REPRODUCTION BY THE OCEANIC COPEPOD RHINCALANUS NASUTUS OFF SOUTHERN CALIFORNIA, COMPARED TO THAT OF CALANUS PACIFICUS

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1 CalCOFl Rp., Vol. 4,99 REPRODUCTON BY THE OCEANC COPEPOD RHNCALANUS NASUTUS OFF SOUTHERN CALFORNA, COMPARED TO THAT OF CALANUS PACFCUS MCHAEL M. MULLN Marin Lif Rsarch Group Scripps nstitution of Ocanography Univrsity of California, San Digo 95 Gilman Driv La Jolla, California 998 ABSTRACT Masuring zooplanktrs rat of gg production can provid stimats of scondary production and of th availability of food for many larval fish. Suprficially, nasutus and Calanus pacijicus hav similar cologis; conditions for succssful raring in th laboratory ar similar, as ar rats of gg production whn fmals ar hld in th laboratory with xcss food; also, th abundancs of th two spcis ar positivly corrlatd through spac and tim. Rats of gg production by ths two spcis in th southrn California sctor of th California Currnt wr masurd in th wintrs and springs of 999 by holding fmals in th ambint sawatr and in sawatr nrichd with phytoplanktonic food. At many locations, fmal Calanus producd ggs whn in th unnrichd sawatr; thy almost always did so whn food was nhancd with culturd phytoplankton. n contrast, sldom producd mor than ggs. (fmal.day) xcpt whn incubatd with xcss food for days, and vn thn, th spatial/tmporal pattrns of gg production diffrd from thos of Calanus. Futur work should focus on whthr thr ar conditions (sason, food, tc.) prmitting high rproductiv rats in fding on th natural sston off southrn California; i.., > ggs(fmalday). RESUMEN La disponibilidad d alimnto para muchas larvas d pcs, asi como la produccidn scundaria, pudn sr stimadas con mdicions d tasas d produccidn d huvos d zooplancton. Suprficialmnt, las cologias d nasutus y Calanus pacijicus s asmjan. Las condicions para su cultivo n laboratorio son similars y las tasas d produccidn d huvos n laboratorio (con ditas d sacidad) son asimismo similars. Admis, la abundancia d Cstas spcis s ncuntran corrlacionadas positivamnt, spacial y tmporalmnt. En s invirnos y primavras d 999, n la corrint d [Manuscript rcivd Novmbr 6,99. California (frnt a California sur), s midiron las tasas d produccidn d huvos d las dos spcis; s pusiron hmbras n aguas no tratadas y n aguas nriqucidas con fitoplancton cultivado. Calanus hmbra produjron huvos n varias stacions con aguas no tratadas. Por otro lado, hub produccidn d huvos n casi todas las stacions con aguas nriqucidas con fitoplancton cultivado. En contrast, raramnt produjron mis d huvos (hmbra*dia). La xcpcidn fuc l trataminto d dicta d sacidad durant dos dias, y aun asi, s patrons spaciotmporals d produccidn d huvos difiriron a s d Calanus. Estudios futuros dbrin nfocars n discrnir si para (con dita d sston natural) xistn condicions (stacidn dl aiio, alimnto, tc.) n s mars d California sur qu produzcan altas tasas d rproduccidn; s dcir, > huvos (hmbra*dia). NTRODUCTON Th rat of rproduction by planktonic coppods is an important indicator of population growth and scondary production. Comparing rats in ambint sawatr and in th prsnc of xcss food indicats how much ths dmographic rats ar limitd by th natural food supply (.g., Durbin t al. 98; Ayukai 988). But it is difficult to dtrmin th ffctiv natural concntration of food bcaus nithr th smallscal spatial distribution of coppods rlativ to whr point sampls of sston (potntial food) ar takn nor th proprty of sston that is most significant to rproduction (. g., chlorophyll, particulat organic carbon or nitrogn, a critical amino acid, a particular siz and typ of particl) ar usually known. Furthr, th gntic constitution and past nutrition of fmal coppods usd in xprimnts is also unknown, though both can affct rproduction and th rspons to food. Finally, diffrnt spcis may rspond diffrntly to th supply of food, or to th proxy variabl for food, vn if thir trophic typ, sasonality, and biogography sm th sam. To compar th rproductiv gography of two similar spcis of larg, planktonic, particlgraz 89

