The distribution of littoral caprellids (Crustacea : Amphipoda : Caprellidea) along the Pacific coast of continental Chile

297 Re is a Chilena de His o ia Na u al 76: 297-312, 2003 The dis ibu ion o li o al cap ellids (C us acea: Amphipoda: Cap ellidea) along he Paci ic coas o con inen al Chile La dis ibución de cap élidos li o ales (C us acea: Amphipoda: Cap ellidea) en la cos a del Pací ico de Chile con inen al MARTIN THIEL1* , JOSÉ M. GUERRA-GARCÍA2, DOMINGO A. LANCELLOTTI1 & NELSON VÁSQUEZ1 1Facul ad de Ciencias del Ma , Uni e sidad Ca ólica del No e, La ondo 1281, Coquimbo, Chile; e-mail: [email p o ec ed] 2 Labo a o io de Biología Ma ina, Depa amen o de Fisiología y Biología Animal, Facul ad de Biología, Uni e sidad de Se illa, Apa ado 1095, E-41080, Se illa, España (*co esponding au ho ) ABSTRACT Many li o al cap ellid species ha e a e y ample dis ibu ion, some ha ing been epo ed om all o e he wo ld. The cosmopoli an dis ibu ion o many li o al cap ellid species migh be acili a ed by he ac ha hey a e o en associa ed wi h ouling communi ies on loa ing objec s, which ha e a high po en ial o a - ange dispe sal. This dispe sal po en ial may also ha e implica ions o he dis ibu ion o cap ellids on local and egional scales. He ein we examined he dis ibu ion o li o al cap ellid species on wo spa ial scales, local ( ens o kilome e s) and egional (hund eds o kilome e s) along he Paci ic coas o con inen al Chile. On he local scale, we s udied he cap ellid auna in di e en habi a s (in e idal boulde s, sub idal algal and seag ass beds, ouling communi y on buoys and opes); on he egional scale we ocused only on cap ellids associa ed wi h he ouling communi y on buoys and opes. We ound a o al o six cap ellid species, some o which we e e y abundan bo h on he local as well as on he egional scale. On he local scale we ound a di e ence be ween he h ee s udied habi a ypes wi h espec o he assemblage o cap ellid species, some o which we e ound in mo e han one habi a . The highes species ichness and abundance o cap ellids was ound in he ouling communi y associa ed wi h ancho ed buoys and opes. On he egional scale we ound e y high numbe s o cap ellids in he ouling communi y o he no he n egion (n o 30° S), and dec easing abundances and species ichness in he cen al egion (30–37° S). No cap ellids we e ound in he sou he n egion o he s udy a ea (37–42° S). This pa e n coincides wi h he global dis ibu ion o li o al cap ellid species, which a e mos abundan and di e se a low la i udes bu occu in low abundances and low di e si y a high la i udes. De ached buoys ha we e ound a ew km o he coas ha bo ed simila cap ellid assemblages (including o ige ous emales) as ancho ed buoys, sugges ing ha buoys and o he loa ing subs a a (li e , mac oalgae) may acili a e dispe sal o cap ellids (and o he epibio a) along he Paci ic coas o Chile. Since a i icial and na u al loa ing subs a a a e also abundan a high la i udes i is in e ed ha he low di e si y o li o al cap ellids a high la i udes is no due o lack o dispe sal ec o s, bu a he o o he ac o s. Key wo ds: C us acea, Amphipoda, Cap ellidea, Chile, biogeog aphy. RESUMEN Muchas especies de cap élidos del li o al p esen an una amplia dis ibución, algunas han sido ci adas a lo la go de odo el mundo. La dis ibución cosmopoli a de muchas especies de cap élidos pod ía debe se al hecho de que se asocian ecuen emen e a las comunidades “ ouling” en obje os lo an es, que p esen an una capacidad impo an e de dispe sión a la gas dis ancias. Es a capacidad de dispe sión puede ene implicaciones en la dis ibución de cap élidos a escala local y egional. En es e es udio, noso os examinamos la dis ibución de las especies de cap élidos li o ales en dos escalas espaciales, local (decenas de kilóme os) y egional (cien os de kilóme os), a lo la go de