesselw/othervectors taxon  60% total  per

of biofoulingw/other   vectors(inclfishing 40% vessels)

percent richness biofoulingaloneincl 20% fishingvessels

0%

 Figure4.Differencesamongtaxaintheproportionofspecieslinkedtofishingvesselsandbiofouling.The percentagebarchartshowsproportionsofspeciesamongtaxafor1)speciesvectoredbybiofoulingalone,2) biofoulingasapossiblevectorincombinationwithothervectors,3)specieslinkedtofishingvessels(butnot biofouling),and4)speciesnotassociatedwithvesselsorbiofouling.Categories1Ͳ3includefishingvesselsas vectors.Thelegendreflectstheshadingforeachofthesecategoriesandthenumberofspeciesforeachtaxonis atthetopofeachbar.The‘other’categoryincludedbacteria,sponges,ctenophores,nematodes,vertebrates (seeFig.1).  Thereare129AISinCaliforniaknownfromjustonelocation(bay)butadditionalspecieswithmorethan onerecord(speciesfromtwobaysormore)fromthesameyearmeanthat133havefirstdetections formjustoneyear(noadditionaldetectionsaftertheirinitialdocumentedpresence).Allothertaxa havemorethanoneyearofdetectionanditunderscorestheroleofvectorsingeneral,andfishing vesselsasacomponentofthis,thatmanyspeciescontinuetoberecordedinnewlocationsmanyyears aftertheirinitialdiscoveryinthestate(Fig.5).Incontrasttothesingleyearandsinglelocationspecies, themusselMytilusgalloprovincialisisknownfromatleast24differentlocationswithfirstrecordsin eachlocationspanningtheyearsbetween1987and2000.SelfͲdispersalandhybridizationisthoughtto playanimportantroleinthisspecies’spread,alongwithreadyassociationwithbiofoulingofvessels.  Amphibalanusimprovisusdoesnothavesuchaprolificspreadamonglocations,butitisthespecieswith thelongesttimespanbetweenfirstdetectionsindifferentbays(150years),andcanalsobelinkedto fishingvesselsasavector.Indeed,SanFranciscoBayisahubfortheearliestAISrecordsinthestate. LikeA.improvisus,thehydroidPinauaycroceawasdiscoveredinthe1850sandhascontinuedtobe dispersedtoseveralotherbaysinthestatesincethattime,includingpossiblybyfishingvessels.Its mostrecent‘new’distributiondataisforHumboldtBayin2003.Otherspeciesthatwererecordedover 100yearsagoandstillpersistinSanFranciscoBayhavenotbeenrecordedelsewhereinthestate, includingtheisopodSynidotealaevidorsalisandthehydroidClavamulticornis.Theirapparent confinementtotheBayplacesthemamongagroupwithsevenotherspeciesthathavenothadanew distributionrecordinover70yearssincetheywerefirstdetected.

19   160

140  and  120 biofoulingalone (years)  first  100 biofoulingw/other vectors record 80  nonͲfoulingfishing between  60 vesselw/othervectors recent  40 notbiofouling&not fishingvessel most duration 20

0 1850 1870 1890 1910 1930 1950 1970 1990 2010 yearofAISfirstrecordinCalifornia  Figure5.Durationbetweenfirstandsubsequentrecords(spreadamongbays)forCaliforniaAIS.Forfour differentcategoriesofvectorassociation(legend),theplotshowsthedurationbetweenfirstandmostrecent recordofAISdetectionindifferentbaysinCalifornia(n=268*).Thefirstthreecategories(black&greysymbols) includefishingvesselsaspossiblevectors.Theplotformsacharacteristicwedge.AllspeciesonthexͲaxisare thoseknowntoonlyoccurinonelocation(133specieswithjustonerecordinthestate).Thefeintgreyline representsthemaximumtimepossiblebetweenfirstandmostrecentrecordsofdetectionforallspecies(105 speciesapproachthisline).Theremainingspeciesoccurbetweenthelines(30species),havingbeenrecorded subsequenttotheirfirstrecords,butnotrecordedrecently(inthelast13years).Theuppermostdatapoint (topleftoftheplot)representsAmphibalanusimprovisus,whosefirstrecordforthestateoccurredinSan FranciscoBayin1853andmostrecentrecordina‘new’differentlocationoccurred150yearslaterinElkhorn Slough. *thetotalis268speciesbecausetenrequirefurtheranalysisoftimingdata.  SanFranciscoisoneofthemostinvadedBaysintheworld,andisthemostinvadedintheNEPacific.It dominatesCalifornia’sinvasionhistory(Fig.6)andfishingvesselscanbeassociatedwith67%ofinitial incursionsforSanFranciscoBay’sextantAIS.TheothercentralCaliforniabayswithsubstantialnumbers ofknownAISincludedElkhornSlough(MossLandinginFig.6),BodegaBay,andTomalesBay.Biofouling wasconsideredasolevectorforbetween16%and26%ofAISamongthesefourbays,althoughfishing vesselscouldbeassociatedwithbetween67%and82%oftheirinvasions.Theroleofbiofoulingasa solevectorwaselevatedinsouthernCalifornia(LA/LongBeachtoTijuanaEstuary)relativetotherestof thestate.SevensouthernCaliforniabayshad20ormoreAISandbiofoulingwasconsideredasole vectorfor54%oftheseforeachbay(onaverage).Incomparison,thesamesoleͲvectorcategorywas linkedtoanaverageof33%ofAISamongtheninebaysintheremainderofthestatewith20ormore AIS.NorthernCaliforniahasjustonebaywithmorethantenknownAIS–HumboldtBaywith70 species.EightyͲonepercentofthese70introductionsincludedfishingvesselsasapossiblevector.  Overall,thereiswidevariationinthenumbersofknownAISamongbayswithinthestateandthefishing vesselwasapossiblevectorforanaverageof85%ofAIS(±10%andincombinationwithothervectors) forbaysthathad20ormorespeciesacrossthewholestate(Fig.6).Itisimportanttounderscorethe

20  pointthatwecannotdistinguishtherelativecontributionoffishingversusrecreationalversusshipping fortheoverallspreadpatternastheseareallpossiblevectorsinmanylocations(especiallymajorbays).

CrescentCity* A Trinidad* B HumboldtBay* EelRiver KlamathRiver Mattole PTAr/Alb/FtBrg* Gualala BodegaBay* TomalesBay* PointReyes* SanFranciscoBay* HalfMoon* MossLanding* Carmel CentralCoast FV+foulingonly MorroBay* FV+fouling+other SLObispo* FV+nonfouling SanAntonio SantaBarbara* notFV Ventura* PortHueneme/OX* SantaMonicaBay LA/LB* Islands SantaAna NewportBay* DanaPoint* Oceanside* MissionBay SanDiegoBay* TijuanaEstuary 200250 50100150 0 0% 25% 50% 75% 100% numberofAISperbay percentofspeciestotal  Figure6.DifferentialAISdistributionsamongbaysandtheroleoffishingvesselsasvectors.ThenumbersofAIS perbay/locationshowsthatSanFranciscoBaydwarfsallothersintermsofAISnumberspresent(A).ThebayͲ levelwasdeterminedusingNEMESISlocationdataoverlappedwithPacFINportswhereappropriate.Insome cases,theNEMESISlocationincludesadditionalspaceoutsideofabay(adjacentcoastline).Baysarelistedfrom northtosouthandthosewithanasteriskarelocationsthatreceivefishingvessels(accordingtothefishing trafficdataset;below).PanelBshowstheproportionofAISineachbaythatwereassociatedwithfishing vessels.AllnonͲwhiteportionsofbarsrelatetofishingvessels(seelegendwhereFVisFishingvessel)andthere arefourlevelsvectorassociationinthelegend:1)fishingvesselsandotherfoulingvectorsonly;2)fishing vesselswithfoulingvectorsANDothervectors;3)nonͲfoulingvectors,includingfishingvessels;4)nonͲfishing vesselintroductions.  4.2VectorAnalysis  HavingevaluatedtheinvasionhistoryofCaliforniawithrespecttofishingvesselvectors,ournextstep wastocharacterizepresentͲdayfishingvesseltrafficinordertounderstandtheirspatialandtemporal (seasonal)patternsofarrivals,voyageroutes,portconnectivity,andinteractionsamongbayswithinand

21  outsideofthestate.Wethenevaluatedvectorbiotausingaliteraturesearchanddirectsamplingof coastaltransientvesselsinCalifornia.  Statewidespatialandtemporalpatternsoffishingvesselarrivals Therewere2464fishingboatsthatreportedarrivalstoCaliforniaharborswithfishticketsduringthe fouryearperiodofJanuary2005toDecember2008.The2464distinctvesselsaccountedfor204,488 arrivals.AdditionalzzzͲlabeledboatsalsocontributed2262arrivals,butwedonotknowhowmany boatswereincludedinthisdesignation.TheportofLA/LongBeach,includingthecombinedPacFIN landingsitesofSanPedro,LA,LongBeachandTerminalIsland,wasrankedhighestforfishingvessel arrivalsandaccountedfor15.4%ofthetotalforthestate(31,498arrivals).TheportsofSantaBarbara (22,193arrivals)andSanDiego(16,388)hadthesecondandthirdhighestnumbersofarrivalsinthe state.ThesethreeSouthernCaliforniaportsaccountedforoveroneͲthird(34.3%)ofthefishingvessel arrivalsoverfouryears.SanFranciscoBay(13,070arrivals)andHalfͲMoonBay(10,077)werethe highestrankedCentralCaliforniafishingports,whileCrescentCity,FortBragg,andHumboldtBayonthe northerncoastofthestateroundedoutthetopeightportsforfishingvesselarrivals(Fig.7). 

 Figure7.NumbersoffishingvesselarrivalsamongCalifornianbays.Thisbubbleplotshowsthenumbersof fishingvesselsthatreportedarrivalstoeachharborinCaliforniaoverfouryears.Bubblesizesarescaledto reflectarrivalnumbersandthescaleisprovidedinthebottomleft.LA/LongBeach,with31,498arrivals,wasthe highestrankedbay. 

22  Thestatewidetemporaltrendrevealedtherewasamonthlyaverageof4000to5000arrivalsfornine monthseachyear.Theaveragenumbersofarrivalsdroppedbelow4000duringMarch,April,andJune (Fig.8).FromJanuarytoApril,therewasadeclinefromtheyearlypeakof4,880arrivalsacrossthe statetotheyearlytroughof2,915arrivals.ThiswasfollowedbyanincreaseinMayandanotherdecline inJuneto3,545arrivals.Thesecondhalfoftheyearwascharacterizedbyasteadyarrivalsrateof approximately4,500permonth(Fig.8).  Threeofthefourhighestrankedbaysforvesselarrivals(SantaBarbara,SanDiego,SanFrancisco)each hadtheirannualminimuminApril,underlyingthestatewidetemporaltrendforlowerarrivalsinthat month.Thetemporaltrendsforeachmajorport(Fig.8)revealedvaryingextentsofseasonalityof arrivals.ThemoststrikingtrendoccurredinSanDiego,wherebyaspikeinarrivalsinOctober,that continuedforthreemonths,representedanincreaseofovertwoͲandͲaͲhalftimes(x2.6)thenumbersof arrivalsfortheotherninemonthsoftheyear.Thisspikeinarrivalscoincideswiththefishlandingsdata reportedbytheCaliforniaDepartmentofFish&Game(DF&G)forthislocation.Forthefouryearsof ourvesseltrafficdata,landingsjumpedfrom142,000poundsonaveragebetweenFebruaryand Septemberto309,417betweenOctoberandDecember.Itappearslandingsofspinylobsterand swordfishwerethefisheriesthatunderliethepattern.SantaBarbaraalsohaditspeakarrivalsin OctoberandNovember,buttheincreasewasn’tasstrikingasSanDiego’sbecauseofacomparatively highrateofarrivalsthroughouttheyearinSantaBarbara.  InSanFranciscoBayandHalfMoonBay,therewasnonotablespikeortroughinfishingvesselarrivals throughouttheyear.InNorthernCalifornia,therewerenotableincreasesinarrivalsinAugustand SeptemberatFortBraggandinthewintermonthsatCrescentCity(Fig.8).Thevariationinthese monthswasalsosubstantialatbothharbors.AtFortBragg,therewere601reportedarrivalsinAugust 2007,butonly147inAugust2008.Itisn’tentirelyclearwhysuchadisparityoccurredbetweenboth yearsbecauseDF&Greportedfishlandingsforthosetimesdifferedbylessthan200,000pounds,but someofthevariationmaybeexplainedbyChinookSalmonlandingswhichwere231,086poundsin August2007butnotlisted(andpresumablyzero)inAugust2008.Similarly,inCrescentCity,therewere 1017arrivalsinFebruary2006butonly249inthesamemonthof2008(Fig.8).TheDungenesscrab fisherylikelyexplainssomeofthisvariation;DF&GdatafromnearbyEurekashowedthatcrablandings wereover7,000,000poundsinFebruary2006butlessthan250,000poundsinFebruary2008. 

23  

 Figure8.TemporaltrendsoffishingvesselarrivalsforCaliforniaandthetopeightrankedbays.Theseplotsshowthemonthlyaverage(andSD)acrossfour yearsoffishingvesselarrivalsdata.ThecenterpanelshowsthestatewidetrendandhasadifferentscaleontheyͲaxistotheothereightpanels.Thenames ofthetopeightrankedbaysareprovidedaboveeachpanel,withharborsinSouthernCalifornia,CentralCaliforniaandNorthernCaliforniashownonthe top,middleandbottomrows,respectively.TheyͲaxisscaleisthesameforeachbayplot. 

24   TransientvesselsandportconnectivitywithinCalifornia AmajorityoffishingvesselsinCalifornia(52.8%)wereresidentboatsthatdidnotreportarrivalstoany otherbayoutsideoftheirhomeharbor(Fig.9).Therewere1162fishingboatsthatweretransient duringthesampleperiodand45%ofthesevesselsreportedtransitstotwoportsonly.Themost transientvesselvisited12differentharbors(seebelow)andtherewerefivevesselsthatvisitednine differentbaysandoneotherthatvisitedtendifferentbays.   

 Figure9.ThefrequencyoffishingboatsandthenumberofdifferentportstheyvisitedinCaliforniaoverfour years.Theplotshowsthat52.8%ofCalifornia’sfishingfleet(n=2464boats)reportedarrivalstojustonebay betweenJan2005andDec2008(greybar).Theremainingvessels(blackbars)weretransient,havingreported arrivalstomorethanonebay.Theasteriskindicatesarrivalsbylessthan0.5%ofboatstonine,tenandtwelve differentharbors.   AlthoughLA/LongBeachreceivedthehighestnumberofarrivalsamongallbays,SanFranciscoBay receivedthehighestnumberofdifferentvessels(589comparedto441uniquevesselsthatarrivedto LA/LongBeach).Transientboatswereoutnumberedstatewidebyresident(soleͲport)boats,theeffect oftransiencymeantthatthenumberoftransientboatsexceededthenumberofresidentboatsfor everybayinthestate(becausetransientboatscountmorethanonceamongbays;Fig.10).Indeed, therewere12baysforwhichtheratiooftransienttosoleͲportboatswasmorethan4:1,including relativelyminorfishingportsofPortHuenemeandBolinasandmajorfishingboatharborslikeHalfͲ MoonBayandBodegaBay.SanDiegorankedhighestforpercentageofsoleͲportboatswith46%of vesselsreportingarrivalsonlyatSanDiego.ThisexplainedwhySanDiegorankedthird,outof27bays, fortotalarrivalsbutonly14thfornumberofdifferentboatsthatarrived.        

25   

 Figure10.Numbersofdifferenttransientandresidentboatsperbay.Thisplotshowsthetotalnumberof differentvesselsthatarrivedtoeachbayoverfouryears,withthegreyportionofeachbarrepresenting transientboatsandtheblackportionrepresentingsoleͲport(resident)boats.AlthoughsoleͲportboats outnumberedtransientsacrossthestateasawhole,eachporthadmoretransientboatsthanresidentsbecause transientboatsgetcountedseveraltimesinthisplot(between2and12dependingonthenumberofbays visitedbyeachboat).Incomparisontothestatewidepatternofarrivals(Fig.7),thisplotshowsthatSan FranciscoBayreceivedmorevesselsratherthanLA/LongBeach,whichreceivedmorearrivals.   Onaverageoverthefouryeartimeperiod,eachofthe27bayswithfishingboatarrivalswasconnected directlyorindirectlyto18otherbays(±5.6bays)byfishingboats.Thatis,eachbaytendedtohave boatsthatreportedarrivalstoafurther18bays(onaverage)duringthecourseoftheirfishing operations.Theleastlinkedbays,withconnectionstosevenotherbaysviafishingvessels,wereamong thosethathadfewestarrivals–Albion,TomalesBay,andBolinas.ThemostconnectedbayswereSan FranciscoandBodegaHarborwithlinks,throughfishingboats,to25oftheother26bays.Therewere 13baysthathadconnectionstomorethan20otherbays.  

