MORI>I-IOMETRIC RELATIONSHII~,GAl\IETOCENIC DEVELOPMENTAND 51'AWNING OFTI-IE GEODUCK CLAl\1 PANOP£A GtOBOSA

(BIVALVIA, 1"IIATELLlI)AE) IN HIE CENTRAL GULF OF CALIFORNIA

EUGENIO ALBERTO ARAG6N-~ORIEGA.I.JORGE CHA \'l:Z·VILLALllA,1PAUL E. GRIBBE~l.l EDGAR ALCANTARA-RAZO. 1 ALFO~SO N. l\IAEOA·MARTiNEZ.-'EDNA l\IARi,\ ARAl\IIIUL,\-I>UJOL.1ADIA ROSA GARciA-JUAREZ!.... ANDROSALio l\lf\LDON,\DO·Al\II)ARO~

lCI'lIlm de 11I1"('.\ligarioJles Iliologil"(f.~ del NlJrO('.~/t'. Ullidml SOl/om. Kill 2.35 Camil/o (II Tular. EsTem,Ila1'Ol'Ilihallll'0. G/I(f.l'III(1~. SOllom N5454. Mh"ico: •DI'fWr/IIII'1If oj ElIl'irOlIll/l'JI/ol 5dell/·l'. Ul/il'l'r.l·ityoj7j'dmofogy. S.I'(III/'Y. P.O. Ilux 113. IJrom!lflly NSJII20{)7. AII.lfrafia: 'Celllm (It, 11II·1'.I'ig(lI'iOlI{'.~

flio/rigim.\· del NOHI/'.\I!'. Mar IJl'rJI/l'jo 195. Playa Plllo dl' SOli/a Rilll. La Po:. IJ.e.S. lJ090. t\((;xico:

"'CI'III/"(/ Regiol/III dl' 11/1·1'.wigaciOlII'.I· PI'Sl/I/l'/·u.~. Cal/t' 10 605 mr. Col. La Cmlle/·u. G"U,l'IIIW·. SOI/o/'{/854(}O. Ml;x;m: ~Ct'1II1"U dl' El'fIllfio.l· T/'l"//o/rigil"O.\· (1<'/ Mal' No.J. II. P. 741. Gllu.rll/a.\·. SOllom85480.Ilfl;xico

AnSTRtiC T Thl' p;lpcr d.·'oCntx.... lI1orpholl1clm: n:bllon~llIJb. ;md Ihc IlmUlJ; of l!:ll1l('"logC11lC d('"\,c!0pll1cnl .LIld 'p;!" nm!!. forlhe J;codud, <."1,1111 /'/III"{'/'/l gllo1><nI/ (1).111 IlNl\) from .. populallon 111 lhe ea'l cenl"'.l1 Gulf of Clliforl11:1 C1J1l1~ "'erc l"OIk.-clL-dmonlhl~ for a }c;Ir (Cklolx-r .:!()O.Ilo Oclolx-r 20051. :Ind "cre nlCJSUrl-d and "el~hl-d 10 obl:un nlOrphOfllClric' rc1;l1Ion~hip<;.

Standard h'~IOloJ;IC'".l1 anal)~t~ and nlC;I,urcmcnl~ of OOC)lc dlanlClCf'o "crc u...:d 10 ..k.......nlx- lhe Imlll1~ of ~amclogcnll."

dc.clopmcnl and 'Pi'" nln~ \10'1 morp.honlCtoc l'anablo \lcre S1J;mflC'".lnll) eonclalL'U. ho"C\er lhe COoCOkll."nI~ofdclcnml'l3l1on

"ere J;ClIC'r.lll~ 10\1 1<0.51 mdlC'".lunl! high lanal",n III mca~urcd tr:Ub. l:arl~ ~anlCtogcn ...· <k.... ('"lopnlCnl \I"~ Obscf\l-d III ble,ummer .lUlunln" ""'n SST v.a~ hlJ;h ( 30 ('I. l)c\clopmcnl Increa~a, \lalcr Icmpcralu~fdl \lIlh nil" Indl\lduals ob!<ncd Incarl) "mter I :!O C). SPi'''llInJ; OIXurrt.-d bt.·t" ......"T1 Janu:II') and "ebrual') lV.lnh:r). "hen SST \lCr.: at lhe,r rooksl (-18"CI.C) tologll.'al characlcmlll." of the fOn:ld and ... cra!"-":> of OOC) Ie dlanlCll.TS for the dlffcr.:nt r.:pmdocll\e ph.......... \I en: )lmlbr 10othcr !"-...)(Juc:t ~p«Il.'" prc\ lOu~l) dc-;cnbt.-d O.craU.;c\ r:U1OS v.-ere equal Thb ~od) l~ lhe li"'ll"'OOI~lC'"al ~tud) 10 be conductedfor /' Xf"htJw, Gl'en the dc.dopmenl of fi~hcTll."S for P.gloh.JMI and lhe Inlcr....l In de.cloptnJ; aqu:ICul1un' for lhl) ~pc'C1I:'S.

lhc dJI .. JH'o'ldc •"Iu;lhk InfomlJllon for Ii,hcn...." nlJ naJ;C1'I and :Iqual'uhumh,t';lnd r.:prc'oCnI lhe ba~I' for fur' hcr TI:"oCarch onlhl' 'pl."I..·l.....

111:")' II ORJ)S: 1',m"I'<~1 XI,01><,,,,. i,......)(Juc:l. cbm. r"pI'od OCllon. 000:) te 'I/e. Gulf of CalifornIa. >eX r:lllt)S

I\;TKOULcno:.

Geodud: dams :II'\.' one of the 1;lrge~1 burying dams in (heIlorld. They lil'e buried del.'!> in lltt' ,cdimcnt (lip tol Ill) :ll1dha\'c long paired siphons that extend 10 Ihe sl.'dillll.'l1( surf"ce,The Pacilic gco{luck. PWIO/l/'(I (formcrly 1'11110/11') ahrul'ltI(Conrad 11'49) C:1I1 obt;lin a ~heJ1lenglh of 210 mill and :t 10t;11\\'CHH'ight of J.2 kg (Guod\\in & l'l'<lW 19X9). Although~m:llkr Ihan I'. (/hrlljllll. ~hl'llll.'nglihup to 127111111 and Ilhok\\1.'1 \\eight~ of 627 g ha\'e been rL'CordL'd for Ihc Ne\\ Zc:llandgeoduck. 1'. :C,/llIlIli("(1 (GrIbben & CrL~ 20(5). GrO\\ Ih IS mpidfor Ihe fir'l 10 ) and 111111im:ll lhere:lftcr (Gnbben & Cr.:csc2005). BOlh ,po..--cit~ :1Tl.. abo 'CT) long-h\cd \\'lth ma>:imum al,'<."Sof 168 ) and 85~. f\.-corded for I'. tlhrllp/tl and I'. :c'/(IIltitru.l'\."Spttll.d). The di)lributlon of both ~IX:cil~b influcnced b) Ihet>pc of ,um.tmtc wilh hlgh('"r dcnsili~ found in fine s<md 10 fine'lit) ~nd bonollls (Cal11pbo.'l1 1.'1:11. 1998. Gnbben et a1. 2()(»).

Populations of bolh I'. (lhrtlflU/ ;Ind I'. :I'lmulim ha\ c b..--cn,ho\\n 10 ,p:II\'n from 'pnn,l;. 10 ~ummer ($10,:111 & Robinson

1984. C;lIllpbell & 1\'Irng 100.\. Gnbbi:n 1.'1 al. 20(4). Thc NCIIZc:lland geoduck cxhibib funClional prol:lIldric diocc~ with :t11geodllck~ Iir-I maluring 111:lks and ;1 ~lg1llIic:lIlt proportion ofindl\idU;Ils eh:lIlging sex 10 fem:lle:> :I~ Ihe) :lge (Gribben &CreeS!.' 2003). These result, in ~c,,-r<llio~ Ihal <Ire !>kc\\cd

lo\\ .. rd~ males in Ihc "11Iall ;Igc si,(c cla"sc!> wilh fCI1l:Ilc~

domin:lling the older larga ~il.e cla~:>cs. Evidence also suggest­Ih;ll function:ll rrot:tndrit dioeey :11,0 exisls for (he P:leiflegcodutk (Vadop:Llas ct :II. 2006). all llllUglt thl~ h:ls 1:lrgdy beendisl1li!>scd as an c.xpl:lnalion for ske'led sc.x r:llios in 1'. IIhI'/lPI/1(e.g.. Clmpb..'11 & Ming 2ooJ).