la cos a Pací ico de Chile con inen al. A escala local se es udió la auna de cap élidos en dis in os hábi a s (bolones in e ma eales, p ade as de algas y ane ógamas ma inas, comunidades “ ouling” de boyas y cue das); a escala egional el es udio se cen ó solamen e en los cap élidos asociados a boyas y cue das. Se encon a on un o al de seis especies de cap élidos, algunos de los cuales ue on muy abundan es a escala local y egional. A escala local, exis ió una di e encia en e los es ipos de hábi a con espec o a la auna de cap élidos, algunos de los cuales es u ie on p esen es en más de un hábi a . Los alo es más al os de iqueza especí ica y abundancia se encon a on en la comunidad “ ouling” asociada a boyas y cue das ancladas. A escala egional, los cap élidos ue on más abundan es y di e sos en las comunidades “ ouling” de la egión no e (n de 30º S), mien as que la abundancia y iqueza de especies disminuye on en la egión cen al (30-37º S). No se encon a on cap élidos en la egión su del á ea de es udio (37-42º S). Es e pa ón coincide con la dis ibución global de especies de cap élidos li o ales, mos ando los alo es más al os de abundancia y iqueza de especies en las bajas la i udes y los alo es más bajos en las al as la i udes. Boyas desp endidas desde sus ama as y encon adas a a ios km de la cos a albe ga on asociaciones de cap élidos (incluyendo hemb as o íge as) simila es a las de las boyas ijadas, sugi iendo que 298 THIEL ET AL. INTRODUCTION Cap ellid amphipods a e common membe s o many li o al habi a s, and hey a e pa icula ly abundan in epibio ic ouling communi ies. They a e e y common and di e se on e ec b yozoans and hyd ozoans and on plan subs a a such as mac oalgae and seag asses (McCain 1968). They eed on suspended ma e ials, p ey on o he o gan- isms, o g aze on epibio ic auna and lo a (Caine 1974). Locally, cap ellids a e impo an p ey o many coas al ish species (Caine 1987, 1989, 1991), and hey may be impo an membe s o li o al communi ies. Many cap ellid species ha e a wide dis ibu ion and he e a e many examples o species ha a e conside ed o be cosmopoli ans (Takeuchi & Sawamo o 1998). Wi h hei gene al mo phol- ogy, cap ellids a e well adap ed o cling o sub- s a a such as algae and hyd oids (Takeuchi & Hi ano 1995). Using hei las pe eiopods hey can i mly hold on o b anches o algae, b yozoans and hyd ozoans. The pleopods, which a e used o swimming in o he amphipod c us aceans, a e educed in cap ellids. The e o e, al hough cap ellids can swim (Caine 1979), hey p obably a e no e y e icien swimme s. This, as well as he lack o a plank onic la al s age, sugges s ha cosmopoli an cap ellid species may be dis ib- u ed passi ely by clinging o loa ing ma e ials a he han by ac i e swimming. Floa ing ma e i- als such as mac oalgae a e easily dis ibu ed be- ween dis an loca ions (Ingól sson 1995, Hobday 2000a) and cap ellids and o he amphipods a e commonly ound on his ype o subs a a (Hobday 2000b). Many cap ellid species a e also e y unselec i e wi h espec o hei subs a um and hey colonize a wide a ie y o di e en sub- s a a. Fo example he species C. equilib a has been ound on algae, seag asses, b yozoans, bi al es, sponges and o he subs a a (K app- Schickel 1993). This low selec i i y o a wide a ie y o subs a a ha ha e high loa ing po en- ial sugges s ha hese species migh ha e a wide dis ibu ion, pa icula ly in egions whe e ocean cu en s anspo suspended o loa ing ma e i- als (algae, b yozoans, wood o buoys and o he an h opogenic ma e ial) o e la ge dis ances. Al hough he abundance and species ichness o cap ellids in many a eas o he wo ld’s oceans las boyas y o os sus a os lo an es pueden acili a la dispe sión de cap élidos (y o a epi auna) a lo la go de la cos a Pací ico de Chile. Teniendo en cuen a que los sus a os lo an es na u ales y a i iciales