J. World Maricul. SOC. 14:546-559 (1983)

THE ROLE O F INTRODUCED BIVALVE MOLLUSC S P E C I E S

IN MARICULTURE~

Roger Mann Biology Department

Woods Hole Oceanographic I n s t i t u t i o n Woods Hole, MA 02543

ABSTRACT

Premeditated in t roduct ions o f non-indigenous molluscan s h e l l f i s h spec ies have been important i n e s t a b l i s h i n g s e v e r a l s u b s t a n t i a l f i sher - i e s . The North American f i s h e r y f o r Crassostrea gigas developed from a c t i v e in t roduct ions t h a t began i n t h e e a r l y p a r t of t h i s century and continued u n t i l 1978. More r e c e n t l y C. g i g a s has been introduced t o many si tes i n Europe, South Afr ica , South America, t h e Mediterranean, and t h e Indian and P a c i f i c Oceans. The European f l a t o y s t e r , Ostrea e d u l i s , has been successfu l ly introduced t o t h e s t a t e of Maine. An in- t e r n a t i o n a code of p r a c t i c e f o r examining and e f f e c t i n g i n t e n t i o n a l in- t roduct ions has been developed which recommends a combination of quaran- t i n e procedures and hatchery r e a r i n g t o a m i d acc identa l in t roduct ion of assoc ia ted spec ies and d isease organisms. Several na t ions have devel- oped comprehensive l e g i s l a t i o n t o c o n t r o l movement of non-indigenous species . Active movement o f spec ies f o r c u l t u r e purposes cont inues, es- p e c i a l l y i n Europe and t h e P a c i f i c I s lands .

INTRODUCTION

This manuscript provides a b r i e f h i s t o r y of t h e movement of selected bivalve mollusc spec ies around t h e world, a d e t a i l e d l i s t i n g of movements t h a t have occurred i n t h e p a s t f i v e years and a d iscuss ion of f u t u r e prospects and problems assoc ia ted with cont inuing movement of b iva lve spec ies f o r c u l t u r e purposes. The d iscuss ion i s devoted predominantly t o i n t e n t i o n a l , premeditated in t roduct ions r a t h e r than a c c i d e n t a l in t ro- duct ions .

An in t roduct ion i s def ined as a d e l i b e r a t e movement of spec ies be- tween hydrographic masses and across j u r i s d i c t i o n a l boundaries. Where hydrographic masses meet wi th in a j u r i s d i c t i o n a l u n i t , movements between t h e former should be t r e a t e d as i n t r o d u c t i o n s ( f o r comprehensive discus-

‘Supported by U.S. Department of Commerce, NOAA, Off ice of Sea Grant, under Grant Number NABO-AA-D-00077. Contr ibut ion No. 5277 from Woods Hole Oceanographic I n s t i t u t i o n .

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sion see Mann 1978). The s t imulus f o r making an in t roduct ion Usually encompasses one o r more of t h e following: economic pressures accompany- ing t h e deple t ion of a n a t i v e f i s h e r y ; devas ta t ion of a f i s h e r y by d is - ease, a n a t u r a l ca tas t rophe , d i s a s t e r r e l a t e d t o human a c t i v i t y (e .g . , large o i l s p i l l s ) , o r t h e o r i g i n a l absence o f a commercial f i shery .

HISTORICAL PERSPECTIVE

P r i o r t o d iscuss ing recent developments i n t h e movement of b iva lves f o r c u l t u r e purposes it i s r e l e v a n t t o g ive a very b r i e f h i s t o r i c a l back- ground. Comments w i l l be r e s t r i c t e d t o t h e Japanese o y s t e r ( C r a s s o s t r e a q igas Thunberg') , t h e European f l a t o y s t e r ( O s t r e a e d u l i s L . ) , and, t o a l e s s e r e x t e n t , t h e Eastern o y s t e r ( C r a s s o s t r e a v i r q i n i c a Gmelin) and Portuguese o y s t e r ( C r a s s o s t r e a a n g u l a t a Lamarck). A comprehensive d is - cussion of t h e movement of C. g i g a s is given i n Mann (1978) t o which the reader i s r e f e r r e d f o r g r e a t e r d e t a i l .

Large q u a n t i t i e s o f a d u l t C r a s s o s t r e a g i g a s were introduced from Japan t o t h e S t a t e of Washington and B r i t i s h Columbia during t h e f i r s t th ree decades of t h i s century (Kincaid 1928; Quayle 1969; Bourne 1978; Chew 1978). Oysters w e r e t ranspor ted as deck cargo on ocean freighEers , consequently t r a n s i t t i m e s were cons iderable , a s were m o r t a l i t i e s . I t was not u n t i l t h e l a t e 1920 ' s and e a r l y 1930's t h a t l a rge-sca le o y s t e r c u l t u r e based on t h e cont inuing importat ion o f seed o y s t e r s became a r e a l i t y . Despi te t h e f a c t t h a t n a t u r a l reproduct ion of t h e introduced s tocks occurs i n both Washington and B r i t i s h Columbia, seed importation was a cont inuing p r a c t i c e u n t i l a lack of seed on t h e domestic Japanese market caused a ban o f m a t e r i a l f o r expor t i n 1978 (Chew 1978).