26    WhileSanFranciscoBaywasconnectedto25otherbays,thestrengthofthoseconnections,basedon thenumbersofboatsthatcreatedthelinks,variedsubstantiallyamongbays.Therewere206fishing boatsthatreportedarrivalstobothSanFranciscoBayandBodegaBay.AfurtherfivebayshadpairͲwise connectionstrengthswithSanFranciscoBayofmorethan80boats(HumboldtBay,FortBragg,Half MoonBay,SantaCruz,andMossLanding).Incontrast,justoneboat(perbay)formedthepairͲwise linksbetweenSanFranciscoandDanaPoint,NewportBay,Albion,andTrinidad.Amongallports,there wasatendencyfortransientvesselstoreportarrivalstoacoregroupofadjacentbaysratherthana widelydispersedgeographicrangeofarrivals(Fig.11).Figure11showsthatthestrongestlinksbetween baysoccurredfarmoreoftenamongadjacentbaysthanfordistantlyseparatedones.Thisisalso reflectedinamutliͲdimensionalscalingplotofbays(notshown)thathadsignificantdifferencesamong clustersofbaysgroupedintofourcategoriesͲnorth,central,southcentral,andsouth.TheAnalysisof similaritiesforthisplot(ANOSIM)showedthatclustersofharborsbasedongeographyweresignificantly differentintermsoftheirvisitingboats(R=0.504,p<0.001).Aresultofzerowouldrepresentclustersof portsthatdidnotdifferintheirvesselvisitors(mostsimilar),whileanR=1resultwouldmeanallclusters sharednoarrivalsofboats(mostdissimilar).ThepairͲwisecomparisonofclustersrevealedthatthe farthestapartclusters(southandnorth)hadthehighestRvalue(0.751)indicatinglittleoverlapinvessel traffic.Incomparison,adjacentclustershadRͲvaluesof0.273,0.384,and0.668(fromnorthtosouth respectively,allp<0.05).  Anotablefeatureofthecolorintensityplot(Fig.11)showingconnectionstrengthsbetweenbays,based onsharedboatarrivals,wastheconnectionsthatexistedforbayswithoutcommercialshipping(nonͲ commercialbays).LocationssuchasFortBraggandBodegaBayhadstronglinkstoeachotherandSan FranciscoBay.Thesethreebaysinturnappearedtohaveawider(geographic)rangeofstrong connectionsthanotherbays.Evenrelativelyminorfishingharborshadstronglinkstocommercialbays; 30ofthe36differentvesselsthatcalledonTrinidadinNorthernCaliforniaalsoreportedlandingsat HumboldtBay.HighproportionsofthevesselsthatvisitedSouthernCalifornianonͲcommercialbays– Ventura,NewportBeach,DanaPoint,andOceansideͲalsoreportedarrivalstoLA/LongBeach(Fig.11). 

27  Bay  Bay  Beach City  Beach  Bay    Bay

Harbors(NͲS)  Bay  Cruz Barbara Arena Reyes Landing   Point    Hueneme  Bragg Moon   Francisco Diego    Obispo  Crescent Trinidad Humboldt Fort Albion Point Bodega Tomales Point Bolinas Marin San Half Santa Moss Monterey Morro SL Santa Ventura Oxnard Port LA/Long Newport Dana Oceanside San CrescentCity Trinidad Humboldt FortBragg Albion PointArena BodegaBay TomalesBay PointReyes Bolinas Marin SanFranciscoBay HalfMoonBay SantaCruz MossLanding Monterey MorroBay SLObispo SantaBarbara Ventura Oxnard PortHueneme LA/LongBeach NewportBeach DanaPoint Oceanside SanDiego

numberofboats 228 36 277 369 20 51 433 8 29 9 57 589 349 201 314 107 218 130 260 178 177 72 441 51 94 82 202

ColorScale percentofboats 0 1to10 11to20 21to30 31to40 41Ͳ50 51Ͳ60 61Ͳ70 71Ͳ80 81+ ineachcolumn  Figure11.Colorintensityplotreflectingthenumberofvesselsthatvisitedeachpairwisecomparisonof Californiaharbors.Eachcellinthegridrepresentstheproportionofvesselsthatreportedvisitingapairof harbors,whicharelistedforcolumnsandrowswithbothaxesarrangedfromnorthtosouth.Thedarkerthe shade,thehighertheproportionofvesselssharedbetweentwoharbors(asafunctionofthetotalvisitstoeach columnharbor).Forexample,thebottomleftcellreflectsthethreeboatsthatvisitedthemostnortherly (CrescentCity)andsoutherly(SanDiego)harborsduringthefouryearanalysisperiod(theshadeintensity denotesthatthisrepresents1.3%ofCrescentCity’stotaldistinctvisitingvessels).Thediagonalfromtopleftto bottomrightshowstheproportionofeachharbor’ssolelyresidentvessels(i.e.vesselsthatonlyreported visitingoneport).Thetendencytowardsdarkercellsnearthisdiagonalandlightercellsattheoppositecorners showsthatmosttransientvesselsdonotvoyagetooppositeendsofthestateveryoften,buttendtovisitacore rangeofadjacentharbors.Thenumberofdifferentvesselsthatarrivedtoeachport(againstwhichthecolor scaleismeasured)isshownalongthebottomofeachcolumnandthescalebarisprovidedbelow.See SupplementaryMaterial,Appendix2forunderlyingdata)

28   Themosttransientfishingvessel ThemosttransientvesselintheCaliforniafishingfleetbetween2005and2008wasvessel701,which visited12differentharborsduring543reportedarrivals.Thenetworkofbaysconnectedbythisvessel rangedfromSanFranciscoBaytothenorthandLA/LongBeachtothesouth(Fig.12).Therecord showedthatthisvesselhada‘home’rangeofSantaBarbara,VenturaandOxnard,whichaccountedfor 87%ofthedistinctarrivalsandamajorityofthesewereuninterruptedreturnvisits(outͲandͲbacktothe sameport).Forexample,therewere204outͲandͲbackvisitstoSantaBarbaraoutof263visitsintotal tothatport.Theconnectionstrengthbetweenthethreecoreportswasthehighestinthisvessel’s largerportnetwork,with146directtransitsamongthem.Acrossthefouryearperiod,SantaBarbara’s roleasahubforthisvesselwasunderscoredbydirectoutwardconnectionstotenharborsanddirect incomingtransitsfromninedifferentharbors.  Overall,34%ofthetotalarrivalsforthisvesselinvolveddistincttransitsfromoneporttoanother(187 transits).Itwasnotablethatthisvessel’snetworkofbayswaslargelycalleduponin2006,whenit visited11differentharbors(Fig.12).Thiscontrastedwiththeotherthreeyearswhentheportnetwork forthisvesselcontractedtofour(in2007)orfivebays(in2005and2008),allbutoneofwhichhadbeen visitedin2006(MorroBay).Thevesselhadsignificantlydifferentnumbersofarrivals(ʖ2=10.63, p<0.05,df=3)andnumbersoftransitsbetweenports(ʖ2=19.9,p<0.001,df=3)amongyears,withhigher numbersofeachfor2006,aswellashighernumbersofharborsvisitedthatyear.Theunderlyingcause oftheadditionalactivityin2006isunknown,butithighlightsthevariationinvoyagepatternsthatcan occurforfishingvessels.  Theconsequenceofthisvessel’smovementsforintroductionsisdifficulttoascertainwithoutknowing thestatusofthevessel’ssubmergedsurfacesthroughoutthisfouryearoperationalwindow.Thestrong connectionsbetweenitscoresites(SantaBarbara,Ventura,andOxnard)certainlyprovidedameansfor organismstobeintermixedamongthosebays,whilethelongerdistancetransitsconnectedthesecore bayswithothersitesupto500kmaway.VoyagesfromSanFranciscoconnectedothersitesinthis vessel’snetworktothemostheavilyinvadedbayinthestate.  Furthermore,biofoulingisaconcatenationofbiotaandtheportͲtoͲportaspectoftransitsisnotas importantforintroductionsasitisforothervectors(ballastwater,forinstance).Ballastwateracts predominantlyasapointͲtoͲpointsourceofspeciesdeliverywhereasbiofoulingcontinuestooperateas a‘diffuse’vectorwithcontinuoustransfersofthesamecommunityovertime.Anyorganismsattached tovessel701mayhavebeentransportedthroughoutthenetwork,withtransittolerance,breeding timesandlocalrecipientͲportconditionsprovidingopportunitiesandbarrierstointroductionacrossthe 12Ͳbaynetwork.Thisistrueforallvesselsthatvisitedmorethanoneport,butahighdegreeof transiency,exemplifiedbyvessel701,providesmoreopportunitiesacrossabroaderrangefor introductionstooccur.  

29   Figure12.Voyagepatternsofthemosttransientfishingvessel.ThefourpanelsshowtheyearͲbyͲyeartransits forafishingvesselthatcalledon12differentbays.Redlines(solid)representsouthtonorthtransitsandgreen (dashed)linesrepresentnorthtosouthvoyages.Thethicknessofeachconnectiondiffersbasedonthenumber oftransitsthatoccurred(scalebarinthebottomleftofeachpanel).Theplotsshowhowvoyagepatternscan differfromyearͲtoͲyearforfishingvessels.Thisvessel’sportnetworkwasmuchlargerin2006,intermsof numbersofportsvisited,thenumbersoftransitsmade,andthegeographicdistancescovered.Notrepresented intheseplotsarethenumbersofuninterruptedreturn(outͲandͲback)transitsbythisvesseltothesameport; forexample,thisvesselreported44uninterruptedreturnstoMossLandinginthesummerof2005.Activeports ineachyearhaveabbreviatednames.Fromnorthtosouth,theseare:SF–SanFranciscoBay,HMB–HalfMoon Bay,SCͲSantaCruz,MLͲMossLanding,MTYͲMonterey,Morro–MorroBay,SLOͲSanLuisObispo/Avila,SBͲ SantaBarbara,VenͲVentura,OxͲOxnard,PHͲPortHueneme,LA/LBͲLA/LongBeach.

30   Threevesselsreportedarrivalstothetwobaysfarthestapartinthestate,CrescentCityandSanDiego. Thefirstofthesevesselsregistered132arrivalsinthemostnortherlybayandtwointhemostsoutherly, aswellascallstosixotherbaysforatotalof159arrivalsoverfouryears.In2005,thisvesselreporteda landinginmidͲSeptemberinCrescentCityanddidnotreportanotherarrivaluntillandinginSanDiego onemonthlater.Itislikelythatthevesselvisitedotherportsinbetweenwithoutcatchingorlanding fish(therebynothavingtoreportthosearrivals).However,aftermovingfromSanDiegotoOceanside inJanuary2006,itreportedanotherarrivaltwodaysafterOceansidebackinCrescentCity.This probablyrequiredanonͲstopvoyagefromoneendofthestatetotheother.  Thesecondvesseltovisitthestate’smostnortherlyandsoutherlybaysreportedjust39arrivalsover fouryears.ItreportedarrivalstoCrescentCity,MossLanding,SanLuisObispo,andSanDiego,withat leastonemonthbetweentransferstodifferentharbors.Thisvesseldidnotreportdirecttransit betweenSanDiegoandCrescentCity,thoughitdidreportsequentialarrivalstoandfromthosebays andMossLanding.Thethirdvesselalsoreportedarelativelymodestnumberofarrivalsacrossfour years(47),withmonthͲlongorlongertimegapsbetweenarrivalsatnonͲadjacentbays.Aswellas CrescentCityandSanDiego,thisvesselcalledonSanFrancisco,HalfMoonBay,andLA/LongBeach.  TransientfishingvesselsconnectedtoCaliforniafromoutͲofͲstate OurrequestfordataontransientboatarrivalsfromaforeignlastͲportͲofͲcallyieldedinitialsummary dataof2535arrivalsovera14monthperiodfromJanuary2009toMay2011.Justover95%ofthe arrivalsinthesummarydatawererecordedinSanDiego,whichpresumablycamefromMexicoand othercountriestothesouth,butthelastportvisitedpriortoU.S.entryorreͲentrywasnotpartofthe CBPdatacollectionavailabletous.OtherforeignlastͲportvesselsarrivedatSanFranciscoandLA/Long Beach.TherecordsshowedthatarrivalsfromforeignsourcesintotheStatehadaseasonalpatternof initialentry,withpeaksofarrivalsinMayandJune(140Ͳ175arrivals)andtroughsinDecemberand January(25Ͳ45arrivals).Therequestformoredetailedinformationonboatarrivalstothestatefrom outsidetheU.S.remainsinprocessingattheCBP.  ThePacFINdataonfishingvesseltrafficrevealedthattherewere356fishingboatsthattraveled betweenCaliforniaandthePacificNorthweststatesbetween2005and2008.Vesselfluxbetween CaliforniaandOregonincluded190boatsandtherewere39thattransitedbetweenCaliforniaand Washington(theremaining127reportedarrivalstoallthreeWestCoaststates).TwentyͲtwoofthe27 bayswithfishingvesselarrivalsinCaliforniahadadirectorindirectconnectionwiththePacific Northwestthroughfishingvesselflux;theexceptionswereAlbion,TomalesBay,Bolinas,Newport Beach,andDanaPoint.Forvesselsthattraveledoutofstate,73%calledonthreeoffewerPacific Northwestbays(Fig.13A),althoughonevesselreportedarrivalstotenNorthwestharbors.Similarly, thenumbersofCalifornianbaysvisitedbyvesselsthathadspenttimeintheNorthwesttendedtobe low;34%oftheseinterͲstateboatsvisitedjustonebayinCalifornia(Fig.13B). 

31  120 A 100 California)  80 boats to   of  60

traveled 40  number also  20

(that 0 12345678910 numberofPacificNWbaysvisited

120 B PNW)

 100  the  80 to  boats  of  60 traveled

 40 number also  20

(that 0 12345678910 numberofCaliforniabaysvisited  Figure13.NumberofbaysvisitedbyvesselsthatreportedarrivalsinCaliforniaandthePacificNorthweststates. TheplotsshowthedecreasingfrequencywithwhichvesselsvisitedmultiplebaysinthePacificNorthwest(A) andinCalifornia(B).Therewere102vesselsthatcalledonjustoneportinthePacificNorthwesthavingalso operatedinCalifornia.Similarly,122vesselsthathadbeenintheNorthwestStatesvisitedoneCaliforniaport, althoughonevesselreportedarrivalsandnineCaliforniabaysinadditiontoits  TheportsoftheNWthathadthegreatesttrafficfluxintermsofnumbersofboatsthatvisitedCalifornia wereNewport(196boatscalledatNewportandaCaliforniaport),CoosBay(195),Astoria(99),and Brookings(90)inOregonandIlwaco(124)andWestport(72)inWashington.Conversely,theportsin Californiathathadsharedvessels’arrivalswiththeNWwereunsurprisinglyfromthenorthandcentral partsforthestate:SanFranciscoBay(150boats),CrescentCity(143),FortBragg(117),HumboldtBay (108),BodegaBay(96),HalfMoonBay(73)andMossLanding(84).Therewere,however,19fishing vesselsthatoperatedinSanDiegoandthePacificNorthweststates,againdemonstratingthelongͲ distancerangesthattheseboatscancoverduringthecourseoftheiroperations.Amongthe19boats thathadvisitedSanDiegoandtheNorthwestwerethree,mentionedpreviously,thatvisitedCrescent City.NinevesselsreportedcallstoSanDiegoandWestport,Washington,which,atadistanceofmore than1750kmbycoastalvoyage,representedthemostdistantpairͲwiseportcomparisoninthevessel fluxdataset.Unfortunately,datafromportsfurthernorthinBritishColumbiaandAlaskathatmayalso haveoperatedinCaliforniawerenotavailablebecauseofdifferencesindatacollectionbytherelevant fishingauthorities. 