son ambién abundan es en al as la i udes se in ie e que la baja di e sidad de cap élidos li o ales en al as la i udes no se debe a la al a de ec o es dispe san es sino a o os ac o es. Palab as cla e: C us acea, Amphipoda, Cap ellidea, Chile, biogeog a ía. is s ill poo ly known, Laubi z (1970) poin ed ou ha su ace wa e empe a u e is an impo an ac o de e mining he dis ibu ion o li o al cap ellids along he Ame ican coas o he No h Paci ic. Simila as o o he axa (e.g., co als – F ase & Cu ie 1996; molluscans – Roy e al. 1998, 2000), species ichness o cap ellids de- c eases g adually owa ds no he n la i udes (Laubi z 1970). Wa e empe a u e may a ec he dis ibu ion o cap ellids along he Ame ican coas o he Sou h Paci ic in a simila way as in he No h Paci ic since he oceanic egime and in pa icula he la i udinal a ia ion in wa e em- pe a u es show simila i ies be ween hese wo egions. I can he e o e be expec ed ha di e - si y o li o al cap ellids along he Paci ic coas o Chile also dec eases owa ds high la i udes. Ne e heless, on a mo e local scale, and in pa - icula in bay sys ems, wa e ci cula ion leads o in ense local mixing (Soba zo 2002), and he dis ibu ion pa e n o cap ellid amphipods he e- o e can be expec ed o be ela i ely uni o m wi hin local bay sys ems. In he p esen s udy, we examined he composi- ion o he cap ellid auna bo h on a local and egional scale. The local dis ibu ion was exam- ined wi hin a sys em o bays, i.e., o e a scale o ens o km, while he egional dis ibu ion o cap ellids was examined along a la i udinal g a- dien a si es sepa a ed by hund eds o km. The p incipal objec i e o his s udy was o e eal he species ichness o li o al cap ellids and hei dis ibu ion pa e n along he Paci ic coas o con inen al Chile. We inco po a e da a on he cap ellid assemblage om de ached buoys ound a ew km o sho e since his in o ma ion con ib- u es o a be e unde s anding o bo h he local and egional dis ibu ion o cap ellids. MATERIAL AND METHODS The local dis ibu ion pa e n o li o al cap ellids was examined in he bay sys em o Coquimbo, no he n-cen al Chile (Fig. 1). In No embe / Decembe 2000, semi-quan i a i e samples we e aken in h ee di e en habi a s, in e idal boul- de s, sub idal algal and seag ass beds and ouling communi ies om buoys and opes. P elimina y su eys had e ealed ha cap ellid amphipods 299DISTRIBUTION OF LITTORAL CAPRELLIDS FROM CHILE we e mo e common in hese han in o he li o al habi a s (Gue a-Ga cía & Thiel 2001). A each o he se en sampling si es we a emp ed o sample all h ee habi a s keeping he minimum dis ance be ween di e en habi a s < 1,500 m; a some si es no all habi a s we e ep esen ed. Sessile auna oge he wi h any adhe ing amphipods was sc aped om boulde s loca ed in he low in e - idal zone. We ocused on a eas ha we e colo- nized by hyd ozoans Obelia dicho oma, which we sc aped om he unde side o se e al boulde s un il comple ing a olume o 10-20 mL. In he sub idal beds o G acila ia chilensis and He e ozos e a asmanica we collec ed he p inci- pal plan species oge he wi h o he occasional algae (Callophyllis a iega a, Chond acan hus chamissoi, Sa codio heca gaudichaudii, Sphae ococcus co onopi olius and Halop e is sp.). Plan s we e aken om he bo om by a semi- au onomous di e and placed in a sampling ja un il comple ing a olume o app oxima ely 1,000 mL. F om buoys and opes associa ed wi h aquac- ul u e o ha bo s uc u es, we collec ed he mos common epibio a (me azoans such as Pyu a chilensis, Bugula ne i ina and B. labella a, Tubula ia c ocea, ci ipeds om he amily Balanidae; and mac oalgae such as Ul a lac uca, Polysiphonia panicula a and P. mollis, Chond acan hus chamissoi, Lessonia abecula a, o en co e ed wi h b yozoans o he genus Memb anipo a) oge he wi h he adhe ing am- phipods. Samples we e ei he aken by a semi- au onomous di e