University of Groningen

E-commerce and CaulerpaWalters LJ Brown KR Stam WT Olsen JL

Published inFrontiers in Ecology and the Environment

DOI1018901540-9295(2006)004[0075eacudo]20co2

IMPORTANT NOTE You are advised to consult the publishers version (publishers PDF) if you wish to cite fromit Please check the document version below

Document VersionPublishers PDF also known as Version of record

Publication date2006

Link to publication in University of GroningenUMCG research database

Citation for published version (APA)Walters LJ Brown KR Stam WT amp Olsen JL (2006) E-commerce and Caulerpa unregulateddispersal of invasive species Frontiers in Ecology and the Environment 4(2) 75-79httpsdoiorg1018901540-9295(2006)004[0075eacudo]20co2

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Download date 11-04-2019

75

copy The Ecological Society of America wwwfrontiersinecologyorg

Many species of the green macroalga Caulerpa(Chlorophyta Ulvophyceae) are highly invasive

and the economics and ecological impacts associated withthese introductions are well documented (eg de Villegraveleand Verlaque 1995 Davis et al 1997 Meinesz 1999Williams and Grosholz 2002a) For example monocul-tures of the aquarium strain of Caulerpa taxifolia extendhundreds of kilometers along the Mediterranean coastline(Meinesz et al 2001) have clogged nine waterways inNew South Wales and two more in South Australia(Schaffelke et al 2002 Millar 2004 A Davis pers comm)and infested two lagoons in southern California (Joussonet al 2000) In all cases this invasive strain of C taxifoliagrew faster larger and in deeper and colder waters than itsnative tropical counterpart (Belsher and Meinesz 1995Williams and Grosholz 2002b) DNA studies confirmedthat the aquarium strain of C taxifolia originated nearBrisbane Australia and was subsequently transported viathe aquarium trade (Jousson et al 1998 Wiedenmann etal 2001 Muesnier et al 2002) In the Mediterranean andthe Canary Islands Caulerpa racemosa is now also recog-nized as invasive (Verlaque et al 2003 2004) Similarlynon-native Caulerpa brachypus was first recognized insoutheastern Florida waters in 2001 where extensiveblooms were overgrowing or displacing native flora andfauna (Jacoby et al 2004)

Despite its invasive reputation many members of thegenus Caulerpa (especially C racemosa C prolifera and

some of the ldquofeather Caulerpasrdquo C taxifolia C sertulari-oides and C mexicana) remain extremely popular withaquarium hobbyists because they are attractive in saltwater tanks and are easy to clonally propagate (Smith andWalters 1999 Padilla and Williams 2004) The genusCaulerpa is also touted by hobbyists for its many addi-tional virtues most notably its ability to remove nutrientsfrom closed aquarium systems and to act as fish foodHowever as their aquaria become overgrown or situa-tions change hobbyists may either sell their extra stockon eBay or dispose of their unwanted algae (and animals)in nearby waters thus setting the stage for a new invasion(Whitfield et al 2002 Semmens et al 2004)

ldquoLive rockrdquo is extremely popular with aquarists becauseit is inexpensive and can potentially harbor a huge diver-sity of marine organisms (including Caulerpa spp) Manyconsider it to be an essential component of saltwateraquariums as it acts as a substrate for sessile species arefuge for fishes and mobile invertebrates and as a biolog-ical filtration system Live rock consists of either pieces ofhard coral directly harvested from reefs or rocks allowedto cure under aquaculture conditions

In response to a stakeholder request the Mediterraneanclone of C taxifolia was added to the Noxious Species Listin 1999 by the US Department of Agriculture Animaland Plant Health Inspection Service (USDAndashAPHIS)making interstate transport and importation illegal Onlythe Mediterranean clone was included in this initialrequest The term ldquoMediterranean clonerdquo has beenreplaced by the more neutral ldquoaquarium strainrdquo by manyscientists and this term will be used here

In 2001 California imposed stricter guidelines than theFederal Government in response to the two southern

RESEARCH COMMUNICATIONS RESEARCH COMMUNICATIONS

E-commerce and Caulerpa unregulateddispersal of invasive species

Linda J Walters1 Katherine R Brown1 Wytze T Stam2 and Jeanine L Olsen2

Professional aquarists and hobbyists are thought to be the source of invasions of the aquarium strain of thegreen macroalga Caulerpa taxifolia in the Mediterranean southern California and Australia The USDepartment of Agriculture Animal and Plant Health Inspection Service (USDAndashAPHIS) restricted interstatecommerce and importation of the Mediterranean clone of C taxifolia prior to the California invasion and is cur-rently deciding if it should strengthen regulation of this genus as more species of Caulerpa are being describedas invasive Here we document the importance of e-commerce as a mode of dispersal for many species ofCaulerpa in the United States We purchased Caulerpa from 30 internet retailers and 60 internet auction sitesrepresenting 25 states and Great Britain Twelve different Caulerpa species were confirmed using DNA sequenc-ing Only 106 of sellers provided the correct genus and species names with their shipments Thirty purchasesof ldquolive rockrdquo provided four species of Caulerpa as well as 53 additional marine species Our results confirm theextensive e-commerce availability of this invasive genus and its high dispersal potential via postal services andhobbyists We recommend that both eBay and the USDA maximize regulation of Caulerpa

Front Ecol Environ 2006 4(2) 75ndash79

1Department of Biology University of Central Florida OrlandoFL 32816 USA (ljwalterpegasusccucfedu) 2Department ofMarine Biology Center for Ecological and Evolutionary StudiesUniversity of Groningen The Netherlands

E-commerce and Caulerpa LJ Walters et al

76

wwwfrontiersinecologyorg copy The Ecological Society of America

Californian invasions by the aquarium strain of C taxifo-lia it became illegal to sell or possess C taxifolia or eightother species some of which are easily confused with Ctaxifolia (C mexicana C sertulariodes C ashmeadii C flori-dana C cupressoides) and others that are considered inva-sive (C racemosa C scalpelliformis C verticillata) The cityof San Diego took this a step further and made it illegal topossess any species of Caulerpa There has been local suc-cess in eradicating Caulerpa in southern California but ata cost of over $5 million (R Woodfield pers comm) Nowa more concerted approach is necessary at the nationallevel The Aquatic Nuisance Species (ANS) Task Forcereleased a National Management Plan for the genusCaulerpa in the fall of 2005 focused on supportingCaulerpa research and outreach and the USDAndashAPHISis currently considering whether to enhance regulation ofthis genus Although both the ANS Task Force andUSDAndashAPHIS acknowledge the potential importance ofe-commerce as a mode of dispersal for these species untilnow the importance of this vector has not been directlymeasured

Methods

Between April 2003 and April 2005 using our centralFlorida address we determined the diversity and avail-ability of Caulerpa species via e-commerce and local retailoutlets The study involved 22 volunteers and over 200internet search hours we therefore consider our findingsto be representative of the online availability of thegenus Volunteers chose their search dates and each timea volunteer began a search heshe had 48 hours to find allthe sources of Caulerpa available via online retail andeBay auctions using their own choice of keywordsKeywords ranged from the obvious (eg Caulerpa macroal-gae) to less obvious terms such as refugia sea grapes ormarine cactus Online purchases were made once fromeach dealer with any species of Caulerpa in stock andfrom all unique eBay auctions that we won betweenMarch 11 and November 16 2004 and between February1 and March 18 2005 We purchased Caulerpa from 51of the online retailers we identified (Caulerpa was fre-quently out of stock) and 44 of the auctions In addi-tion we obtained Caulerpa spp from 25 of 47 (53) salt-water aquarium retail shops in central Florida (all YellowPage-listed shops in the Tampa Orlando and DaytonaBeach areas) We compared our data to those of Zaleskiand Murray (in press) who conducted a similar survey of50 southern California retailers between November 2000and August 2001

To determine the likelihood of purchasing live rockwith Caulerpa growing on it we purchased rocks from tenonline retailers ten eBay auctions and ten local retailersduring the same periods as described above On the inter-net ldquolive rockrdquo was the only keyword we used and we pur-chased it from the first ten retailers and eBay auctions weencountered that would sell us quantities of 10 kg or less

Many distributors only wanted to supply 100 kg or moreshipped directly from the country of origin All of thepurchased live rock was maintained in separate recircu-lating aquaria for 1 month