32   Vectorbiota1:Speciesassociatedwithbiofoulingofboats Therehavebeenrelativelyfewstudiesconductedontheboatfoulingvector,withmanyremainingin grayliterature,despitetheprevalenceofincidentalmentionsaboutthevectorthroughoutthe literature.Therearedoubtlessmanymorerecordsofspeciesfromboathullsthanweencountered,but thesearenoteasilyextractedfromtaxonomicaccounts,museumliterature,andothersources.There havealsobeenstudiesofthevectorthatdonotreportspecieslistsoridentificationsinthetext.Wedid find23papersorreports(Supplementarymaterial,Appendix3)recording455marineorbrackishwater organismssampleddirectlyfromsmallvessels.Thesestudiesemanatedfrom12countriesfromstudies publishedsince2000.  Asagroup,foulingspeciesrepresentabroadspectrumoflifeformsandtrophiclevels,includingboth sessile(attached)andmobiletaxa.Insomecases,organismswereidentifiedtospecieslevel,inother casesdescriptivetermssuchas“greenmacroalgae”or“fish”wereused.Takingaconservative approach,thisappearstorepresent243distinctanimal,protist,andplantspeciesortaxain15phyla (Fig.14).  80

60 species  of

 40

20 number

0

 Figure14.Taxonomicbreakdownofspeciesrecordedfromboathullsintheliterature.Theplotshowsthe numberofspeciespertaxonthathavebeenrecordedonthehullsandnichesareasofboats(n=243)reported from23differentstudies.  Mobilearthropodswerebyfartherichesttaxonomicgroup,withatleast76distincttaxareported.Over halfofthesespecieswereamphipods,withsmallernumbersofisopods,decapods(exclusivelycrabs) andcopepods.Thesecondlargestgroup,Annelids,comprisedalmostentirelyofpolychaetesand consistedof34distincttaxa.Therewere33bryozoanspeciesand24ascidians.Barnaclesmadeupa significantgroupwith17speciesreported,whilethecombinedrichnessofgreen,brownandredalgae totaled24distincttaxa.  ThemostͲreportedtaxonwasafolioseformofthegreenalgaEnteromorpha(formerlyUlva),whichwas recordedsixtimes.ThearborescentbryozoanBugulaneritinawasreportedfivetimes.Eachofthese mayactuallyrepresentmultiplespecies,asB.neritinaisnowrecognizedasaspeciescomplex,andthere areseveralspeciesoffolioseEnteromorpha.ThetunicatesBotrylloidesviolaceus,Botryllusschlosseri andDiplosomalisterianum,thebarnacleAmphibalanusamphitrite,andthebryozoanWatersipora subtorquatawereeachreportedfourtimes.

33   Wesuspectthatthenumbersofspeciesknownfromboathullsandnicheareasofboatsarevastly underreported,eventhoughthenumbersofexplicitstudiesofthisvectorappeartobeaccountedforin thisreview.Theavailabledatadoesshowhowdiversetheboatbiofoulingcommunitycanbe.There havealsobeenaccountsofveryhighabundanceoforganismsonresidentandtransientboats, highlightingthehighdosesoforganismsthatcanbetransferredinonevectorevent.Noreports evaluatedtheconditionofthespeciesreportedfromhulls,althoughsomenotedthepresenceofgravid individuals,eggs,larvae,andjuveniles,indicatingthatatleastsomeofthespeciespresentwerecapable ofreproducinganddispersingintotheenvironment.  VectorBiota2:SpeciessampledonsubmergedsurfacesoftransientboatsinCalifornia Ourlimitednumberoffishingvesselssampledyieldedthefollowinginformation:  VesselA:ThisfishingboatwassampledinMontereyharboranddidnothaveanyaccompanying questionnairedata.Ithadjusttwospeciesattachedtonicheareasurfaces,theintroducedBryozoan WatersiporasubtorquataandanunidentifiedCaprellidamphipod(thoughconfirmedthatitwasnotthe introducedCaprellamutica).  VesselB:ThisvesselwasalsosampledinMontereyharborandthelimiteddataprovidedbyanoperator suggestedthatithadnothadhullmaintenanceinthelast15months(paintapplicationorcleaning).It hadalsobeenquitestationaryinthepast12monthsbuttherespondentcouldnotprovidedetailson whereithadbeen.Werecordedfivespeciesonthisvessel,threenativetoCalifornia(thebryozoan Cellaporariabrunnea,thecolonialascidianDiplosomasp,andtheamphipodCaprellacalifornica)and twononͲnativetothestate(thebryozoanBugulaneritinaandtheamphipodCaprellamutica).  VesselC:ThisfishingboatwassampledinSantaBarbaraandtheunderwatersamplingresultedinthe collectionofoneortwoindividualsofthestalkedLepasbarnacleatthebowendofthevessel.The operatorreportedthatthevesselhadbeenfishingoutofSantaBarbaraforthepastthreemonths,but hadvisitednootherharborsinthattime.Thevesselhadalsohadareapplicationofantifoulingpaint onemonthpriortosampling,whichexplainedtheflawlessnatureoftheunderwatersurfacesofthis vessel.TheoperatoralsoreportedthatthevesselwasabouttoembarkonatriptoOregonrelatedto theAlbacorefishery.  VesselD:Theownerofthisboatprovideddetailedinformationonhisrecentvoyageandmaintenance historyandconsentedtoanunderwatersurveyofhisboat.Thevesselhadnothadanewcoatof antifoulingpaintappliedforover30monthsandcleaningwasdonecursorilybytheoperatorwitha brush(withafocusonthepropeller).Themostrecentcleaninghadoccurredsixmonthspriorto sampling.IthadbeeninSantaBarbara(samplinglocation)forjustoveronemonth,andarrivedfrom fishingtripsinMexicoandSanDiego.Underwatersamplingrevealedthistransientboathadalmost 100%coverofbiofoulingacrosshullandnicheareasurfaces.Thiswasevidentfromthewaterline,and ourinitialimpressionwasofaresidentnonͲmovingvesselratherthananactivetransientfishingvessel. Werecordedatleast81differentmorphoͲtaxaonthisvessel,includingsponges,mobilecrustaceans, polychaetes,bryozoans,bivalves,barnacles,hydroids,ascidians,andalgae.Weareendeavoringtoget identificationsforthesespeciescompleted,butthenonͲnativespeciesamongthisboat’sfouling communityincludedthesolitaryascidiansCionaintestinalisandStyelaclava,theamphipodCaprella mutica,andthebryozoansWatersiporasubtorquataandBugulaneritina.Anotablerecordwasalso madeforthecolonialascidianBotrylloidesperspicuum,whichisnotknowntobeestablishedinSanta Barbaraasyet.

34   Forthe49othervesselssampled,weencounteredarangeofzeroto72differenttaxaonvessels(Fig. 15).Tenvesselshadmorethan30speciesintheirbiofoulingcommunities,whiletheaveragewas16 taxa.Bryozoans,mobilecrustaceans(includingisopodsandamphipods),andascidianswerethemost frequentlysampledtaxonomicgroups(Fig.16)whilepolychaetesandbarnacleswerealsorelativelywell representedamongsamples.  

14 12 10 vessels

 8 of  6 4

number 2 0 012Ͳ56Ͳ10 11Ͳ20 21Ͳ30 31Ͳ40 40Ͳ50 >50 numberofdistinctmorphoͲspeciesperboat  Figure15.Initialestimatesofspeciesrichnesson49transientboatssampledinSanDiegoandSantaBarbara. TheseestimatesarebasedondistinctmorphoͲtaxaandshowthat7vesselshadserobiota,twohadmorethan 50morphoͲspecies,andthehighestfrequencywasfor11Ͳ20species.    Thecurrentlistof119speciesidentifiedbyourgroupandbytaxonomistsforthesevesselsisshownin supplementarymaterial(Appendix4).Amongthesespecies,37%werenativetoCaliforniaand29% werenonͲnativebuthavebeendescribedfrombaysalongthecoastpreviously.Afurther26%could onlybeidentifiedtogenuslevelbecausetheywerejuvenilesorlackingtaxonomiccharacterstoidentify further,andothermembersofthesegeneraareknowntobepresentinCalifornia.Thebiogeographyof sevenspecies(6%)isundeterminedatpresentandthesespecieswereconsideredtobecryptogenicfor now.  AnotablerecordwasthebryozoanHippoporinaindica,whichhasnotbeenidentifiedfromthewest coastofNorthAmericapreviously.Ataxonomicexpertprovideddetailsofanewspecieswithinthe polychaetegenusBranchioma,whichhasonlyrecentlybeendescribedfromthewestcoast(since2008) andislistedasBranchiommasp.2Harris(thetaxonomyofthisgenusneedsrevisionandnospecies namesareprovidedasyet;L.Harris,pers.comm.).Anotherpotentiallynewrecordisforthepolychaete Syllissp.37Harris,whichexhibitedanovelcombinationofpigmentpatternandmorphologicalfeatures thatsuggestsitmaybeanewrecordfortheregion.Otherspeciesthatareofinterestincludethe ascidianBotrylloidesperspicuumandpolychaetePileolariatiaratawhichhaveonlybeendescribedfrom limitedrangesinSouthernCaliforniatodate.AsmallbladeofUndariapinnatifida,alargekelpthathas invadednumerouslocationsinCaliforniaandaroundtheworld,wasalsofoundonaboathullinSan Diego,alocationinwhichitisnotyetreportedtobeestablished.  

35     

180  160

of Arthropoda  140 120

number 100  specimens

 Algae 80 Cnidaria 60 Mollusca 40 distinct

cumulative 20 0

 Figure16.Numbersofspecimenswithinbroadertaxonomicgroupssampledfromhullfoulingof49boatsin SantaBarbaraandSanDiego.Thesedatareflectthetotalnumbersofspecimenscollectedfrom49vessels (n=718).Thesamespeciescanbecountedseveraltimesinthesedatabasedonthenumberofvesselsthey werecollectedfrom.Almost120differentspecieshavebeenidentifiedtodate.   Aminorityofjustover14%ofthe49transientvesselssampledduringthisprojecthadnodetectable macroͲfaunaormacroͲalgae(Fig.17).Usingcategoricalabundanceestimates,wefoundthat22%of vesselshadonlyisolatedindividualsontheirsubmergedsurfaces,whileafurther12%hadbetween elevenand100organisms.Themostcommonextentcategoryrecordedcomprisedofboatswith between101and1000organisms(26.5%ofvessels).Wefounditsomewhatsurprisingthatnearly25% oftransientvesselssampledhadmorethan1000organisms,especiallythevesselsattheupperendof thedistributionthathadhundredsͲofͲthousandsofindividualsandcolonies(Fig.17).Theseextensive biofoulingassemblagesaremoreoftenassociatedwithresidentorlaidupvessels,butweobservedfive vesselswithover10,000organismseach,suggestingthatasignificantminorityofvesselstransportvery largequantitiesofbiotafromharbortoharborontheircoastaljourneys.Oneofthetransientfishing boatshadasimilarlevelofbiofoulingcover. 

36  30 25 boats  20 15 sampled  of  10 5

percent 0

categoricalabundanceestimate  Figure17.Frequencyoftransientvesselswithdifferentbiotaabundancecategories.Thisplotshowsthe proportionofsampledboatsthatwereassignedtooneofsevenabundancecategories.Underwater observationsandsubsequentassessmentsofimageswereusedtoassigneachboatintoalogͲscalecategoryof organismabundance.  Asrecordedinoursandothers’previousstudies,biofoulingtendedtooccurmoreoftenonnicheareas ofvesselsratherthanhullsurfaces.Thiswascertainlytrueforvesselsthatwererecordedinthelower abundancecategories(1Ͳ10,11Ͳ100,101Ͳ1000organisms;Fig.18).Vesselsinthehigherabundance categories,however,tendedtohavefoulingonbothhullandnonͲhullsurfaces.Onthemostheavily fouledvessels,therewasanincreaseintheaveragepercentcoveroffoulingonhulls,butalsoawide variabilityinfoulingonhulls(Fig.18),reflectingthepatchynatureoffoulingcoveronlaminarsurfacesof heavilyfouledboats. 

 Figure18.Comparisonofbiofoulingpercentcoveronhullswithwholevesselbiofoulingextent.Thecategories offoulingabundancecorrespondtothesevencategoriesoutlinedinfigure17(whererank1correspondsto abundance1to10,11to100,andsoon).Thepercentoverofbiofoulingonhullstendstoincreaseon extensivelyfouledvessels,butvariationinpercentcoveralsoincreases.

37    For46ofthe49sampledvessels,wehadcorrespondingquestionnairedatawithresponseson antifoulingpaintage.Antifoulingpainthadbeenappliedwithinthreeyearsofsamplingforamajorityof vessels(87%).Therewasasignificantcorrelationbetweenantifoulingpaintageandabundanceof foulingorganismsonhulls(Pearsoncorrelationr=0.514,p<0.001;Fig.19).Therewasalsoamajorityof vesseloperatorsreportingsomemaintenanceactivity(hullcleaningorpaintapplication)within12 monthsofsampling(90%),butthecorrelationbetweenbiofoulingextentanddurationsincelast maintenancewasnotsignificant(r=0.265,p>0.05).   

80

60 (months)  age  40 paint 

20 antifouling 0 0123456 rankofabundancecategories  Figure19.Comparisonofbiofoulingabundancewithreportedageofantifoulingpaint.Thecategoriesoffouling abundancecorrespondtothesevencategoriesoutlinedinFigure17and18(whererank1correspondsto abundance1to10andsoon).Therewasasignificantcorrelationbetweenpaintageandextentoffouling(see text).   4.3ImpactsofCaliforniaAISwithfishingvesselbiofoulingasapossiblevector  Theliteraturesearchesforimpactsstudieswereconductedfor95biofoulingspecies(thatareassociated withfishingvesselsandotherbiofoulingvectors).Thisincluded53crustaceans,22molluscs,and20 algae.Afterthestepwiseprocessofeliminatingirrelevantpapers,therewere134paperswithimpact information(fromaroundtheworld,notjustCalifornia)for22oftheinitial95species.The22species included7algae,9crustaceaand6molluscs(Table2).Theearlieststudyretrievedwaspublishedin 1926(Miller,1926)butalmost60%oftheimpactstudies(n=80)werepublishedsince2006.  Thenumberofrelevantpapersperspeciesrangedfrom1to30withalgae,Sargassummuticum,having themost.OtherspecieswithalargenumberofimpactpapersincludedthealgaCodiumfragilessp fragile(n=25),thegreencrabCarcinusmaenas(n=24)andthe(shipworm)molluscTeredobartschi (n=17).OneͲthird(34%)ofimpactpapersdescribedstudiesconductedintheUSA,and14ofthesewere conductedinCalifornia. 

38   ThemostcommontypeofimpactreportedinthesestudiesdescribedimpactsofnonͲnativespecieson nativespecies(56%).Impactstonativecommunities(12%),ecosystemprocesses(7%),andthewhole community(native/nonͲnativenotspecified,5%)werealsoreportedinthesepapers.Almosthalfofthe studies(48%)werebasedonexperimentalanalyses,includingfieldandlaboratoryexperiments,while manyoftheremainingstudiesmeasuredimpactswithoutmanipulations(40%)orreportedsimple observations(11%).  DifferenttypesofimpactswererecordedwithinandamongAIS.Forexample,theimpactsofthealgae Sargassummuticum,thefoulingspeciesforwhichthegreatestnumberofstudieswereretrieved,were firststudiedin1982inCalifornia(Ambrose&Nelson,1982).Thiswas38yearsafterthespecieshad beenfirstrecordedoutsideofitsnativerange,inBritishColumbia(Wallentinus,1999).Furtherstudies ofthisspecieshavebeenconductedfromseveralcoastlinesinEurope(includingAtlanticcoastlinesand theNorthSea)andbothcoastsofNorthAmerica.Thearticlesrangefromdescribingasingleimpacton asinglespecies,mainlytheAIS’simpactonnativespecies(e.g.,Ambrose&Nelson,1982),to multifacetedevaluationsofabundance,speciesrichness,diversity,evennessandcompositionof differentcomponentsoftheimpactedcommunity(e.g.,mobileepifauna,sessileepifauna,epibiota; Harriesetal.,2007).WhilemoststudiesontheimpactsofS.muticumwerefocusedonanumerical effectonnativespeciespopulations,othersincludedeffectsonbiogeochemistry,physicalhabitatand nonͲnumericalnativespeciesresponses(e.g.abehavioralorphysiologicalresponses).  The14studiesofbiofoulingspeciesimpactswereconductedinCaliforniaandinvolvedsevenspecies; Sargassummuticum,Batillariaattramentaria,Musculistasenhousia,Mytilusgalloprovincialis,Teredo navalis,Carcinusmaenas,andSphaeromaquoyanum.ThestudiesspanthecoastbetweenBodegaBay andSanDiegoBay,includingSanFranciscoBay,BolinasLagoonandSantaCatalinaIsland.Thelag betweenaspeciesbeingfirstrecordedinCaliforniaandthefirstimpactstudybeingpublishedvaried between10years(forC.maenas)and103years(forSphaeromaquoyanum).Themeanlagtimewas41 years.Theimpactedentitiesincludednativespecies(moststudies),ecosystemprocesses,and anthropogenicconcerns(e.g.economicimpacts).Forexample,theoneimpactstudyinCaliforniaonthe woodboringmollusc,Teredonavalis,examinedtheeconomicimpactofthespeciesonmaritime infrastructure.  Itisimportanttorememberthatthesesummaryresultsreflectastandardizedreviewapproachfor threetaxaonly.ThereareimpactsliteratureforthesetaxathatwerenotreturnedinasearchͲengine basedreview,andtherearemanyotherspeciesforwhichimpactdatahavebeenreported(see discussion)

39   Table2.ListofbiofoulingAIS,withfishingvesselsasapossiblevector,forwhichimpactsdatawerereturned duringastandardizedliteraturesearch.Thesearchofimpactsliteratureyieldeddataforthe22speciesof crustacean,mollusc,andalgae.ThestepͲbyͲstepreductioninrelevantpapersisshownfortheinitialoutput resultfromBIOSIS(initialresult),thosethathadrelevanttitles,andultimatelythosefromwhichdatacouldbe gleaned.