The a c t i v e in t roduct ion o f C r a s s o s t r e a g i g a s t o new s i tes during t h e l a t e 1960's and e a r l y 1970's was extensive with movement of seed t o France, Great B r i t a i n , West Germany, Sweden, Cyprus, I s r a e l , B r a z i l , Mauri t ius , South Afr ica , New Zealand, A u s t r a l i a , Tasmania and a number of i s l a n d s throughout t h e P a c i f i c inc luding Hawaii. Precaut ionary mea- sures assoc ia ted with e f f e c t i n g t h e s e in t roduct ions were genera l ly much b e t t e r than t h e procedures appl ied t o e a r l y movements of C. g i g a s across the P a c i f i c . Sporadic, i s o l a t e d a t tempts t o introduce C. g i g a s t o t h e e a s t c o a s t of t h e United S t a t e s have been unsuccessful .

The European f l a t o y s t e r ( O s t r e a e d u l i s ) was introduced t o t h e S t a t e of Maine i n 1949 by Vic tor Loosanoff. Although progeny of t h i s in t ro- duced s tock have been moved t o t h e w e s t c o a s t of t h e United S t a t e s , no movement south o f Maine has been ef fec ted . A small bu t expanding o y s t e r indus t ry s p e c i a l i z i n g i n 0. e d u l i s c u l t u r e e x i s t s i n Maine today (Hidu 1981). The p o s s i b i l i t y e x i s t s of opening o r expanding European markets f o r 0. e d u l i s seed o r i g i n a t i n g i n Maine and U . S . west c o a s t ha tcher ies .

The American e a s t e r n o y s t e r (Crassostrea v i r g i n i c a ) has been suc- c e s s f u l l y introduced t o H a w a i i (Brock 1960; Sakuda 1966). Unsuccessful a t tempts have been made t o introduce C. v i r g i n i c a t o t h e west coas t of

2A number of " s t r a i n s ," " v a r i e t i e s " o r "geographical types" of C r a s s o s t r e a y i g a s have been i d e n t i f i e d i n Japan, t h e s e genera l ly being descr ibed by t h e i r geographical region of o r i g i n , e.g., Myagi, Kumamoto, e t c . Although some recent in t roduct ions have emphasized s p e c i f i c " s t r a i n s " they are not d i s t i n c t spec ies ( see Torigoe 1981), therefore t h e present manuscript does not d i s t i n g u i s h between them.

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North America (Bourne 19781, Great Britain (see comments in Cole 1942 and Elton 1958), Fiji (Glude 1983), Puerto Rico (Walters and Prinslow 1975) and the Bahamas (Glude 1981).

in range to the west and south coasts of Portugal and Spain (Korringa 1976). French oyster farmers began transporting the species north dur- ing the mid-nineteenth century. nated f r m stock dumped as supposedly dead in the Gironde estuary in 1868 (Korringa 1976) and stock in transit on board a ship that sank in the Bay of Biscay at Arcachon in 1870 (Orton 1937). The northern limit of recruitment from these stocks was the Loire River on the west coast of France; however, continued intentional movement of oysters to Brit- tany and even southeast England for fattening purposes was commonplace until the fishery was decimated by epizoan diseases in 1970-71 (Marteil 1974).

This brief history illustrates only part of the extensive histori- The unintentional movement of associated mar-

The Portuguese oyster ( C r a s s o s t r e a a n g d a t a ) was originally limited

Actively reproducing populations origi-

cal movement of oysters. ine species has been equally extensive, indeed Elton (1958) notes that one of the foremost mechanisms responsible for the spread of exotic spe- cies in the marine environment has been the business of oyster culture. The examples listed above illustrate that the range of success encoun- tered with active introductions varies from very successful (Crassostrea g i g a s in France) to unsuccessful (Crassostrea v i r g i n i c a in Great Britain). They also illustrate that while prior examination of available litera- ture and expertise can help in matching specific "donor" stocks of po- tential species for introductions with specific "acceptor" sites our knowledge still cannot adequately explain why certain movements are suc- cessful while others are not. For example, the generalization that spe- cies from the climatically harsh western boundaries of ocean basins gen- erally fare well when moved to the milder eastern boundaries (Andrews 1971) appears applicable to C. g i y a s but inapplicable to C. v i r g i n i c a . Carlton and Mann (1981) have characterized the introduction process, be it accidental or intentional, as a series of "filters" or "constrictions" through which the species in question must successfully pass to attain an actively reproducing population in a new location. In an intentional introduction the problems of selecting initially vigorous brood stock, transporting that stock across natural barriers to movement (e.g., ocean basins or land masses), choosing an "acceptor" environment that is plen- tiful in suitable food, devoid of environmental excesses, protected from endemic predators and diseases, and beneficial to reproduction and sur- vival of the larval and juvenile stages are all constrictions which can be alleviated by human intervention. Yet, the resulting unpredictability of success in establishing breeding populations underscores the need for further study of the interaction of introduced species with a new and foreign physical and biological environment.