Results and discussion

From 90 internet sites (30 online commercial retailers and60 eBay auctions) Caulerpa spp were shipped to centralFlorida from shipping addresses in Great Britain and 25US states 52 of which were landlocked (Figures 1 and2) Figures 1 and 2 document extensive interstate trans-port of this genus especially via eBay We separated ourpurchases into online retail versus eBay auctions for tworeasons First internet retailers should be aware of federalregulations pertaining to the organisms they sell as part oftheir livelihood while this may or may not be the casewith eBay vendors many of whom are home hobbyistsInformation about restrictions on shipping Caulerpa toCalifornia was found on only two of the 30 retail websitesfrom which we purchased material eBay states that sellersare responsible for knowing all federal and state regula-tions for all live plants animals or animal products theysell and that vendors stand to have their accounts sus-pended and forfeit all eBay fees on the cancelled listingsfor breaking federal regulations Of the 60 eBay auctionswe won only three vendors included information showingthat they were aware of the restrictions on interstatetransport of Caulerpa In addition one eBay vendor of Cprolifera proudly and correctly stated that this species waspermitted in and could be shipped to California Wenever saw the aquarium strain of C taxifolia specificallylisted on eBay but ldquofeather Caulerpardquo was frequently seenfor sale Twelve of the 30 internet retailers were located inFlorida and collected macroalgae locally on demand Wealso bought from two out-of-state retailers that supply live

Figure 1 States with Caulerpa available for purchase from com-mercial internet retailers Numbers associated with pie-charts indi-cate the number of retailers

Internet retail sites selling Caulerpa

CaliforniaFloridaIdahoIndianaMarylandNew JerseyNew YorkNorth CarolinaOhioWisconsin

12

5

1

2

1

312

2

1

LJ Walters et al E-commerce and Caulerpa

77

copy The Ecological Society of America wwwfrontiersinecologyorg

materials to educational institutionsthat contracted with south Floridaharvesters to supply Caulerpa asneeded Thus 47 of our internetretail purchases never crossed statelines Caulerpa spp were purchasedfrom seven eBay auctions listingFlorida as their address (12) Thissuggests much greater interstate dis-persal of Caulerpa from eBay auctionsthan from internet retailers It is alsoimportant to note that all of our pur-chases were delivered via the USpostal service or one of many privateshipping services USDAndashAPHIShas no direct regulatory inspectionauthority over these entities

Caulerpa costs varied greatly amongsellers with the least expensive beinglocal retailers The average cost for ahandful of any species of the genusCaulerpa locally was $400 Notincluded in this average is the freeCaulerpa that we received from 43 of the local retailersWe always purchased the smallest amount available onlineUnits of purchase also varied greatly among dealers rangingfrom 2ndash3 individuals to enough to fill a quart-size plastic bag(22 x 17 cm) to ldquoenough for a class of 35 studentsrdquo Theaverage cost for any single species of Caulerpa from internetretailers was $4308 and $1809 from eBay In both casesthis price included packing and shipping charges whichranged from $10 to over $35 per shipment

From all purchased material 13 different Caulerpaspecies were identified by us at the University ofGroningen using DNA sequencing (Figure 3) Details ofall sequences and relationships for all collections alongwith those of Zaleski and Murray (in press) will soon besubmitted to GenBank and for publication (Stam et alunpublished) Four species were available from allsources whereas C cupressoides was only available via theinternet (Figure 3) Of the 12 species shipped to centralFlorida two species Caulerpa serrulata and C taxifoliahave not been reported in Floridarsquos coastal waters (Littlerand Littler 2000 C Glardon pers comm)

Specimens of C taxifolia were purchased only oncefrom a southern California internet retailer (November2004) and were listed online as ldquogreen feather CaulerpardquoIt proved to be the non-invasive type based on DNAsequence analysis (Stam et al unpublished) The onefinding of C taxifolia suggests that this species is not beingwidely distributed in the US via e-commerce hopefullyas a result of awareness campaigns and USDAndashAPHISregulations The potential success of this early (pre-California invasion) USDA decision to restrict theaquarium strain of C taxifolia indicates that a genus-wideban could be very effective in preventing future invasionsand associated extremely costly eradication efforts

Reported origins of live rock included Haiti theCaribbean Florida Keys Marshall Islands Pohnpei FijiTonga Samoa and Vanuatu Following one-month labora-tory cultivation we observed C racemosa C sertularioidesC mexicana and C verticillata plus 25 other species ofmacroalgae 27 species of invertebrates and multiplespecies of cyanobacteria In many cases Caulerpa was notvisible on the rocks until the fourth week of cultivationCosts of live rock ranged from $2029 per pound from inter-net retailers $682 per pound from eBay vendors (bothinclude shipping) to $723 per pound from local retailers

From our e-commerce purchases we learned that bothretailers and eBay vendors frequently do not identify theirproduct scientifically by including the genus and species(141 included both genus and species) When all pur-chases were considered sellers correctly identifiedCaulerpa at the species level only 106 of the timeMisidentifications at the species level occurred 35 ofthe time (all associated with ldquofeather Caulerpasrdquo) whileonly the name Caulerpa (or green Caulerpa or Caulerpaalgae) was used 157 of the time The genus nameCaulerpa plus a common name descriptor (eg grapeCaulerpa feather Caulerpa) was used in 444 of caseswhile only a common name (eg grape weed fern algaeetc) was used 111 of the time The term ldquogreenmacroalgaerdquo was used 51 of the time and the term ldquofishfoodrdquo was used on one occasion At the genus level mis-takes occurred in 96 of cases This is in part becauseCaulerpa is a popular internet keyword which encouragessellers to mislabel their stock We found ldquored grapeCaulerpardquo (actually Botrycladia) ldquored feather Caulerpardquo(actually Gelidiella) ldquored Gracilaria Caulerpardquo (actuallyGracilaria) ldquolettuce Caulerpardquo (actually Ulva) ldquoCaulerpaHalimeda macroalgaerdquo (actually Halimeda opuntia) and

Figure 2 Statescountries with Caulerpa available for purchase from eBay auctionsNumbers associated with pie-charts indicate the number of auctions

Internet auction sites selling Caulerpa

CaliforniaConnecticutFloridaGeorgiaIllinoisIndianaIowaKentuckyLouisianaMarylandMichiganMissouriNew JerseyNew MexicoNew YorkNorth CarolinaOhioOregonPennsylvaniaSouth CarolinaTennesseeTexasVermontGreat Britain

7

11

5

21

4141

5

11

2

4

11

11

1

42 7

2

E-commerce and Caulerpa LJ Walters et al

78

wwwfrontiersinecologyorg copy The Ecological Society of America

sumers to the dangers of ldquoaquariumdumpingrdquo Locally only two of 47 retail-ers had signs asking patrons not to dumpunwanted organisms On the internet wefound only six distributors (five retailersone eBay auction) who warned againstaquarium dumping This limited amountof warning on improper disposal ofunwanted marine organisms indicatesthat more and better outreach is neededA new website wwwhabitattitudenetwas recently created for just this reasonThis national initiative has been devel-oped by the ANS Task Force and theaquarium pet nursery and landscapeindustries to raise consumer awarenessabout invasive species and alternatives torelease of unwanted organisms into thewild A number of other partners are alsoinvolved including US and state-levelFish and Wildlife Services and theNational Sea Grant College Program Byengaging and receiving support from the

industries that distribute non-native flora and fauna forthe first time this outreach program has a much greaterchance of success than previous federal and state-levelefforts that operated on a more confrontational level Todate only a limited number of retail outlets and suppliershave shown interest but expectations are high that thiscampaign will help reduce the number of releases of inva-sive species in terrestrial fresh and marine systems

Acknowledgements

We thank P Sacks C Glardon M Black and all thesearchers For funding we thank the National and FloridaSea Grant College Programs Pinellas CountyEnvironmental Fund Tampa Bay Estuary ProgramFlorida Department of Agriculture University ofGroningen and the University of Central FloridaSuggestions by P Windle substantially improved thismanuscript

ReferencesBelsher T and Meinesz A 1995 Deep water dispersal of the tropi-

cal alga Caulerpa taxifolia introduced into the MediterraneanAquat Bot 51 163ndash69

Davis A Roberts D and Cummins S 1997 Rapid invasion of asponge-dominated deep-reef by Caulerpa scalpelliformis(Chlorophyta) in Botany Bay Aust J Ecol 22 146ndash50

de Villegravele X and Verlaque M 1995 Changes and degradation in aPosidonia oceanica bed invaded by the introduced tropical algaCaulerpa taxifolia in the north western Mediterranean Bot Mar38 79ndash87