2 CalCOFl Rp., Vol. 4,99 ing, calanoid coppods, as wll as thir rsponss to chlorophyll biomass, masurd th gg production of fmal nasutus at svral locations in th southrn California sctor of th California Currnt systm, and contrastd th pattrns of rproduction to thos of th mor intnsivly studid spcis Calanus pacificus (s Mullin 99a, and rfrncs thrin) at th sam locations. Earlir work (Mullin and Brooks 96, 9; Hakanson 98) compard mtabolic and dmographic proprtis of th two spcis, including fding and growth whn th diatom Thalassiosiva wisogii (= juuiatilis) was providd as food. n ths studis, th similaritis btwn th two spcis wr mor striking than thir diffrncs. Both xtnd into th southrn California sctor from farthr north, not south or wst, and both can rang farthr south to th tip of Baja California (Flmingr 964), but th southrn limits of rproduction and rcruitmnt ar not known. This zoogography ld m to xpct that would rproduc most radily in th northrn part of th rgion studid. Longhurst t al. (966) found th vrtical distribution of to ovrlap that of Calanus in th uppr 5 m off San Digo in May, but to xtnd dpr, to at last 5 m. Populations of th two spcis wr studid concurrntly off La Jolla, California, in 96. From this st of data, Koslow and Ota (98) found indirct vidnc of a diffrnc btwn th spcis in th sasonal pattrn of dil vrtical migration rlativ to diatom blooms, and Mullin (99b) found that though rats of juvnil mortality of both populations wr dnsitydpndnt, th spac/tim distributions of ths rats wr uncorrlatd btwn th spcis. METHODS Similarity in th msoscal distributions of and Calanus imply cological similarity. thrfor countd fmals of both spcis in sampls takn by th California Cooprativ Ocanic Fishris nvstigations (CalCOF) from January and April 989 and March and April 99 (cruiss 89, 894, 9, and 94) and tstd whthr th abundancs corrlatd. n Jun 969, found sprmatophorcarrying (i.., nwly matd) fmal in nt tows mad off La Jolla. placd of ths individually in litr bakrs of filtrd sawatr with culturd Thalassiosiva addd as food. No prcautions wr takn against cannibalism. Th bakrs wr kpt at 5 C for up to 4 months, and vry 4 days rmovd and countd ggs and nauplii, rplacd th sawatr, and addd frsh food = 9 Y log [(fmal a/anus/m) + Y = R =. p <. Figur. Abundancs (logtransformd) of fmal and Calanus in th uppr m of th rgion of study in January and April 989 and March and April 99 (cruiss 89,894,9, and 94). S figur for rgion. Th corrlation is significant at p <.. On svral CalCOF cruiss, masurd th production of ggs during days incubation in sawatr plus natural sston ( unfd ), and in th sam sawatr nrichd with Thalassiosiva ( fd ), by fmal capturd in nt tows at various stations, with mthods dscribd in Mullin 99a. Th masurmnts wr mad irrgularly in April and August of 99 (cruiss 94 and 98), and at all stations whr sufficint animals wr capturd in January and March 99 (cruiss 9 and 9), Fbruary and April 99 (cruiss 9 and 94), and January 99 (9). masurd th pr capita rproduction of Calanus similarly. n addition to dtrmining th daily production rat of both spcis with and without supplmntal food, usd two ratios (from Mullin 99a) to xprss th dgr by which food limitd production: th ratio (b) of th total production ovr days of unfd fmals to that of fd ons, and th ratio (c) of th production of fd fmals during th scond day to that of th sam coppods during th first day. Ratio b incrass, and c dcrass, as food bcoms lss limitd. Fmal at th dinoflagllat Gymnodinium splndns and naupliar Avtmia (Mullin and Brooks 96, 9), so tstd how ths two altrnat foods stimulat fcundity, although nithr is as convnint to us at sa as is Thalassiosiva. Nithr rsultd in gglaying rats as high as thos whn Thalassiosiva was th supplmntal food. RESULTS As shown by th xampl in figur, th aral distributions of th two populations in th southrn California sctor of th California Currnt ar similar on th larg scal (th statistically significant trnd) but far from idntical on smallr scals (th scattr). Calanus is th mor widsprad (fwr absncs) and gnrally th mor abundant of th two. 9