Commercial harvcsling of P. flhrlljllll form!> the most impor.1:1111 cl:UIl li,her> on lhc 1':Kific CO:I,I of Nonh Amcrie:1(Camplx.'l1 t'l :11. 1998) and i~ \\orlh in e\ee» of 535 million:lIlnuall) 111arbo 1998. Hoffman t'l al. 2000). The major lishcTlC<>arc found In Wa~hinglon Stale. Ilnll,h Columbia. and Al:bka.A ~mall ex pcrl1lll.'l1t;llli~heT) (c:1.1 00 1.m nll:lll) ) for I'. :I'I(II/(Iimbegan lrl IIJS8 (Breen 1:1 :11. 19911. :Ilthough Ihe fishl'f) Wil!>c1o..oo III Iht' early 1990s pcnding Its IIllrodUCIIOn 1Il10 Ihe quol:!m:lIla.Gcment sy~tclll (Breen 1994). 110\11.'\ l.'r. thel'\.' is conlinuedtrllerc)1 III de\c1oping. fishcri..-s and aquacullurc for this Spo..""Cl......(Gnblx.·n & Crees<: .2005).

1\lorc 1'\."0.'1111). ~mall·scal ... CXp10l1:1l10n of :lIlother .Geoduck~pct·il~. /'lIIlO(If'(1 J:.1IJhmfl (1):111 11I911). h:I' begun. Pww{J('/I

1t11'1I/,.w b:I )ublropical sp.'Cic, endcmic 10 the GulfofCaliforlll:l

(I kndnch el :11. 2005). Exploltallon or thiS species is a rd:lti\ene\\ :,CII\,II) on Ihe tl'lc.\lcan CO:l'1. Imll:lll). n:llion:II fi,herie,

reports trldudC'd landings of I'. It/llb/'I(I in :1 general C:llq;OT)

togelher I. ilh OltH:r clam sp.'Cic, (Ar:ltIlhuhl-Pujol 20(6). 1-10\\­C\i.. r. once it !x'Calll('" a distinel li,hery. 1:Il1(ting~ of this slx'cie~

were 1't'Cordcd separately. ProdllCli"ll e~ti11l:ltcs for the yCilr!>

42.\

.g .• ,,\II.\(,(),-NORlIl,\ 1-1" \1 .

~. 1001. :md 2002 lIeIT' It) 1011'. 51 ton~. and .'5 toll".n:spcctiwl). CurTCIlII~. there ,Ire onl~ four COOp..'r.lllh'" Illth

licenses for the pro-p..'i:tl\\' exploitation of ".tloh..." In th\' n:};I,mHO\ll...·er. Ihe commercial potcntMI of Inc ~J'l.'i:k."" h b..'i:Ollllllglocrc;lsingl) allr:lCIl\<.· 10 Ihe lhhing mdu~tl} through both n,ll­uml h;IT\l:Sting :Hld aquaculture. 1-l0\\l:ll:r, :lP;lrI from doeulIIl·n·I:llion of the pf\,.~'nl'C of P, gln/ll/Mi III San Fcli~ 11\ Illl' Gulfof California (J I"N. 115"\\1) (Kl'Cn 1971) ;Illd Tl"t...·1ll dl:.....·nptlllihof l:lrgl: b....ds to the south in the centr"l Gulf of C,lifoTl1la nearGuaymas, Sonor;1 (Arambul,I-Pujol 2006), thcre i, no ,-'\.·,)logl>:aland biological inform,ltion a\'aihlble from thi, ~[X.'Cie,.

Developing ~u~tainabl... ti:)heric, i~ rehant on obt;l1I11ng:1l'Curate cstimale' of hancSI;lblc blom..,:). A lir,t 'tl'P III

prol'iding thl.. informalion i:) del.:rmining morphonl\·tr!c rd.l­tionships (q;.. ~helll.:ngih IW,UI.\ Ilhole \Ieighl rdal1011'hlp'lfor indiliduah IllIhlll a popul;lIlon 1/'.':11.:11 & J-1ldu 19S2j.Funhermore. compari,on of 1110rphom.:tric n:latlOn,hlp':lmong popu!:llIon.. l-..tn ;llso b.: used to ,bloiC'.... \\hcthcr ,toel,haH' 10 b.: m:magl-d IIldi\ iduall~ or collccll\d~.:lIld 11l\1:'l1galeh011 popul:llion.. ad:lpi to ;:n\"irollinent:tl chang... (c.g.. blgact al. 1984. Cerr.l1o & K\'i!h 1992), Su:)t:1I11:Ible m..n<1gel1ll:n1 ofhar\'cStl-d populal1on, 011..0 requires determining th ... r...g"'lll:ra­tion capabiliti... s of natuml st(x:ks. Initbll} this i~ rell.lllt 011 ..

thorough underst;l11ding of the reprodtu:ti\(' biolog~ .. nd lif~'­

hiSI ory of Ihe sl>l.'Cie~ 10 Ix.' han ested ( B;I roll 1991). N(li on I~ \I(lwe need dl'I:II!t:d knOll k-dgc of th ... II111rng of g:lmetogelllcdeldopmenl and :i>pallning_ but abo :>cX-r..ttIO.. :Icro" ,I bm;ldr.tng;: of Sill: da....c'. Sl~'lll-d !oi.'.x-r.ltio:) could 1.::ld 10 li:.hene~

in;ldlertentl~ t:lrj;ctrng:1 ..ingle SC'l: r.....uhmg in li:)hem.... th.lt.tT...nOl sustainabl\' (Gnboc'n & Cr~'I.~ 20()'\). Inili;llh, 'ul."(.'C"fulaquaculture I~ 011'0 reli;IIH to Ihe Ilmmg of gaml:logeni>:deldopment and 'p'I\\lI1ng elcnb '0 polcnu:11 br,XN,hlod e:mbe COliecled;1I the :Ippropriale lime.

The :lim:) Oflhl' 'lUd~ :lTC 10 t 1) d...termllle Ih... rd:lllon,lup..b.:twccn ke} morphometric \';Lri:lblc:i>; (2l U1\C>otigale Ihe t1l\ungof gamelOgenic dl'l elopml'nt and ..p;I\1 ning, and (3) determInesex ralios acro~s a range of "i!.e da~ ....., for I'. ,d"h'HIl III :l

population loc;11ed in thc ccnlr;r! part (If the Gulf of ClllrOrnr,1.

110'45'

•

•27"55'

\I \TERI\I-S "I)\IETIIOUS

Stui/.I· Silt' u"J Ort:u";'m

The lllorpholog~ and reprOOUClI\e l'}de of the geoouckdam. PIII//I/H.'11 XloM!.,,,. II:I~ lll\e~llgated using geoducl:)coll~'\'lcd from B:lhi.. de Gua}l1Ia,.Empalme (-!7"5J'N.110 4.\'\\1) (Fig. I). Monthl) sample, of ;Ipproximatel) 10chlm~ ('11.' range 6X 239 1111ll ,hell length) Ilere I.·olleeted,ubtidall~ b... tlleen :It X 12 III depth using SCUBA rrom

O<.:lOlx.'r 2~ through Octob.:r 2005. I-lowe\er. no s;1111p1c,\\ere I.·olkcled from June through Scptemlx.'r 2005 OC'C;IU"<: hIghkId, of 'Lbpcnded materi;ll in the Ixl} Ill:lde II impo..~iblc to

1000·'ltl: geodllcl,; "Iphon hok..". OIlC\.'l'\Ir..tct\'<! from th.......'diment.the d;lm' \\ere tr.lll~portcd 10 Ihc boorJlol} in coolcT:i>. andpl;Il'Cd m .I!anl 111Ih running ......;I\I.lter.

I-or each mdl\iduaJ. 1\0.' IllItlJll} mea..urcd thrl" ~hell

I;lriabb l~hel1 knglh. ,hell \Iidlh. ,lIld bod~ IhickllCS~) u'rng\ernler l";lhpcf) (!Iol.'C Fig, 21. After th.- 1\1.' me:lsurcd total \\;:t

Ill:l'~. lI..~u;: 111.'1 m:l". :lnd :.h;:11 \\;:Ighl b} ~p:lr.tling Ihe ,hellfrom the lI"ue and blotting bolh dr) 10 remo\e e'l:l'CSS 11,111.'1',All \\eight111e,,'uremenb II ere d...termrned to the nearest 0.1 g

lIsing an e1cclronie b01I:lllce. Morphometric r... l<ttionship"lx:twl't:n all ~i,'I: l:rri01blcs wer.' ill\e~lig;lled using corrd,llion:rn01l~:>c.. for all geoducks collccted (1/ 77 in lOla I).