Jacoby C Lapointe B and Creswell L 2004 Are native and non-indigenous seaweeds overgrowing Floridarsquos east coast reefsGainesville FL Florida Sea Grant College Program SGEF-156

Jousson O Pawlowksi J Zaninetti L et al 1998 Molecular evi-dence for the aquarium origin of the green alga Caulerpa taxifo-

ldquoChaetomorpha Caulerpardquo (actually Chaetomorpha) Thishigh level of unreliability and variability makes bothmorphological identification by customs agents andinternet tracking of Caulerpa difficult

Finally we discovered that Caulerpa especially speciesof Caulerpa with feathery blades was frequently picturedin entire aquarium set-ups for sale on internet auctionsites Items had to be collected in person so we were ableto acquire C racemosa and C mexicana by this means fromonly one auction initiated in Clermont Florida In totalten states were represented in 13 auctions for complete30ndash120-gallon tank set-ups

Improving the future

Internet availability of the genus Caulerpa as well asnumerous other algal species and invertebrates repre-sents a serious threat to Floridarsquos coastlines in terms ofnon-native introductions from hobbyists The $5 millionspent on Caulerpa eradication in California would beequivalent to 142 857 purchases of loose Caulerpa at anaverage of $35 per purchase If 1 of these hobbyistsdumped Caulerpa into nearby waters and 1 of thesereleases became established then at least $70 million (14eradications x $5 millionresponse) will be required toachieve eradication Pressuring eBay to eliminate all auc-tions of Caulerpa and enhanced federal regulation ofCaulerpa would be considerably more cost-effective

Commercial retail of invasive species is not limited tomarine macroalgae or live rock For example Semmens etal (2004) found 16 species of non-native marine fishesin Florida waters their data suggest aquarium dumping asthe source for all these species Only limited informationwas available online and in local retail shops to alert con-

Caulerpa availability by species

Per

cent

50

40

30

20

10

0

C ashmeadii

C brachypus

C cupressoides

C mexic

ana

C paspaloides

C prolifera

C racemosa

C serru

lata

C sertu

larioides

C taxifo

lia

C microphysa

C vertic

illata

C webbiana

Figure 3 Percent availability of Caulerpa species from eBay auctions and onlineCentral Florida and Southern California retail sources

Online retaileBay auctionsCentral FL retailersSouthern CA retailers

LJ Walters et al E-commerce and Caulerpa

79

copy The Ecological Society of America wwwfrontiersinecologyorg

lia introduced to the Mediterranean Sea Mar Ecol Prog Ser172 275ndash80

Jousson O Pawlowski J Zaninetti L et al 2000 Invasive algareaches California Nature 408 157ndash58

Littler D and Littler M 2000 Caribbean reef plants WashingtonDC OffShore Graphics Inc

Meinesz A 1999 Killer algae Chicago IL University of ChicagoPress

Meinesz A Belsher T Thibault T et al 2001 The introduced greenalga Caulerpa taxifolia continues to spread in the Mediter-ranean Biol Invas 3 201ndash10

Meusnier I Valero M Destombe C et al 2002 Polymerase chainreaction-single strand conformation polymorphism analyses ofnuclear and chloroplast DNA provide evidence for recombina-tion multiple introductions and nascent speciation in theCaulerpa taxifolia complex Mol Ecol 11 2317ndash25

Millar A 2004 New records of marine benthic algae from NewSouth Wales eastern Australia Phycol Res 52 117ndash28

Padilla D and Williams S 2004 Beyond ballast water aquariumand ornamental trades as sources of invasive species in aquaticecosystems Front Ecol Environ 2 131ndash38

Schaffelke B Murphy N and Uthicke S 2002 Using genetic tech-niques to investigate the sources of the invasive alga Caulerpataxifolia in three new locations in Australia Mar Pollut Bull 44204ndash10

Semmens B Buhle E Salomon A and Pattengill-Semmens C2004 A hotspot of non-native marine fishes evidence for theaquarium trade as an invasion pathway Mar Ecol Prog Ser 266239ndash44

Smith C and Walters L 1999 Fragmentation as a strategy for

Caulerpa species fates of fragments and implications for man-agement of an invasive weed PSZN I Mar Ecol 20 307ndash19

Verlaque M Afonso-Carrillo J Candelaria Gil-Rodriacuteguez M et al2004 Blitzkrieg in a marine invasion Caulerpa racemosa varcylindracea (Bryopsidales Chlorophyta) reaches the CanaryIslands (north-east Atlantic) Biol Invas 6 269ndash81

Verlaque M Durand C Huisman J et al 2003 On the identity andorigin of the Mediterranean invasive Caulerpa racemosa(Caulerpales Chlorophyta) Eur J Phycol 38 325ndash39

Whitfield P Gardner T Vives S et al 2002 Biological invasions ofthe Indo-Pacific lionfish (Pterois volitans) along the Atlanticcoast of North America Mar Ecol Prog Ser 235 289ndash97

Wiedenmann J Baumstark A Pillen TL et al 2001 DNA finger-prints of Caulerpa taxifolia provide evidence for the introduc-tion of an aquarium strain into the Mediterranean Sea and itsclose relationship to an Australian population Mar Biol 138229ndash34

Williams E and Grosholz E 2002a International Caulerpa taxifoliaConference Proceedings California Sea Grant CollegeProgram University of California La Jolla Pub No T-047

Williams S and Grosholz E 2002b Preliminary reports from theCaulerpa taxifolia invasion in southern California Mar EcolProg Ser 233 307ndash10

Williams S and Schroeder S 2004 Eradication of the invasive sea-weed Caulerpa taxifolia by chlorine bleach Mar Ecol Prog Ser272 69ndash76

Zaleski S and Murray S Taxonomic diversity geographic distribu-tion and commercial availability of aquarium-traded species ofCaulerpa (Chlorophyta Caulerpaceae) in southern CaliforniaUSA Mar Ecol Prog Ser In press

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E-commerce and Caulerpa LJ Walters et al

76

wwwfrontiersinecologyorg copy The Ecological Society of America

Californian invasions by the aquarium strain of C taxifo-lia it became illegal to sell or possess C taxifolia or eightother species some of which are easily confused with Ctaxifolia (C mexicana C sertulariodes C ashmeadii C flori-dana C cupressoides) and others that are considered inva-sive (C racemosa C scalpelliformis C verticillata) The cityof San Diego took this a step further and made it illegal topossess any species of Caulerpa There has been local suc-cess in eradicating Caulerpa in southern California but ata cost of over $5 million (R Woodfield pers comm) Nowa more concerted approach is necessary at the nationallevel The Aquatic Nuisance Species (ANS) Task Forcereleased a National Management Plan for the genusCaulerpa in the fall of 2005 focused on supportingCaulerpa research and outreach and the USDAndashAPHISis currently considering whether to enhance regulation ofthis genus Although both the ANS Task Force andUSDAndashAPHIS acknowledge the potential importance ofe-commerce as a mode of dispersal for these species untilnow the importance of this vector has not been directlymeasured

Methods

Between April 2003 and April 2005 using our centralFlorida address we determined the diversity and avail-ability of Caulerpa species via e-commerce and local retailoutlets The study involved 22 volunteers and over 200internet search hours we therefore consider our findingsto be representative of the online availability of thegenus Volunteers chose their search dates and each timea volunteer began a search heshe had 48 hours to find allthe sources of Caulerpa available via online retail andeBay auctions using their own choice of keywordsKeywords ranged from the obvious (eg Caulerpa macroal-gae) to less obvious terms such as refugia sea grapes ormarine cactus Online purchases were made once fromeach dealer with any species of Caulerpa in stock andfrom all unique eBay auctions that we won betweenMarch 11 and November 16 2004 and between February1 and March 18 2005 We purchased Caulerpa from 51of the online retailers we identified (Caulerpa was fre-quently out of stock) and 44 of the auctions In addi-tion we obtained Caulerpa spp from 25 of 47 (53) salt-water aquarium retail shops in central Florida (all YellowPage-listed shops in the Tampa Orlando and DaytonaBeach areas) We compared our data to those of Zaleskiand Murray (in press) who conducted a similar survey of50 southern California retailers between November 2000and August 2001