3 CalCOFl Rp., Vol. 4,99 W t ui ( ( W 4 m a > r: i DAYS Figur. Cumulativ production of ggs by nwly matd fmal nsutus fd Thalassiosira in th laboratory. Th history of anothr fmal which producd a total of 4 ggs is not shown. ndividual fmal maintaind in th laboratory could produc up to 95 ggs in days, and ovr ggs during adult lif (figur ). Th maximal daily production rat slightly xcdd gratst rats by Calanus from th sam ara (Mullin 99a, figur 8). Man liftim fcundity of was 48 ggs; th mdian was 449 (compard to about 65 for Calanus; Mullin and Brooks 96). Bcaus of th possibility of cannibalism in th litr containrs in which fmals wr hld, ths stimats must b considrd minimal. Thus, fmal ar rproductivly activ at 5 C as far south as La Jolla, at last at tims, whn fd Thalassiosiva ovr long priods. n April 99 producd vry fw ggs south of Palos Vrds unlss food was supplmntd, and vn thn did not approach th rproductiv rat of Calanus at ths stations (Appndix). Rproduction did not qual that of Calanus vn farthr north (unfortunatly, no sampls wr takn north of Point Concption during this cruis). Similarly, thr was littl rproduction by south of Palos Vrds in August, and only on station in th ntir ara whr ggs wr laid in th absnc of addd food, although Calanus was rproductivly activ at svral stations (Appndix). With on xcption on th two cruiss, producd ggs*(fmal.day) only whn fd for mor than 4 hours. Th imprssions rsulting from ths two cruiss, whr sampling of was sporadic, ar that conditions at many stations (or th condition of th fmals thmslvs), though suitabl for Calanus to rproduc, wr unsuitabl for, spcially in August. Figurs 9 and of Mullin 99a show th rproductiv gography of Calanus during ths two priods mor compltly. Thy also show th tmpraturs at m (approximatly th tmpratur of th shipboard incubations) and intgratd biomasss of chlorophyll; comparison with th Appndix tabl suggsts that s rproduction was mor inhibitd by scarcity of food (as indicatd by spars chlorophyll) or high tmpratur than was Calanus s rproduction. n April thr was no clar rlation btwn s rproduction and th chlorophyll biomass at th sam stations; in August th only rproduction was at thr stations whr chlorophyll xcdd 8 mgm. As notd abov, this could b ithr an xprimntal artifact or a symptom of longrtrm limitation: prhaps rproduction would hav bn gratr with othr conditions of incubation, or prhaps th fmals wr physiologically incapabl of intnsivly producing ggs within two days undr any conditions. will prsnt th mor xtnsiv masurmnts of gg production mad in January and March 99 (cruiss 9 and 9) and Fbruary and April 99 (9 and 94) as if thy had bn mad in conscutiv months of on yar, thus mphasizing sasonality and supprssing intrannual variability. ntrannual variability might wll b important, sinc th wintr of 99 was charactrizd by El NiAo conditions (Hayward 99). Th distributions of tmpratur and chlorophyll biomass during ths cruiss ar shown in figur, and th actual daily rats of pr capita gg production in th Appndix. n only on cas in January 99 did unfd produc ggs; only onc did fd 9

4 CalCOFl Rp., Vol. 4,99 5 Om Tmpratur Chlorophyll to loom, mg/m L i >, 5 5 Figur. Distributions of tmpratur at m, and intgratd chlorophyll (mg.m', to m) in January 99 (9), Fbruary 99 (9), March 99 (9), and April 99 (94). 9