PROTOCOL FOR EFFECTING AN INTRODUCTION

The fact that the success of introductions is unpredictable, that the chance of associated introduction of potentially deleterious species is high, and that the development of hatchery technology and air trans- port in particular facilitate rapid movement of large numbers of juve- nile organisms has long been cause for concern. introduction results in "biological catastrophe," through either uncon- trolled proliferation of the introduced species or the introduction of disease, with radical change in the immediate biological community is

The scenario whereby an

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not d i f f i c u l t t o envisage. Examples e x i s t i n both t e r r e s t r i a l systems, such a s t h e spread o f t h e fungus Cerastomella u l m i which causes Dutch elm d isease throughout North America, o r t h e damage caused by t h e gypsy moth Lymantria d i s p a r i n nor theas te rn s t a t e s , and i n f reshwater systems such a s t h e spread o f Cichl id f i s h e s of t h e genus Ti lap ia both around the world (Ling 1976) and i n t h e s t a t e of F lor ida i n p a r t i c u l a r (Courte- nay 1978). These examples underscore t h e f a c t t h a t once a spec ies is released i n t o a new environment l i t t l e o r nothing can usua l ly be done t o influence f u t u r e proceedings, which may vary from t h e extreme of p r o l i f - e ra t ion t o r a p i d death of t h e s tock. For tuna te ly , no such "b io logica l catastrophes" have, t o d a t e , occurred i n marine systems and t h e i n t r o - duction o f spec ies i s now regula ted i n many count r ies . code of p r a c t i c e f o r examining and e f f e c t i n g i n t e n t i o n a l in t roduct ions has been developed, predominantly through t h e e f f o r t s of t h e Working Group on In t roduct ions and Transfers of Marine Organisms of t h e I n t e r - na t iona l Council f o r t h e Explorat ion of t h e Seas ( ICES) . 3

An i n t e r n a t i o n a l

Although t h e ICES has no i n t e r n a t i o n a l l e g i s l a t i v e power t h e signa- to ry n a t i o n s , which inc lude most North American and European count r ies , have input t o t h e guide l ine development process and at tempt to comply with t h e code of p r a c t i c e . The code w a s o r i g i n a l l y adopted a t t h e Statu- tory ICES meeting on October 10, 1973, and was rev ised i n 1979. I n es- sence t h e code suggests t h e fol lowing procedure f o r a l l spec ies p r i o r t o reaching a dec is ion regarding new in t roduct ions :

a ) t h e prepara t ion o f a comprehensive d e s c r i p t i o n of t h e proposed in t roduct ion , d i scuss ion of t h e proposal with t h e ICES Council and t h e cons idera t ion of t h e proposal by ICES;

b) a thorough examination of a candidate spec ies i n i t s n a t i v e en- vironment;

c) an examination of p o t e n t i a l impact a t t h e proposed s i t e of in- t roduct ion and examination of previous in t roduct ions of t h e spe- c i e s elsewhere;

d ) a f u r t h e r eva lua t ion of b and c toge ther .

I f t h e in t roduct ion is deemed reasonable it is e f f e c t e d i n t h e fo l - lowing manner:

e ) a brood s tock i s e s t a b l i s h e d i n quarant ine , F1 progeny a r e ob- t a i n e d and t h e brood s tock destroyed. be t r a n s f e r r e d t o t h e new environment, only t h e F1 generat ion can be t r a n s f e r r e d , and t h i s only a f t e r c a r e f u l observat ion of t h e Fi generat ion while it is s t i l l i n quarant ine.

The brood s tock i s = t o

f ) a cont inuing s tudy o f t h e in t roduct ion is made following t h e re- l e a s e of t h e F1 progeny.

S t r i c t adherence t o these guide l ines presents severa l problems: a time delay i n growing t h e F1 progeny t o provide brood s tock f o r subse- quent genera t ions , producing enough seed animals t o support e i t h e r natu-

3For f u r t h e r information on ICES Working Group r e p o r t s contac t e i t h e r : General Secre ta ry , I C E S , Palaegade 2-4, DK-1261 Copenhagen K , Denmark; o r D r . C a r l J. Sindermann, Chairman, ICES Working Group on In- t roduct ions and t r a n s f e r s of Marine Organisms, NOAA, Northeast F isher ies Center , Sandy Hook Laboratory, Highlands, NJ 07732 USA.

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ra l p r o l i f e r a t i o n , a n a c t i v e f i s h e r y o r both, and considerable expense. The h i s t o r y o f in t roduct ions t h a t have followed these guide l ines , not- ably t h e in t roduct ion of C. g i g a s t o Great B r i t a i n (Walne and Helm 19781, have encountered no adverse e f f e c t s from assoc ia ted spec ies , un l ike pro- grams using d i r e c t importat ion of seed ( see Bourne 1978; Chew 1978; Maurin and Le Dantec 1978). For tuna te ly t h e development o f b iva lve ha tcher ies combined with t h e enormous fecundi ty of commercially valuable mollusc spec ies does much t o o f f s e t t h e c o n s t r i c t i v e na ture of t h e I C E S gu ide l ines . Compliance wi th t h e ICES guide l ines may a l s o be hindered t o a s m a l l ex ten t by t h e lack o f a c t i v e disseminat ion of t h e recommendations of t h e ICES Working Group on In t roduct ions and Transfers of Marine Orga- nisms. For example, I have r e c e n t l y been made aware of t h e in t roduct ion of marine shrimp of t h e genus Penaeus i n t o t h e southern United S t a t e s from South America. Although t h e s e in t roduct ions were made with regula- t o r y approval a t t h e S t a t e l e v e l it is ev ident t h a t n e i t h e r of t h e par- t i e s involved, t h e ind iv idua l e f f e c t i n g t h e in t roduct ion nor the regula- t o r y agency, were aware o f t h e ICES document. It is my hope t h a t t h i s manuscript w i l l se rve both t o h i g h l i g h t t h e ICES e f f o r t and f o s t e r in te r - e s t i n it by p r i v a t e p a r t i e s and regula tory agencies through t h e United S t a t e s .