who sepa a ed he ouling o - ganisms om he buoys and opes and placed hem in a sampling ja a he wa e su ace. Al e - na i ely, buoys and opes we e pulled in o a boa Fig. 1: Bay sys em in es iga ed in he p esen s udy. Samples we e aken om buoys, seag ass and algal beds, and boulde s on exposed ocky sho es along s a ions A-G; he h ee di e en subs a a we e no p esen a all sampling s a ions. Do s along he Paci ic coas o con inen al Chile indica e sampling si es o egional s udy. Sis ema de bahías in es igado en el p esen e es udio. Las mues as ue on ecolec adas en boyas, p ade as y bolones a lo la go de las es aciones A-G. Los es subs a os conside ados no siemp e es u ie on p esen es en odos los pun os de mues eo. Los cí culos a lo la go de la cos a Pací ico de Chile con inen al indican los si ios de mues eo del es udio egional. 300 whe e ouling o ganisms we e sepa a ed and im- media ely placed in he ja . Fouling o ganisms we e ga he ed om di e en buoys and opes un il comple ing a olume o 500 mL. The main objec i e o his su ey was o de e - mine he species ichness o li o al cap ellids in di e en habi a s. In o de o ob ain ep esen a- i e es ima es o species, we selec ed di e en sample olumes in each habi a (20 mL unde boulde s, 500 mL in buoys and opes and 1,000 mL in algal beds) he eby aking s uc u al di e - ences among habi a s in o accoun . P elimina y sampling had indica ed ha unde boulde s cap ellids cling o small hyd oids o o he sub- s a um di ec ly, while on algae hey oam o e la ge a eas o algal su ace. A su ey by Gue a- Ga cía & Thiel (2001) in he bay sys em o Coquimbo indica ed ha he selec ed sampling olumes a e su icien o ob ain ep esen a i e es ima es o species ichness in he habi a s s ud- ied he ein. Since his p elimina y su ey had e ealed la ge di e ences in cap ellid abundance, he ein we used a semi-quan i a i e me hod in o - de o es ima e cap ellid abundances in he di e - en habi a s: p esen (1-10 indi iduals sample-1), common (11-100 indi iduals sample-1), abundan (101-1,000 indi iduals sample-1) and supe abun- dan (> 1,000 indi iduals sample-1). We exp essed he abundance o cap ellids as indi iduals pe sample and no as indi iduals pe sample olume he eby aking in o accoun he di e en habi a s uc u e. The use ulness o a semi-quan i a i e scale in mul i a ia e analysis has been demon- s a ed in ecological s udies dealing wi h ma ine in e eb a es (Maldonado & U iz 1995, Ca ballo e al. 1996, Na anjo e al. 1996, Gue a-Ga cía 2001). Ne e heless, acco ding o Cla ke & Wa wick (1994), when sampling a i ac s ende quan i a i e compa isons un easible, a educ ion o simple p esence o absence o each species is ecommended. Following hese sugges ions, simi- la i ies o cap ellid occu ence among di e en habi a s on he local scale we e examined by means o a classi ica ion analysis based on p es- ence/absence da a ins ead o he semi-quan i a- i e da a. The Jacca d simila i y index (Jacca d 1908) and he UPGMA (unweighed pai -g oup a e age me hod) agg ega ion algo i hm (Snea h & Sokal 1973) we e used. The signi icance o he esul ing clus e s was es ablished ollowing he boo s ap me hodology as in Lancello i & T ucco (1993) (a e Jaksic & Medel 1987). F om he ini ial species*habi a ma ix wi h p esence/ab- sence da a, 1,000 s ochas ic eassignmen s we e made, compu ing on each occasion simila i y pseudo- alues o each possible combina ion o habi a s. All pseudo- alues gene a ed a e 1,000 shu les we e plo ed in a equency his og am, es ablishing he signi icance, i.e., a a 0.05 o 0.10 α-le el, a he 95 h o 90 h pe cen ile, espec- i ely. The simila i y alue o which he 95 h pe cen ile co esponded was conside ed he c i i- cal alue. Thus, o any clus e , a simila i y alue abo e his c i ical alue was conside ed highe han expec ed a andom, and i was conside ed signi ican a he