Initial Relevent Articleswith Taxon Species results titles impactsdata

Algae Sargassummuticum 132 71 30 Algae Codiumfragilesspfragile 137 68 25 Algae Undariapinnatifida 116 50 9 Algae Gracilariavermiculophylla 34 14 6 Algae Grateloupiaturuturu 32 9 2 Algae Neosiphoniaharveyi 18 4 2 Algae Dasyasessilis 41 1 Molluscs Mytilusgalloprovincialis 278 62 17 Molluscs Crassostreagigas 415 42 12 Molluscs Musculistasenhousia 56 13 8 Molluscs Batillariaattramentaria 14 4 4 Molluscs Potamopyrgusantipodarum 136 21 2 Molluscs Teredonavalis 16 7 1 Crustaceans Carcinusmaenas 394 149 24 Crustaceans Mytilicolaorientalis 10 6 5 Crustaceans Amphibalanusimprovisus 51 10 3 Crustaceans Rhithropanopeusharrisii 74 13 3 Crustaceans Sphaeromasp. 45 6 3 Crustaceans Caprellamutica 42 11 2 Crustaceans Sphaeromaquoianum 14 4 2 Crustaceans Caprellascaura 71 1 Crustaceans Amphibalanusamphitrite 100 11 1    4.4Vectordisruption  Inthissection,weconductanevaluationofthevectorprocessandthetoolsthatexisttodisruptthis process.Thisevaluationofexistingpracticesissplitintothescaleofanindividualvesselandatthescale ofstatemanagementpolicies.Wediscussthesemanagementissueswithrespecttofutureprospects andrecommendationsinthediscussionsectionofthisreport.  CriticalcontrolpointsinthebiofoulingvectorprocessandvesselͲscalemanagement Thevectorprocessthatsuccessfullytransfersbiofoulingorganismsfromonelocationtoanotherisquite straightforwardwhenconsideredfromthepointofviewofonevesseltransitratherthanacomplex networkofoverlappingvectorsintimeandspace.ThestraightforwardvesselͲlevelprocessisalsothe levelatwhichmanagementactionhappens,regardlessofthelargerscalepoliciesgoverningthataction

40  (e.g.anepidemiologicalmodelofcontrolatthestatelevelwouldstillresultinactiononthevessel level).Thevectorprocessforfishingvessels(andotherbiofoulingvectors)hasthreestepsandthree importantpointswheremanagementcanacttoimpedetheprogressoftransferringspecies(Fig.20). Thecriticalpointsofinteractionbetweenorganismsandthevesseloccuratcolonization,translocation, andrelease.Ateitherendoftheprocess,organismbehaviordeterminestheinitialcontactwiththe vectorandtheoutcomeafterarrivalatarecipientlocation.Thecriticalcontrolpointsintheprocess relatetocolonizationprevention,transferdisruption,andreleasecontainment.(Note:thisisrelatedto theHazardAnalysis&CriticalControlPointsApproachthatisincreasinglybeingadoptedinAIS management.WedidnotusetheexplicittermHACCPinthisstudybecausewefollowedthevector analysisapproachofRuiz&Carlton(2003)morethananyexplicitHACCPapproach).Eachofthesesteps intheprocessisalsoafilterthatoccursinnaturewithoutadditionalinterventionbypeople(e.g.the transferstagecanexertdislodgmentforcesonbiota).Additionaldisruptionthoughmanagementcan enhancethefilterandgreatlyreducethenumbersofsuccessfulvectorevents. 

Retention Source Survival Initial Propagules Translocation Introduction

Colonization Release Attach Spawn Adhere Clone Cling Reproduce Dislodge Move  Figure20.Thebiofoulingvectorprocess.Therearethreesteps(arrows)involvedinthesuccessfultransferof organismsfromonelocationtoanother.Thevessel’scomponentsareinblackandtheorganisminteractions withthevesselareingray.Attheoutset,sourcepopulationsoforganismsmustinteractinspaceandtimewith thevectorandbehaveinawaythatallowsthemtotakeadvantageofcolonizablespace.Uponcolonization,the organismsmustattach,adhereorotherwiseclingontothevesseldirectlyortootherorganismsalready attached.Aftercolonization,organismsmustwithstandanydisturbancesthatcanaffectavesselpriorto departureandduringtransit,andmustbeabletoretainitspositiononthevessel.Uponarrivalatadestination, thetiminginrelationtothespeciesabilitytoreleasefromthevesseliscritical.Speciescandisembark themselves,throughdislodgement,fragmenting,orsimplymovingortheymustreleasepropagules.Atthis point,thevectorprocesshassuccessfullytransferredtheorganisms,buttheorganismshaveadditionalhurdles afterhereafterinordertobecomeestablished.  Theoptionsforinterruptingthevectoreventateachpointoftheprocessarenumerousand summarizedinTable3.Colonizationpreventionmethodsincludeseparatingtheboatfromthewater, separatingitfrompropaguleswhileitremainsinwater,andapplying(andmaintaining)anantifouling surfacethatallowsorganismstocomeintocontactwiththevesselbutpreventstheirattachmenttoit. Theseapproachesvaryintheirutilityforfishingboats(frombasicallynouptaketofleetwide application;Table3)andvaryintheirconvenienceandexpense.  Disruptingtransfersafterthevesselhasbeencolonizedisusuallyaresponsetoafirstphasefailure. TheseincludeinͲwatercleaningbyownersorprofessionalserviceproviders,andsometimesutilizing

41  freshwaterharborstoactasabiocidethatkillsmarineorganisms.Theintensityoftheseapplicationsis thekeytotheirsuccess;partialcleaning,orhullonlycleaning,doesoftennotdisruptnichearea transferswhilefreshwaterimmersionforshortdurationsisoflittleconsequence.Infact,freshwater immersionisreallyonlyapplicabletoboatswithhomeportsinfreshwaterthattraveltomarinewaters andback,whichappliestoasmallminorityofvesselsstatewide,butmaybesignificantatthelocalscale. Inaddition,thereisonetransferdisruptorthatisdesignedtoworkwiththeexistingvectorfilteratthis pointintheprocess.FoulͲreleasecoatingsarenotdesignedtopreventcolonizationbuttoallow attachmentbyspeciesandprovidesuchlimitedadherenceforcethatorganismssloughoffavessel almostimmediatelyafterdeparture.Thisprocessenhancesthesloughingeffectthatexistsfor biofouling,regardlessofpaintapplication,whenvesselsareunderway.  Thefinalstepintheprocessinvolvescontainmentofbiotaafteritstransfertoarecipientharbor.Atthis pointinalinearconceptualizationofthesteps,preventionofspeciesreleasesfromthevesselto surroundinghabitatsislargelyunknowninthecaseofregularboatingandfishingvesselactivities.Ithas onlybeentriggeredintheeventofaspecifichighͲprofileincursionthathascometotheattentionof concernedcitizensoragencies(Hayesetal.,2005).TheoptionsaresimplytocleaninͲwateroroutͲofͲ waterwhileensuringtoretainallpropagulesthatareremovedfromthevesselanddisposeofthemon land.Anotheroptionforanagencywithauthoritytopreventunwantedincursionistodemand immediatedeparture,althoughagain,thisismoreofanemergencyresponsethanagenerallyapplied tool(anditisnotboatoperatordriven).  Anadditionalconsiderationforvectordisruptionisthatthebiofoulingvectordoesnotactsolelyasa sourceͲtoͲpointvector,asislargelythecaseforballastwater(forexample).Biofoulingisa concatenationvectorwithorganismsaccumulating,anddispersing,overtimethroughoutthelifeͲcycle ofaninterͲdrydockingperiod.Thestraightlineprocessdescribedinfigure20couldjustaseasilybe presentedasaloop,withtheendpointofonevoyageactingsimultaneouslyasthestartingpointofthe next,andspeciescolonizationhappeningcontinuouslyduringperiodsofinactivity.Becauseofthis, applicationsthatareavailableforvectordisruptionmustbecarriedoutfairlycontinuouslyiftheefficacy oftheprimarymethod(generallyantifoulingpaint)beginstosubside.Also,disruptiontoolsthatare designedtooperateinconcertwiththenaturalfilteringeffectofthevectorprocessareprobablymore convenientandmorereadilymaintainedthanonesthatreacttothefailureofanapplicationintendedto affectapriorstepintheprocess.  Table3.Products,servicesandstrategiesforapplyingmanagementefforttocriticalcontrolpointsinthefishing vesselbiofoulingvector.Thetableshowsthemethods,benefitsandissuesrelatedtoapplicationsoftoolsto disruptabiofoulingvectortransferbyfishingvessels. Action Method Benefits Issues Prevent Keeptheboaton Ͳ Separatingthe Ͳ Expense species ahoistorstored vesselfromthe Ͳ Inconvenience colonization onland wateristhemost Ͳ Impracticalformostfishingboats effective Ͳ InͲwaterhoistsareunheardoffor preventative largefishingvessels(recreational measure vesselsonly)  Useaskirtor Ͳ Relativelysimple Ͳ Expense containeraround tool Ͳ Inconvenience vesselatberth Ͳ Allowsforvesselsto Ͳ Thistreatmentismoreeffectiveif (e.g.boatbath) remaininwater freshwaterorchlorineisused (moreconvenient insidethebath,butthishasother

42  thanabove) environmentalimplicationsand Ͳ Skirtalsoremainsin maybeprohibitedinsome waterforconvenient locations reͲapplicationafter Ͳ Ifnotmaintained,theskirts voyages becomefouledontheoutside, addingtothemaintenanceburden Ͳ Ifnotmaintained,theskirtssag andsink(becomeineffective) Ͳ Unheardofforlargerfishing vessels  Maintaina Ͳ Antifoulingpaintis Ͳ Expense pristine themostcommonly Ͳ Maintenanceburden(reͲ antifouling availableprevention applicationsmaybenecessary) coatingwithtoxic optionmakingit Ͳ Interimmeasuresareusually agents(including readilyavailable required(inͲwatercleaning) nicheareas) Ͳ Convenience Ͳ Requiresregularvesselusage becausestationaryperiodscan compromiseefficacy Ͳ Pollution Ͳ Toxicityissues(e.g.copper) conflictwithotherenvironmental management Disrupta UseanonͲtoxic Ͳ Preventspollution Ͳ Expense transferafter foulͲrelease Ͳ Doesnotconflict Ͳ Maintenanceburden(reͲ colonization coating withother applications) hasoccurred environmental Ͳ Interimmeasuresrequired(soft regulations scrubs) Ͳ Convenience Ͳ Partialefficacymaycontributeto AISspread(ifdislodgement doesn’toccursoonafter departure)  CleanhullinͲ Ͳ Straightforward Ͳ Applicationrigorvarieswidely waterbyowner Ͳ Inexpensive Ͳ Nicheareasoftenignored Ͳ Awareness/trainingusually neededtoimproveefficacy Ͳ Usuallylesseffectivethan professionalservice Ͳ Releasesspecies/propagulesinto theenvironment Ͳ Mustbedoneregularly(cleanͲ beforeͲyouͲgo)toensure propagulereleasedoesnot includetransferredbiota  CleanhullinͲ Ͳ Convenience Ͳ Expense waterby Ͳ Usuallymore Ͳ Limitedavailabilityofdiver professional effectivethan servicesinbusyharbors service amateurcleaning Ͳ Applicationrigorgenerallybetter thanamateurcleaningbutstill

43  varies Ͳ Nicheareasnotalwaystargeted Ͳ Releasesspecies/propagulesinto theenvironment Ͳ Mustbedoneregularly(cleanͲ beforeͲyouͲgo)toensure propagulereleasedoesnot includetransferredbiota  Usefreshwater Ͳ Generally Ͳ Notpracticalforvesselsthatdo harbors inconvenient notfrequentFWharbors Ͳ Haphazardstrategy Ͳ ShorttermFWexposure(days) Ͳ Usuallyworksin hasvariableefficacy concertwithother Ͳ FullFWratherthanlowsalinityis methodsabovefor oftenrequiredforefficacy boatswithFWhome Ͳ EfficacyoftenoverͲestimatedby ports boatoperators Containa Cleanhullin Ͳ Canbeeffectiveif Ͳ Thecontainmentpartofthis releaseafter water(byowner conductedproperly processisgenerally(always?)not transferhas orprofessional) Ͳ Relatively adopted occurred inexpensive Ͳ CleaninginͲwatercancause organismreleases(doingmore harmthangood) Ͳ ContainmentusingnonͲsuction devices(netting)restricts containmenttolargerorganisms Ͳ Suctiondevicesareexpensiveand notwidelyused Ͳ Evensuctiondevicecleaningisnot 100%effective(atcontainmentof propagulesfromtheenvironment  CleanhulloutͲofͲ Ͳ Canbeeffectiveif Ͳ Expensive water(byowner conductedproperly Ͳ Shorelinecleaning(bytraileror orprofessionally) Ͳ Allowsforother hoist)mustalsoincludea maintenanceissues containmentstrategy tobeattendedto Ͳ Drydocksmusttreatallsolidand (e.g.painttouchͲ liquideffluent(treatmentorlandͲ ups) fill)  Ͳ Availabilityoffacilitiescanbevery limitedatmanyharbors Ͳ Largervesselsrequireprofessional work  Therangeofoptions(inTable3)doesprovideflexibilityforboatownerstoadapttheirstrategiesto theirpreferredlevelsofconvenienceandexpense.However,thereisno‘silverbullet’approachthat doesnotrequireupkeepandcontinuousreͲevaluationbyboatownerstomaintainapristine(unͲfouled) hullandnicheareas.Technologicaladvancesinantifoulingpainttendtoprovidearangeofpainttypes thatcanbetailoredtovesselusagepatterns,butthemostcommonlyappliedpaints,usingcopperasan activeantifoulingagent,mustbemaintainedandareincreasinglycomingintoconflictwithother