RECE bTC INTRODUCTIONS OF BIVALVE MOLLUSCS

Having o u t l i n e d t h e present regula tory and "advisory" c l imate with respec t t o in t roduct ions I w i l l focus on summarizing recent (1978- present ) movements of b iva lves . Unless otherwise s t a t e d t h e following mater ia l w a s obtained from t h e r e p o r t s of t h e ICES Working Group meet- ings a t Conwy, U.K.; S'ete, France; and La Coruna, Spain (ICES references C.M. 1979/E:22, C.M. 1981/F:46 and C.M. 1982/F: undesignated, respec- t i v e l y ) . A c t i v i t i e s a r e l i s t e d by t h e country e f f e c t i n g t h e introduc- t i o n .

Canada

There have been t w o r e c e n t a t tempts t o in t roduce t h e bay s c a l l o p ( A r y o p e c t e n i r r a d i a n s L . ) t o e a s t e r n Canada from t h e e a s t c o a s t of t h e United S t a t e s . The f i r s t shipment of 390 animals was he ld through two generat ions i n quarant ine before being destroyed a f t e r t h e discovery of inc lus ions i n t h e d i g e s t i v e d i v e r t i c u l a . A second shipment was e f fec ted i n mid-1980. By December 1981, 1 2 2 ind iv idua ls o f an F3 genera t ion o r i - g ina t ing from t h i s s tock were s t i l l i n quarant ine. F i e l d t r i a l s with t h e Fq generat ion were planned f o r 1982.

O s t r e a e d u l i s , r e c e n t l y obtained from Maine and t h e United Kingdom, a r e s t i l l i n quarant ined experimental systems i n Nova Scot ia . T r i a l p lan t ings of 0. e d u l i s seed produced i n t h e P leasant Poin t hatchery i n Nova Scot ia , and o r i g i n a t i n g from an in t roduct ion e f f e c t e d during t h e 1960's , a r e underway a t s e v e r a l l o c a t i o n s on t h e e a s t and w e s t shores of Nova Scot ia .

and Tapes j a p o n i c a 4 were imported t o B r i t i s h Columbia f o r experimental On t h e w e s t c o a s t o f Canada a small number of seed C r a s s o s t r e a g igas

*The nomenclature of t h i s spec ies remains i n c o n s i s t e n t . Source documentation f o r t h i s manuscript conta ins re ferences t o Tapes j a p o n i c a (Deshayes, 1853), Tapes s e m i d e c u s s a t a (Reeve, 1859) , V e n e r u p i s j a p o n i c a

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r a f t c u l t u r e .

France

By 1979 Crassostrea g i g a s was e s t a b l i s h e d and propagated by hatcher- i e s and n a t u r a l recrui tment . Production now s tands a t 90,000 tonnes per year i n Br i t tany . The p a r a s i t i c copepod Myt i l ico la o r i e n t a l i s Mori in- troduced from Japan wi th e a r l i e r shipments of C. gigas had not spread outs ide of France. Continuing problems with c e r t i f i c a t i o n of seed from Japan, one example o f which w a s found t o conta in t h e haplosporidian Min- chinia arnwricana a f t e r being c e r t i f i e d as c lean , r e s u l t e d i n ban of i m - por ta t ion of C. g i g a s i n 1982.

I n 1981 i n t e r n a l movement of Ostrea e d u l i s was r e s t r i c t e d t o pre- vent spread o f a protozoan pathogen Bonamia o s t r e a e . Importation of seed 0. e d u l i s from C a l i f o r n i a , which had previous ly been shown t o con- t a i n B. o s t r e a e , was banned. Experimental c u l t u r e of Ostrea c h i l e n s i s P h i l i p p i from Chile was undertaken i n quarant ined system i n 1981 but proved t o be o f l i t t l e value. S imi la r s t u d i e s with Ostrea densalamellosa from Korea were planned f o r 1982. N o d a t a on t h e success of t h e l a t t e r s t u d i e s a r e a v a i l a b l e a t p resent .

A shipment of Ruditapes semidecussata (see footnote 4) was obtained from a U.S. w e s t c o a s t hatchery and placed i n quarant ine . Fur ther de- t a i l s a r e unavai lable . Experimental i n t r o d u c t i o n s of Mercenaria merce- n a r i a L. from t h e United Kingdom ( o r i g i n a l l y from t h e U.S. e a s t c o a s t ) and Pecten jacobeus from I r e l a n d were a l s o made.