G:l1l1elogenic de\elopment :111d ,e>; r:ltio~ were dcterminl-d

lhing :1Il:L1)~I" of hi..tologic:lll~ prcp01r\-d ,Iides. Hi"lOlogic;11pron'dur~" follollcd ml:(hoo:-. uscd III prcI 10th ~Iudie:i> (M;lldo­

n:ldo-Amp,lro & Ilxlrr.t 2oo2a. M;Lldon"do-Amp;lfo & Ilxlrr:l2oo2b). Once \\hoh: tl:)~ue Ilelght w;.- determined for ...aeh

rndilldu:l1 .100\1: Ihe gon;ld and a"ocialcd liscera \\ercn.'mol\'d. a porl1on of the lI'sue \\a, t;llen from a :)tandardp(h1110n In thl.' nuddk arc-a of the gon:ld and li'l:cd in DOlI I,on'~

Solulion for .ltlc:I'l 24 h. S:lmplcs \\eTC deh~dr:II.-d in:l loiC'ne.. ofelh:lIlol Ire,lImen" of incr...a .. ing concentr:l1ion, de:lred in\}lcne. and ;:mlx-ddl-d in P,lmp];l .. t :II 56~C ;illd :>l'l:tionl-d :It

5 ~11l. All .....'ttion' Ilere ..l:lin...d I'ith h...maIOX)lin ;Illd co.. in,"lUI ion and mdi\idu,llI} Illounted on gl;I~~ slides. TIl(' slides

ANO<1•

27"51'

Z Gulf of California

j II ~~~~........:.....~,,~, ::::::;J.~;"'w 110·45' 110"40'

27·5"

~-iltun' I. c:olln;-lion ...iu.' ..r "/lIWprU J:loIH;~/I in lbhia d,' (;u.. ~ m......Emp:llmr in , .... n,' n'tI'r-.I1 Gulf ur C.:Ilirorni:l.

G",\II'fOGJ:N1C DI VI·1.01':l.1E"\JT I" P IW}/'!:I ("-OliOS.' 425

Th

~,,

Jar:tll1illo et :11. cwo 1). Sigma Stan'" image analYler ~on\\';lre

was 1lS!.'(1 to rIle,lsme at ka ..i1 100 oo(:yles per fcllMIc. Mea~ure­

111ent~ follol\'~'d a slandardi7.ed proccdure 10 redu".... bias whcnselt'Cling fields for Ineasuring. Transects on gonad p1"<:p;rr:ltion~

wcre traced in sIKh :r \\';IY that Ihe longest :l.~is cOIlI;liningoocytes (vertic;r1 or hori/onl;rl) was always followed to 111;I.~i­

Illi?(~ iield c()\'Crage. /\11 oo(:ytes contained wilhin ;1 tiekt ;1I1dpresenling;1 Ilcll-defined g<:'rminal I<csicle wcr<:' measured.

The r;lIio of nwles to I"<:nwk's \\'a~ determined from micro­scopic e)(;lmin;ltinn of the hislOlogic:t1 slides. Cl;lm~ weredeemed se)(u;llIy l11alur~' il" gam<:'tcs were present. Cbrns werealso e,~;llllined for any evi(ll'm:e of hermaphroditislll_

~ E."i II LTS

Length

Width

Fig"'" 2. Shdl ",<'aStlrt'rn~"IS"r 1'",,,,1"-''' gil""'''''' from 11K" .'aSI cClllral(;lIlf of C" Ii f"rllia.

were eX;lIl1ined under ;111 oplicalmkroM:ope al 4 x. 10 X and-to X 1\l;lgnilic,ttion. GOlwds from bOlh l1Iale ;tnd female damswere pl;teed inlo five qualitali\''' t'alegori"s based 011 those(kscribed for f'. ;('/lIIltlil'/I and 1'. /1/11'111'/11 (sec Campbell &Ming 2001 Gribocn d ,d. 2004 for det;lils): early active.late active. ripe. pani;i1ly spawned. ;l1ld spenl resorbing.The gon:ldal st:l1e of each C];Ull was descriocd a~ OIl(' of Ih"Ii,,, M;lges based on lhe 11l0~1 dominanl stage present in10 h;lpha7.ardly seleck'd follicles frolll each sample.

Tht' timing of gametogenic development and spawning ingeoduck species (as with Illany olher biv;dves) {SI');lll &I~ohillson 19X4. Grihben cl ;11. :WO-t) is correlated with changesin w;ller temperalures. We ,i1~0 investlgat('d wlwther gam.:'to·g('nic development and ~pawning in P. g{o!J""1I was correlatedto p;ltlerns in se,l-s\lrface k'mpcratures (SST). MOnlhly SSTscovering lhe duralion of th... ~tud~ were obliLined from theComprehensive Oceanic all{! Atmospheric Dat;1 Sel (COf\DS)(data provided by NOAA-Cl RES Climate Diagnostics Center),The COADS SST ticlds are rom pUled hy oplimum interpola·tion of all ill .Iiw and s;ttdlile-deri\'ed information 'l"ai1;lbk.amI ;tre commonly distributed as monlhly 1° X 1° grid d"t;l(Reynolds ct al. (20U2). The :!~oN. IlloW data were sek<:ted asCentral Gulf of California. SSTs and :Lre prescl1lcd as tlK'monthlya\'erage.

For all females colli.'Cted. monthly mean oocyte diameters(±SE) were c;r1tlll;tled lIsi Ilg prO<......dur"'S des('ri 1x,,1 by Rod riguc~-

,\ I or"/",,,,,,,"j,. H"lmj",olriI'S

The shclilength of all gcoducks colicc!<.'d nlnged from 68 mm10 23') mm. shell width r;rngcd from 39 120 1111ll. shelllhicknes~

ranged from 36 1.1(, mm. shell nws~ rang('<l from 5.-t g to 165 g.IOlal rna~:> ranged from 68 g to ').10 g. and lotal tbstlc wcightranged from .'4 g to 696 g (Fig. J). r-.'klll shell knglh. thicknessand width mass for all g<:'oducks l;(llle("\ed \\,er(' 1-t7 (1.1.5) mm.90.4 (5.0) rnm. and 72.S (5.1) 111111 resp<-'Cti\'Cly (Table I). Overallmean wtal wet Illass. tissue wctm;lss ,111<1 shell m:r~s wer<:' 533 ..'(4.1.1) g. 264.5 (20.1) g. ;llld :Sl.-t (.'.')) g. r,,·~pi"Clil·<'I}. Monthlymcan shell Icngth. thickness and width. towl Ilet nw~~. andtissue wet lIlass of 1'. gloh",~1/ did not f0110\\ ;1 d iSterni ble paItcm(Table I): thc large~t clanh were collecl<:'d in D~'C<:'l1Iocr 20{)-tand the smallcst in i\'!;ly 2005.

There were signilicant correlalion~ 1X:lw.:('n all shcll trailSexccpt for shell thickness t·('I".\/I,\'Shdl1cngth ;llId shelllllas~(Fig ..1: Tahle 2). There we..... ;llso signilic;llll rel,ltionships belweenmost shdlt 1':1 its 1'/'1'511.' tot;lll1Iass and tissue wet l1Ia~s. ('xcept forshell length 1'('1".\11.\ lis~ue weI lllas~. and shell thi(~kne~s 1'('/'.'11.'

tot;l! weI rtl;ISS ;Ind lisSlI<:' wet mas~. Thcre was also;1 signitic;lntcorrel;lt ion bet I\,<:,ell tot;1 1W('I mass a nd Iissue wet rnas~. E.~cept

for correlations between shdl ma~s n'r,lW lotal 11,~t rn:ls~ andtissue lI'... t 1Il;I~S. ;lIllltotal Il'<.'t l1la~s l"I'I'.IIIS tissue wet Ill:lSS (all1'2;> 0.50). tll<:' co<:,fficicnts of del,'rmination were generally lOll(r2 < 0..'0) indicating high v;lri;lliol1 in lhe rchtti()l1ship~belwccntraits.

From hislological prqxlrations. we continued the criteriadescrihed b} Gribocn el ;11. (20t)4). who reported 5 r.:productiwsl;rg<:'s: early ;tttivc. latc activc. npe. p,lnially spawned. andspent reahsorhing (Fig. 4/\ to J: sec Gribben CI al. 2004 fordetailed descriptions).