44  environmentalregulations(asoccurredwithtributyltinpaintsinthepast).Thelongertermefficacyof newgenerationfoulͲreleasepaintsinregardstospeciestransfersremainsanopenquestion,evenifthis advanceinpainttechnologyhelpstocounteracttheconflictbetweenvectordisruptionand water/sedimentquality.  Finally,therearealsoothernonͲfoulingrelatedspeciesthatcanbetransferredasaresultoffishing, eitherfromboatsorontheshore.FishinggearcanactasamechanismforspreadingsomemarineAIS, ashasbeenimpliedfortheinvasivegreenalgaeCaulerpataxifoliaintheMediterranean(Relinietal., 2000)andthecolonialascidianDidemnumvexillumontheEastCoastoftheU.S.(Bullardetal.,2007).It isconsideredrelativelyminorvectorbutmaybeimportantforsomespeciesincertaincontexts.Release ofbaitspeciesisanotherpotentialvectorandthefinalcrucialstepinalargervectorprocesswhereby bait,oftenshippedinfromoutsideofthestate,isreleasedtotheenvironmentbyfishermen.Wehave notconsideredthesesubͲvectorsextensivelyinthisreportbecausewewereunabletogarnerdataon theseissuesfromfishermenanditisthoughttobeamuchlesservectorthantheprimarybiofouling mechanism.Also,inthecontextofbait,thesespeciesdonotresultfromthefishingvesselvector(but thefishermenthemselves)andthebaitvectoristhesubjectofanotherstudyinthisoverallsixͲvector project.However,theremaybespeciesͲspecifictransferassociationswithbaitandgearthatwarrant furtherinvestigationbecausethereislikelysomeriskattachedtothesesubͲvectors.  Statescalemanagement Whilethearrayoftoolsavailabletotakeadvantageofthevectorprocessinordertodisruptspecies transfersislarge,itisclearfromthehistoryofAISintroductionstothestate,andoursamplingof vectors,thatthesetoolsarenotbeingappliedeffectivelyoverthelargescaleofvesselsinoperation. Thisistrueofbothrecreationalandfishingvessels.Unfortunately,thelimitedparticipationoffishing boatoperatorswithourquestionnaireandunderwatersurveysmeanswedonotyethaveasubstantial datasetonanyspecificdifferencesregardingmaintenancethataffectsfishingvesselsbutnot recreationalboats.Ourconversationswithsomefishermensuggestedthathullmaintenanceconcerns werenotmoreacuteforfishingboatoperatorsthanforrecreationalboats.Afewfishermenhavesaid thathullcleaningandreͲapplicationofantifoulingpaintislargelybasedontheirinterpretationofneed basedonfuelefficiency,enginestrain,orvesselspeed.ThissuggeststhatactionissometimestakenreͲ activelyratherthanproͲactively,butwedonothaveadatasettoevaluatetheextenttowhichthisis trueacrossapopulationoffishboatoperators.Itshouldalsobestatedthatsomerecreationalboaters applythesame‘needsͲmust’strategy.  TheState’sexistingregulationsformanagingbiofoulingvectorsarelargelyconfinedtocommercial ships.TheStateLandsCommissionmanagescommercialshipbiofouling(andballastwater)througha shipͲfundedmarineinvasivespeciesprogram (http://www.slc.ca.gov/spec_pub/mfd/ballast_water/Ballast_Water_Default.html).Thisagencymakes rulesregardingtherequiredpracticestoreduceandpreventspeciestransfersintoandwithinthestate, throughanopenprocessofstakeholderͲdrivendeliberations.Existingandproposedrulesincludethe maintenanceofabiofoulingmanagementlogbookoneachship,thesubmissionofahullreportingform (annually),thedurationofinterͲdrydockingperiods,andlimitsontheextenttowhichbiofoulingcan developoverhullandnicheareasurfaces.Manyoftheserulescoincidewithmandatoryfederaland classificationsocietyrequirements.ShipsthathavehadlonglayͲupperiodsarealsosubjectto additionalassessmentsbecauseoftheirhigherriskoftransferringspeciesintothestate.  TheStateLandsCommissionprogramalsofundsresearchtoevaluatevectoractivityandmanagement efficacyofthecommercialfleetwhilethefundinginstrumentalsosupportscoastalmonitoringforAIS.

45  Theremitforthisprogramisstrictlylimitedtovesselsover300grossweighttons(thatcancarryballast water).  Inadditiontothestatemanagementofcommercialshipbiofouling,theU.S.CoastGuardmanagesship biofoulingatthefederallevel,focusingonhullhusbandryandrequiringanunspecifiedregularityof cleaningonhullandothersurfaces(CodeofFederalRegulations,Section151.2035(5)and(6)).The InternationalMaritimeOrganization(IMO)providesbestpracticeguidelinestotheglobalshippingfleet thatmaybecomemandatoryinfuture(Davidson&Simkanin,2012).  TherearenoequivalentprogramsorpoliciesinplaceinthestatetomanagenonͲlargecommercialship biofoulingvectors.  5. DISCUSSION  5.1MarineintroductionsinCaliforniaandtheroleoffishingvessels  FishingvesselsareanimportantmaritimevectorinCaliforniabecausetheymaybeassociatedwith transfersof74%oftheAIScurrentlyestablishedonthestate’scoast.Theyalsonumberinthe thousands,makearrivalstoharborsannuallyinthetensofthousands,createstrongconnectionsamong harborsthatothervectorsdonot,travelthelengthofthestate’scoastandbeyond,mayplayarolein AISspreadbyfishinggear,andmayactasanimportantfinalstepinthecauseofbaitAISintroductions. AlloftheAISthatwereassociatedwiththefishingvesselvectorinthestatecanbeconsidered polyvectic–speciesthatcanbetransferredbyotherfoulingandnonͲfoulingvectors–andthe‘possible vector’designationisrequiredbecauseitisdifficulttoisolateasinglevectorformostspecies,especially forspecieslinkedtobiofouling.Nonetheless,theoverlapbetweenexistingAISdistributionsandfishing vesselharbors,combinedwithabetterunderstandingofvoyagesandbiotaassociatedwithcoastally transitingboats,suggestsfishingvesselshavetransferredAISinthepastandwillcontinuetodoso.  FishingvesselsareunlikelytoberesponsibleforlongͲdistancetransͲandinterͲoceanicintroductions enteringthestate,however,becausetheseboats’voyagestendtobeintraͲcoastalinnature.These includedomesticvesselsarrivingfromMexico(andpossiblyfarthersouth)andthroughouttheNE PacificasfarnorthasAlaska(Ashtonetal.,2010).FirstrecordsofAISinCaliforniatendtobefirst recordsfortheNEPacific(Ruizetal.,2011a),suggestingthatlongͲdistanceprimaryandsecondary introductionstothestatearebroughtbyothervectors,ratherthanfishingvesseltransfersfrom adjacentterritorialwaters.Therangeanddomesticnatureoffishingvesselsoperatingonthecoast appearstobeaconsistenthistoricalfeatureoffishingfleetsinCalifornia,andcertainlyby1976,withthe passageoftheMagnusonͲStevensFisheryConservationandManagementActthatclaimedjurisdiction overfisheriesextending200milesoffshore(McEvoy,1986),California’sfishingvesseltrafficwas exclusivelyAmericantraffic.Intheabsenceofotherinformationregardingforeignfishing(orforeignͲ travelingdomestic)vesselsarrivingonthecoast,itappearsthatAISassociatedwithfishingvesselsare1) thosefromoutsidetheNEPacificbroughtinbyothervectors,or2)thosethataretransferredoutsideof theirnativeNEPacificrangeintoanonͲnativeNEPacificrange(intraͲcoastalprimaryinvasions).  ThisdistinctionbetweenpotentialsourcesofAISisimportantbecauseitprovidesastarkcontrast betweenfishingvesselbiofoulingandotherbiofoulingvectorsonthecoast.Commercialships,toa largeextent,involvearrivalstothestatefrommuchfartherafield.Theyaremorelikelythanfishing vesselstotransferAISfromtheothersideofthePacific,orthroughthePanamaCanal.Subsequentto

46  theseinitialestablishmentsinthestateoradjacentcoastalwaters,fishingvesselscanactaspartofthe vectorratcheteffectfortheseAISandcausewiderangingsecondaryspread(Davidsonetal.,2010).The effectisafunctionofmultiplevectorscoͲoccurringinspaceandtime(sharingthesamebay)withAIS populationsthatmaybebroughtinbyonevectorbecoming‘available’toothervectors.Fromthis juncture,thedifferentialpatternsofoutwardvoyagesfromthefocalbaymultiplytheopportunitiesfor rangeexpansionbytheAISusingseveraldifferentvectors.Itisthroughthismechanismthatfishing vesselsaremostlikelytohavecontributedtothepatternsofAISdistributionsinthestate.  Fishingvesselsconnectbaysviabiofoulingvectorsthatareunconnectedbycommercialvesselsand possiblyofferuniqueconnectionsrelativetorecreationalboatstoo.Althoughresidentboats outnumberedtransientonesinthefishingfleet,thetransientboatsmadeupahigherproportionof vesselsperharbor(acrossfouryears)thanresidentboats.Thiswasthefirstindicationofstrong connectivityamongbays.BayͲtoͲbayconnectionstendedtobestrongestforadjacentsitesratherthan longͲdistanceones,althoughdirectandindirectlinksfromoneendofthestatetoanotherdidoccur. Thisdifferentiatessmallboatvesselfluxpatternsfromlargeshiponeswherebyahigherintensityof shortstepwisecoastallinkagesdevelopamongbays(fishing)withanoverlappinglongerdistance connectionbetweenmajorbays(shipping).Thelackofastandardizedstatewidedatasourcefor recreationalvesselsprecludesaformalcomparisonwithfishingvesselsasyet(Ashtonetal.,inreview), butthereislikelytobesignificantdifferencesintheintensityofoverlapforfishingandrecreational boats,rangingfromzerotohighsimilarity.Thisdistinctionwouldyieldusefulinformationforuntangling someinvasionhistoriesandprospectivemanagementoptions(spatialfocus)betweenfishingand recreationalboats.  Otherdifferencesamongbiofoulingvectors,asidefromtheobviousdifferenceofvesselsize(for commercialshipsversustheothertwovesseltypes),arethenumericalcomparisonsofvesselflux.The statereceivesaround5,000Ͳ6,000commercialshiparrivalsperyear,withtwiceasmanyoverseas arrivalsascoastalones(Davidsonetal2006).Morethan800,000recreationalboatswereregisteredin Californiain2010(Ashtonetal.,inreview).Fishingvessellandingsoccuratarateofapproximately 50,000peryearacrossthestatebyapproximately2400differentvessels.Thereisnosuchthingasa ‘resident’commercialvesselunlessitislaidͲup,butthisstudyindicatedthat52%offishingvesselstend toarrivetoonehomeportonly(residentboats).Thiscomparestoarateof80Ͳ50%ofrecreational boatersacrossdifferentbaysthatreportednovoyagestoharborsoutsideoftheirhomebay(Ashtonet al.,inreview).Thus,forthistriumvirateofvesseltypes,fishingvesselsmostlikelyranksecondfor arrivals(afterrecreationalboats)andprobablysecondfortransiencyrateofthefleet(afterships).Of course,afullscalecomparisonofallthreevesseltypeswouldrequireabiota×vessel×voyage comparisonoffleets,whichisnotyetpossibleforthiscoastfromexistingdata.  TemporalvariationisapartofthevesselfluxpatternforCalifornia’sfishingfleet,thoughitisn’tclear howitinteractswithAIStransfersordistributions.Ourpreviouswork(Ashtonetal.,2010)foundthat longdistancecoastwisevoyagestosoutheastAlaskafromthesouth(California–BritishColumbia) tendedtooccurduringatimeofpeakspawningforWestCoastmarineinvertebrates(ApriltoJune, Reitzeletal.,[2004]).ThistemporaloverlapmayextendtoAIS,exposingthesenorthwardmoving vectorstoAISpropagulesattheopportunetimefortheirvectordispersal.ForCalifornia’sfishingfleet, thereisseasonalityinthearrivalpatternsofsomeharborsandnotatothers,andthereisalsointerͲ annualvariationinthevoyagepatternsexhibitedbyindividualvessels(suchastheverytransientboat highlightedinFig.12).Thiscanbepartiallyexplainedbytheunpredictabilityofsomefisheries,whichis asourceofworryinginstabilityinfishingcommunities(Pomeroyetal.,2010).Temporalpatternsin fishingvesselmovements,withageneralreductioninactivityinAprilbutwithoutmajorseasonal

47  fluctuationsatmanyports,contrastsquitestarklywithrecreationalvesselsthathaveaveryseasonal aspecttotheirtempothroughouttheyear(Ashtonetal.,inreview).Thismaybeusefulinformationfor adivisionofeffortacrosstheyear(targetingfishingboatsinwinterandrecreationalonesinsummer) foranyoutreachcampaigntargetingbothvesselvectors.  ThehighnumbersofAISinthestatethathavefishingvesselsasapossiblevectorisafunctionofthe diversityoforganismsthathavebeenintroducedtothestatethatarealsomembersofboatfouling communities.Speciesfromfourmajorgroupsofprimarilysessile(attached)organisms–algae, cnidarians,bryozoans,andascidians–couldallbelinkedtotransfersviafishingvessels.Forexample, thearborescentbryozoan,Bugulaneritina,isoneofthemostcommonlyencounteredspeciesinour samplingoforganismsonWestCoastboats.Itisknowntooccurin19differentbaysthroughoutthe statefromSanDiegotoTrinidad,beingfirstrecordedinElkhornSloughin1905(citedfromNEMESIS data).Thisincluded16bayswithfishingvessellandings,elevenofwhichdidnotalsohavecommercial shipping,andtwobaysthathadneitherfishingnorcommercialshipharborsbutdoreceiverecreational vessels.Giventhewidespreadrecordsforthisspeciesinthestate,distributedamongcommercial shippingandnonͲshippinglocations,itisunlikelythatjustoneofthebiofoulingvectorsisresponsible forallofitstransfers.  Mobile(unattached)speciesarealsoacomponentofthefishingvesselvector,includedinfoulingand nonͲfoulingcomponents.TherichestgroupofAISinthestateiscrustaceanswith82species,onlyfour ofwhicharesessile(barnacles).FishingvesselswereapossiblevectorinpartoftheirCaliforniarange for26ofthe29amphipodcrustaceansandfor14of17isopodAIS.Wehaveencounteredsituations wheremobilespecieshaveoutnumberedsessileonesinthebiofoulingcommunitiesoftransientcoastal vessels,butmobiletaxausuallyrequireatleastsomesessilebiofoulingcovertooccur(usingthematrix ofbiogenicsurfacescreatedbysessiletaxa).Thisstudyhighlightedthesometimesextensivecoverof sessilespeciesthatcanoccuronboats,andleadtoveryrichassemblagesofmobiletaxa.Such encounterswith‘floatingreefs’arenotcommonfortransientboats,buttheynumberedalmostasmany inthisstudyastheboatsrecordedwithzerobiota.  ThenonͲfoulingcomponentoffishingvesseltransfersinvolvesincidenceswherefishingvesselscanbe implicatedinaccidentalfisheriesͲrelatedtransfers.Forexample,thecrabRhithropanopeusharissiiis establishedinSanFranciscoBayanddesignatedpolyvectic,includinganonͲfoulingcomponentoffishing vesselsasapossiblevector.IthasalsobeenrecordedinDrake’sEsteroandhasbeenassignedvector unknownatpresent.  Whenweconsiderthecurrentstatusofthevector,itisusefultomovefromthecompletehistorical recordtoexaminerecentyearsofAISfirstdetectionsamongbays.NEMESISrecordsrevealednew distributiondatafor133ofthe278speciesinCaliforniabetweenyears2000Ͳ2009.Theserecordscome from26differentlocations(ofthe32analyzed,Fig.6)and20oftheseincludefishingharbors.Fishing vesselsareapossiblevectorfor87%ofthe318species×baydetections.Itisimportanttoacknowledge thattheserecordsarebasedonlocationswherestudieshaveoccurred(ratherthanastandardizedand eveneffortamongbays)andRuizetal.(2000&2011a)provideaninͲdepthdiscussionofthisandother potentialbiasesinthedata.Nonetheless,itappearsthattheroleoffishingvesselsasapossiblevector forspeciesreͲdistributionsisnotabating.  TherichnesscomponentofAISintroductionsisanimportantmetricofinvasionhistory,andacritical componentofvectoranalysis,buttheconsequencesofAISintroductionsarealsoimportantto understandwhenconsideringoptionstomanagevectors.Tothatend,thereisafocusonimpactofAIS