United Kingdom

Brood s tock o f Crassostrea gigas were imported t o t h e Conwy labora- t o r y from Oregon i n 1979. Importat ions were a l s o made of C. g igas from Hong Kong and Israel, of Crassos t rea c u c u l l a t a Born from E i l a t , and Cras- s o s t r e a rhizophorae Guilding from B r a z i l . All w e r e maintained i n quaran- t i n e systems, spawned, t h e parent s tock destroyed, and t h e progeny reared. Thir ty-s ix thousand C. rhizophorae seed were t ransplan ted t o t h e Menai S t r a i t s i n North Wales but subsequently died.

United S t a t e s t o quarant ine a t Conwy. The s tock w a s spawned as f o r t h e Crassostrea spec ies and then destroyed. The progeny were c u l t u r e d and 12,000 seed subsequently p lan ted i n t h e Menai S t r a i t s . Smaller numbers were a l s o o f f e r e d t o p r i v a t e h a t c h e r i e s within t h e United Kingdom t o de- velop l o c a l brood s tock.

Bonamia o s t r e a e has r e c e n t l y been found i n o y s t e r s i n southwest England (M. M. H e l m , F i s h e r i e s Experiment S t a t i o n , Conwy, U.K. , personal communication 1982). Oysters moved from t h e s e si tes t o southeas t Eng- land p r i o r t o t h e f ind ing have a l s o been examined f o r B. o s t r e a e and

Venerupis semidecussata (see footnote 4 ) w e r e imported from the

(Deshayes) , Venerupis semidecussata (Adams and Reeve) (but not Venerupis decussata L. which i s endemic t o western Europe), Ruditapes semidecussata and Ruditapes phi l l ippinarum. I n s u f f i c i e n t d e t a i l i s a v a i l a b l e t o accu- r a t e l y l o c a t e t h e o r i g i n of a l l introduced s tocks ; however, t h e majori ty of t h e s e s tocks can be t r a c e d h i s t o r i c a l l y t o t h e w e s t c o a s t of North America and a r e probably T. japonica. I r o n i c a l l y , t h i s l a t te r s tock was i t s e l f an a c c i d e n t a l in t roduct ion (see Bourne 1978; Chew 1978). Consis- tency i n use of nomenclature of t h i s spec ies i s despera te ly needed.

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found t o be infec ted . Precaut ionary measures t o monitor B . o s t r e a e and prevent f u r t h e r movement have been implemented.

Federal Republic of Germany

Work with Crassostrea g igas , o r i g i n a t i n g h i s t o r i c a l l y a t Conwy i n t h e U.K. and being obtained e i t h e r d i r e c t l y o r from a S c o t t i s h hatchery, has progressed from quarant ined systems t o l i m i t e d re lay ing and growth tr ials (Neudecker 1981). Importat ion w a s e f f e c t e d as both 10 mm seed o y s t e r s (80,000 ind iv idua ls ) and as "eyed-larvae'' (200,000 i n d i v i d u a l s ) . The s a l e of "eyed-larvae'' r a t h e r than seed s h e l l f i s h is gaining i n popu- l a r i t y on t h e U.S. west c o a s t and may o f f e r a number of advantages i n e f f e c t i n g "clean" f u t u r e in t roduct ions . This op t ion is discussed la ter i n t h e present manuscript.

I re land

The seed o f Ostrea e d u l i s , Crassostrea g i g a s and Tapes japonica (see footnote 4 ) have been imported from t h e United Kingdom.

The Netherlands

Crassostrea g igas had been r e g u l a r l y imported from France s i n c e 1963, bu t it was only a f t e r an unusual ly hot summer i n 1976 t h a t n a t u r a l recrui tment occurred. Annual recrui tment now occurs t o t h e e x t e n t t h a t C. g igas t h r e a t e n c u l t i v a t e d beds of Ostrea e d u l i s and a r e a c t i v e l y re- moved from t h e l a t t e r a reas . 0. e d u l i s had also been imported from France, Greece and England. Importat ions from France have been c i t e d a s responsible f o r outbreaks of M a r t e i l i a r e f r i n g e n s , Minchinia a r m r i c a n a and Bonamia o s t r e a e i n Dutch 0. e d u l i s . Importation of French o y s t e r s w a s banned i n 1981.

Denmark

P r o l i f e r a t i o n o f Crassostrea g igas imported from t h e Federal Repub- l i c of Germany ( p r e c i s e source unspec i f ied) presented t h r e a t s t o n a t i v e Ostrea e d u l i s s i m i l a r t o those encountered i n t h e Netherlands. Active removal of C. gigas w a s undertaken.

Sweden

The o r i g i n a l importat ion o f Crassos t rea g igas has d ied o r disap- peared.

Spain - Venerupis japonica ( see footnote 4) seed have been imported from

both English and French ha tcher ies . Juveni le Ostrea e d u l i s a r e being imported f o r c u l t i v a t i o n . Record keeping of movements i n t o Spain is poor.

United S t a t e s

Small numbers of Arca noae L. w e r e imported t o a quarant ined system i n Maine f o r research purposes. A s i m i l a r importat ion of Crassos t rea rhizophorae Guilding and Crassostrea c o r t e z e n s i s H e r t l e i n w a s made i n F lor ida . No new spec ies were imported f o r commercial ventures . M y t i l u s e d u l i s L. were imported t o Maine from t h e Bay of Fundy, Canada.