Gamctogenic dcwlopmenl and sp;lwning lias synchronoll~

between the scx...s so only Ihe owrall pallnns of gamelogcnicdel'doprnent ,lrc (kserihcd (Fig. SA. II), In ;lutl111111 (OCIOber)200-t. 50% of Ihc dams were in Ihe e:rrl~ aclive stage with therem;lindcr lInditT.:rentiated, suggesting tlWl gamelOgenie devel­opmcnt 11<Id ju~t begun. Gamet",~ delcloped quickly ;md bywinter (December) :!004 IOou u of Ihe d;lIIh IIW<:' ripe. Sp;lll'ningbeg;1I1 in midllillll'r (January) 2005 I\hen sonn of c1;Hll' I\erepartiallr ~penl. ;rnd thL' r,,'nwining dam' L'omp1ctcl~ ,pawnedOllt. By lak' wInter (Ft'bnlary) 2005. nearly all clams were spent(90U/u). and lOUIn had r<:,surbed all gametes and we're undini:r·enti;lted. All clams tolk'C!<.'d through spring ,md ...arly ~Ul11lller

, .,

•· • I, •· ... ,. '"....~~ ...'. -.'. .

• •• ••"'" L''---:::c-'l,::::---:~--,'"!iO MXl 150 2lIO ZiO

Shelllengch (mm)

'"'"'00..'".." l---~-_~~

25 !iO ~ 100 125

Shell width jmm)

'00

••1~

•

•• •• •

•

•.~.~

..."....".-;; :,,".111 ,,-•• ••

..

'" '":•;: 100

· '"L•

AR \(,O,-NOKIl (i \ I:T \1.

- '"I 120

• '00~•~L

••

•

..

••

, ,•

•

•

•

".· ' ,~

_ ..... .,. '... .. ....•• • • •

••

•, l---~-'--.---,-_~.50 IIXi 150 200 250

Shell length (mm)

MlO 150 2lIO ZiO

Shell length (mm)

~..· .' .· .... ' ...

•

'00

"'""'"00'

•:E-I•,••"

L

;;•

-126

'00•~

.~• I. • I

• •, .'" .., l----->-=~-_~

2!i 50 ~ 100 125

SheW width (mm)

•'''''"'00

'":1•L•

•-.... .~

.,-:- .. " .• • •'. .• •,l-~-'-'~-_~

25 so ~ 100 125

Shell width (mm)

"''''''•• '00•~"'"I "'"•,•~

"'"~..,'" ,-,, l-----'-''--.-_~

25 SO 75 100 125

SIMM width (mm)

40 IlO 110 100 120 l.co

Stlellthickness (mm)

,"

.~SO ~ ••••

•••• •, l-o;..:.....~~~~

"

'''''00

~•••E

•L•

•

•••••

; 100 -.~ ,+---.''--.----~2D .. IlO IlO 100 120 14O

Shell thickness (mm)

•· "'"

"''''''•• '001, '.

•

,,,•"'" -,, l-,..c.,~_~~

20 .co 1IO 110 100 120 UO

SlMllthickness (mm)

....,"' ..••1~•~

••• •

,,

, ·,'"'C,ooC-C",C:-=",,"--=.ooC--,.,CTIssue wei mass (g}

'''':•L•

'"•••E•

, ~::-c::-c::-c::-:::.o 200 oro 600 800 1COO

Total wetmus (g}

~· ''''•e 100

•'00

"'""'"'00

, F:c-c=--:=--:c-c:.o 200 oro 600 IlOO 1COO

Total wet man (g)

i~•,••"

Figure J. \ l.,qlhol,~ic~l ~"rrdati"n~ for /'unuf'<'u Jl/uhmu frum lh" ...~st ......"tral Gulf of C~ Ii fomi~.

(L\'larch lhrough L\la) )2005 had r.:~rbed ;111 gamet.:s aod couldnOI be :.t:!(OO, Gametogenic de\c1opmenl had begun ag;lln h~

sprlO£ (Oclober) 1005 wtlh 95°. or dams 10 the earl~ ;lCtl\eslage. Again de\·elopment ma~ h;l\e st:lTted earher. ho\\ .'\er \\ecould not col1l'Ct dams from June to $l:plember.

Earl) £:III1':lo£<."nic d.:\c1opmcnl was o~ned III I.lt<." ~um­

mer autumn \\hen SST \\as htgh (-30=C) (Fig. 51_ Dc\c1op­melll tnCreaSl-d as \\.lIer Il'mpcr.llute fell \\ith ripe indi\lduahoh:!ICt\oo in carl} \\inler \\hen the SST \\a~ -:20~c. SpJI\ntngOl.:curn.-d bet\\ccn Januaf) and febrmlr) (winl ....r). \\hl'n SST\\ :l~ at th 10\\eSI (- 18"C).

lI1c;ttl OOI.'~IC di;llI1elets occurred in Oclober:2~ (8 ± 1.3 ~m).

corresponding to Ihc C:lrI~ ;IClL\e slage. B} No\ember. duringthe IJle ;cr.:ll\e stage. mC:tt1 OOC)IC di'lm...ler h'ld risen 10 32::t"­11.17 ~m. Ripe ooc~ Ie" (DL'CCmber) h:ld an a\ er.lge diamcler or-I6:r: KA7 ~m. The largcst mean OOC)t ... dmmeter (51 ::t"- 11 ~m)

occurroo ttl JanuaQ. :2005. corrcsponding to the parti:lll~.

'IXI'" noo and spcnl ~lag('s. Onl~ larg... unspawncd o\·a remainoo10 the roillcles dunng this penod.

OOC~le~ ranged in ~ilc from 5 78 ~m belllccn October :200-1and hnU;lr) :WQS. Mcan (.:l:SE) OOC~H' diameler_ follo\\.'dp;llleTtl~ observed in Ihe his1CJlogical ~lagings (Fig. 6). Smalle'l

t\lale, ranged in 'hel1lcnglh from 100.:2 .1.'9.0 mm. fcmaksfrom Illl 1J7 mill. and unscxed rrom 68 220 (fig. 7). Ul'(';IU:>Cof lhe e~lemlcd re~ling 'Iage mO,1 datlls (-1:2 oul or 77 ehullScollecled ttl IOlal) could nOI be '(,~l"(1. I-Io\\,e\l;r. during game·IOgcnc~isall clams (II = .1-1) could be sc.~cd. The ovcrall ralio ofm;tle~ 10 females II a~ I: 1(II = 17 in lolal for bolh scxc~). Ik'(';1U~C

GA \l U OGt "lC" DI' \ 1 LOI'\1l VI' 1:-. P. \01'1. I (.I.O/JO'i •

T,\HU: l.

\Ionthl~ mean (±SE) morpholo!:k:1I mcasurcm('nls for /'QIIII(H'Q X1oho5Q coll«:h'il durin!: Ih(' slud~ period.

Shell I.l'ne.lh SMII Tbid.:~ Slw-II \\ idlh T<)lal '''''s.. Tubl Trs..- ~11 \\ C'i~hl

l):lle " (mm) (milt) (mm) (,) mas., (RI (~)

Oct 2004 , 117.9-,,5.1:<6 9.19::. 6.17 7J.6:t J, 19 6:!O.0:t 7.l.l< 177.9 -'- .U.J li730:o 1.1,.-11....tIt 2004 10 IHO:o 615 960:0117 72.2:t I 16 692.1:0 16.9 :!966:oI-l1 "'500 :t II 711I>.."C 2004 '0 1'0-1,7:0 9.56 89.1 :t 2.0; 70.9 :t 1115 62-10:0 -11.5 297.2:0 1-18 Ill': 1-1 • 1"'26J.1n 2005 7 1S9 -I :t 09 111.1 '" 5.35 66.11 '" -I 16 1-12.8 i -15.5 111 -I :t 11.li 5:'-1-1," IlU7I cb 2OO~ '0 169,7 i 106 "'lU :t 11.3 70.1 :0 3.-17 57-1.-1 ;l; -10.9 255.-1 :t 22.1 1'J..3O ' IIUI"<lr 2005 7 167,1.,11,5 117.7:0 6.0-1 1091:0367 55.l.S '" SJ.1 105.3:0 SJ 1 751-1.2.175Arr 2005 '0 115.5 i 111:<1 80. I :0 -1 .•1(, 716:o5Ul -I1l5.7;l; 66.5 313.7," 57.7 11-1.11 :0 16.07M.,> 2005 6 11-1.2 i 2.5'} 6,l.0 :t 2.39 51.1 or 2.57 -I71U;l; 111.9 2.30.5 '" t':.6 711-12 i 10.500<.', 1005 , t1-1.I:o:>:-I7 90.2 i 1.511 69.5 l. 2.01 5J6.11 :t 10 1 271,; '" IIJ.J 119.72:t 15.1.\(ht'ull 77 1-I7.7;l; lJ.5 ')(),-I ± 5.0 7H '" 5.1 5.1.3..1 '" ·B.I 2fH.5 :t 20.1 ~ 1.-1 * J.'I

of 10\1 lIumbers. we could 1101 te~t for differences in scx·ratio~ indilferent ~i/c cla~»es. However. the 111;L1e to female sex· ratio ofclaim < I50 mm was 2: I. and I: 1.2 In geoducks 1;lrger >150 m111W:I~. No elldenee of hennaphroditislll WilS detecled during the~Iud) penod.