To determine the likelihood of purchasing live rockwith Caulerpa growing on it we purchased rocks from tenonline retailers ten eBay auctions and ten local retailersduring the same periods as described above On the inter-net ldquolive rockrdquo was the only keyword we used and we pur-chased it from the first ten retailers and eBay auctions weencountered that would sell us quantities of 10 kg or less

Many distributors only wanted to supply 100 kg or moreshipped directly from the country of origin All of thepurchased live rock was maintained in separate recircu-lating aquaria for 1 month

Results and discussion

From 90 internet sites (30 online commercial retailers and60 eBay auctions) Caulerpa spp were shipped to centralFlorida from shipping addresses in Great Britain and 25US states 52 of which were landlocked (Figures 1 and2) Figures 1 and 2 document extensive interstate trans-port of this genus especially via eBay We separated ourpurchases into online retail versus eBay auctions for tworeasons First internet retailers should be aware of federalregulations pertaining to the organisms they sell as part oftheir livelihood while this may or may not be the casewith eBay vendors many of whom are home hobbyistsInformation about restrictions on shipping Caulerpa toCalifornia was found on only two of the 30 retail websitesfrom which we purchased material eBay states that sellersare responsible for knowing all federal and state regula-tions for all live plants animals or animal products theysell and that vendors stand to have their accounts sus-pended and forfeit all eBay fees on the cancelled listingsfor breaking federal regulations Of the 60 eBay auctionswe won only three vendors included information showingthat they were aware of the restrictions on interstatetransport of Caulerpa In addition one eBay vendor of Cprolifera proudly and correctly stated that this species waspermitted in and could be shipped to California Wenever saw the aquarium strain of C taxifolia specificallylisted on eBay but ldquofeather Caulerpardquo was frequently seenfor sale Twelve of the 30 internet retailers were located inFlorida and collected macroalgae locally on demand Wealso bought from two out-of-state retailers that supply live

Figure 1 States with Caulerpa available for purchase from com-mercial internet retailers Numbers associated with pie-charts indi-cate the number of retailers

Internet retail sites selling Caulerpa

CaliforniaFloridaIdahoIndianaMarylandNew JerseyNew YorkNorth CarolinaOhioWisconsin

12

5

1

2

1

312

2

1

LJ Walters et al E-commerce and Caulerpa

77

copy The Ecological Society of America wwwfrontiersinecologyorg

materials to educational institutionsthat contracted with south Floridaharvesters to supply Caulerpa asneeded Thus 47 of our internetretail purchases never crossed statelines Caulerpa spp were purchasedfrom seven eBay auctions listingFlorida as their address (12) Thissuggests much greater interstate dis-persal of Caulerpa from eBay auctionsthan from internet retailers It is alsoimportant to note that all of our pur-chases were delivered via the USpostal service or one of many privateshipping services USDAndashAPHIShas no direct regulatory inspectionauthority over these entities

Caulerpa costs varied greatly amongsellers with the least expensive beinglocal retailers The average cost for ahandful of any species of the genusCaulerpa locally was $400 Notincluded in this average is the freeCaulerpa that we received from 43 of the local retailersWe always purchased the smallest amount available onlineUnits of purchase also varied greatly among dealers rangingfrom 2ndash3 individuals to enough to fill a quart-size plastic bag(22 x 17 cm) to ldquoenough for a class of 35 studentsrdquo Theaverage cost for any single species of Caulerpa from internetretailers was $4308 and $1809 from eBay In both casesthis price included packing and shipping charges whichranged from $10 to over $35 per shipment

From all purchased material 13 different Caulerpaspecies were identified by us at the University ofGroningen using DNA sequencing (Figure 3) Details ofall sequences and relationships for all collections alongwith those of Zaleski and Murray (in press) will soon besubmitted to GenBank and for publication (Stam et alunpublished) Four species were available from allsources whereas C cupressoides was only available via theinternet (Figure 3) Of the 12 species shipped to centralFlorida two species Caulerpa serrulata and C taxifoliahave not been reported in Floridarsquos coastal waters (Littlerand Littler 2000 C Glardon pers comm)

Specimens of C taxifolia were purchased only oncefrom a southern California internet retailer (November2004) and were listed online as ldquogreen feather CaulerpardquoIt proved to be the non-invasive type based on DNAsequence analysis (Stam et al unpublished) The onefinding of C taxifolia suggests that this species is not beingwidely distributed in the US via e-commerce hopefullyas a result of awareness campaigns and USDAndashAPHISregulations The potential success of this early (pre-California invasion) USDA decision to restrict theaquarium strain of C taxifolia indicates that a genus-wideban could be very effective in preventing future invasionsand associated extremely costly eradication efforts

Reported origins of live rock included Haiti theCaribbean Florida Keys Marshall Islands Pohnpei FijiTonga Samoa and Vanuatu Following one-month labora-tory cultivation we observed C racemosa C sertularioidesC mexicana and C verticillata plus 25 other species ofmacroalgae 27 species of invertebrates and multiplespecies of cyanobacteria In many cases Caulerpa was notvisible on the rocks until the fourth week of cultivationCosts of live rock ranged from $2029 per pound from inter-net retailers $682 per pound from eBay vendors (bothinclude shipping) to $723 per pound from local retailers

From our e-commerce purchases we learned that bothretailers and eBay vendors frequently do not identify theirproduct scientifically by including the genus and species(141 included both genus and species) When all pur-chases were considered sellers correctly identifiedCaulerpa at the species level only 106 of the timeMisidentifications at the species level occurred 35 ofthe time (all associated with ldquofeather Caulerpasrdquo) whileonly the name Caulerpa (or green Caulerpa or Caulerpaalgae) was used 157 of the time The genus nameCaulerpa plus a common name descriptor (eg grapeCaulerpa feather Caulerpa) was used in 444 of caseswhile only a common name (eg grape weed fern algaeetc) was used 111 of the time The term ldquogreenmacroalgaerdquo was used 51 of the time and the term ldquofishfoodrdquo was used on one occasion At the genus level mis-takes occurred in 96 of cases This is in part becauseCaulerpa is a popular internet keyword which encouragessellers to mislabel their stock We found ldquored grapeCaulerpardquo (actually Botrycladia) ldquored feather Caulerpardquo(actually Gelidiella) ldquored Gracilaria Caulerpardquo (actuallyGracilaria) ldquolettuce Caulerpardquo (actually Ulva) ldquoCaulerpaHalimeda macroalgaerdquo (actually Halimeda opuntia) and

Figure 2 Statescountries with Caulerpa available for purchase from eBay auctionsNumbers associated with pie-charts indicate the number of auctions

Internet auction sites selling Caulerpa

CaliforniaConnecticutFloridaGeorgiaIllinoisIndianaIowaKentuckyLouisianaMarylandMichiganMissouriNew JerseyNew MexicoNew YorkNorth CarolinaOhioOregonPennsylvaniaSouth CarolinaTennesseeTexasVermontGreat Britain

7

11

5

21

4141

5

11

2

4

11

11

1

42 7

2

E-commerce and Caulerpa LJ Walters et al

78

wwwfrontiersinecologyorg copy The Ecological Society of America

sumers to the dangers of ldquoaquariumdumpingrdquo Locally only two of 47 retail-ers had signs asking patrons not to dumpunwanted organisms On the internet wefound only six distributors (five retailersone eBay auction) who warned againstaquarium dumping This limited amountof warning on improper disposal ofunwanted marine organisms indicatesthat more and better outreach is neededA new website wwwhabitattitudenetwas recently created for just this reasonThis national initiative has been devel-oped by the ANS Task Force and theaquarium pet nursery and landscapeindustries to raise consumer awarenessabout invasive species and alternatives torelease of unwanted organisms into thewild A number of other partners are alsoinvolved including US and state-levelFish and Wildlife Services and theNational Sea Grant College Program Byengaging and receiving support from the

industries that distribute non-native flora and fauna forthe first time this outreach program has a much greaterchance of success than previous federal and state-levelefforts that operated on a more confrontational level Todate only a limited number of retail outlets and suppliershave shown interest but expectations are high that thiscampaign will help reduce the number of releases of inva-sive species in terrestrial fresh and marine systems

Acknowledgements

We thank P Sacks C Glardon M Black and all thesearchers For funding we thank the National and FloridaSea Grant College Programs Pinellas CountyEnvironmental Fund Tampa Bay Estuary ProgramFlorida Department of Agriculture University ofGroningen and the University of Central FloridaSuggestions by P Windle substantially improved thismanuscript