5 , MULLN: REPRODUCTON BY RHNCALANUS CalCOFl Rp., Vol. 4,99 Calanus r q t i t ' T 5 B.l /Pt Concption. 5 4 k,,',,,,, 9 5 c. t,,pt Concptron 5 c. l 5 O L ' " " ' ' ' \, 8 l '! ' /pt Concption i t,,,,,, u ' ' ' ' ' 5 u ' ' 5 Figur 4. Contour maps of gg production by Calanus () and () on cruiss 9 (A), 9 (E), 9 (C), and 94 (D). Poorst production is in stippld rgions: clar rgions rprsnt rats of 4 ggs.(fmal.day)' on th first day, with or without supplmntal food, but production xcding this on th scond day with food. produc as many as ggs*(fmal.day)' on th first day (horizontally stripd ara in figur 4A.), and at only two additional stations did th pr capita rat xcd this valu on th scond day (nonstippld aras in figur 4A.). Th rat of production by Calanu in unsupplmntd sawatr south of Palos Vrds was gnrally small, but, unlik, fmal Calanus wr rady to rproduc at much 9

6 CalCOFl Rp., Vol. 4,99 EGGYFEMALEDAY, FED, DAY o Y = 9X R = Y = 5 + X R^ = o D. P Y. 9 6X R i 6 9 Y = 8r5X RL=64 j Y=8 OX R =5 lo 6, 5 F 94 Y=8+9X RL= Calanus Figur 5. AF. Egg production of fd on th scond day of incubation vrsus that of Calanus, for 6 cruiss. Only th corrlation for cruis 9 was statistically significant (p <.). gratr rats in th prsnc of xcss food (horizontal striping in figur 4A.). North of Palos Vrds, Calanus was rproductivly activ at many stations, r vn in th unsupplmntd sawatr, whr was not (figur 4A. and ; s also figur 5C). s rproduction was foodlimitd vrywhr; food limitation affctd Calanus s rproduction much lss north of Palos Vrds than south ofit (figur 6A. and B.l). Th lack of gg production by at vn th northrnmost stations of 9 maks it unlikly that high tmpratur, pr s, causd s failur to rproduc at many southrn stations whr Calanus did rproduc. n Fbruary 99 (9; figur 4B. and ) no masurmnts wr mad north of Point Concption. Th distribution of chlorophyll was rlativly uniform (figur ), th absnc of lvatd biomass around Point Concption prhaps bing du to El Nifio. Thr wr no stations at which fmal producd ggsday on th first day of incubation, with or without supplmntal food, vn though Culanur xcdd this rat at svral stations. Whn food was supplmntd for days, howvr, producd a ggs.(fmal. day) at almost half th stations (nonstippld aras in figur 4B.), primarily thos in th Southrn California Bight whr Calanus s rproduction was also strong (s also figur 5D). Calanus s rproduction was foodlimitd mor oftn than in January, at last as indicatd by ratio b (figur 6C.), but thr was lss obvious gographic pattrn to this limitation. s rproduction was again foodlimitd ovr much of th ara (figur 6C. and D. ). Again in March 99 (9; figurs 4C. and 5E) on thir scond day of supplmntal food (but, with on xcption, only thn) producd mor than ggs.(fmal*day) at svral stations. This was tru vn at rathr warm tmpraturs along th southrnmost lin of stations, again suggsting that tmpratur had not causd th poor rproduction thr two months arlir (9). Also, fmals incubatd at.5 C wr no mor fcund than thos incubatd at ambint surfac tmpraturs in th southrn part of th ara. As on cruis 9, no masurmnts wr mad north of Point Concption. Rhincalunus rproducd at stations whr th concntration of chlorophyll was <8 mgm, a rang in which littl or no rproduction had occurrd on cruiss 98 and 9 (compar figur 4C. with ; figur C.). Again, howvr, producd many fwr ggs on th first day ofincubation than Calanus at most stations (figur 4C. and ), and was mor foodlimitd (figur 6E and F). Similar rsults wr obtaind in April (94; figur 4D.), vn though svral stations north of 94