The popul'llion of I>. xlf/llm(/ "Impled In lhlS stud) wasdomrnillt'd b) large indi\iduab ",lh:m ab»ence of ~mall gco­ducl..~. Sm.-h population size ~trUC"turt~ h:l\c commonly b..--cnreported for both P. tthrllPW ;md P. =l'/tminl (Good\\ in & Shaul198-1. Gnbben & CrC\."Se 10031. Rl,'cruitment ;n popul:ltion~ ofP. tlhmpll/ 01 nd /'. :t'1l11lllim b highl) I ,lri;1 ble bot h spali;lll) andlempor;lll~ (Good\\in & Shaul 198-1. Gribben & Cn:esc 2003).:lIld II :lppe;H'~ that. despite thl.' ,,;unpk size in this slud) nolbelllg pilrlieulart) largc (l1:-: 77 g~'o<lucl~ in 101;11). this ma~' :11~o

be true for P. 8f"hoJlt. There is Irnle e\idencc 10 suggesl th:ltre~ident rl"t:ruitment in geodut'k porul:ltion~ i;; densit) depen·dent (Orelhan7 el al. 2QO(1). Allhough the met ho<I of samplingti.e.. the loc:tlion of siphon holes) may h;lle biased the ~ize rangeof P. gllllm.WI eollecled (Goo<twin & Pea,e 1991). Gribben &Crec1>C (200.1) found lhal I>. =t'fll//lIiC"/l as ~m:11l ;,~ 45 11IIll couldbe rl.'adily found if preS\."lll. If poor reCrUilrtl~'nl i~ :1 geller:lll)fe:IlLlre for populations of I'. 8/(1110.\(( then fhherit-s managerswill have to earefull) eonsidl'r appropri;lle r:lte~ of harvcsting.

Of the 1\\0 other geodud. ~1X'<.·les for \\hich signilic;mtmorphological d;tt;1 is :l\·ililable. I>. j:lulllJtu b 11Iorc simil;lr in"Ilt' to I'. ((hmplll lh;m I'. =I'/{//ulit·tl. The mean ~hell lenglh(1-17.7111111) and maximum indl\ldu..1 ,hell length (239 mm)rl'Cordl'd for I'. Xlohos/I in thl~ ~Iud) \\cre similar to thcmaxImum shelllcnglhs (>200 mm). :md mc;ms (130 ISO mm)rl"'(()r(!I.'d for population~ of I'. /lhmpw m IJrilish Columbia :mdWa,hlnglon Slate (Harbo el ;11. 1983. Good" in & I'c-..".,. 1991).The mOl Xlmum Icngth rC('"orded length for P. =t'ftllldiclI h 1-16 mm\1 rlh t~lllmlted popul:llion me;lIl~ of bell\ccn 100 110 mm(Gribbcn & Crccsc :!OO5). In lenllS of 1\ holt: \Iel \lcight.I'. X/(Ilwwl eotlcctt'd in Ihh ,I tid) ;tPPC;1 r ,nMHer th:lll P. uhruptrthUlI;lrj;er than I>. -:t'1tllldiclI. The he;I\le~1 geoduck in this stud)\\;I~ 1)(14) g whole \11" \leight with Ihe O\·er:.tlllllean C;I. ;30 g.IndilidU;11 \\holt: wet wcight;; 01'>3 19 Ita\e been recorded for1'. uhmpw \\ith population means belwl....n l)()() ;llId 1.100 gcommonly reported (Good\\in &. Pease 1991. Ihtnd &. Dove)'19(9). Maximum rccordl'd individual whole \\"et weighl for

I'. =l'fllllt/il'll i~ 620 g with PO]lul;lliollll1e:rn~ bel\\cert 2-12 )59 g(Gribben 2003. Gribben et OIL 2(04).

Ahhough lhcre was a ~ignifieant correlalion bel\\ccn 9 out oflhe 15 morphOmClric eompari~ons. in 1Il0~t insl:LrIees thecocffieienh of determination were lOll rndicating rca-loOIl;lhl)higher \"ariabilit) betwccn lhe variables measured. F:leton.rnnucncrng both shell mC".I~ures. and the \\ hole \\et \\I,~ighl :llld\\et tl»UC "eight arc hkcl) 10 eOllInbute 10 this I·anabllit).Firstl~. lhe sh:lpc of b'<:oduck ~hell~ i, gre;l1l) :lffcctL'<I b) tht·::>L'dimenh III l\hlCh gL-oduch ;Irc 1000.ltL't1. Gcoducl~ m pca­gr:.t\ cl or ,hell ~ub~lr.tla oncll hal e mi»hapell l>hell~ (Good" III

, I'o:asc 1991). l\1orCOl cr. ~ulhtr.llC I~ pc c:.111 afft"t:l buria Idepl h."hich can 1c;ld 10 shorler ~lphon, and potenliall~ n.'dUL"C 1I,~ue

Tt\IU.E 2.

MurphnmCI ric relalillllships of !:l'oduck elOIln (Pun/JPj'u KllJhw'Q).COIl('('I('d ill nahia de Gua~·m ..s-Empahnc ;\lrxico from Octoher

20U--Ilo OClol.K'r 2IKI:-. ,) d{'lnmination eocflicienl;:1 = intl'reelll: II sIOIK'. /I = 77.

St... 11 Sllell Shell SIII'Il T'll:111...·IIl: lh Widlh \l~" Tllid.:nt'Ss \l~s,

Shell \\ldlh• 0,52 ••,

, 5K6

h 11.11:<3-1Shell ma,~

• 026· 0,-1 I··,, 57.71 67.3Jh 016.\1'< 0.2.105

ShdllhlCJ"l'\(."<"• 009 0..176 01-1,

, 5519 ,m 55, t7h 0.12 0.76 021

TOI.!.I ma~), o l()1-1·· 0.51·· O.RI·· 0181, .155.11 N,03-1 IHSI 52.57h I 2571 ;.9763 0.m3 0.03

Tissue \\ ...1ma,~• o 1.1 0..15·· 0.13··, 0.~12 0.111··

" 12-11,\ -10.155 70.S61 50.10 -1'1.2 I'!h 0.2562 2. HilI! 1.3262 001'<,} OYIl'}

• Sil!l1Ilk;'IlC" (I' < 0.051: •• (I' < 0.00 II: 1/ 77.

418

Female

...\It \(,(),\-NOItIl.G \ IT \1..

.·igurt~. II islul,,!.:Kal ....'("1 il"" "flilt' rt'pr.odocli. l' ~Ia!ll"iof frmall"i and mak-s J:nnad, "f 1'.",,,1""" /1:11>1", ...: ...~rl~ al'"li,t ( \. Fl. lall'" al'"lin- (8. G). ripl" tC,II), p:miall~ sp.... 1lt'd II), I), "1K'n1 (.:). lind undiff,'rrnliaINlIJj. .". f"nklt>: n .....m....'("I;" I;,,,IJC': So. S«tlnd,.r~ <>O('~ll": \10. m:II"", OOC~It': Ro.rnboooMbi",,,! <>O('~ It: lind Sp. "p.'rm:llol.Oith: ScI, Spl'rm doc!. ~aw h:u 100 .....