ReferencesBelsher T and Meinesz A 1995 Deep water dispersal of the tropi-

cal alga Caulerpa taxifolia introduced into the MediterraneanAquat Bot 51 163ndash69

Davis A Roberts D and Cummins S 1997 Rapid invasion of asponge-dominated deep-reef by Caulerpa scalpelliformis(Chlorophyta) in Botany Bay Aust J Ecol 22 146ndash50

de Villegravele X and Verlaque M 1995 Changes and degradation in aPosidonia oceanica bed invaded by the introduced tropical algaCaulerpa taxifolia in the north western Mediterranean Bot Mar38 79ndash87

Jacoby C Lapointe B and Creswell L 2004 Are native and non-indigenous seaweeds overgrowing Floridarsquos east coast reefsGainesville FL Florida Sea Grant College Program SGEF-156

Jousson O Pawlowksi J Zaninetti L et al 1998 Molecular evi-dence for the aquarium origin of the green alga Caulerpa taxifo-

ldquoChaetomorpha Caulerpardquo (actually Chaetomorpha) Thishigh level of unreliability and variability makes bothmorphological identification by customs agents andinternet tracking of Caulerpa difficult

Finally we discovered that Caulerpa especially speciesof Caulerpa with feathery blades was frequently picturedin entire aquarium set-ups for sale on internet auctionsites Items had to be collected in person so we were ableto acquire C racemosa and C mexicana by this means fromonly one auction initiated in Clermont Florida In totalten states were represented in 13 auctions for complete30ndash120-gallon tank set-ups

Improving the future

Internet availability of the genus Caulerpa as well asnumerous other algal species and invertebrates repre-sents a serious threat to Floridarsquos coastlines in terms ofnon-native introductions from hobbyists The $5 millionspent on Caulerpa eradication in California would beequivalent to 142 857 purchases of loose Caulerpa at anaverage of $35 per purchase If 1 of these hobbyistsdumped Caulerpa into nearby waters and 1 of thesereleases became established then at least $70 million (14eradications x $5 millionresponse) will be required toachieve eradication Pressuring eBay to eliminate all auc-tions of Caulerpa and enhanced federal regulation ofCaulerpa would be considerably more cost-effective

Commercial retail of invasive species is not limited tomarine macroalgae or live rock For example Semmens etal (2004) found 16 species of non-native marine fishesin Florida waters their data suggest aquarium dumping asthe source for all these species Only limited informationwas available online and in local retail shops to alert con-

Caulerpa availability by species

Per

cent

50

40

30

20

10

0

C ashmeadii

C brachypus

C cupressoides

C mexic

ana

C paspaloides

C prolifera

C racemosa

C serru

lata

C sertu

larioides

C taxifo

lia

C microphysa

C vertic

illata

C webbiana

Figure 3 Percent availability of Caulerpa species from eBay auctions and onlineCentral Florida and Southern California retail sources

Online retaileBay auctionsCentral FL retailersSouthern CA retailers

LJ Walters et al E-commerce and Caulerpa

79

copy The Ecological Society of America wwwfrontiersinecologyorg

lia introduced to the Mediterranean Sea Mar Ecol Prog Ser172 275ndash80

Jousson O Pawlowski J Zaninetti L et al 2000 Invasive algareaches California Nature 408 157ndash58

Littler D and Littler M 2000 Caribbean reef plants WashingtonDC OffShore Graphics Inc

Meinesz A 1999 Killer algae Chicago IL University of ChicagoPress

Meinesz A Belsher T Thibault T et al 2001 The introduced greenalga Caulerpa taxifolia continues to spread in the Mediter-ranean Biol Invas 3 201ndash10

Meusnier I Valero M Destombe C et al 2002 Polymerase chainreaction-single strand conformation polymorphism analyses ofnuclear and chloroplast DNA provide evidence for recombina-tion multiple introductions and nascent speciation in theCaulerpa taxifolia complex Mol Ecol 11 2317ndash25

Millar A 2004 New records of marine benthic algae from NewSouth Wales eastern Australia Phycol Res 52 117ndash28

Padilla D and Williams S 2004 Beyond ballast water aquariumand ornamental trades as sources of invasive species in aquaticecosystems Front Ecol Environ 2 131ndash38

Schaffelke B Murphy N and Uthicke S 2002 Using genetic tech-niques to investigate the sources of the invasive alga Caulerpataxifolia in three new locations in Australia Mar Pollut Bull 44204ndash10

Semmens B Buhle E Salomon A and Pattengill-Semmens C2004 A hotspot of non-native marine fishes evidence for theaquarium trade as an invasion pathway Mar Ecol Prog Ser 266239ndash44

Smith C and Walters L 1999 Fragmentation as a strategy for

Caulerpa species fates of fragments and implications for man-agement of an invasive weed PSZN I Mar Ecol 20 307ndash19

Verlaque M Afonso-Carrillo J Candelaria Gil-Rodriacuteguez M et al2004 Blitzkrieg in a marine invasion Caulerpa racemosa varcylindracea (Bryopsidales Chlorophyta) reaches the CanaryIslands (north-east Atlantic) Biol Invas 6 269ndash81

Verlaque M Durand C Huisman J et al 2003 On the identity andorigin of the Mediterranean invasive Caulerpa racemosa(Caulerpales Chlorophyta) Eur J Phycol 38 325ndash39

Whitfield P Gardner T Vives S et al 2002 Biological invasions ofthe Indo-Pacific lionfish (Pterois volitans) along the Atlanticcoast of North America Mar Ecol Prog Ser 235 289ndash97

Wiedenmann J Baumstark A Pillen TL et al 2001 DNA finger-prints of Caulerpa taxifolia provide evidence for the introduc-tion of an aquarium strain into the Mediterranean Sea and itsclose relationship to an Australian population Mar Biol 138229ndash34

Williams E and Grosholz E 2002a International Caulerpa taxifoliaConference Proceedings California Sea Grant CollegeProgram University of California La Jolla Pub No T-047

Williams S and Grosholz E 2002b Preliminary reports from theCaulerpa taxifolia invasion in southern California Mar EcolProg Ser 233 307ndash10

Williams S and Schroeder S 2004 Eradication of the invasive sea-weed Caulerpa taxifolia by chlorine bleach Mar Ecol Prog Ser272 69ndash76

Zaleski S and Murray S Taxonomic diversity geographic distribu-tion and commercial availability of aquarium-traded species ofCaulerpa (Chlorophyta Caulerpaceae) in southern CaliforniaUSA Mar Ecol Prog Ser In press

TAKE THIS JOURNAL TO YOUR LIBRARIAN PLEASEDid you enjoy this issue of Frontiers

If your library had a subscription colleagues and students could enjoy it tooPlease consider recommending Frontiers in Ecology and Environment to your library

Clip or copy the form below Thank you for your support

Library Recommendation Form

To Acquisition Librarian Serials

From

Dept

Signature Date

I recommend the library subscribe to Frontiers in Ecology and the Environment (ISSN 1540-9295)

To request a free sample issue of Frontiers in Ecology and the Environment call (301) 588-4691 or email Sika Dunyoh

at sikaesaorg Order Frontiers by contacting ESA Headquarters at (202) 833-8773 online at wwwesaorg or through your subscription agent

LJ Walters et al E-commerce and Caulerpa

77

copy The Ecological Society of America wwwfrontiersinecologyorg

materials to educational institutionsthat contracted with south Floridaharvesters to supply Caulerpa asneeded Thus 47 of our internetretail purchases never crossed statelines Caulerpa spp were purchasedfrom seven eBay auctions listingFlorida as their address (12) Thissuggests much greater interstate dis-persal of Caulerpa from eBay auctionsthan from internet retailers It is alsoimportant to note that all of our pur-chases were delivered via the USpostal service or one of many privateshipping services USDAndashAPHIShas no direct regulatory inspectionauthority over these entities

Caulerpa costs varied greatly amongsellers with the least expensive beinglocal retailers The average cost for ahandful of any species of the genusCaulerpa locally was $400 Notincluded in this average is the freeCaulerpa that we received from 43 of the local retailersWe always purchased the smallest amount available onlineUnits of purchase also varied greatly among dealers rangingfrom 2ndash3 individuals to enough to fill a quart-size plastic bag(22 x 17 cm) to ldquoenough for a class of 35 studentsrdquo Theaverage cost for any single species of Caulerpa from internetretailers was $4308 and $1809 from eBay In both casesthis price included packing and shipping charges whichranged from $10 to over $35 per shipment