7 CalCOFl Rp., Vol. 4,99 5 Calanus Ca lanus 9 A. At all stations ratio b for was <.5 5 B.l B. At all stations ratio c for was >. c < s Pt concrpt,on c< Figur 6. Maps of food limitation of gg production in Calanus () and Rhncalanus (). n ach cas, shadd aras man lss limitation by food, as masurd by ratios b (A, C, E. and G) and c (E, D, F, and H). S txt for xplanation of ratios. Point Concption wr sampld, and th biomass of chlorophyll was rlativly grat north and south of Point Concption. 's rat of gg production was aloday' at a minority of stations, and thn gnrally as a rsult of two days' fding. Again, rproduction was mor likly to b stimulatd by supplmntal food (nonstippld aras in fig ur 4D.) in th Southrn California Bight than lswhr. Th rproductiv rat of Calanus was high ovr much of th ara (figur 4D.). At thr northrn, inshor stations of cruis 94, on th scond day in unsupplmntd sawatr producd > ggs.(fmalday) ' (th sam rat as with supplmntal food), and rhor than 95

8 CalCOFl Rp., Vol. 4, A 9 unfd fd % rp l.. l. Rh in ca la n us unfd Y = ".8 fd Y.5.X R". o ' l c. 9 unfd fd a m n. a ma ' c. 9 Y =.4 +.8X R" =.6 fd Y = 5..58X R" =.8. n D. 94 * E l unfd fd 94 unfd Y = X RA =.8 4 fd Y =..X R" =.5 5..n a m L m.. El P 4 D 5 ml CHLOROPHYLL TO OOm, mg/m Figur. Rlations of gg production by on th first day of incubation, with (fd) or without (unfd) supplmntal food, to th biomass of chlorophyll (s figur ) in A, January 99 (9); B, Fbruary 99 (9); C, March 99 (9); and D, April 99 (94). For cruiss 9 and 94, corrlations wr calculatd only for thos stations whr th biomass of chlorophyll was 4 mg.m* (graph in ach cas), bcaus nonlinaritis might occur at gratr biomasss. All corrlations ar nonsignificant (p >.5). 4 fiv tims th firstday rat. This incras virtually nvr occurs in Calanus (Appndix, and Mullin 99a, figurs ), in which dpltd food in unsupplmntd sawatr by th scond day rsults in a rat that is ithr lss than th firstday rat, or <lo ggs(fmalday)', or (most oftn) both. A singl station on cruis 94 nar Palos Vrds was th only xcption for Calanus. This rsult suggsts that 's rproduction is mor divorcd from th immdiat supply of food than is that of Calanus. Basd on th ratios indicating th xtnt that th ambint food supply limits gg production at ach station, 's rproduction was mor widly limitd by food (unshadd aras in figur 6) on all 96