552

Crassos t rea g i g a s has r e c e n t l y been introduced t o B a j a C a l i f o r n i a from a C a l i f o r n i a hatchery. I n i t i a l p l a n t i n s have been successfu l and ha tcher ies a t Erendira , Baja C a l i f o r n i a and Tortugas Bay, Baja Cal i for - n i a Sur a r e now producing C. g igas seed (Baqueiro 1983).

Costa Rica

Crassostrea q i q a s w e r e in t roduced t o Bahia Bal lena on t h e P a c i f i c coas t of Costa Rica i n 1979 and have grown wel l . This region experien- ces a seasonal upwelling of co ld , deep ocean water which appears t o s t i m u l a t e o y s t e r growth (Glude 1983).

Chi le - Crassostrea g i g s s has r e c e n t l y been introduced f o r an experimental

program ( W i n t e r e t a l . 1983). These s t u d i e s a r e s t i l l i n progress .

P a c i f i c I s l a n d s

The demonstration of good growth and s u r v i v a l of Ostrea e d u l i s i n F i j i i n 1977 and 1978 has f a i l e d t o s t i m u l a t e f u r t h e r i n t e r e s t i n t h i s spec ies (Glude 1983). Crassostrea i r e d a l e i , a spec ies endemic t o the Phi l ipp ines , grew w e l l i n i n i t i a l t r i a l s i n F i j i i n 1975 and 1976. No f u r t h e r t r i a l s have taken p l a c e .

Crassostrea q i q a s w a s int roduced i n t o T a h i t i i n 1976 (parent source not s t a t e d ) bu t r a p i d l y succumbed t o a t t a c k by Polydora sp . (Coerol i e t a l . 1983) . In 1978 t h e o y s t e r Saccostrea echina ta (Quoy and Gaimard) w a s in t roduced t o T a h i t i from S t . Vincent, New Caledonia. During t h e per iod 1978-1982 th i r ty- two l a r v a l c u l t u r e s were reared t o se t t lement i n t h e CNEXO' hatchery. Over two m i l l i o n j u v e n i l e o y s t e r s w e r e t r a n s f e r r e d t o nursery c u l t u r e i n ponds f e r t i l i z e d by seasonal f reshwater runoff . Marketable ind iv idua ls were obtained a f t e r a one-year grow-out per iod but market response t o t h e spec ies has been poor.

T a h i t i and Raiatea I s l a n d s by CNEXO (Coerol i e t a l . 1983). Juveni les were cu l tured i n ponds a s descr ibed f o r S. echinata . Natural spawnings occurred i n t h i s s i t u a t i o n and l a r v a e were c o l l e c t e d on a v a r i e t y of c u l t c h inc luding bamboo, c o r a l , wood and rope. This work i s s t i l l i n progress (Coerol i e t a l . 1983) . Venerupis senidecussata has a l s o been introduced t o T a h i t i (Coerol i e t a l . 1983). No f u r t h e r information i s a v a i l a b l e on t h i s in t roduct ion .

The green mussel P e r m v i r i d i s L. has r e c e n t l y been introduced t o

Four spec ies of t r i d a c n i d clam (Tridacna maxima Roding, T. squanosa, T. crocea Lamarck and Hippopus hippopus L.1 have been successfu l ly cul- tu red through l a r v a l development and t o matur i ty i n l a r g e , outdoor tanks (Heslinga e t a l . 1983). Each t r i a l produced 5,000-10,000 clam seed of 5

mm mean length i n a four-month per iod. Experimental shipments of these seed t o Guam, Hawaii and t h e United S t a t e s mainland have been made.

5Centre Nat ional pour 1 'Explora t ion des Oceans, BP 7004, Vairao, T a h i t i , French Polynesia.

553

The preceding summary of recent in t roduct ions addresses movement of A consider- s tocks f o r re lay ing o r eventual r e l a y i n g i n n a t u r a l waters .

a b l e t r a d e a l s o e x i s t s i n t h e i n t e r n a t i o n a l t r a n s p o r t of s h e l l f i s h f o r d i r e c t consumption without re lay ing . The magnitude of t h i s indus t ry i s i l l u s t r a t e d i n T a b l e 1. While it i s unl ike ly t h a t t h e in t roduct ion of assoc ia ted p e s t o r d i s e a s e spec ies w i l l be t ransmi t ted v i a t h i s rou te t h e p o s s i b i l i t y of i s o l a t e d , i l l e g a l re lay ings cannot be el iminated.

T a b l e 1. I n t e r n a t i o n a l Movement of Live Bivalve Species f o r Human Con- sumption without Relaying i n Receiving Waters

Importing country

Canada

France 1 1

Germany 3 3 3

I r e land 2 2 ,3 ,5 1 , 2 2 2

Netherlands 2,3 3 2

UnitedKingdom 8 5 5 3,8 2,5,7,8

Key of spec ies : 1 = C r a s s o s t r e a g i g a s ; 2 = O s t r e a e d u l i s ; 3 = M y t i l u s e d u l i s ; 4 = Tapes j a p o n i c a ( see footnote 4 ) ; 5 = Veneru- p i s d e c u s s a t a L. ; 6 = P r o t o t h a c a s taminea Conrad; 7 = P e c t e n rnaxirnus L.; 8 = Mercenar ia m e r c e n a r i a .