48  inresourcemanagement.InCalifornia,oneofthemostnotableimpactsoccurredinSanFranciscoBay wherebyacascadeofinvasionsinvolvingtheAsianclam(Corbulaamurensis)andplanktonicmysidand copepodspecieshavealteredthefoodwebandcausedorcontributedtodeclinesinstripedbassand theendangeredDeltaSmelt(Ruizetal.,2011b).Forbiofoulingspecies,theimpactsofascidiansonthe EastCoastofNorthAmerica,includingStyelaclava,Cionaintestinalis,andDidemnumvexillum(all establishedinCalifornia)hasbeenparticularlyacuteonshellfishaquacultureoperations(Arsenaultet al.,2009;Edwards&Leung,2009;Carmanetal.,2010).Witheffectsassignificantastheendangerment ofthreatenedspeciesandthereductionofincomesthatthreatenlivelihoods,itisclearthatimpact evaluationsplayanimportantroleindetermininghowmanagementprioritiesareestablished.  However,theimpactliteratureisveryunevenlydistributedamongspeciesandtendstofocusonasmall subsetofapparentlyimpactfulones(e.g.thereviewresultsforSargassummuticumandCarcinus maenusabove).Ourpreliminaryresultsarealsoconfinedtocertaintaxaandonesearchengineand requireevaluationastowhichstudieswerenotprovidedinsearchresults.Still,aliteraturereview approachtendstobetheonlyapproachthatyieldsdataonacommunityofAISinonelocationbecause therearenobaysthathavehadmultipleinvestigationsofimpactsacrossarangeofAISoverasustained period(theSanFranciscoBayexampleisoneofthemostcomprehensive).Ruizetal.(1999)suggested that<5%ofthespeciesinmostbayshavehadanyimpactevaluationswhatsoever.Ourreviewforthis projectdidhighlightfourspeciesforwhichseveralimpactstudieshadbeencarriedout,butfewofthese werefromCaliforniasites.Goingforward,ifresourcemanagersaretorelyonimpactmetricsofAISto directmanagementefforts,thepaucityofdataonimpactsformostAISwillhavetobeaddressed.  Finally,animportantconsiderationinvectoranalysesistheextenttowhichvectorscrossimportant biogeographicboundaries.Fishingvesselstendtoengageincoastwisetrafficonly,butthisstillinvolves passagethroughdifferentbiogeographicprovinces.Californiastraddlestwomajormarineprovinces, theCalifornianandOregonian,withtheboundarybetweenthemgenerallyconsideredtobePoint Conception.TheseprovinceshavecharacteristicassemblagesofcoͲevolvedmarineanimalsandplants, andithasbeennotedthattheOregonianprovincehasahighdegreeofendemicity(Niesen,2007).A relativelywideenvironmentaltoleranceisconsiderednecessaryforAIStooccuroneithersideofPoint Conceptionboundary,andsuchspeciesareprevalentintheAIScommunityofthestate(basedontheir occurrencenorthandsouthofthispoint).Withinthislargerbiogeographicalframework,foursmallerͲ scalesubͲprovinces(Ensenadian,SouthernCalifornian,Montereyan,andMendocinian)displayaffinities ofspeciesthathighlightamesoͲscalepatternofecologicalcommunitydifferences(Blanchetteetal., 2008).Ofcourse,AIScommunitiesamongbaysdonotbelongtotheseprovinces,andoutercoast ecologicalcommunitiesusuallyformthebasisforthedivisions(ratherthanbays),butfishingboatsare regularlycrossingthesedivideswithbiotathatlackanaturalmeanstodoso.Theexamplesofboats travellingfromsouthernCaliforniatonorthernCalifornia,OregonandWashingtonexemplifiedthe longestdistancetravelersinthisdataset.Thus,fishingvesselscanengageincoastwiseprimary introductionsofspeciesnativetooneprovincebutnotothers.Whencombinedwithoceanwarming, thetrendofapparentnorthwardspreadofAISinCaliforniaandfurthernorthcanbeexpectedto continue(Ruizetal.,2011a).  5.2Prospectsforstatewidefishingvesselvectormanagement  Asnotedattheoutset,thevectormanagementframeworkproposedbyCarltonandRuiz(2003)was adoptedwherepossibleinthisanalysisoffishingvesselvectors:1)Weevaluatedtheinvasionhistoryof Californiaandvectorassociationsofspeciestodeterminethepossibleroleoffishingvesselsintheinitial

49  establishmentofAISinthestate(vectorstrength;74%ofAIScanbeconsideredpossiblefishingboat related);2)Wecharacterizedthevector’scurrentstandingstockofvesselsandtheirrouteandtempo patterns,andthebiotaassociatedwithtransientcoastalvessels;and3)weassessedtheimpact literatureasitrelatestoAISinCaliforniathathavefishingvesselsasapossiblevector(notpartofthe framework);and4)weassessedthecriticalcontrolpoints(Fig.20)todisruptthevectorandthetools Table3)thatcanbeusedcanbetakenadvantageofthem.  ItisimportanttonotewhenconsideringmanagementoptionsthatthefishingvesselvectorofAISisan inadvertentone.Speciesaremovedaroundoftenwithouttheknowledgeofthevesseloperator,and sometimestotheirannoyancebecauseoftheirimpactonvesselefficiency.Thiscontrastswithother vectorswherethelongerpartsofthevectorjourney(e.g.shipmentsofornamentalspeciesfrom anothercontinent)aredesignedwiththeintentionofbringingthespeciesintoCalifornia,andtokeepit alivewhiledoingso.Ofcourse,inthisexample,thecriticalvectorstepofreleaseintotheenvironment muststillbeachievedafterarrivaltothestate,andthisisnotastepthatbiofoulingvectorsmust overcome(biofoulingspeciesarealreadyintherecipientenvironment).However,thepointisthatthe causeofvectortransfers(Carlton&Ruiz,2003)issomethingtoreflectonwhendesigningstrategiesto engagewithendͲusers–managementofaninadvertentvectormaybewellreceivedbytheuser communityifthebenefitstothem(inadditiontopreventingAIStransfers)canbecommunicated.  Anotheritemtonoteaboutastatewidepolicyorprogramthatconsidersfishingvesselvector managementisthatthesizeofthefleetandthelargelywithinͲstateaudiencemaymakeitmore tractableandenhancethepossibilityofsuccess.Certainlythisistrueinrelativetermswhenwe compareapproximately2400boatsofthefishingfleetwiththecirca800,000oftherecreationalfleet. Thecommercialversusrecreationalmotivationcanalsowarrantdifferentialstrategiesbetweenboth sectors,eveniftheprescribeddisruptiontoolsarebroadlysimilar.Furthermore,alargeproportionof fishingvesselsaresoleͲportboats.ThisisbeneficialinrelationtoinvasionsbecausethereisnointerͲ harbortransferfortheseboats,althoughwemustrememberthatthisdatasetrelatestoreportedfish landingsandnotallvoyagesbytheseboats(i.e.nonͲfishlandingtrips)areincludedhere.Inanycase,it wouldprobablybeimpracticaltofurthersubͲdividethefleetfortargetedcommunicationsonthisbasis.  Itisclearthatresponsibilityforboatmaintenancefallsonindividualfishingboatowners,someofwhom maynotknoworcareabouttheissueofnonͲnativespeciesandmeasurestheycouldtaketoprevent speciestransfers.Also,thehistoryoffishingregulationinCaliforniaisacasestudyinthetugͲofͲwar betweenresourceexploitationandpreservingthecommons(McEvoy,1986).Assuch,thebiofouling vectorisamuchlowerͲlevelconcernforfishermen,ifitisaconcernatall,andthereappearstobewide scalewarinessofconsentingtoevaluationsoftheirequipmentandactivitiesthatmaysubsequentlybe usedassupportingevidencetoaddtotheirregulatoryburden.  Havingdescribedthemodelofvectortransfersandtoolsthatcanbeapplied(byusers)atcriticalcontrol pointstointerruptthevector(reduceorpreventtransfersfromoccurring),thebroaderstatewide strategyofpersuadinguseruptakemustbeconsidered(Table4).ThevesselͲscalemanagementofthe vectorisrelativelywellcateredtointermsofproductsandservicesthatcanbeusedtodisruptthe vector.Themarketineachofthoseproductsandservicesshoulddrivetheirefficacyovertime, althoughcertainissues(e.g.managementofnicheareasofvessels)requireamanagementroleinorder toincentivizeuptake.Thestatescalepolicyofensuringmanagementoccursattheuserlevelisvirtually nonͲexistent.ExceptinregardstocrossͲoverbenefitsofoutreachcampaignstorecreationalboaters (e.g.SeaGrant),weareunawareofanyfishingvesselvectorinitiativeinthestate. 

50  Table4describesarangeofoptionsthatcouldbeconsideredforstatewidemanagementaction.These rangefromtheleastonerousintermsofbudgetandresourcesneededforimplementation(andeffect onfishermenstatusquo),tothemostonerousthatwouldinvolveregulationandenforcement(and probablepushbackfromfishermen).Ourrecommendationwouldbefortargetedoutreachtooccurto enhancetheuptakeofproductsandservicestoaffectvectordisruption.However,wehighly recommendthatthisbedonewithscientificpollingbeforeͲandperiodicallyafterͲtheimplementation ofthecampaignsothatefficacyofoutreachcanbemeasured.Simplyconductingoutreachwithout determiningwhetherornotitishavingthedesiredeffect(increasingawarenessanduptakeof management)isafarlessoptimalalternative.Thebalancednatureofthisapproach,atthemidpointof optionsbetweenretainingthestatusquoandenactingstatewideenforcementofregulations,isa featurethatmayhelpreduceconflictwithausergroupthatmaybereceptivetotheneedforaction withouttheneedforregulation.Italsocanbeafirststeptowardregulationifsocialandbiologicaldata suggestitisrequired.Forexample,explorationofthesocialͲpolicyaspectsofvectormanagement withinthefishingcommunitywouldprovideusefulinsightintothelikelihoodofuptakeofguidelinesand thepossibleneedtoenforcedregulation.ThecombinedscienceͲbaseddesignofmonitoringusergroup responseandthemarinebiologicalresponsemeanoursuggestionisadaptabletomeasuredoutcomes.  Table4.Strategiesforfishingvesselvectormanagementofbiofouling.Thetabledescribesarangeofmeasures thatcouldbeadopted,fromtheleasttothemostresourceintensive(toptobottom).Whilethesestrategiesare describedasindependentapproaches,someitemscouldbeundertakeninsequence. Item Action Outcomes Retainthestatusquo Ͳ Donothing Ͳ Potentialconflictwith stakeholdersconcernedat thelackofactiononvector management Ͳ Noconflictwithfishermen Ͳ Unintendedconsequences avoided(e.g.additional copperpollution) Ͳ Fishingvesselinfluenceon AISspreadremains unchanged Ͳ But,the‘donothing’option isnotstaticandtheper capitaeffectofAIS×Area affectedwillexpand dramaticallyovertime Conductoutreachto Ͳ AttempttoincreaseawarenessofAIS Ͳ Canbescaledtosuitbudget commercialfishermen andvectorissuesamongcommercial andresourceavailability (withoutpolling) fishermen Ͳ Mayprovideveryfavorable costͲbenefitoutcome Ͳ Theeffectsofoutreachwill belargelyunknowable Ͳ Fishingvesselinfluenceon AISspreadmaydecline Conductoutreachto Ͳ AttempttoincreaseawarenessofAIS Ͳ Canbescaledtosuitbudget commercialfishermen andvectorissuesANDdetermine andresourceavailability withscientificpolling efficacy/uptake Ͳ Mayprovideveryfavorable

51  costͲbenefitoutcome Ͳ Theeffectsofoutreachwill beassessedwithbeforeand afterpollingtodetermine efficacy Ͳ Efficacymeasurescanbe usedinadaptivestrategy andtoinformfuturepolicy directions Ͳ Higherchance(thanabove) forbeneficialeffectonAIS transfers Proposevoluntary Ͳ Addguidelinesregardingvector Ͳ Maybeinexpensive guidelinesona managementtootherpermitsissued Ͳ Linkingvoluntaryguidelines statewidebasis bythestateDF&G. tootherpermitting interactionsmayenhance uptakeofvector management Ͳ Additionalmonitoring requiredtodetermine uptake Ͳ Fishingvesselinfluenceon AISspreadmaydecline Proposemandatory Ͳ Createregulationandenforcement Ͳ Amodelofstatevector rulesgoverningvector mechanismforvectormanagement managementalreadyexists management offishingvessels inthestatethatcanbe mimicked(SLC) Ͳ Anagencyisalready responsibleforoceanfishery management(DF&G) Ͳ Highestlikelihoodof effectivevector management Ͳ Highandcontinuous expense Ͳ Highpossibilityofconflict withfishermen Ͳ Possibilityofunintended consequences(e.g.copper pollutionorinappropriate useoffoulͲreleasecoatings)  AnimportantfinalstepintheCarlton&Ruiz(2003)frameworkforvectormanagementistheroleof monitoringefficacyaftermanagementactionshavebeenadopted.Thisinvolvesashortertimescale evaluationofvectortransfersaftermanagement(preferablywithabeforeͲcomparison)andalonger timescalemonitoringofAISdistributionstodetermineiftheultimategoalofpreventingnewinvasions isoccurring.Thistypeofactionisunderwayforcommercialvesselsandtheeffortstoevaluatevectors andinvasionsthroughtimeforonevectorcanbeunderminedbyalackofactiononanother.Tothat

52  end,thereareoverlappinginterestsandefficienciesthatcanbeattainedbyworkingwithexistingvessel vectormanagersinthestate(e.g.SLCmarineinvasivespeciesprogramandDF&Gmarineinvasions monitoringprogram).  Vectormanagementandsubsequentmonitoringshouldalsoconsidertheroleofinfrastructurein providinghabitatforAIS.Marinas,docks,pierwalls,pilingsandotheranthropogenicstructuresarethe realfocalpointswithinbaysformuchoftherichnessofAIScommunities(Ruizetal.,2009;Simkaninet al.,inpress).AmajorityofourdataonAISdistributionsemanatesfromsamplingdoneinthebuilt environmentthatsupportsfishingandrecreationalboating.Totheextentpossibleoverthelonger period,designaspectsofmarinadocksshouldbeevaluatedtodetermineifbettermaterials,strategies ortoolscanbeusedtopreventtheestablishmentofAISinthoselocations,orcreateabarrierbetween themandthevectorsnearby.Oneexamplewouldbethedesignofdocksinwhichtheberthshavea preͲinstalledandeasilymanipulableskirt(orboatbath)topreventcolonizationduringstationary periods.  Finally,thevalueofvectormanagementshouldberestated.Theroleofpreventiveratherthanreactive managementinregardstomarineAISisbroadlyaccepted(Ruiz&Carlton,2003).Vectormanagement representsanAISstrategicactionthatisn’tsolelydefensiveandthatworksontheunderlyingprocess involvedinAISdispersal.Itdoesn’tsimplydefendaterritoryfromunwantedorganismsand consequences–anapproachthatsuperimposespoliticalboundariesthatmaybemeaninglesstothe broaderecologicalscaleoftheprocessͲbutattackstheunderlyingmechanismofunwantedecological change.Inthissense,thebeneficialeffectofvectormanagementisfeltatboththeenactingterritory andatinteractinglocationsdownstreamoftheterritory,whichpromotesa‘neitherͲsinkͲnorͲsource’ outlookthatmaybetterserveAISandresourcemanagementoverlargerscales.       6. ACKNOWLEDGEMENTS  WewouldliketothankChrisBrownforhiscontributionstofieldandlabcomponentsofthisprojectand KimHolzerforherefficientgenerationofcrustaceanimpactdata.RachelFontanaandEliotCrafton generatedthemolluscandalgaeimpactdata.DaleCalder,JeffCordell,LeslieHarris,LindaMcCann,and KathyAnnMillerprovidedspecimenidentificationsandconfirmationsthatwereinvaluableforthis project.WealsothanktheNEMESISresearchteamforprovidingandamendingdataasrequiredinthis project,particularlyBrianStevesandPaulFofonoff.Weareindebtedtoanumberofharbormasters andstaffatseveralmarinasthroughoutthestate,andparticularthanksgotoJudyNeidertandTimat SanDiegoPolicedock,andKathySangsterandMickKronmanatSantaBarbaraMarina.Wearealso verygratefultoalloftheboaters(fishingandrecreational)whoengagedindiscussionswithusatthe harbors,answeredourquestionnairesandconsentedtodivesamplingoftheirboats.Wearevery appreciativeofourbroaderAISvectorprojectpartnersfortheirdiscussionandcollaboration;JaePasari, SusanWilliams,TedGrosholz,EliotCrafton,RachelFontana,andAndyCohen.Finally,wethankthe OceanScienceTrustandOceanProtectionCouncilfortheirsupportandcommitmenttothisprojectand particularlySkylieMcAfee,RebeccaGentry,andErrinKramerͲWiltfortheirinsightsanddiscussions throughouttheproject.