α = 0.05 le el. Fo he s udy o he egional dis ibu ion o cap ellids we ocused on he species associa ed wi h he ouling communi y om buoys and opes, since p e ious s udies had e ealed ha his is a e y impo an habi a o li o al cap ellid spe- cies (Bynum 1978, Caine 1987). A 12 di e en si es be ween 18.4° and 41.9° S, spanning ~ 3,000 km along he Paci ic coas o con inen al Chile (Fig. 1), samples we e aken om buoys and opes associa ed wi h aquacul u e o ha bo s uc- u es. Fo Coquimbo we conside ed he esul s om Bahía La He adu a (si e C in Fig. 1). Sam- pling was done du ing aus al summe 2001 in he same way as desc ibed abo e. Fouling o ganisms we e sepa a ed om di e en buoys and opes and placed in o he sampling ja un il comple ing a olume o 500 mL. In his way we ob ained one cumula i e sample o each o he 12 di e en si es. All samples we e ixed wi h 5 % o malin and la e washed o e a mesh o 250 µm be o e so ing hem in he labo a o y. The B ay-Cu is dis ance index (B ay & Cu is 1957) and he UPGMA (unweighed pai -g oup a e age me hod) agg ega ion algo i hm (Snea h & Sokal 1973) we e used. The analysis was conduc ed using he semi-quan i a i e da a, i.e., wi h an o de o mag- ni ude co esponding o a loga i hmic ans o - ma ion, which is ypically used o his so o analysis in o de o s anda dize in e speci ic a i- abili y (Cla ke & Wa wick 1994). Be o e conduc - ing he analysis we added he alue o 1 x 10-5 o each elemen in he o iginal ma ix, which al- lowed o inco po a e he locali ies wi h no cap ellids (ze o alues) in o he analysis – his p ocedu e p oduced no changes in he gene al associa ion pa e n. The signi icance o he clus- e s esul ing om his analysis was es ablished ollowing he same p ocedu e as on he local scale bu based on he species*si e semi-quan i a- i e da a ma ix. Du ing a wo-day oceanog aphic c uise con- duc ed du ing he aus al all 2002 in coas al wa e s o he Bay sys em o Coquimbo we col- lec ed six de ached buoys oge he wi h hei oul- ing communi y. Addi ionally, du ing se e al oceanog aphic c uises along he Chilean coas , which we e conduc ed du ing aus al summe 2002 (nine c uises be ween A ica, 18° S, and Isla Mad e THIEL ET AL. 301 de Dios, 50° S, each c uise 10-30 Nm o he coas ), we collec ed wo de ached buoys o he coas a app oxima ely 27° S. On mos occasions we sampled he en i e buoy and a e washing i o e a mesh o 250 µm we sc aped he ouling communi y om he buoys. Due o logis ic ea- sons di e en olumes we e sampled o he oul- ing communi y om hese de ached buoys. In all cases he semi-quan i a i e es ima es ep esen minimum es ima es o he o al cap ellid abun- dance on each buoy. Following p ese a ion in he ield, hese samples we e p ocessed in he labo a o y in he same way as desc ibed abo e. De ailed in o ma ion abou he de ached buoys can be ound in Appendix 1. RESULTS Local dis ibu ion o cap ellids om di e en li o al habi a s A o al o six cap ellid species we e collec ed in di e en li o al habi a s along he bay sys em o Coquimbo. None o hese species was ound in all sampled habi a s, bu some species (Cap ella equilib a Say, 1818, C. scau a Temple on, 1836, Deu ella enenosa Maye , 1890) occu ed in wo o he h ee s udied habi a s, while o he s (Cap ellina longicollis (Nicole , 1849), Cap ella e ucosa Boeck, 1871, Pa acap ella pusilla Maye , 1890) we e only ound in one o hese habi a s (Table 1). The species C. scau a was one o he mos widesp ead species, being common in almos all samples om buoys and p esen in all samples om algal and seag ass beds. Al hough he p esence o C. scau a in algal and seag ass beds was cons an along he bay sys em s udied, i s abundance was compa a i ely low, ne e ex- ceeding 10 indi iduals pe sample. The species D. enenosa was e y abundan on buoys and did also occu unde in e idal boulde s. Cap ella e ucosa also was e y