Source: ICES (1982), S t a t u s (1980) o f In t roduct ions of Non-indigenous Marine Species t o North A t l a n t i c Waters. (Amendments and addi- t i o n s t o Cooperative Research Report No. 32, 1972.)

RECENP DEVELOPMENTS I N REGULATION OF INTRODUCTIONS

A summary of n a t i o n a l laws r e l a t i n g t o t h e in t roduct ion of non- n a t i v e spec ies has been prepared by t h e members of t h e ICES Working Group and i s deposi ted with t h e ICES S e c r e t a r i a t i n Copenhagen (see foot- note 3 ) . Space does not permit a comprehensive summary of a l l these laws i n t h i s repor t . I n t h e United S t a t e s s e v e r a l p ieces of l e g i s l a t i o n r e l a t e t o in t roduct ions of non-native spec ies . Brown (1978) provides a summary of mater ia l t o t h a t da te . Recently s t r i c t e r c o n t r o l of w i l d l i f e movement has been provided by t h e Lacey Act Amendments o f 1981.6 I n

6Public L a w 97-79. 97th Congress of t h e United S t a t e s of America, November 16, 1981. Lacey A c t Amendments o f 1981 16.USC 3401. Also re- f e r r e d t o t h e Committee on Merchant Marine and F i s h e r i e s J u l y 28, 1981.

554

summary t h e Lacey Act and implementing regula t ions " r e s t r i c t t h e impor- t a t i o n i n t o , o r t r a n s p o r t a t i o n between t h e United S t a t e s and any terri- tory o r possession o f t h e United S t a t e s of any nonindigenous spec ies of w i l d l i f e determined t o be i n j u r i o u s o r p o t e n t i a l l y i n j u r i o u s t o t h e natu- r a l ecosystem except f o r zoologica l , educat ion, medical, or s c i e n t i f i c purposes, o r by Federal agencies s o l e l y f o r t h e i r own use."'l

and s u b s t a n t i a l p e n a l t i e s , i n terms o f imprisonment, f i n e s and f o r f e i t of t r a n s p o r t i n g v e s s e l s , can be imposed on of fenders . The f u l l impact of these amendments on t h e r e g u l a t i o n of in t roduct ions a t t h e ind iv idua l S t a t e l e v e l has y e t t o be determined i n t h a t many indiv idua l S t a t e s have within t h e i r l e g i s l a t i o n provis ions t o r e g u l a t e in t roduct ion . I n t h e Commonwealth of Massachusetts, f o r example, no s p e c i f i c s t a t u t e s e x i s t but t h e Direc tor of t h e Divis ion o f Marine F i s h e r i e s has power under Massachusetts General Laws, Chapter 130, Sect ion 17, Subsection 1 0 t o promulgate r e g u l a t i o n s a s required. There i s an increas ing awareness a t t h e S t a t e regula tory l e v e l of t h e p o t e n t i a l l y harmful e f f e c t s of uncon- t r o l l e d movement of s h e l l f i s h , both from t h e s tandpoint of in t roduct ion of non-native spec ies and movement of n a t i v e spec ies t h a t may harbor p a r a s i t e s o r d i sease organisms. This "awareness" has s t imula ted t h e for- mation of s e v e r a l U.S. r e g i o n a l s h e l l f i s h t r a n s p o r t working groups,' com- posed o f f e d e r a l and s t a t e r e p r e s e n t a t i v e s , whose goa l i s t o produce workable and enforceable r e g u l a t i o n s t o c o n t r o l i n t e r s t a t e s h e l l f i s h t ranspor t . The work of t h e s e groups i s s t i l l i n progress .

The wording o f t h e A c t allows f o r very s t r i c t c o n t r o l of movements

FUTURE PROSPECTUS

Despi te t h e p r e s e n t c l imate o f increas ing r e g u l a t i o n a t t h e n a t i o n a l l e v e l and p o s i t i v e movement towards compliance with a comprehensive code of p r a c t i c e a t t h e i n t e r n a t i o n a l l e v e l it is probable t h a t in t roduct ions w i l l continue t o play an important r o l e i n both t h e development and main- tenance of b iva lve mollusc aquacul ture ventures and harves t f i s h e r i e s .

A major problem common t o a l l e f f o r t s i s t h e c e r t i f i c a t i o n of seed o r brood s tock a s f r e e of p e s t s o r d i seases . The t e r m c e r t i f i c a t i o n , although commonly used i n regula tory terminology, i s probably inappro- p r i a t e because it i s p r a c t i c a l l y impossible t o guarantee c l e a n l i n e s s of a l i v i n g organism. A thorough documentation of p a s t h i s t o r y and t h e ap- p l i c a t i o n of quarant ine measures, as recommended by t h e ICES Code of Prac t ice , are reasonable and, t o a g r e a t e x t e n t , enforceable measures and probably represent t h e b e s t p o s s i b l e compromise. The continued u s e of an h i s t o r i c a l l y "clean" brood s tock i s advised t o maintain f i s h e r i e s based s o l e l y on hatchery production of seed ( f o r example, t h e continuing u s e of C. gigas seed o r i g i n a t i n g from t h e U.K. Conwy labora tory t o main- t a i n t h e German hatchery and grow-out program).. The long-term use of such brood s tock would a l s o al low t h e incorpora t ion o f a g e n e t i c se lec- t i o n component i n t o in t roduct ion programs a s suggested by Newkirk (1980).