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57  Supplementary Material

Appendix 1: 278 AIS in California and possible link to fishing vessels

taxon species name vector (binary for fishing vessels) Algae Aglaothamnion tenuissimum Fishing vessel possible Algae Antithamnion hubbsii Fishing vessel possible Algae Ascophyllum nodosum not fishing vessels Algae Asparagopsis armata Fishing vessel possible Algae Bryopsis sp .1 Fishing vessel possible Algae Caulacanthus ustulatus Fishing vessel possible Algae Ceramium kondoi Fishing vessel possible Algae Codium fragile ssp .fragile Fishing vessel possible Algae Cutleria cylindrica Fishing vessel possible Algae Gelidium vagum not fishing vessels Algae Gracilaria vermiculophylla Fishing vessel possible Algae Grateloupia lanceolata Fishing vessel possible Algae Lomentaria hakodatensis Fishing vessel possible Algae Neosiphonia harveyi Fishing vessel possible Algae Polysiphonia denudata Fishing vessel possible Algae Sargassum filicinum Fishing vessel possible Algae Sargassum muticum Fishing vessel possible Algae Undaria pinnatifida Fishing vessel possible Annelids-Leeches Myzobdella lugubris Fishing vessel possible Annelids-Oligochaetes Chaetogaster diaphanus not fishing vessels Annelids-Oligochaetes Limnodriloides monothecus Fishing vessel possible Annelids-Oligochaetes Protodactylina pamelae Fishing vessel possible Annelids-Oligochaetes Tubificoides apectinatus not fishing vessels Annelids-Oligochaetes Tubificoides brownae Fishing vessel possible Annelids-Oligochaetes Tubificoides wasselli Fishing vessel possible Annelids-Oligochaetes Varichaetadrilus angustipenis Fishing vessel possible Annelids-Polychaetes Alitta succinea Fishing vessel possible Annelids-Polychaetes Amaeana sp. A .Harris Fishing vessel possible Annelids-Polychaetes Amblyosyllis sp. A Harris Fishing vessel possible Annelids-Polychaetes Boccardiella ligerica not fishing vessels Annelids-Polychaetes Crucigera websteri Fishing vessel possible Annelids-Polychaetes Ficopomatus enigmaticus Fishing vessel possible Annelids-Polychaetes Geminosyllis ohma Fishing vessel possible Annelids-Polychaetes Heteromastus filiformis Fishing vessel possible Annelids-Polychaetes Hydroides diramphus Fishing vessel possible Annelids-Polychaetes Hydroides elegans Fishing vessel possible Annelids-Polychaetes Laonome sp SF1 not fishing vessels

1

Annelids-Polychaetes Marenzelleria viridis not fishing vessels Annelids-Polychaetes Myrianida pachycera Fishing vessel possible Annelids-Polychaetes Neodexiospira brasiliensis Fishing vessel possible Annelids-Polychaetes Nicolea sp. A. Harris Fishing vessel possible Annelids-Polychaetes Sabaco elongatus not fishing vessels Annelids-Polychaetes Streblospio benedicti Fishing vessel possible Annelids-Polychaetes Typosyllis nipponica Fishing vessel possible Bacteria Xenohaliotis californiensis Fishing vessel possible Coelenterates-Anthozoan Bunodeopsis sp. A Fishing vessel possible Coelenterates-Anthozoan Diadumene ?cincta Fishing vessel possible Coelenterates-Anthozoan Diadumene franciscana Fishing vessel possible Coelenterates-Anthozoan Diadumene leucolena Fishing vessel possible Coelenterates-Anthozoan Diadumene lineata Fishing vessel possible Coelenterates-Anthozoan Nematostella vectensis Fishing vessel possible Coelenterates-Hydrozoans Amphinema sp. Fishing vessel possible Coelenterates-Hydrozoans Bimeria vestita Fishing vessel possible Coelenterates-Hydrozoans Blackfordia virginica Fishing vessel possible Coelenterates-Hydrozoans Cladonema pacificum Fishing vessel possible Coelenterates-Hydrozoans Clava multicornis Fishing vessel possible Coelenterates-Hydrozoans Climacocodon ikarii not fishing vessels Coelenterates-Hydrozoans Cordylophora caspia Fishing vessel possible Coelenterates-Hydrozoans Corymorpha sp. A Carlton 1979 Fishing vessel possible Coelenterates-Hydrozoans Garveia franciscana Fishing vessel possible Coelenterates-Hydrozoans Laomedea calceolifera Fishing vessel possible Coelenterates-Hydrozoans Maeotias marginata Fishing vessel possible Coelenterates-Hydrozoans Moerisia sp. Fishing vessel possible Coelenterates-Hydrozoans Pinauay crocea Fishing vessel possible Coelenterates-Scyphozoan Aurelia sp. 1 Fishing vessel possible Coelenterates-Scyphozoan Phyllorhiza punctata Fishing vessel possible Crustaceans - Leptostracans Epinebalia sp A. not fishing vessels Crustaceans-Amphipods Abludomelita rylovae Fishing vessel possible Crustaceans-Amphipods Ampelisca abdita Fishing vessel possible Crustaceans-Amphipods Ampithoe longimana Fishing vessel possible Crustaceans-Amphipods Ampithoe sp. Fishing vessel possible Crustaceans-Amphipods Ampithoe valida Fishing vessel possible Crustaceans-Amphipods Aoroides secunda Fishing vessel possible Crustaceans-Amphipods Calliopiella sp. Fishing vessel possible Crustaceans-Amphipods Caprella drepanochir Fishing vessel possible Crustaceans-Amphipods Caprella mutica Fishing vessel possible Crustaceans-Amphipods Caprella scaura Fishing vessel possible Crustaceans-Amphipods Caprella simia Fishing vessel possible Crustaceans-Amphipods Chelura terebrans Fishing vessel possible Crustaceans-Amphipods Corophium alienense not fishing vessels

2

Crustaceans-Amphipods Corophium heteroceratum Fishing vessel possible Crustaceans-Amphipods Eochelidium miraculum Fishing vessel possible Crustaceans-Amphipods Eochelidium sp. A Fishing vessel possible Crustaceans-Amphipods Gammarus daiberi not fishing vessels Crustaceans-Amphipods Grandidierella japonica Fishing vessel possible Crustaceans-Amphipods Incisocalliope derzhavini Fishing vessel possible Crustaceans-Amphipods Jassa marmorata Fishing vessel possible Crustaceans-Amphipods Melita nitida Fishing vessel possible Crustaceans-Amphipods Microdeutopus gryllotalpa Fishing vessel possible Crustaceans-Amphipods Monocorophium acherusicum Fishing vessel possible Crustaceans-Amphipods Monocorophium insidiosum Fishing vessel possible Crustaceans-Amphipods Monocorophiun uenoi Fishing vessel possible Crustaceans-Amphipods Paracorophium lucasi Fishing vessel possible Crustaceans-Amphipods Paradexamine sp. Fishing vessel possible Crustaceans-Amphipods Stenothoe valida Fishing vessel possible Crustaceans-Amphipods Transorchestia enigmatica not fishing vessels Crustaceans-Barnacles Amphibalanus amphitrite Fishing vessel possible Crustaceans-Barnacles Amphibalanus eburneus Fishing vessel possible Crustaceans-Barnacles Amphibalanus improvisus Fishing vessel possible Crustaceans-Barnacles Amphibalanus reticulatus Fishing vessel possible Crustaceans-Copepods Acartiella sinensis not fishing vessels Crustaceans-Copepods Eurytemora carolleeae Fishing vessel possible Crustaceans-Copepods Harpacticella paradoxa Fishing vessel possible Crustaceans-Copepods Limnoithona sinensis not fishing vessels Crustaceans-Copepods Limnoithona tetraspina not fishing vessels Crustaceans-Copepods Mytilicola orientalis Fishing vessel possible Crustaceans-Copepods Oithona davisae not fishing vessels Crustaceans-Copepods Pseudodiaptomus forbesi not fishing vessels Crustaceans-Copepods Pseudodiaptomus marinus Fishing vessel possible Crustaceans-Copepods Sinocalanus doerrii not fishing vessels Crustaceans-Copepods Tortanus dextrilobatus not fishing vessels Crustaceans-Crabs Carcinus maenas Fishing vessel possible Crustaceans-Crabs Eriocheir sinensis Fishing vessel possible Crustaceans-Crabs Rhithropanopeus harrisii Fishing vessel possible Crustaceans-Crayfish Orconectes virilis Fishing vessel possible Crustaceans-Crayfish Pacifastacus leniusculus not fishing vessels Crustaceans-Crayfish Procambarus clarkii Fishing vessel possible Crustaceans-Cumaceans Nippoleucon hinumensis Fishing vessel possible Crustaceans-Isopods Asellus hilgendorfi not fishing vessels Crustaceans-Isopods Caecijaera horvathi Fishing vessel possible Crustaceans-Isopods Dynoides dentisinus Fishing vessel possible Crustaceans-Isopods Eurylana arcuata Fishing vessel possible Crustaceans-Isopods Gnorimosphaeroma rayi not fishing vessels

3

Crustaceans-Isopods Iais californica Fishing vessel possible Crustaceans-Isopods Ianiropsis serricaudis Fishing vessel possible Crustaceans-Isopods Limnoria quadripunctata Fishing vessel possible Crustaceans-Isopods Limnoria tripunctata Fishing vessel possible Crustaceans-Isopods Orthione griffenis not fishing vessels Crustaceans-Isopods Paranthura japonica Fishing vessel possible Crustaceans-Isopods Pseudosphaeroma sp. Fishing vessel possible Crustaceans-Isopods Sphaeroma quoianum Fishing vessel possible Crustaceans-Isopods Sphaeroma sp. Fishing vessel possible Crustaceans-Isopods Sphaeroma walkeri Fishing vessel possible Crustaceans-Isopods Synidotea laevidorsalis Fishing vessel possible Crustaceans-Isopods Uromunna sp .A Fishing vessel possible Crustaceans-Mysids Deltamysis holmquistae not fishing vessels Crustaceans-Mysids Hyperacanthomysis longirostris not fishing vessels Crustaceans-Mysids Neomysis japonica not fishing vessels Crustaceans-Mysids Orientomysis aspera not fishing vessels Crustaceans-Mysids Orientomysis hwanhaiensis not fishing vessels Crustaceans-Ostracods Aspidoconcha limnoriae Fishing vessel possible Crustaceans-Ostracods Eusarsiella zostericola not fishing vessels Crustaceans-Ostracods Redekea californica Fishing vessel possible Crustaceans-Ostracods Spinileberis quadriaculeata not fishing vessels Crustaceans-Shrimp Exopalaemon carinicauda Fishing vessel possible Crustaceans-Shrimp Exopalaemon modestus Fishing vessel possible Crustaceans-Shrimp Palaemon macrodactylus not fishing vessels Crustaceans-Tanaids Sinelobus cf. stanfordi Fishing vessel possible Ctenophores Vallicula multiformis Fishing vessel possible Ectoprocts Aeverrillia armata Fishing vessel possible Ectoprocts Anguinella palmata Fishing vessel possible Ectoprocts Aspidelectra melolontha Fishing vessel possible Ectoprocts Bugula flabellata Fishing vessel possible Ectoprocts Bugula neritina Fishing vessel possible Ectoprocts Bugula stolonifera Fishing vessel possible Ectoprocts Conopeum tenuissimum Fishing vessel possible Ectoprocts Cryptosula pallasiana Fishing vessel possible Ectoprocts Nolella stipata Fishing vessel possible Ectoprocts Schizoporella errata Fishing vessel possible Ectoprocts Schizoporella japonica Fishing vessel possible Ectoprocts Schizoporella unicornis Fishing vessel possible Ectoprocts Victorella pavida Fishing vessel possible Ectoprocts Watersipora arcuata Fishing vessel possible Ectoprocts Watersipora sp. A Fishing vessel possible Ectoprocts Watersipora subtorquata Fishing vessel possible Ectoprocts Zoobotryon verticillatum Fishing vessel possible

4

Entoprocts Barentsia benedeni Fishing vessel possible Mollusks-Bivalves Corbicula fluminea Fishing vessel possible Mollusks-Bivalves Corbula amurensis not fishing vessels Mollusks-Bivalves Crassostrea gigas Fishing vessel possible Mollusks-Bivalves Gemma gemma not fishing vessels Mollusks-Bivalves Geukensia demissa Fishing vessel possible Mollusks-Bivalves Laternula marilina not fishing vessels Mollusks-Bivalves Lyrodus pedicellatus Fishing vessel possible Mollusks-Bivalves Macoma petalum not fishing vessels Mollusks-Bivalves Mercenaria mercenaria not fishing vessels Mollusks-Bivalves Musculista senhousia Fishing vessel possible Mollusks-Bivalves Mya arenaria not fishing vessels Mollusks-Bivalves Mytilus galloprovincialis Fishing vessel possible Mollusks-Bivalves Nuttallia obscurata Fishing vessel possible Mollusks-Bivalves Petricolaria pholadiformis not fishing vessels Mollusks-Bivalves Teredo bartschi Fishing vessel possible Mollusks-Bivalves Teredo furcifera Fishing vessel possible Mollusks-Bivalves Teredo navalis Fishing vessel possible Mollusks-Bivalves Theora lubrica not fishing vessels Mollusks-Bivalves Venerupis philippinarum Fishing vessel possible Mollusks-Gastropods Anteaeolidiella indica Fishing vessel possible Mollusks-Gastropods Babakina festiva Fishing vessel possible Mollusks-Gastropods Batillaria attramentaria Fishing vessel possible Mollusks-Gastropods Boonea bisuturalis not fishing vessels Mollusks-Gastropods Busycotypus canaliculatus not fishing vessels Mollusks-Gastropods Catriona rickettsi Fishing vessel possible Mollusks-Gastropods Crepidula convexa Fishing vessel possible Mollusks-Gastropods Crepidula plana Fishing vessel possible Mollusks-Gastropods Cuthona perca Fishing vessel possible Mollusks-Gastropods Eubranchus misakiensis Fishing vessel possible Mollusks-Gastropods Haminoea japonica not fishing vessels Mollusks-Gastropods Ilyanassa obsoleta not fishing vessels Mollusks-Gastropods Littoridinops monroensis not fishing vessels Mollusks-Gastropods Littorina littorea Fishing vessel possible Mollusks-Gastropods Littorina saxatilis Fishing vessel possible Mollusks-Gastropods Melanoides tuberculatus not fishing vessels Mollusks-Gastropods Myosotella myosotis not fishing vessels Mollusks-Gastropods Ocinebrellus inornatus not fishing vessels Mollusks-Gastropods Okenia plana Fishing vessel possible Mollusks-Gastropods Philine aperta not fishing vessels Mollusks-Gastropods Philine auriformis not fishing vessels Mollusks-Gastropods Philine japonica not fishing vessels Mollusks-Gastropods Philine orientalis not fishing vessels

5

Mollusks-Gastropods Potamopyrgus antipodarum Fishing vessel possible Mollusks-Gastropods Sakuraeolis enosimensis Fishing vessel possible Mollusks-Gastropods Tenellia adspersa Fishing vessel possible Mollusks-Gastropods Urosalpinx cinerea not fishing vessels Nematodes Capillaria catenata Fishing vessel possible Nematodes Hysterothylacium brachyurum Fishing vessel possible Platyhelminthes Alloglossidium corti Fishing vessel possible Platyhelminthes Atractolytocestus huronensis Fishing vessel possible Platyhelminthes Austrobilharzia variglandis not fishing vessels Platyhelminthes Bothriocephalus cuspidatus Fishing vessel possible Platyhelminthes Cercaria batillariae not fishing vessels Platyhelminthes Corallobothrium fimbriatum Fishing vessel possible Platyhelminthes Dactylogyrus extensus Fishing vessel possible Platyhelminthes Gigantobilharzia sp. not fishing vessels Platyhelminthes Himasthla quissetensis not fishing vessels Platyhelminthes Khawia iowensis Fishing vessel possible Platyhelminthes Lepocreadium setiferoides not fishing vessels Platyhelminthes Leptoplana limnoriae Fishing vessel possible Platyhelminthes Ligictaluridus pricei Fishing vessel possible Platyhelminthes Maritrema arenaria not fishing vessels Platyhelminthes Megathylacoides giganteum Fishing vessel possible Platyhelminthes Microphallus pygmaeus Group not fishing vessels Platyhelminthes Microphallus similis not fishing vessels Platyhelminthes Pisciamphistoma stunkardi Fishing vessel possible Platyhelminthes Stephanostomum tenue not fishing vessels Platyhelminthes Zoogonus lasius not fishing vessels Protozoans Ancistrocoma pelseneeri Fishing vessel possible Protozoans Ancistrum cyclidioides Fishing vessel possible Protozoans Bonamia ostreae not fishing vessels Protozoans Boveria teredinidi Fishing vessel possible Protozoans Conidophrys pilisuctor Fishing vessel possible Protozoans Cothurnia limnoriae Fishing vessel possible Protozoans Haplosporidium nelsoni not fishing vessels Protozoans Lagenophrys cochinensis Fishing vessel possible Protozoans Lankesteria ascidiae Fishing vessel possible Protozoans Lobochona prorates Fishing vessel possible Protozoans Mirofolliculina limnoriae Fishing vessel possible Protozoans Sphenophrya dosiniae Fishing vessel possible Protozoans Trochammina hadai not fishing vessels Sponges Chalinula loosanoffi Fishing vessel possible Sponges Clathria prolifera Fishing vessel possible Sponges Cliona sp. not fishing vessels Sponges Halichondria bowerbanki Fishing vessel possible