G \\" rO(.1 "I( On n.ot'\lr1'Or 1:-. I>. \01'1: r (.U)H(J~ I

o ElIIty' aewe o Late aclr¥e OR.. C Partially spent ~Spon< C Uodilferenbaled

CAl Females",. """eo """ '"",,,

60 '"" '"" ,"" '".. " '"'"- " '"... " '"" '"• 20 '"~ " '"

~ " ,"" '","

0 "•~ (6) Males, ",.¥ " ""~ eo "•~ " "" "

60 " """"'0 ",""" "20 ".,"" "" "0

0 N 0 J F M A M J J A S 0

Months (2004 - 2005)

32 (C) Monlhly sea surface temperatures

30

- 28\:

26•-~ "8- 22i~ 20

"" 0 N 0 J F M A M J J A S

Fijtun'~, R~pf(ldlll.·ti,~ ~)d\' "f l'an"p"11 XI"''''.'11 in till.' ~ast ~cntnl (:Illr "r California: fA) rl'nl:ll(', (II) mal\-. m", (C) munlhl)· mcan St'a SlIrraC\'

h'n1~ra'lIrc.

in )h;Lllow buri.:d geodutks. We did nOI eolllX:t infornwtion on~imell\ Iype. howe\'er. \\ithin bed~ geodueks o".'eur aero)s awide r:mge of substrata (from 1;lrge )Iones of "<tnd-sih Sl..-di­Illents) (Gribben et ill. 2(lO.l). Colk-ction of gl-ooucks fromheterogeneous substr:ll;1 is likcl~ 10 incn:;I"" \·'lri;lbilit~ beh\ttnshell tmits and potentiall~ tissue \\eighl~. St.'l'ondl~. the usc ofweI \\eights. \\hith al'>O includc water eont:linl-d in the mantleea\·il~ and in \\ ithin ti))ues themschcs. ma~ h'l\·e al'>O increilscdv:ilriOlbility within tnllts. Diffcrenti;tl retention of watcr in them,mtle c;l\'it~ or I\ithin tissue) b~ indl\iduals mil) h;\\ccontributed to \"ariabilit) in wholc wet \\eight. and wet tissueweigh!. I-Iowe\"er. Gribben & Creesc (2003) found a slrongcorrd,uion between whole weI weight ,HId whole dr:lined wetweight (1.(,'., rcmOI';t! of W,tter from the m,lI11le cal'ity) for IWOpopul~ltiolls of I'. ;dlllulim (r~ = 0.79 lind 0.92).

The reproducti\"e stages dcscribed by C:lmpbell andMillg (1003) for P. "hrl/pUt ;ll1d by Gribben et al. (WlH)correlatcd well I\ilh the reproducthe 'tag...~ obscr\"...-d in r.xlubo.m in this !otudy. Reproduclhe dc\ c1opm(,'nt ,Ind sp,lwningof P.1!loboso from Bahia de Guaym:b-Emp;tlme \\';IS s)rlehro­nous bcl\\een the SC'l:es. Similar (Xiltern~ hil\(.' also been

reporled for the Pacific geoduck. I'(IIUI/Ji'l/ t/hmJ!w, and IheN~II Zealand geoduck. l'wwl'l.'ll ;dllllllim (Ander!>Cn 1971.Gribben el al. 10Q..l). although. slighl differences in the timina;of g:lllletogcnie dc\clopment and S(XI" ning for popul:ltion, ofP. t/hmp1lJ h,l\e al-.o Ix.-cn reporloo (Goodwin 1976. Slo..rl &Robinson 198.f),

Gamelogenie de\l.'lopmcllt for bolh I'. ahrllpw :lndP. ;,.1t11ulict/ !o1;lrts during 1;lle autumn \lInler \\hen W:ltertemper.llures afe 10\\ \\ilh eontinm.-d de\l:loprnent :lIld sp:lwn,ing occurring through spring and )umrner as \\',Iter temper­alures risco The TC\'Cr..c (XlIlern was obscn'cd in lhis slud~ forP. Klt/ho.m \\ilh gametogenic d~\'clopmenl commencing in I;l\~

)Ullllller \\hen water tem[1'i.'ratur~s \\ere high (-28°C) ,llldconlinued dewlopmenl and spawning occurring lhroughwinter as WOller lcmperatures fell. I-Iowe\'er. these patterns arcl'onSlslent II illl lhe palternS of reproductive dc\ dopmcnt and)pawning dc~rihcd for olhcr infaunal bi\al\"c species foundin the Gulf of California (e.g.. Villalcjo-Fuerte et 31. 1996:md references therein). Winter spa\\ning of bj":II\'es in thisregion correlates with ~asonall) high lan'al food a\":lil:lbilil)(Villalcjo-Fuerle et :11. 1996).

reproducthe e) de of P. IIhl'llfllll from populations in Wash­ington Slat" and Urilbh Columbi;\ has been sho\\n 10 be,'ontinuou~ \Iilh no resling pl'riod occurring (Andersen 1911.Sloan and Robinson 1984). Vill>llejo-Fuerte el al. (1996) sllg­gcslcd thai high Ilali:r 11."11l1X'rature~ in th,' Gulf of C:lliforni,1In hi hi I ga nK'lOgellesi s of in fa unaI biva h e~ frOIll Ihis region_

/llean month I) ooe)le dlametl'r Ila~ :l good qU<lnlil;llivedl'~l'riplor of reproduClive de\'elopmenl :lnd ~p;lwning in". ;"/Ul//lini (Gribben el al. 20(4). A dose relationship belwccnmonlhly mean ooc),le diameler and the gamctogenic cycle wasaho fou nd in Ltl/' ril'llrdilllll dill 11111 in Baja Clli fornia (Villalcjo­Fucrle el al. 19<)6). ;1Ild Spi.wl/l .,olidiuimll similis in StCalherine~ Sound. G/' (K;mli 1'1 .. I. 1993). In Ihis study.monthl~ me;m ooc~ I... di'lllll.'lers of I'. g/..fJ<I.I'lI increased withgametogenic delclopmcnl. Gi\en Ihe ;tpp;trent shorl reproduc­live ~l.'<l~on of I'. gfoho.l'II. monlhly mean O()(:ytc diamelers<lpll":;lr 10 he a good descriptor of reproductive developmenl(If km;tk~,

O{ll'~ Ie dbmeli:rs for P. glohosa in Ihi~ sludy f<ltlgtd from 6­64 pm. A ~it1libr ,;ize range (5 781-\m) W<1S reporled by Gribben1.'1 ;11. (2:004) for 1'. :dlllll/im. Gribben el al. (2:004) <llso rl.'porl~itllibr l1l<."lI1 mOl1lhl) oo':yte diamelers through lh ... diOi:rent~t<lgc' of reproductil'e delclopmenl. The~ found Ih,ll smallprinwr) oOl.'~les had an alerage sizc bclw....tn 10.3 and 13 ~U11 intllO diOi:renl populations and thes<: cells dotllinal,'d during theearl~ wink'r (JUtK' and Jllly). 1·lere. we found ;tn ;lI'cragc size ofX± 1.3 ~Im during carly aUlumn (Oclober). Thc mcdian size of1'. ;dlllllliru oocytes in AugU~1 ;md Seplember (late winter in,oU1h,'rn hemi~phere). II hen itl('fea~ing gametogenic aClivil)'0l'currcd. wa~ -WJ ~tm. We ob~enoo ,HI a\ crage si7.c of 38 ± 12l-inlror NOlembcr and Deccmber karl)' wInler). Finally. inP. ;d1/l/llinl. the 1;lrgl.'sl monlhly l11e;1tl oocyte diamelers occurrlxlin Ihe month~ inllllcdi'lll.'ly ,Ifter Ihe beginning of sp<ll\'ningin sumnler (hnuar) and Februar~). Similar results Iwreohl;litllxl in thi,; siudy with Ihe highl'St ooc~ Ie dianwters (52~111l1 found ;tfter sp;tllning in Ilinter (J;IllIJ<lr) ,HId FebruarYI(Fig. 6).

Allhough oll.'r;tll m:l1e 10 fetll;tle scx-r;tlio of P. glnho,\{/

in lhb ~llIdy \\'as 1:1. Ih ... r... \\'ere more males lh;ln kmales<150 IIltll and more wilh female,; lhan nl;tlcs >150 mm. Thesmall samplc ~izc and absence of smal! individuals meansIW e;tIl ~;tl lillie aboul the ~exu;tl dcvelopmenl and size ,IIlIwlurit~ for P. gf"ho,'a, I-Iowewr_ giv('n thai functionalprotalldri,' din...'C) ha~ been ~hOII n 10 occur in P. ;('/wulic(/and m;l~ abo <xx'ur in J'. l/fJru!,1lI (Gribb..'n & Creese 2003.V;ldopal"s el a1. 2006) then fUllIre studi....s nced to addressIhe ~xual de\'l.'lopmctlt of Ihis species. b..'callsc Ihe prescnecof protandr) has polenli,ll ramificalions for the suslainabilityof han'('~I('(1 populalions (sec dis('\l~~ion in Gribben &Cree_e 20031.