9 CalCOFl Rp., Vol. 4,99 cruiss than was that of Calantrs. Furthr, most of th shadd aras for Rhincalantrs in figur 6 wr not du to strong rproduction by unfd fmals (as th shadd aras for Calantrs usually wr), but to vry low rats vn aftr two days with supplmntal food. Sinc th masurs of food limitation wr basd on th coppods rspons to supplmntal phytoplankton, this conclusion dpnds on th assumption, drawn from xprimntal raring, that both spcis ar particlgrazrs, ating primarily phytoplankton. Egg production by Calanus usually corrlats positivly with chlorophyll biomass, though thr is much unxplaind variability (Mullin 99a, figur 5). Howvr, on non of th four cruiss in 999 was thr a significant rlation btwn production of ggs on th first day of incubation by fmal, ithr with or without supplmntal food, and th chlorophyll biomass in th watr column (figur ). Analogous rlations for Calantrs wr highly significant (p <.) for cruiss 9 and 9, and positiv but nonsignificant for cruiss 9 and 94. Only on 94 was thr a significant rlation btwn s gg production on th scond day of fding and th biomass of chlorophyll; this rlation was positiv. n January 99 s rproduction was poor ovr much of th rgion, as it had bn in January 99 (compar figur 8A with 4A.; stippld aras rprsnt poorst rproduction) and was again foodlimitd at most stations (figur 8B). Calantrs producd > ggs.day at fwr stations in 99 than in 99, and food limitation was mor widsprad, but Calanus s rproduction was as strong in 99 in th prsnc of xcss food as in 99. Had mad mor xtnsiv masurmnts of s rproduction in April 99 (Appndix), it might hav bn possibl to discuss intrannual variability causd by anomalis in physical proprtis during wintrspring 99 (Hayward 99). n fact, th rproductiv rats of Calanus, and thir food limitation, did not diffr gratly from th situation in springs of othr yars (compar figurs 4D. and G. and H.l with figurs,, and of Mullin 99a). DSCUSSON AND CONCLUSONS Though additional months and yars should b sampld to tst th sasonality of rproduction in, th prsnt rsults suggst that it may b mor markd than in Calanus, which producs ggs in at last th coastal parts of th rgion in all sasons (Mullin 99a). n January 99 and 99, 9 station fd, day 5 B m.. b >.5 5 ggs/(fmalday), fd, day 6 so * i 4... t. P Calanus Figur 8. January 99. A, Contour maps of pr capita gg production by ; E, dgr of limitation by food as rflctd in ratio b. C, rlation of gg production by to that of Calanus aftr days fding. Compar to figurs 4A.,6A., and 5C. 9

10 CalCOFl Rp., Vol. 4,99 not only faild to lay ggs in unsupplmntd sawatr, but also faild, ovr much of th ara, to rspond to th prsnc of xcss food. FbruaryApril sms to b a mor favorabl sason, at last in trms of th potntial to rspond to xcss food (nonstippld aras in figur 4AD.), and lat summr is somwhat lss favorabl (Appndix). Howvr, figur shows that fmals can b stimulatd to rproduc as lat as Jun. Th production of ggs on th scond day of incubation with supplmntal food, mor than th othr masurmnts mad, is a masur of th rproductiv potntial not limitd by food, rflcting th ffcts of th fmals nutritional history and rproductiv stat ovr a longr trm. f is rproductivly affctd by th nvironmnt in th sam way that Calanus is, a tstabl (altrnativ) hypothsis is that th scondday rats of production by fd fmals of th two spcis ar positivly corrlatd. As shown in figur 5AF and 8C, this was th cas only on cruis 9, suggsting that in spit of th ovrall zoogographic similarity in th ara (figur l), th two populations oftn diffr on th scal sampld in rspct to th aspcts of th nvironmnt that lad to th most fcund fmals. On smallr scals, Mullin (99b) concludd that th two populations also diffrd in sourcs of juvnil mortality. Ths rlations could aris simply from diffring rats of rspons to food if Calanus fmals rspondd on th first day, and wr to som dgr spnt on th scond, whil rquird two days to rspond (as sms to b th cas). But sinc th rlation btwn th rats of production by fd fmal Calanus on th first and scond days of incubation is nvr ngativ (.g., Mullin 99a, figur 8), this altrnativ xplanation is untnabl. Though th positiv rlation btwn Calanus s gg production and th local biomass of chlorophyll varis considrably, th lack of any positiv rlation btwn s production and chlorophyll is striking, givn th apparnt similaritis in th two spcis and th fact that food availability frquntly limits production (figur 6), as shown by th stimulatory ffct of supplmntary phytoplankton. Smith and Lan (99) argud that rproduction in anothr larg coppod, Eucalanus calijhicus, off cntral California dpnds in th summrtim on fmals living in th cold, chlorophyllrich watrs of coastal upwlling or in jts originating in th coastal zon. Th CalCOF stations ar too coarsly spacd to dfin such msoscal faturs off southrn California, whr upwlling is gnrally wakr than off cntral California. But th rsults shown in figur ar not consistnt with a similar dpndncy by in wintr and spring. For th rproductiv rat of to approach that of Calantts in th studid rgion, th fmals must ncountr supplis of food (or prhaps othr conditions) gnrally not rprsntd in my xprimnts, or at tims must rspond diffrntly. Th adquacy of Thalassiosira for longtrm production (figur ), and for raring from gg to adult, dmonstrats that can thriv solly on plants, but thr may b othr food sourcs, prhaps highly patchy ons in tim or spac, that wr not prsnt in most of my incubations but that som can locat in th natural watr column to achiv high rats of production. Futur work obviously should focus on this issu whthr thr ar conditions (sason, food, tc.) prmitting to rproduc at a high rat on th natural sston; i.., > ggs.(fmalday) ; vrtical striping in figur 6A.D.. Altrnativly, th distribution of off southrn California must b xplaind ithr by vry low mortality rats or by advctiv immigration of immatur stags. ACKNOWLEDGMENTS am gratful to th tchnicians of th Marin Lif Rsarch Group, Scripps nstitution of Ocanography, and th Coastal Division, Southwst Fishris Scinc Cntr, National Marin Fishris Srvic, who do th work of th CalCOF cruiss, for assistanc and comradship at sa. Andrw South and Odtt Rocha countd most of th prsrvd sampls rsulting in figur, and an anonymous rfr stimulatd m to prpar th Appndix and rduc th numbr of figurs. This study was supportd ntirly by th Marin Lif Rsarch Group, Scripps nstitution of Ocanography, Univrsity of California, San Digo. LTERATURE CTED Ayukai, T Egg production by th planktonic calanoid coppod Acartia omorii in Onagawa Harbor during springsummr. Bull. Plank. Soc. Japan 5:. Durbin, E. G., A. G. Durbin, T. J. Smayda, and? G. Vrity. 98. Food limitation of production by adult Acartia tonsa in Narraganstt Bay, Rhod sland. Limnol. Ocanogr. 8:99. Flmingr, A Distributional atlas of calanoid coppods in th California Currnt rgion. Part. Calif Coop. Ocanic Fish. nvst. Atlas, pp. Hakanson, J. L. 98. Th fding condition of Calanus pacificus and othr zooplankton in rlation to phytoplankton pigmnts in th California Currnt. Limnol. Ocanogr. : Hayward, T. L. 99. Prliminary obsrvations of th 9999 El NiAo in th California Currnt. Calif. Coop. Ocanic Fish. nvst. Rp. 4 (this volum). Koslow, J. A., and A. Ota. 98. Th cology of vrtical migration of thr common zooplanktrs in th La Jolla Bight, AprilAugust, 96. Biol. Ocanogr. :4.