From all purchased material 13 different Caulerpaspecies were identified by us at the University ofGroningen using DNA sequencing (Figure 3) Details ofall sequences and relationships for all collections alongwith those of Zaleski and Murray (in press) will soon besubmitted to GenBank and for publication (Stam et alunpublished) Four species were available from allsources whereas C cupressoides was only available via theinternet (Figure 3) Of the 12 species shipped to centralFlorida two species Caulerpa serrulata and C taxifoliahave not been reported in Floridarsquos coastal waters (Littlerand Littler 2000 C Glardon pers comm)

Specimens of C taxifolia were purchased only oncefrom a southern California internet retailer (November2004) and were listed online as ldquogreen feather CaulerpardquoIt proved to be the non-invasive type based on DNAsequence analysis (Stam et al unpublished) The onefinding of C taxifolia suggests that this species is not beingwidely distributed in the US via e-commerce hopefullyas a result of awareness campaigns and USDAndashAPHISregulations The potential success of this early (pre-California invasion) USDA decision to restrict theaquarium strain of C taxifolia indicates that a genus-wideban could be very effective in preventing future invasionsand associated extremely costly eradication efforts

Reported origins of live rock included Haiti theCaribbean Florida Keys Marshall Islands Pohnpei FijiTonga Samoa and Vanuatu Following one-month labora-tory cultivation we observed C racemosa C sertularioidesC mexicana and C verticillata plus 25 other species ofmacroalgae 27 species of invertebrates and multiplespecies of cyanobacteria In many cases Caulerpa was notvisible on the rocks until the fourth week of cultivationCosts of live rock ranged from $2029 per pound from inter-net retailers $682 per pound from eBay vendors (bothinclude shipping) to $723 per pound from local retailers

From our e-commerce purchases we learned that bothretailers and eBay vendors frequently do not identify theirproduct scientifically by including the genus and species(141 included both genus and species) When all pur-chases were considered sellers correctly identifiedCaulerpa at the species level only 106 of the timeMisidentifications at the species level occurred 35 ofthe time (all associated with ldquofeather Caulerpasrdquo) whileonly the name Caulerpa (or green Caulerpa or Caulerpaalgae) was used 157 of the time The genus nameCaulerpa plus a common name descriptor (eg grapeCaulerpa feather Caulerpa) was used in 444 of caseswhile only a common name (eg grape weed fern algaeetc) was used 111 of the time The term ldquogreenmacroalgaerdquo was used 51 of the time and the term ldquofishfoodrdquo was used on one occasion At the genus level mis-takes occurred in 96 of cases This is in part becauseCaulerpa is a popular internet keyword which encouragessellers to mislabel their stock We found ldquored grapeCaulerpardquo (actually Botrycladia) ldquored feather Caulerpardquo(actually Gelidiella) ldquored Gracilaria Caulerpardquo (actuallyGracilaria) ldquolettuce Caulerpardquo (actually Ulva) ldquoCaulerpaHalimeda macroalgaerdquo (actually Halimeda opuntia) and

Figure 2 Statescountries with Caulerpa available for purchase from eBay auctionsNumbers associated with pie-charts indicate the number of auctions

Internet auction sites selling Caulerpa

CaliforniaConnecticutFloridaGeorgiaIllinoisIndianaIowaKentuckyLouisianaMarylandMichiganMissouriNew JerseyNew MexicoNew YorkNorth CarolinaOhioOregonPennsylvaniaSouth CarolinaTennesseeTexasVermontGreat Britain

7

11

5

21

4141

5

11

2

4

11

11

1

42 7

2

E-commerce and Caulerpa LJ Walters et al

78

wwwfrontiersinecologyorg copy The Ecological Society of America

sumers to the dangers of ldquoaquariumdumpingrdquo Locally only two of 47 retail-ers had signs asking patrons not to dumpunwanted organisms On the internet wefound only six distributors (five retailersone eBay auction) who warned againstaquarium dumping This limited amountof warning on improper disposal ofunwanted marine organisms indicatesthat more and better outreach is neededA new website wwwhabitattitudenetwas recently created for just this reasonThis national initiative has been devel-oped by the ANS Task Force and theaquarium pet nursery and landscapeindustries to raise consumer awarenessabout invasive species and alternatives torelease of unwanted organisms into thewild A number of other partners are alsoinvolved including US and state-levelFish and Wildlife Services and theNational Sea Grant College Program Byengaging and receiving support from the

industries that distribute non-native flora and fauna forthe first time this outreach program has a much greaterchance of success than previous federal and state-levelefforts that operated on a more confrontational level Todate only a limited number of retail outlets and suppliershave shown interest but expectations are high that thiscampaign will help reduce the number of releases of inva-sive species in terrestrial fresh and marine systems

Acknowledgements

We thank P Sacks C Glardon M Black and all thesearchers For funding we thank the National and FloridaSea Grant College Programs Pinellas CountyEnvironmental Fund Tampa Bay Estuary ProgramFlorida Department of Agriculture University ofGroningen and the University of Central FloridaSuggestions by P Windle substantially improved thismanuscript

ReferencesBelsher T and Meinesz A 1995 Deep water dispersal of the tropi-

cal alga Caulerpa taxifolia introduced into the MediterraneanAquat Bot 51 163ndash69

Davis A Roberts D and Cummins S 1997 Rapid invasion of asponge-dominated deep-reef by Caulerpa scalpelliformis(Chlorophyta) in Botany Bay Aust J Ecol 22 146ndash50

de Villegravele X and Verlaque M 1995 Changes and degradation in aPosidonia oceanica bed invaded by the introduced tropical algaCaulerpa taxifolia in the north western Mediterranean Bot Mar38 79ndash87

Jacoby C Lapointe B and Creswell L 2004 Are native and non-indigenous seaweeds overgrowing Floridarsquos east coast reefsGainesville FL Florida Sea Grant College Program SGEF-156

Jousson O Pawlowksi J Zaninetti L et al 1998 Molecular evi-dence for the aquarium origin of the green alga Caulerpa taxifo-

ldquoChaetomorpha Caulerpardquo (actually Chaetomorpha) Thishigh level of unreliability and variability makes bothmorphological identification by customs agents andinternet tracking of Caulerpa difficult

Finally we discovered that Caulerpa especially speciesof Caulerpa with feathery blades was frequently picturedin entire aquarium set-ups for sale on internet auctionsites Items had to be collected in person so we were ableto acquire C racemosa and C mexicana by this means fromonly one auction initiated in Clermont Florida In totalten states were represented in 13 auctions for complete30ndash120-gallon tank set-ups

Improving the future

Internet availability of the genus Caulerpa as well asnumerous other algal species and invertebrates repre-sents a serious threat to Floridarsquos coastlines in terms ofnon-native introductions from hobbyists The $5 millionspent on Caulerpa eradication in California would beequivalent to 142 857 purchases of loose Caulerpa at anaverage of $35 per purchase If 1 of these hobbyistsdumped Caulerpa into nearby waters and 1 of thesereleases became established then at least $70 million (14eradications x $5 millionresponse) will be required toachieve eradication Pressuring eBay to eliminate all auc-tions of Caulerpa and enhanced federal regulation ofCaulerpa would be considerably more cost-effective

Commercial retail of invasive species is not limited tomarine macroalgae or live rock For example Semmens etal (2004) found 16 species of non-native marine fishesin Florida waters their data suggest aquarium dumping asthe source for all these species Only limited informationwas available online and in local retail shops to alert con-

Caulerpa availability by species

Per

cent

50

40

30

20

10

0

C ashmeadii

C brachypus

C cupressoides

C mexic

ana

C paspaloides

C prolifera

C racemosa

C serru

lata

C sertu

larioides

C taxifo

lia

C microphysa

C vertic

illata

C webbiana

Figure 3 Percent availability of Caulerpa species from eBay auctions and onlineCentral Florida and Southern California retail sources

Online retaileBay auctionsCentral FL retailersSouthern CA retailers

LJ Walters et al E-commerce and Caulerpa

79

copy The Ecological Society of America wwwfrontiersinecologyorg

lia introduced to the Mediterranean Sea Mar Ecol Prog Ser172 275ndash80

Jousson O Pawlowski J Zaninetti L et al 2000 Invasive algareaches California Nature 408 157ndash58

Littler D and Littler M 2000 Caribbean reef plants WashingtonDC OffShore Graphics Inc