abundan on buoys bu did no occu in any o he o he wo habi a s. Cap ella equilib a was p esen on some buoys, bu also occu ed unde boulde s oge he wi h D. enenosa, bo h species being associa ed wi h he hyd oid Obelia dicho oma. The p esence o Pa acap ella pusilla was es ic ed o he boul- de s om sampling si e C. Cap ellina longicollis TABLE 1 Abundance o cap ellid species in he di e en habi a s (1 - buoys, 2 - algal and seag ass beds, 3 - boulde s) and he sampling si es (A-G) in he bay sys em o Coquimbo; (*) indica es he seag ass bed; sample olume o buoys is 500 mL, o algal and seag ass beds is 1,000 mL and o boulde s app oxima ely 20 mL. Fo u he de ails see ex Abundancia de las especies de cap élidos en los dis in os hábi a s (1 – boyas, 2 – p ade as, 3 - bolones) y es aciones mues eadas (A-G) a lo la go del sis ema de bahías de Coquimbo; (*) indica la p ade a de ane ógama. El olumen de mues eo pa a boyas ue 500 mL, pa a p ade as 1.000 mL y pa a bolones ap oximadamen e 20 mL. Ve ex o pa a más de alles Buoys Algal and seag ass beds Boulde s A1 B1 C1 E1 F1 G1 A2 B2 C2 D2 E2 F2 G2* A3 C3 D3 E3 F3 Cap ellina longicollis Cap ella equilib a Cap ella scau a Cap ella e ucosa Deu ella enenosa Pa acap ella pusilla (A) Bahía de Coquimbo, no h Abundance pe sample: (B) Bahía de Coquimbo, sou h P - p esen (1-10 indi iduals) (C) Bahía de La He adu a Co - common (11-100 indi iduals) (D) Bahía de To o alillo Ab - abundan (101-1,000 indi iduals) (E) Bahía de Guanaque os (F) Bahía de Tongoy, no h (G) Bahía de Tongoy, sou h (*) Seag ass bed (He e ozos e a asmanica) DISTRIBUTION OF LITTORAL CAPRELLIDS FROM CHILE 302 was, oge he wi h C. scau a, he only species eco ded om he algal and seag ass beds. The epi ouling communi y om buoys and opes was he habi a wi h he highes species ichness and abundance o li o al cap ellids. The cap ellid auna di e ed among he s udied habi a s, bu on a local scale ( ens o km) li le a ia ion was ound wi hin habi a s, wi h he excep ion o boul- de s (Fig. 2). The samples om buoys and algal/ seag ass beds we e g ouped in wo sepa a e g oups, bo h connec ing wo subg oups. While he g oup connec ing cap ellid auna om buoys was signi ican (P < 0.05), hose om he algal/ seag ass beds o med dis inc subg oups a 0.10 > P > 0.05. In con as , samples om boulde s o med no dis inc g oup sugges ing a compa a- i ely he e ogeneous habi a , possibly exposed o equen ex inc ion/coloniza ion e en s. Regional dis ibu ion o cap ellids associa ed wi h ancho ed buoys Fou cap ellid species we e ound on he an- cho ed buoys along he Chilean coas (Fig. 3). Simila as in he bay sys em o Coquimbo, Cap ella e ucosa and C. scau a we e he mos abundan species on buoys, being widely dis ib- u ed in he no he n egion o he Chilean coas . Cap ella equilib a was only p esen in a ew locali ies and he species Deu ella enenosa only occu ed in Coquimbo. Bo h, abundance and spe- cies ichness o cap ellids on he buoys and opes dec eased om no h o sou h, and no cap ellids we e ound in he sou he n egion (a 39.8° and 41.9° S) (Fig. 3). The classi ica ion analysis showed h ee dis inc clus e s, one in he no he n egion cha ac e ized by ela i ely high species ichness and abundances, whe e wo subg oups a e connec ed wi h P < 0.10, one in he cen al egion wi h highe he e ogenei y, whe e species ichness and abundance dec eased, and one in he sou h whe e no li o al cap ellids we e ound in he ouling communi y associa ed wi h buoys (Fig. 4). Some in aspeci ic mo phological a ia ion has been ound o Cap ella scau a and C. e ucosa a some si es. The s iking head spine, ypical o C. scau a epo ed h oughou he wo ld, was e y educed in he specimens collec ed om Isla S a. Ma ia (23.4° S). Ne e heless, examina ion o an ennae, gna hopods, mou hpa s and abdo- men o hese specimens con i med ha hey be- longed o C. scau