In ~l1mlll;If). thi~ slud) repre~ent~the lirsl dcl;likd ecological,IudI' of P. glolm.w. Giv~n the eminenl del'elopmenl of fisheriesand inlcre~1 in del'doping <tqu;lI:ulture ror this species. Ihi~

~lUd) i~ timd) :md forl1l~ Ihe basi~ for fUlure rtse;tn:h.1Iml~I~'r, 10 obtain a more :u:eur"te represcnlalion of the size'I rltel ur,' of Ihe populal ion a 1,1 rgCf number ofsa mples \\'ill nel'd10 be colkcted. To develop sU~I"in,lble fi~herk's for Ihis SlX'Cil's.fUlur(' n.'se;lrdl needs 10 addres~ issues such <IS reeruilmenl and'e,wal del'e1opment and 10 inveslig;lte dilTerence~ in populatione~limale~ ;tnd life.hhlory Ira its beillcen populations of

1'. glol>rI"l.

JanuaryDecember

Months (2004 - 2005)

November

3

2

6

5

Males

,

Figurt 7, Slldllfrl::lh rrl~lul'n,'~ di'.rillluious "r ;udi"idu,,1 mal.,. r~nt:tll·.

:Iud uu""",'d l:~,Jd"cks.

0

" ," ," <d' <d' ,0' ....<f ....& ,~ ,," .f4' ,," ,<d'Females

6

5

• ,0c• 3~c,

2~

~ ,0

" ," ," <d' ," ,0' ....<f ....b~ ,~ ," .f4' ,," -f,Unsexed

6

5,J

2,0

" f' ," <d' <d' ,S>: ....~ ,b~ ,~ ....<§J '),<S- 'I,'),~ -f'-~ '),~

Size (mm)

Fi::url' 6. ", \'r~~t tn"'ll hl~ 'HI("~ I,· d;:omN~rs (=5E) or "IIIWI"'(1 ):/01,,,,,.in .hl' ~3.~t t!,.,lnll {;ulr or Calirumi".

Comp,lrcd II ilh nlh... r geoduck ~pccie,. f'. g/oho'li. appe<lf~

10 h<l\'(' a short r~'proJuctile l')ck and :111 l',~lemkd fe~ling

period during \Ihidl dam~ could not be ~exed (pos~ihl~ up hI 1mol. Grihben et:ll. (20()..ll found Ihat P. ;t'!/III/Iil'll had a r....,lingpha~(' of only I 2 mo during which limecl<lm~c(luld , ..."....d. Th...

430

"'"-E 50

~-~*"E• 30~

~8 200

"0

(ktober

G,\ \ll~r()(a "1(" 01 "flOl'\11 'T I" f> 1\ON • (,!.ORO.\ r 431

Thl:. :'lud~ W;I:. supporl<."d b~ CIBNOR ProjeCt 9:!5·1 ,ll1dfrom the regubr budgel oflhe In~lllulO Nacion;11 de 1;1 Pl'~a In

GU;I}nl:l~. Sonor-I. Mexico. The SC BA dhing team of lhe"RlC;lrdo Loreto" fishenlo:. eooper-Ill\e ll"i~ll-d in lidd :,.;UlI·piing. Thl' manuscript greall) bcnclitcd from Ih... commenb ofI" 0 anon~mous referees.

un:R,\TlRE crn:!)\nde~n. A \1 1971. SP'l"nlnJ;. ~rf)"lh.•lIld ~pallal dlSlnbulion of

lhe ~oodocl. e1am. Pl1Iwp<' uI>r"f'III Gould. In llood Canal. \\ ..~h·1n~lon. Lnpubl.I'hD. The,,~. Lnl\e....,t) ofWa~hm~lon.LSA

Ar..mbuIOl·I'ujol. E, \1.1006 Cic"1o repr,ldtJl:!llo de I.. alme,a de ~lfon

1'lm"f'C'I' X'"ht>.-q, en la l'l;a~a dd Sill. I·mpalme. Sonor... MC\Il:OMa~lc(~ llaes,~. C...nlro de Im'NI~cIOIIl.'"~Illolo~I(""~del l\.OrOC'lc.La 1':11. II.C.S.. Mnico. 56 I'll"

n;1 ron. J. ll}ln. Rcproducl i' e .'>·.:Ic, of Ihe hl\'al' e mollu-es A /<Iflml, 'II

.\Irill/II (Gmelinl. Gilfrarllllll l/lmulwII Rodll1~ and Amlilura "'111'111I(L.l III New Caledonia. A 11.". J. \/f/r. I-"n',I,,, (1/('1' Rl". -H:W.' 402.

IIreen. I'.. A. (". Gahricl & T. Tysol1 1'J<J I I'rdimi liar} eSlimales oraJ,l':.morlahl}. gro\\lh. ,!lId reprOOUClI"n 1Il Ihe hi:uclluJ dam I'(//WIW<I:('/11"11" ('"l Nl'\\ Zeabnd.•\'. /.. 1. If"r. Fr,·,llIlfllU H,·,.15:.!3 I 237.

IIr.,'".... A 1Y94. Suslain:lbh: lhhlll~ pallcrns ror Ihe J;.'Odllck l:1:lIn(/'(II"'f'I'":dm,,licul popubllon,111 l\.e" I.eal:md N L.1·I~h.A~>c..sIt., 1M'. 9-1 4.11 PI".

C:lInphclL 1\ • M.ll. Min~.1003 .'\'I"lUnI} and gro"lhoflh.: I'.,eiliet,...'Odllel. dam. 1'''''''1'''11 uhr"f'r". III Soulhern BrollS-h Columbl...COInad... J SIIdllull R;'•. 12;145 90.

Camphcll. ,\.. It Cbpp. C. \1 Il..nd. R lIarho. J 11ume .. G. Sharf1m SIlT''''} of gooducl. population .,lens,l} III Gok'ias Channel(""n r....(;. Rep f-i5JJ. o4,,'H,I. Sn 221-1 .\19 3·U.

O..rr"I". R M D. L Kellh 1992, ,\);C ,lru,:lure. ~ro"lh...nd1l10rphomcme \.mallOI1S III Ihe 1\11.lIllle ~urf dOlIl1. 51'/5//1<1 wlt,l·'0"'"'. from ..~luannc and ,"shore" .Ilel'>. Ifur. 8",1. I 14:581 593

F....t,'Cr.R \1 .. N. M.Slonc&: I' "Dlebon.19K-I.Correlal,onshct"crn~h:lpc. II e,ght 0I1Id lhic"l.:r1CSS orMlell," rour populations of le'l(Tl/f'url",,,,IH,,,h(l'ennanl). >. 11,,1' S"',' 501938

Good"lII. (' l. 1976. ObM-n:lllOn) 011 'P;'" nmg and gro" Ih or)ublldal~l-odlld (/'III/opt' gl'III'ro'll. Gouldl I',.,,€,. \/111. SII/'II{1,". A"65:49 58

Good"m. C. L & B. 1''::1'1:. IY8Y. Spo......'e' I'wfile~: hfe hl~lonc~ :ll1dell\ Ir"lllllenl;,1 r'Xluir.:tnelli ~ or ,'o;l\I:t1 Ii'h "nd nlwrlehr.. l,-s \ 1';lellleNnrlh"e,l) l':,t'irll." g.:o..hlek d,l1\1 u.s. Wild Fi>h. s':rl. 111"1. Rt'p.K1 f 11.1201. U .$. MillY ("orrs <)f I' nglileet>. TR EIA.! ·4. I5 I'll".

Gno..h'lIl. C. L. &: 1.1. I'easc. IlJ91. O.:oou.:k. 1'1/1"'111'11 111>1'111'/11 (Conrad.Ilol-l'»). si/e. (lcn..il). a lid qU:I Ii I} :" rcl:ll.·d 10 \ ariou, cm ironmentalp;I r:uneler~ in l'u~,'1 Sound. W;,)h, nl;lun. J. SIII'/ljl,1t H"" I0:65 77.