Meinesz A 1999 Killer algae Chicago IL University of ChicagoPress

Meinesz A Belsher T Thibault T et al 2001 The introduced greenalga Caulerpa taxifolia continues to spread in the Mediter-ranean Biol Invas 3 201ndash10

Meusnier I Valero M Destombe C et al 2002 Polymerase chainreaction-single strand conformation polymorphism analyses ofnuclear and chloroplast DNA provide evidence for recombina-tion multiple introductions and nascent speciation in theCaulerpa taxifolia complex Mol Ecol 11 2317ndash25

Millar A 2004 New records of marine benthic algae from NewSouth Wales eastern Australia Phycol Res 52 117ndash28

Padilla D and Williams S 2004 Beyond ballast water aquariumand ornamental trades as sources of invasive species in aquaticecosystems Front Ecol Environ 2 131ndash38

Schaffelke B Murphy N and Uthicke S 2002 Using genetic tech-niques to investigate the sources of the invasive alga Caulerpataxifolia in three new locations in Australia Mar Pollut Bull 44204ndash10

Semmens B Buhle E Salomon A and Pattengill-Semmens C2004 A hotspot of non-native marine fishes evidence for theaquarium trade as an invasion pathway Mar Ecol Prog Ser 266239ndash44

Smith C and Walters L 1999 Fragmentation as a strategy for

Caulerpa species fates of fragments and implications for man-agement of an invasive weed PSZN I Mar Ecol 20 307ndash19

Verlaque M Afonso-Carrillo J Candelaria Gil-Rodriacuteguez M et al2004 Blitzkrieg in a marine invasion Caulerpa racemosa varcylindracea (Bryopsidales Chlorophyta) reaches the CanaryIslands (north-east Atlantic) Biol Invas 6 269ndash81

Verlaque M Durand C Huisman J et al 2003 On the identity andorigin of the Mediterranean invasive Caulerpa racemosa(Caulerpales Chlorophyta) Eur J Phycol 38 325ndash39

Whitfield P Gardner T Vives S et al 2002 Biological invasions ofthe Indo-Pacific lionfish (Pterois volitans) along the Atlanticcoast of North America Mar Ecol Prog Ser 235 289ndash97

Wiedenmann J Baumstark A Pillen TL et al 2001 DNA finger-prints of Caulerpa taxifolia provide evidence for the introduc-tion of an aquarium strain into the Mediterranean Sea and itsclose relationship to an Australian population Mar Biol 138229ndash34

Williams E and Grosholz E 2002a International Caulerpa taxifoliaConference Proceedings California Sea Grant CollegeProgram University of California La Jolla Pub No T-047

Williams S and Grosholz E 2002b Preliminary reports from theCaulerpa taxifolia invasion in southern California Mar EcolProg Ser 233 307ndash10

Williams S and Schroeder S 2004 Eradication of the invasive sea-weed Caulerpa taxifolia by chlorine bleach Mar Ecol Prog Ser272 69ndash76

Zaleski S and Murray S Taxonomic diversity geographic distribu-tion and commercial availability of aquarium-traded species ofCaulerpa (Chlorophyta Caulerpaceae) in southern CaliforniaUSA Mar Ecol Prog Ser In press

TAKE THIS JOURNAL TO YOUR LIBRARIAN PLEASEDid you enjoy this issue of Frontiers

If your library had a subscription colleagues and students could enjoy it tooPlease consider recommending Frontiers in Ecology and Environment to your library

Clip or copy the form below Thank you for your support

Library Recommendation Form

To Acquisition Librarian Serials

From

Dept

Signature Date

I recommend the library subscribe to Frontiers in Ecology and the Environment (ISSN 1540-9295)

To request a free sample issue of Frontiers in Ecology and the Environment call (301) 588-4691 or email Sika Dunyoh

at sikaesaorg Order Frontiers by contacting ESA Headquarters at (202) 833-8773 online at wwwesaorg or through your subscription agent

E-commerce and Caulerpa LJ Walters et al

78

wwwfrontiersinecologyorg copy The Ecological Society of America

sumers to the dangers of ldquoaquariumdumpingrdquo Locally only two of 47 retail-ers had signs asking patrons not to dumpunwanted organisms On the internet wefound only six distributors (five retailersone eBay auction) who warned againstaquarium dumping This limited amountof warning on improper disposal ofunwanted marine organisms indicatesthat more and better outreach is neededA new website wwwhabitattitudenetwas recently created for just this reasonThis national initiative has been devel-oped by the ANS Task Force and theaquarium pet nursery and landscapeindustries to raise consumer awarenessabout invasive species and alternatives torelease of unwanted organisms into thewild A number of other partners are alsoinvolved including US and state-levelFish and Wildlife Services and theNational Sea Grant College Program Byengaging and receiving support from the

industries that distribute non-native flora and fauna forthe first time this outreach program has a much greaterchance of success than previous federal and state-levelefforts that operated on a more confrontational level Todate only a limited number of retail outlets and suppliershave shown interest but expectations are high that thiscampaign will help reduce the number of releases of inva-sive species in terrestrial fresh and marine systems

Acknowledgements

We thank P Sacks C Glardon M Black and all thesearchers For funding we thank the National and FloridaSea Grant College Programs Pinellas CountyEnvironmental Fund Tampa Bay Estuary ProgramFlorida Department of Agriculture University ofGroningen and the University of Central FloridaSuggestions by P Windle substantially improved thismanuscript

ReferencesBelsher T and Meinesz A 1995 Deep water dispersal of the tropi-

cal alga Caulerpa taxifolia introduced into the MediterraneanAquat Bot 51 163ndash69

Davis A Roberts D and Cummins S 1997 Rapid invasion of asponge-dominated deep-reef by Caulerpa scalpelliformis(Chlorophyta) in Botany Bay Aust J Ecol 22 146ndash50

de Villegravele X and Verlaque M 1995 Changes and degradation in aPosidonia oceanica bed invaded by the introduced tropical algaCaulerpa taxifolia in the north western Mediterranean Bot Mar38 79ndash87

Jacoby C Lapointe B and Creswell L 2004 Are native and non-indigenous seaweeds overgrowing Floridarsquos east coast reefsGainesville FL Florida Sea Grant College Program SGEF-156

Jousson O Pawlowksi J Zaninetti L et al 1998 Molecular evi-dence for the aquarium origin of the green alga Caulerpa taxifo-

ldquoChaetomorpha Caulerpardquo (actually Chaetomorpha) Thishigh level of unreliability and variability makes bothmorphological identification by customs agents andinternet tracking of Caulerpa difficult

Finally we discovered that Caulerpa especially speciesof Caulerpa with feathery blades was frequently picturedin entire aquarium set-ups for sale on internet auctionsites Items had to be collected in person so we were ableto acquire C racemosa and C mexicana by this means fromonly one auction initiated in Clermont Florida In totalten states were represented in 13 auctions for complete30ndash120-gallon tank set-ups

Improving the future

Internet availability of the genus Caulerpa as well asnumerous other algal species and invertebrates repre-sents a serious threat to Floridarsquos coastlines in terms ofnon-native introductions from hobbyists The $5 millionspent on Caulerpa eradication in California would beequivalent to 142 857 purchases of loose Caulerpa at anaverage of $35 per purchase If 1 of these hobbyistsdumped Caulerpa into nearby waters and 1 of thesereleases became established then at least $70 million (14eradications x $5 millionresponse) will be required toachieve eradication Pressuring eBay to eliminate all auc-tions of Caulerpa and enhanced federal regulation ofCaulerpa would be considerably more cost-effective

Commercial retail of invasive species is not limited tomarine macroalgae or live rock For example Semmens etal (2004) found 16 species of non-native marine fishesin Florida waters their data suggest aquarium dumping asthe source for all these species Only limited informationwas available online and in local retail shops to alert con-

Caulerpa availability by species

Per

cent

50

40

30

20

10

0

C ashmeadii

C brachypus

C cupressoides

C mexic

ana

C paspaloides

C prolifera

C racemosa

C serru

lata

C sertu

larioides

C taxifo

lia

C microphysa

C vertic

illata

C webbiana

Figure 3 Percent availability of Caulerpa species from eBay auctions and onlineCentral Florida and Southern California retail sources

Online retaileBay auctionsCentral FL retailersSouthern CA retailers

LJ Walters et al E-commerce and Caulerpa

79

copy The Ecological Society of America wwwfrontiersinecologyorg

lia introduced to the Mediterranean Sea Mar Ecol Prog Ser172 275ndash80

Jousson O Pawlowski J Zaninetti L et al 2000 Invasive algareaches California Nature 408 157ndash58