6

Sponges Prosuberites sp. Fishing vessel possible Tunicates Ascidia sp. A Fishing vessel possible Tunicates Ascidia zara Fishing vessel possible Tunicates Bostrichobranchus pilularis Fishing vessel possible Tunicates Botrylloides perspicuum Fishing vessel possible Tunicates Botrylloides violaceus Fishing vessel possible Tunicates Botryllus schlosseri Fishing vessel possible Tunicates Botryllus sp. A. Fishing vessel possible Tunicates Ciona intestinalis Fishing vessel possible Tunicates Ciona savignyi Fishing vessel possible Tunicates Didemnum sp. Fishing vessel possible Tunicates Didemnum vexillum Fishing vessel possible Tunicates Diplosoma listerianum Fishing vessel possible Tunicates Microcosmus squamiger Fishing vessel possible Tunicates Molgula ficus Fishing vessel possible Tunicates Molgula manhattensis Fishing vessel possible Tunicates Perophora japonica Fishing vessel possible Tunicates Polyandrocarpa zorritensis Fishing vessel possible Tunicates Styela canopus Fishing vessel possible Tunicates Styela clava Fishing vessel possible Tunicates Styela plicata Fishing vessel possible Tunicates Symplegma reptans Fishing vessel possible Vertebrates Rana catesbeiana not fishing vessels Vertebrates Xenopus laevis not fishing vessels Vertebrates Ondatra zibethicus not fishing vessels Vertebrates Trachemys scripta not fishing vessels

7

Appendix 2: Port connectivity (data underlying Figure 11 in report)

ports San Diego Oceanside Dana Point Newport Beach LA/Long Beach Hueneme Port Oxnard Ventura Santa Barbara SL Obispo Morro Bay Monterey Moss Landing Santa Cruz Bay Moon Half Bay Francisco San Marin Bolinas Reyes Point Tomales Bay Bodega Bay Arena Point Albion Fort Bragg Humboldt Trinidad City Crescent San Diego 46 65 26 12 11 0 7 8 6 2 7 2 4 2 2 1 2 0 0 0 1 0 0 1 1 0 1 Oceanside 26 10 32 12 8 0 2 2 0 0 0 0 0 1 0 0 0 0 0 0 0 2 0 0 1 0 0 Dana Point 12 37 26 25 11 0 4 3 5 3 2 0 0 2 1 0 0 0 0 0 0 0 0 0 0 0 0 Newport Beach 3 7 14 22 8 6 4 2 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 LA/Long Beach 25 45 51 71 44 75 26 48 17 5 9 13 11 3 3 3 4 0 7 0 3 2 0 1 4 6 2 Port Hueneme 0 0 0 8 12 7 13 25 5 5 5 10 5 1 1 1 2 0 3 0 0 2 0 0 0 0 0 Oxnard 6 4 7 14 10 32 17 42 35 12 15 5 4 1 3 2 2 0 3 0 2 2 0 2 1 3 0 Ventura 7 4 6 6 19 63 42 10 27 12 11 12 9 2 3 1 0 0 3 0 1 2 0 1 1 3 0 Santa Barbara 8 1 13 6 10 19 51 39 38 22 21 6 5 3 6 2 2 0 0 0 5 2 10 3 1 0 1 SL Obispo 1 0 4 0 2 10 9 8 11 31 29 8 8 4 7 3 2 0 7 0 7 0 0 4 2 0 1 Morro Bay 7 1 4 0 5 14 19 13 17 49 29 13 19 16 14 9 9 0 14 0 14 6 0 11 6 3 6 Monterey 1 0 0 2 3 15 3 7 2 7 6 36 17 7 4 2 0 0 0 0 2 0 0 2 1 0 1 Mos s Landing 5 0 1 0 8 24 7 16 6 18 28 50 23 37 26 17 7 11 17 13 25 8 0 22 9 0 12 Santa Cruz 2 2 4 0 2 3 2 3 3 6 15 13 24 16 28 16 11 11 17 0 22 25 0 21 12 0 10 Half Moon Bay 3 1 3 0 2 4 7 6 8 18 22 12 29 48 15 31 25 11 48 0 43 22 10 39 21 0 7 San Francisco Bay 2 0 1 2 3 6 5 4 4 13 25 12 31 46 52 33 49 78 52 38 48 27 5 49 35 3 31 Marin 0 0 0 0 0 1 1 0 0 1 2 0 1 3 4 5 30 11 7 13 5 2 0 2 1 0 2 Bolinas 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 11 7 0 1 0 0 0 0 0 0 Point Reyes 0 0 0 0 0 1 1 1 0 2 2 0 2 2 4 3 4 22 3 0 5 2 0 3 1 0 1 Tomales Bay 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 0 0 38 1 0 0 0 0 0 0 Bodega Bay 2 1 1 0 3 3 5 3 8 23 28 9 35 47 53 35 35 56 69 50 17 41 20 54 26 3 25 Point Arena 0 1 0 0 0 1 1 1 0 0 1 0 1 6 3 2 2 0 3 0 5 20 20 8 5 0 2 Albion 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 8 25 4 1 0 0 Fort Bragg 1 1 0 0 1 1 3 1 4 11 18 7 26 39 42 31 12 0 38 13 46 61 70 15 42 6 28 Humboldt 1 2 0 0 3 0 1 1 1 4 8 4 8 17 16 16 5 0 7 13 17 25 10 31 26 83 27 Trinidad 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 11 14 2 Crescent City 1 1 0 0 1 1 1 0 1 2 6 2 9 11 5 12 7 0 7 13 13 10 0 17 22 11 43

TOTAL BOATS 20 16 15 11 24 19 24 22 23 20 23 18 23 23 24 26 20 8 18 8 26 19 8 24 23 10 22

8

Appendix 3: Boat fouling papers in the literature (fishing and Recreational boats) with species data

References for literature search biofouling taxa reported from small craft ƐŚƚŽŶ'͕ĂǀŝĚƐŽŶ/ĂŶĚ'ZƵŝnj͘ϮϬϭϬ͘,ŝƐƚŽƌLJĂŶĚďŝŽĨŽƵůŝŶŐŽĨƐŚŝƉƐ͛ŚƵůůƐĂƌƌŝǀŝŶŐƚŽ<ĞƚĐŚŝŬĂŶ͕ůĂƐŬĂ͗ a case study. Final report submitted to Alaska Department of Fish and Game. 42 pp. Clarke Murray C, Pakhomov EA and TW Therriault.2011. Recreational boating: a large unregulated vector transporting marine invasive species. Diversity and Distributions:1-12. Darbyson, EA, A Locke, JM Hanson and JHM Willison. 2009. Marine boating habits and the potential for spread of invasive species in the Gulf of St Lawrence. Aquatic Invasions 4:87-94. Davidson IC, CJ Zabin, AL Chang, CW Brown, MD Sytsma and GM Ruiz. 2010. Recreational boats as potential vectors of marine organisms at an invasion hotspot. Aquatic Biology 11:179-191. DeBlauwe H and Faasse M. 2001.Extension of the range of the bryozoans Tricellariainopinataand Bugula simplex in the North-East Atlantic Ocean (Bryozoa: Cheilostomatida).NederlandseFaunisticheMededelingen 14: 103-112. Farraperia CMR. 2011. The introduction of the bryozoan Zoobotryonverticillatum (Della Chiaje, 1822) in northeast of Brazil: a cause for concern. Biological Invasions (2011) 13:13-16. Floerl O. 2002. Intracoastal spread of fouling organisms by recreational vessels. PhD thesis, James Cook University, Townsville. Floerl O and GJ Inglis. 2005. Starting the invasion pathway: the interaction between source populations and human transport vectors. Biological Invasions 7:589-606. Godwin LS, Eldredge LG and K Gaut. 2004. The assessment of hull fouling as a mechanism for the introduction and dispersal of marine alien species in the main Hawaiian Islands. Bishop Museum Technical Report No. 28. August 2004. 114 pp. Leonard J. 2009.Hull Fouling Surveys of Recreational Boats in Hawaii. Hawaii Department of Land and Natural Resources, Department of Aquatic Resources Report. 32 pp. Lougheed VL and RJ Stevenson. 2004. Exotic marine macroalga(Enteromorphaflexuosa) reaches bloom proportions in a coastal lake of Lake Michigan. Journal of Great Lakes Research 30(4): 538-544. Kerckhof F. 2002.Barnacles (Cirripedia, Balanomorpha) in Belgian waters, an overview of the species and ƌĞĐĞŶƚĞǀŽůƵƚŝŽŶƐ͕ǁŝƚŚĞŵƉŚĂƐŝƐŽŶĞdžŽƚŝĐƐƉĞĐŝĞƐ͘ƵůůĞƚŝŶĚĞů͛/ŶƐƚŝƚƵƚZŽLJĂůĞƐ^ĐŝĞŶĐĞƐ Naturelles de Belgique, Biologies, 72-Supplement: 93-104. Meinesz A, Belsher T, Thibaut T, Antolic B, Mustapha KB, Boudouresque C-F, Chiaverini D, Cinelli F, Cottalorda J-M, Djellouli A, El Abed A, Orestano C, Grau AM, Ivesa L, Jaklin A, Langar H, Massuti- Pascual E, Peirano A, Tunesi L, de Vaugelas J, Zavodnik N and A Zuljevic. 2001. The introduced green alga Caulerpataxifolia continues to spread in the Mediterranean. Biological Invasions 3: 201-210. Mineur F, MP Johnson and CA Maggs. 2008. Macroalgal introductions by hull fouling on recreational vessels: Seaweeds and sailors. Environmental Management 42:667-676. Minchin D and Holmes JMC. 2007. The first record of CaprellamuticaSchurin, 1935 (Crustacea:

9

ŵƉŚŝƉŽĚĂͿĨƌŽŵƚŚĞĂƐƚŽĂƐƚŽĨ/ƌĞůĂŶĚ͘dŚĞ/ƌŝƐŚEĂƚƵƌĂůŝƐƚƐ͛:ŽƵƌŶĂl, 28 (8):321-323. Minchin D and Sides E. 2006. Appearance of a cryptogenic tunicate, a Didemnum sp. fouling marina pontoons and leisure craft in Ireland. Aquatic Invasions 1 (3):143-147. Mintz CT. 2001.Vessel hulls as a dispersal vector for coastal marŝŶĞŽƌŐĂŶŝƐŵƐ͘ĂĐŚĞůŽƌ͛ƐdŚĞƐŝƐ͕ Williams College, Williamstown, Ma.41pp Neves CS, Rocha RM, Bettini-Pitombo F and JJ Roper. 2007. Use of artificial substrata by introduced and cryptogenic marine species in Paranagua Bay, southern Brazil. Biofouling 23(5): 319-330. Savini D, Marchini A, Forni G and M Castellazzi. 2006. Touristic harbours and secondary spread of alien species. Biol. Mar. Medit (1):760-763. Zabin, CJ, Zardus J, Bettini-Pitombo F, Fread V and MG Hadfield. 2007. A tale of three seas: consistency of natural history traits in a Caribbean-Atlantic barnacle introduced to Hawaii, Biological Invasions: 9: 523-544. Zabin, CJ, Ashton GV, Brown CW &Ruiz GM. 2009.Northern range expansion of the Asian kelp Undaria pinnatifida (Harvey) Suringar (Laminariales, Phaeophyceae) in western North America. Aquatic Invasions 4 (3): 429-434. Zabin CJ, Ashton G, Brown CW, Davidson I, Chestnut T, Draheim R, Sytsma MD and GM Ruiz. 2011. Hull Fouling: Characterizing Magnitude and Risk of Species Transfers by Recreational and Fishing Vessels. Final report to the Pacific States Marine Fisheries Commission. 105 pp.

10

Appendix 4: Specimens identified to species level from boat sampling

List of species identified from recreational vessels. Numbers indicate number of vessels that the species was sampled from. Letters indicate status of the species in California: N- Native, I- Introduced, G- could not be identified to species, but there are native members of this group. * indicates species not yet recorded from CA. Algae 1 I Lomentaria hakodatensis 1 N Polyneura latissima 1 I Undaria pinnatifida

Cirripeds 5 I Amphibalanus amphitrite 8 I Amphibalanus eburneus 5 I Amphibalanus improvisus 1 G Amphibalanus (blank) 11 N Balanus crenatus 3 N Balanus glandula 1 G Balanus sp. 9 N Balanus trigonus 1 N Conchoderma auritum 1 G Conchoderma sp. 1 N Lepas anatifera 2 N Lepas pacifica 2 G Lepas sp. 3 ? Megabalanus cf tanagrae 3 ? Megabalanus coccopoma 1 G Megabalanus sp. 1 G Megabalanus sp.A 1 G Megabalanus sp.B 2 N Megabalanus tintinnabulum

Ascidians 6 N Ascidia ceratodes 1 N Ascidia paratropa 1 G Ascidia sp. 2 I Ascidia zara 6 N Botrylloides diegensis 2 I Botrylloides perspicuum 3 G Botrylloides sp. 14 I Botrylloides violaceus 19 I Botryllus schlosseri 9 I Ciona intestinalis 1 I Ciona savignyi 1 I Molgula cf. manhattensis 1 I Molgula ficus 6 I Molgula sp.

11

1 G Riterella sp. 4 I Styela clava 10 I Styela plicata 8 G Styela sp.

Hydrozoa 3 N Aglaophenia diegensis 1 N Amphisbetia furcata 2 I Bougainvillia muscus 1 G Bougainvilliidae (blank) 3 N Campanulinidae (blank) 2 G Clytia sp. 1 G Coryne sp. 2 N Ectopleura sp. 1 N Gonothyraea loveni 5 N Obelia dichotoma 8 N Obelia longissima 1 N Plumularia setacea

Bryozoans 2 G Diaperoforma sp. 13 G Bowerbankia sp. 32 I Bugula neritina 23 I Bugula stolonifera 17 N Celleporaria brunnea 1 N Celleporella hyalina 1 G Celleporella sp. 1 G Celleporina sp. 1 I Conopeum cf. tenuissimum 2 G Conopeum sp. 1 N Crisia cf. occidentalis 2 G Crisia sp. 1 G Crisidae sp. 3 G Crisulipora sp. 14 I Cryptosula pallasiana 1 G Electra cf. crustulenta 2 G Electra sp. 1 I Hippoporina indica* 3 N Membranipora villosa 1 N Microporella setiformis 4 I Schizoporella japonica 2 G Schizoporella sp. 2 N Scrupocellaria bertholetti 8 N Thalamoporella californica 2 N Tricellaria occidentalis 1 N Tubulipora cf pacifica 3 I Watersipora arcuata 21 I Watersipora subtorquata 5 I Zooobotryon sp.

Polychaetes 5 N Paleanotus bellis 1 G Cirratulidae

12

1 C Dorvillea moniloceras 1 G Nereididae 2 I Alitta succinea 1 N Nereis latescens 1 N Nereis mediator 1 N Nereis vexillosa 6 N Platynereis bicanaliculata 1 N Eualia quadrioculata 3 N Halosydna brevisetosa 1 N Halosydna johnsoni 1 C Harmathoe imbricata complex 1 C Thormora johnstoni 1 C Bispira sp.7 Harris 1 I Branchiomma sp. 1 3 I Branchiomma sp. 2 Harris 1 N Eudistylia polymorpha 1 G Eudistylia sp. 1 C Megalomma coloratum 2 N Paradialychone ecaudata 4 I Parasabella fullo 2 N Pseudopotamilla ocellata 1 G Serpulidae 2 I Ficopomatus enigmaticus 1 I Hydroides crucigera 1 I Hydroides diramphus 9 I Hydroides elegans 6 N Hydroides gracilis 2 Hydroides sp. 9 C Salmacina tribranchiata 1 I Boccardiella hamata 2 N Polydora narica 3 G Spirorbidae 10 N Pileolaria marginata 1 N Pileolaria tiatara 3 G Autolytinae 1 C Syllis gracilis complex 2 I Syllis sp. 37 Harris 2 G Trypanosyllis sp. 1 N Eupolymnia heterbranchia

13