Good" In. (" L. & W. Sh:lul. I'>IS-I. Agc. r..... rullllleill and I;ro" lh of Ihet,....oollel. elam (Pw,,'f'C' g,"II'''''''I. GOllldl m l'ul;el Sound. W:I,h·m~lon 1It1.<II.I),'-I'I. ri.<II. Tn" R..p 215.:29.

Gnhh....n.I·. 1:..1OO3.IJo..--rnOJ;raph} and life hl'IOI'} ,·haraclerblK.." Oflhcl\.1:'" I.caland J;COduck. Pmwf'l'U :"''''1</1<'0. Ph. D T!Jt.~I~. Um\'cl'll)"f ,\ud:land.J82 pp.

Gnbhcn. I' E. &. R. G. C,.....'SC 100.1. I'rt)(andr} III the NC\\ Zealand~...'Odock. Pu'wpt'U : ..lu"Jim I :\ lollu"",... 1l" ..1\ 1.1. I /i,,·...,.,rhr. Repr...l.1),01', -U.1I9 1:29.

Gnbben. I' 1:. R. G. CI"C'C'>C.1OO!i. \g.:. rrov.lh. and monahl} oflhe'I:'" I.c'..land geoduck dam. POtIOf'C'U :cU"..lico( 81\-:.1\1.1.. HlJ.udlK.lac1In 1\\0 l\.orlh bland popu!;rl,ons. 8,,11 Ifl,r S,i, 77:119 135.

Gnbhi:n. I'. E.. J. IIc!:.on & A. G klf.~. 2004. ReprodtJl:II\C C}cle of theNe" I'..caland gcoducl.. ,·/111",....., :"'",,,1Im. III 1"0 IlQrlh I~land

popU!;ltlon,. 1'('Jig!'r -17:53 65Grrbhcl1. 1'. E.• J. llelson & R. Millar l~ 1'0pUI;"'011 ahllndaTltt

c,IIlI1:'Il, ur the N.:" Zc,llamJ J!codu,·l. d;ull. I'm",f'I'u :1"I<lmlku.I",ng NOrlh Amcri...... n melhodoloj!)· h Ihe Icchnoloj!) lr;1I1,f"r;I!lk~

J. SI,dljlll, HI" . .!.\:68.\ 691.

Iland. C M & G. l)ow). 1999. A sune} offOOducl. populallOfl' m Illl..J:lbo" &ink and Ycllo" K:lIlk :m'a of Cb}oqual Sound. We..lV:ulCou,er hl.lI1d. III 1m ..lid 1995. Can \bnu.cr. Rql h~h

I\qual Sei 1·f79.33 Pfl.Ibrho. R 1998. l\.C" drrt:cllon~ m l!1\crtc!lr;,lc fbheriC'S m,lIlaJ;,"rncnI

III Ilnllsh Columbia. Can-:.da, Om S'''·c. I'"M. '·",11. .4""", :'ili.1.!5A.!9 -1)7,

llar!lo. R,. 11.1:.. Adkl11~. P. A 1In......n& K. L.llobh,. 19R3. Age .111I1 weIII 1ll,1rkel 'ample, or gcOdllC darn' (1'''/1''111' x,'m''''''III. (":111 .M;mu",,·r. Rep. Fish. Aqual. St:l. 171-1.711 I'll".

IlcndTld.\. M I: .. R. C. 111'1.1)(::1 & L T l'imlle)'. 2005. A o.Ii<lrlhullou:t1ch,~k I1<1 of 1h.: Il1:1CrOra una or Ihe Gulf of C':llirorilla. "'In 'co, 1':1 rt

I. In"ertehr:ll':'. ,\ril.OlI:l-Sonum I:>':,.:tl MU'lCllll1. ..\1'J PI".Ilorrll1.lIl. A.. J\. 1I101dblll'} ..(,: C. L Goud" III 2000. Modelmg gcodul.'"l..

I'''''''pt'" /Ihrtll'l/I IConr..d 1ll-J91 pOpUI.lllon d~nam,•.". l. Gro'\lhJ SI".llj"II R", 1'>1:57 61.

K.II1I1. A. I' II. HdT"man .(,: R l.. W..lkcr 1~3. Gamel0l;cllleC}dl.'" or 1!Jt.· soulhern surfcbrn. Sp""I" ,,>li,li.fSilllll ,iII/IIi., lSa}.

Ill.!2). from SI. Calhem....... Sound. G.:orl;l<I. J. SJwlljl51l RI" I~.

255 161Kren. A M 1971 Sea ..hcll~ofIroJllC"JI ",,",I AnlCrK.""". \I :Inn<: moll ..,l.,

from 8aJ" Callforma 10 I'.:-ru Sianford Lm\eNl) I'ress. Second l:dSianforo. C \ 106-J Pfl

\bldonadO*\mparo. R. & ,\ \1 Iharr.. 100.!a Lltr..~lruclur-JIchar,tCICn~l>e of ~JlCrmal~ellCSl' III diploid and lnplold ...... lann.1...... ll,op I lrf,dfNT'"'' '....uric"'''.' SmI frb) II. 18-1.!). J. SI/I"III"(; Re..!1:9.' 101

M.lldonado-Anlparo. R. & A. M.1oorrJ. ~2b. ('omparJ\I'e anal}""of OOC} I" I} pc frcqucnc,c, III diplOId and trlplo,d calarllla -e;,lklp(Ar'.'l'I/I"/-"'1I ,'/'1/11';<"11.'1/'I ~1' md>e:lI""" or mC,OIlt' rail ure. J. Shdll,,11HI'" .! 1.597 61B.

Nc\\ell. N. D. & H. Hidu. 19S.!, The Crr,'CH or .....d'melll l~ pc Oil gr,'" thr:lle ;'Ild ,hdl allOlllelr} on llie ~un ,hl.'"lkd dam. M,'/I url'l//lriu L. J.

/:'1·". ,\/(11', Ui"l. ",.,,1. 65:2~5 295.Orell~lIl1/. J. "'I .. C. M. Iialld. 1\. M, 1':mn:l. J. V:llcro &. R. IIllhorn.

:!()(J.f. I'r....."ullon in Ihe hane'l or Melhu<cl:lh'~el:1I11> Ihe ,lilli·cull}' I,r gClllll1; limel} re"dh;ll'~ from ..lUll ·pal'l'<l d)'Illlmk,"? e"". J."',,/, Al/um. Sri. 61:1355 U7.!,

R'·}IIUkh. R W.. N.A. Ra}ller. r. M. Sm'th. D C. Slu~e~&: W W:II1j!100.!, An IInpro\·,'<l III ,IIU .lI1d ...aldlue SST anaIY)l~ ror chm;lle.J nlll"HI.' 16:1609 16.!5.

Roorij,t1lC/·J:lr"n1,1I0. c.. A N. Maoo..·MartmeJ.. M E. \'alde/. TRC)llow-Gr..nad(».,. P Monsah,,·Spcn,:cr. ll. Pr..do-AllI.'ona. I'C:lnI"fA4~\'dasco. M. Robk._MunJ;ar..} &: M T. SlCard.1OIJ1. The.:11'....1 of tempcr.. ture (In Ihe rcprodllClI' C Ill:llunty of the pen,hell4lr"'u muurtllSo\lerb}. 11l35J /8I\:lI\la PlIlnldael. J. Shrll/l.<11 Rr~

10,39 -17.SIo;>Il. r-.,\ S. M. C. Rohtnson 198-l At,'C and gooOld dc.elopmcnlm

the' b'COducl. clam PU'IOpt' uhrupl/l (Con",d) from soulhe'rn IIntl.JlColumrn:l. Canada. J. SI/I"lIj"h R... ~ 131 l.l7.

VadopalOis. B.. C. S. Y. \101. J P D:I\l' &: C S. Fnl'<lman :?OOliI'rotaoof). malur;lIion. and 'P;III mnj,\ III eullur..'<l mlcrlldal gt.--oducl,;1/'<11"'1"'/1 uhr"plul dams. J. SIK"lIjuh Re.f. 15: 78-1.

V,II'lleJo·l·uerl':. \,1 .. B P. ('eh;IIl.....·Vi,/qucr & I·. Garcia·Domingucf,1996. Reprooucll.·e e} dc or 1.L1I'1',wrtllllll/ I'I"/l"" (SoI\l.'"rh}. lIP.' I(111\:11\",· ('ardlldael III Il;lhi:, COIK'\:pcion. Ibj:, Clhromla Sur.M<:\lCo. J. SlwllJuh RI'(. 15:7-11 7-15.