Littler D and Littler M 2000 Caribbean reef plants WashingtonDC OffShore Graphics Inc

Meinesz A 1999 Killer algae Chicago IL University of ChicagoPress

Meinesz A Belsher T Thibault T et al 2001 The introduced greenalga Caulerpa taxifolia continues to spread in the Mediter-ranean Biol Invas 3 201ndash10

Meusnier I Valero M Destombe C et al 2002 Polymerase chainreaction-single strand conformation polymorphism analyses ofnuclear and chloroplast DNA provide evidence for recombina-tion multiple introductions and nascent speciation in theCaulerpa taxifolia complex Mol Ecol 11 2317ndash25

Millar A 2004 New records of marine benthic algae from NewSouth Wales eastern Australia Phycol Res 52 117ndash28

Padilla D and Williams S 2004 Beyond ballast water aquariumand ornamental trades as sources of invasive species in aquaticecosystems Front Ecol Environ 2 131ndash38

Schaffelke B Murphy N and Uthicke S 2002 Using genetic tech-niques to investigate the sources of the invasive alga Caulerpataxifolia in three new locations in Australia Mar Pollut Bull 44204ndash10

Semmens B Buhle E Salomon A and Pattengill-Semmens C2004 A hotspot of non-native marine fishes evidence for theaquarium trade as an invasion pathway Mar Ecol Prog Ser 266239ndash44

Smith C and Walters L 1999 Fragmentation as a strategy for

Caulerpa species fates of fragments and implications for man-agement of an invasive weed PSZN I Mar Ecol 20 307ndash19

Verlaque M Afonso-Carrillo J Candelaria Gil-Rodriacuteguez M et al2004 Blitzkrieg in a marine invasion Caulerpa racemosa varcylindracea (Bryopsidales Chlorophyta) reaches the CanaryIslands (north-east Atlantic) Biol Invas 6 269ndash81

Verlaque M Durand C Huisman J et al 2003 On the identity andorigin of the Mediterranean invasive Caulerpa racemosa(Caulerpales Chlorophyta) Eur J Phycol 38 325ndash39

Whitfield P Gardner T Vives S et al 2002 Biological invasions ofthe Indo-Pacific lionfish (Pterois volitans) along the Atlanticcoast of North America Mar Ecol Prog Ser 235 289ndash97

Wiedenmann J Baumstark A Pillen TL et al 2001 DNA finger-prints of Caulerpa taxifolia provide evidence for the introduc-tion of an aquarium strain into the Mediterranean Sea and itsclose relationship to an Australian population Mar Biol 138229ndash34

Williams E and Grosholz E 2002a International Caulerpa taxifoliaConference Proceedings California Sea Grant CollegeProgram University of California La Jolla Pub No T-047

Williams S and Grosholz E 2002b Preliminary reports from theCaulerpa taxifolia invasion in southern California Mar EcolProg Ser 233 307ndash10

Williams S and Schroeder S 2004 Eradication of the invasive sea-weed Caulerpa taxifolia by chlorine bleach Mar Ecol Prog Ser272 69ndash76

Zaleski S and Murray S Taxonomic diversity geographic distribu-tion and commercial availability of aquarium-traded species ofCaulerpa (Chlorophyta Caulerpaceae) in southern CaliforniaUSA Mar Ecol Prog Ser In press

TAKE THIS JOURNAL TO YOUR LIBRARIAN PLEASEDid you enjoy this issue of Frontiers

If your library had a subscription colleagues and students could enjoy it tooPlease consider recommending Frontiers in Ecology and Environment to your library

Clip or copy the form below Thank you for your support

Library Recommendation Form

To Acquisition Librarian Serials

From

Dept

Signature Date

I recommend the library subscribe to Frontiers in Ecology and the Environment (ISSN 1540-9295)

To request a free sample issue of Frontiers in Ecology and the Environment call (301) 588-4691 or email Sika Dunyoh

at sikaesaorg Order Frontiers by contacting ESA Headquarters at (202) 833-8773 online at wwwesaorg or through your subscription agent

LJ Walters et al E-commerce and Caulerpa

79

copy The Ecological Society of America wwwfrontiersinecologyorg

lia introduced to the Mediterranean Sea Mar Ecol Prog Ser172 275ndash80

Jousson O Pawlowski J Zaninetti L et al 2000 Invasive algareaches California Nature 408 157ndash58

Littler D and Littler M 2000 Caribbean reef plants WashingtonDC OffShore Graphics Inc

Meinesz A 1999 Killer algae Chicago IL University of ChicagoPress

Meinesz A Belsher T Thibault T et al 2001 The introduced greenalga Caulerpa taxifolia continues to spread in the Mediter-ranean Biol Invas 3 201ndash10

Meusnier I Valero M Destombe C et al 2002 Polymerase chainreaction-single strand conformation polymorphism analyses ofnuclear and chloroplast DNA provide evidence for recombina-tion multiple introductions and nascent speciation in theCaulerpa taxifolia complex Mol Ecol 11 2317ndash25

Millar A 2004 New records of marine benthic algae from NewSouth Wales eastern Australia Phycol Res 52 117ndash28

Padilla D and Williams S 2004 Beyond ballast water aquariumand ornamental trades as sources of invasive species in aquaticecosystems Front Ecol Environ 2 131ndash38

Schaffelke B Murphy N and Uthicke S 2002 Using genetic tech-niques to investigate the sources of the invasive alga Caulerpataxifolia in three new locations in Australia Mar Pollut Bull 44204ndash10

Semmens B Buhle E Salomon A and Pattengill-Semmens C2004 A hotspot of non-native marine fishes evidence for theaquarium trade as an invasion pathway Mar Ecol Prog Ser 266239ndash44

Smith C and Walters L 1999 Fragmentation as a strategy for

Caulerpa species fates of fragments and implications for man-agement of an invasive weed PSZN I Mar Ecol 20 307ndash19

Verlaque M Afonso-Carrillo J Candelaria Gil-Rodriacuteguez M et al2004 Blitzkrieg in a marine invasion Caulerpa racemosa varcylindracea (Bryopsidales Chlorophyta) reaches the CanaryIslands (north-east Atlantic) Biol Invas 6 269ndash81

Verlaque M Durand C Huisman J et al 2003 On the identity andorigin of the Mediterranean invasive Caulerpa racemosa(Caulerpales Chlorophyta) Eur J Phycol 38 325ndash39

Whitfield P Gardner T Vives S et al 2002 Biological invasions ofthe Indo-Pacific lionfish (Pterois volitans) along the Atlanticcoast of North America Mar Ecol Prog Ser 235 289ndash97

Wiedenmann J Baumstark A Pillen TL et al 2001 DNA finger-prints of Caulerpa taxifolia provide evidence for the introduc-tion of an aquarium strain into the Mediterranean Sea and itsclose relationship to an Australian population Mar Biol 138229ndash34

Williams E and Grosholz E 2002a International Caulerpa taxifoliaConference Proceedings California Sea Grant CollegeProgram University of California La Jolla Pub No T-047

Williams S and Grosholz E 2002b Preliminary reports from theCaulerpa taxifolia invasion in southern California Mar EcolProg Ser 233 307ndash10

Williams S and Schroeder S 2004 Eradication of the invasive sea-weed Caulerpa taxifolia by chlorine bleach Mar Ecol Prog Ser272 69ndash76

Zaleski S and Murray S Taxonomic diversity geographic distribu-tion and commercial availability of aquarium-traded species ofCaulerpa (Chlorophyta Caulerpaceae) in southern CaliforniaUSA Mar Ecol Prog Ser In press

TAKE THIS JOURNAL TO YOUR LIBRARIAN PLEASEDid you enjoy this issue of Frontiers

If your library had a subscription colleagues and students could enjoy it tooPlease consider recommending Frontiers in Ecology and Environment to your library

Clip or copy the form below Thank you for your support

Library Recommendation Form

To Acquisition Librarian Serials

From

Dept

Signature Date

I recommend the library subscribe to Frontiers in Ecology and the Environment (ISSN 1540-9295)

To request a free sample issue of Frontiers in Ecology and the Environment call (301) 588-4691 or email Sika Dunyoh

at sikaesaorg Order Frontiers by contacting ESA Headquarters at (202) 833-8773 online at wwwesaorg or through your subscription agent