7Quote from Federal Regis te r , Vol. 46, No. 230, December 1981.

8For f u r t h e r d e t a i l s contac t : M r . John W. Hurst, Chairman, North- e a s t Region S h e l l f i s h Transport Workshop, Department of Marine Resources, West Boothbay Harbor, ME 04575 USA; or D r . W i l l i a m J. Hargis, Chairman, Mid- and South A t l a n t i c S h e l l f i s h Transport Workshop, Vi rg in ia I n s t i t u t e of Marine Science, Gloucester Poin t , VA 23062 USA.

555

New in t roduct ions , e s p e c i a l l y those s t imula ted by immediate eco- nomic c r i s e s , pose s i g n i f i c a n t problems i n terms of r e a l t i m e response and q u a n t i t a t i v e product ion. Compliance with I C E S s t y l e guide l ines re- q u i r e s a quarant ined, hatchery s t y l e opera t ion on s i t e before any move- ment of s tock can be e f fec ted . A l s o , t rea tment of e f f l u e n t from quaran- t i n e d f a c i l i t i e s i s expensive. Holding l a r g e numbers of seed o r brood s tock p r e s e n t s a much l a r g e r q u a n t i t a t i v e t reatment problem than holding l a r v a l forms. One opt ion t o f a c i l i t a t e f u t u r e in t roduct ions is based on t h e s a l e and shipping of “eyed-larvae‘‘ by h a t c h e r i e s on t h e U.S. w e s t coas t . Larvae of t h e spec ies t o be introduced would be c u l t u r e d by pre- s e n t commercial ha tcher ies i n quarant ined condi t ions . The in t roduct ion of eyed-larval forms, d i r e c t l y from t h e hatchery without exposure t o un- t r e a t e d n a t i v e waters, t o holding f a c i l i t i e s i n t h e rece iv ing country would follow. A per iod o f inspec t ion and observat ion would follow be- f o r e r e l e a s e i n t o t h e new environment. Such a proposal has s e v e r a l prom- i s i n g a t t r i b u t e s . These a r e :

(i) The development of “in-house” quarant ine f a c i l i t i e s i n high technology h a t c h e r i e s i s not an excessive suggest ion i n t h a t these hatch- e r i e s , by des ign , a l ready exerc ise considerable c o n t r o l over t h e l a r v a l c u l t u r e environment.

(ii) National regula tory pressures w i l l probably increase a s i n t e r - s t a t e commerce o f hatchery-produced m a t e r i a l grows. A c lean product a t t h e hatchery l e v e l i s i n t h e b e s t i n t e r e s t of t h e hatchery opera tor i n order t o comply with any f u t u r e i n t e r n a l regula t ion designed t o prevent spread of d i sease .

(iii) The product ion capac i ty and growing experience of commercial ha tcher ies could be used immediately t o s e r v i c e a problem many thousands of miles d i s t a n t without a time de lay r e s u l t i n g from a need t o develop o r t r a n s f e r technology f o r hatchery product ion i n t h e rece iv ing region.

( i v ) The p o t e n t i a l market f o r t h e hatchery opera tor i s expanded.

(v) The governmental involvement i n t h e in t roduct ion i s reduced from a c t i v e p a r t i c i p a t i o n t o an advisory o r regula tory capac i ty . (This may not always be advisable , e s p e c i a l l y where re levant e x p e r t i s e res ides predominantly i n government funded l a b o r a t o r i e s ; however, scenar ios where government i n t e r v e n t i o n would be de t r imenta l t o process are not d i f f i c u l t t o envisage.)

( v i ) Hatchery o p e r a t o r s might even welcome such a procedure i n t h a t it would provide an indus t ry s tandard which can only promote a more de- s i r a b l e image of h a t c h e r i e s t o t h e on-grower.

Such a proposal might provide a p r a c t i c a l means f o r real time re- sponse t o an immediate c r i s i s and thereby prevent an e s s e n t i a l l y uncon- t r o l l e d in t roduct ion as w a s e f f e c t e d f o r Crassostrea gigas i n France. Furthermore, it would promote t h e i d e a l t h a t a commercial hatchery should produce high q u a l i t y , c lean l a r v a e i r r e s p e c t i v e of whether o r no t they a r e t o be s o l d and grown by an immediate neighbor o r a customer on d is - t a n t shores--an i d e a l t h a t I doubt anyone i n t h e hatchery indus t ry , on- growing indus t ry , n a t i o n a l regula tory bodies o r i n t e r n a t i o n a l advisory bodies would d isagree with.

556

ACKNOWLEDGMENTS

The conten ts of t h i s manuscript represent t h e opinions of t h e author and do not n e c e s s a r i l y represent t h e view of ICES. I a m g r a t e f u l t o mem- bers o f t h e ICES Working Group on In t roduct ions and Transfers of Marine Organisms, e s p e c i a l l y D r . James T. Car l ton and D r . C a r l J. Sindermann, f o r much s t imula t ing d iscuss ion . Thanks are also extended t o M s . Elaine M. Lynch f o r typing t h e manuscript and t o t h e U.S. Department of Com- merce, NOAA, Off ice of Sea Grant f o r f i n a n c i a l support under Grant No. NA80-AA-D-00077.

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