11 CalCOFl Rp., Vol. 4,99 Longhurst, A. R., A. D. Rith, R. E. Bowr, and D. R. L. Sibrt A nw systm for th collction of multipl srial plankton sampls. Dpsa Rs.. Mullin, M. M. 99a. Production ofggs by th coppod Calanuspac$cus in th southrn California sctor of th California Currnt Systm. Calif. Coop. Ocanic Fish. nvst. Rp. : b. Rlativ rproduction and mortality in two plagic coppod populations. J. Plank. Rs. :88. Mullin, M. M., and E. R. Brooks. 96. Laboratory cultur, growth rat, and fding bhavior of a planktonic, marin coppod. Limnol. Ocanogr Growth and mtabolism of two planktonic, marin coppods as influncd by tmpratur and typ of food. n Marin food chains, J. H. Stl, d. Olivr and Boyd, Edinburgh, pp Smith, S. L., and P. V. Z. Lan. 99. Thjt off Point Arna, California: its rol in aspcts of scondary production in th coppod Eucalanus calijornirus Johnson. J. Gophys. Rs. 96:4,8494,

12 CalCOFl Rp., Vol. 4,99 APPENDX Calanus Calanus Calanus Calanus _ Station* Day *For CalCOF Basic.Station Plan, s insid back covr.

13 CalCOFl Rp., Vol. 4,99 Station Day Calan us Calanus Calanus continud on nxtpag

14 CalCOFl Rp., Vol. 4,99 APPENDX (continud) 94 Station Dav Calanus Calanus Calanus

15 CalCOFl Rp., Vol. 4,99 Station Dy