a. In he specimens o Cap ella e ucosa om Cale a Tumbes (36.6° S), he sou he nmos s a ion whe e cap ellids we e ound, he ube cles on he do sal pe eoni es we e ab- sen . Taking in conside a ion he ea u es o an- ennae, hese specimens we e assigned o C. e ucosa. These obse a ions, howe e , con i m he g ea need o u u e axonomic s udies in he complex o species simila o C. e ucosa (see also Gue a-Ga cía & Thiel 2001). Rega dless o he mo phological a ia ions in some o he speci- mens ound he ein, a s ong dec ease in abun- dance and species ichness o li o al cap ellid owa ds highe la i udes was ound (Fig. 3). Cap ellids associa ed wi h de ached (= pelagic) buoys On he six de ached buoys ha we e collec ed while loa ing in coas al wa e s o he Bay sys- em o Coquimbo, a o al o ou di e en cap ellid species was ound (Table 2). The mos common cap ellid species we e Cap ella scau a and C. Fig. 2: Clus e analysis showing he ela ionships among samples on he local scale. Simila i ies based on p esence/absence o cap ellid species on di e en subs a a (buoys: 1, algal/seag ass beds: 2; boulde s: 3) and sampling s a ions (A-G). Dashed lines indica e signi ican le els: G oups o habi a s 1 (buoys) and 2 (algal/seag ass beds) signi ican a 0.10 > P > 0.05. Análisis de conglome ados mos ando las elaciones en e subs a os en una escala local. Las simili udes es án basadas sob e la p esencia/ausencia de cap élidos en los di e en es subs a os (boyas: 1, p ade as: 2; bolones: 3) y es aciones de mues eo (A-G). Las líneas somb eadas indican ni eles de signi icancia: los g upos de hábi a s 1 (boyas) y 2 (p ade as) ue on signi ica i os a una p obabili- dad 0,10 > P > 0,05. THIEL ET AL. 303 equilib a, which we e each ound on ou o he six buoys. The o he wo cap ellid species, C. e ucosa and Deu ella enenosa, we e each ound on wo buoys. Abundances o indi idual cap ellid species equen ly exceeded 100s o indi iduals pe buoy (Table 2). On all buoys, we also ound o ige ous emales. Du ing he nine esea ch c uises be ween A ica and Isla Mad e de Dios we ound wo de ached buoys loa ing in coas al wa e s o Calde a. Each o hese wo buoys ha bo ed h ee cap ellid spe- cies (C. equilib a, C. scau a and C. e ucosa) (Table 2). Abundances o C. equilib a was high- es on he buoys i sel , while C. scau a domina ed on he ope s ill a ached o one o hese wo buoys. O all h ee cap ellid species and on each o he wo buoys, o ige ous emales we e ound. DISCUSSION The esul s o he p esen s udy demons a ed ha he cap ellid auna along he Paci ic coas o con inen al Chile is compa a i ely poo . Despi e a ela i ely la ge sampling e o on he local and egional scale only six species o li o al cap ellids we e ound. Rega dless o he low species num- be , dis inc geog aphic pa e ns we e ound. In Fig. 3: Abundance and dis ibu ion o he cap ellid species associa ed wi h he ouling communi y o buoys and opes along he Paci ic coas o con inen al Chile. A each si e, epi aunal o ganisms om di e en buoys and opes we e ga he ed un il comple ing a olume o 500 mL. Abundancia y dis ibución de los cap élidos asociados a la comunidad epi i a de boyas y cue das a lo la go de la cos a Pací ico de Chile con inen al. En cada localidad, se ecolec a on o ganismos epí i os de di e en es boyas y cue das has a comple a un olumen de 500 mL. DISTRIBUTION OF LITTORAL CAPRELLIDS FROM CHILE 304 he ollowing we will compa e he dis ibu ion pa e ns o li o al cap ellids on di e en geo- g aphic scales, and we discuss he ac o s in lu- encing hese pa e ns. Local dis ibu ion o cap ellid species in he bay sys em o Coquimbo Wi hin he bay sys em examined he ein, mos cap ellid species we e ound in wo ypes o habi- a . Those habi a s we e e y di e en (e.g., oul- Fig. 4:Clus e analysis showing he ela ionships among sampling si es along he Paci ic coas o con inen al Chile ( egional scale). Dis ance was based on semi-quan i a i e alues o cap ellid abundance. Dashed lines indica e signi ican le els: g oup o sampling si es om he no he n egion signi ican a 0.10 > P > 0.05. Análisis de conglome ados mos ando las elaciones en e las localidades de mues eo a lo la go de la cos a del Pací ico de Chile con inen al (escala egional). Las dis ancias es án basadas en los alo es semi-cuan i a i os de la abundancia de cap élidos. Las líneas somb eadas indican ni eles de signi icancia: el g upo de es aciones de mues eo de la egión no e ue signi ica i o a una p obabilidad 0,10 > P > 0,05. THIEL ET AL. 305 ing communi y on buoys and opes e sus algal and seag ass beds) sugges ing ha he cap ellid species ound in he bay sys em o Coquimbo a e ela i ely unselec i e wi h espec o hei subs a- um, which appea s o be gene ally ue o li o al cap ellid species. Fo example, Cap ella scau a has been epo ed om b yozoans, sponges, seaweeds and seag asses (Lim & Alexande 1986, Takeuchi & Hino 1997, Se ejo 1998). Cap ella equilib a has been collec ed om seaweeds, b yo- zoans, sponges and ascidians (K app-Schickel 1993). Aoki & Kikuchi (1990) ound C. e ucosa on e y di e en subs a a, and Cap ellina longicollis has been collec ed om algae, b yozo- ans and ascidians along he coas o New Zealand, whe e i is he mos abundan species (McCain 1969). Maye (1890) epo ed ha C. e ucosa and D. enenosa we e o en ound on a ious subs a a belonging o he ouling communi y along he coas o Coquimbo. In gene al, a he local scale, he en i onmen al habi a condi ions (such as hyd odynamics, sedimen a ion a e, u bidi y, subs a um s abili y) seem o be mo e impo an in de e mining he dis ibu ion o li o al cap ellids han subs a um cha ac e is ics (Takeuchi e al. 1987, 1990, Gue a-Ga cía & Ga cía-Gómez 2001). Recen ly, Gue a-Ga cía & Ga cía-Gómez (2001) ound ha he species composi ion o he Cap ellidea om one pa icula subs a um ( he seaweed Cys osei a usneoides) along he coas o Ceu a (No h A ica) changed conside ably ac- co ding o en i onmen al ac o s such as local hyd odynamics. This sugges s ha en i onmen al condi ions a e usually mo e impo an in de e - mining he dis ibu ion o li o al cap ellids han subs a um cha ac e is ics. The impo ance o hy- d odynamic condi ions o he dis ibu ion o li - o al cap ellids is no su p ising since many spe- cies eed di ec ly on o ganisms o ma e ials cap- u ed om he wa e column (Takeuchi & Hi ano 1995). Hyd odynamic condi ions may also ha e impli- ca ions o cap ellid dispe sal wi hin bay sys- ems. Mos bays along he con inen al coas o Chile a e cha ac e ized by s ong ci cula ion and e icien mixing o su ace wa e s (Soba zo 2002). This con ibu es o e icien exchange and a ela- i ely uni o m dis ibu ion pa e n o ben hic spe- TABLE 2 Abundance o cap ellid species on de ached buoys o he Paci ic coas o Chile: p esen (1-10 indi iduals); common (11-100 indi iduals); abundan (101-1,000 indi iduals); supe abundan (>1,000 indi iduals). All abundance es ima es ep esen minimum alues; (Cq) Coquimbo; (Ca) Calde a. Fo de ails abou buoys see Appendix 1 Abundancia de las especies de cap élidos en boyas desp endidas y encon adas en e a la cos a Pací ico de Chile: p esen e (1-10 indi iduos); común (11-100 indi iduos); abundan e (101-1.000 indi iduos); supe abundan e (>1.000 indi iduos). Todas las es imaciones de abundancia ep esen an alo es mínimos; (Cq) Coquimbo; (Ca) Calde a. Pa a más de alles e Anexo 1 Coquimbo Calde a Cq1 Cq2-b Cq2- Cq3 Cq4 Cq5 Cq6 Ca1 Ca2-b Ca2- Sample ype Buoy Buoy Rope Buoy Buoy Buoy Buoy Buoy Buoy Rope La i ude 29 o 49’23” 29 o 47’06” 29 o 58’38” 30 o 03’56” 30 o 13’00” 29 o 37’59” 27 o 01’23” 27 o 05’45” Longi ude 71 o 26’39” 71 o 27’44” 71 o 24’59” 71 o 40’55” 71 o 42’35” 71 o 31’33” 70 o 56’55” 71 o 00’15” Dis ance om sho e (km) 12.5 11.8 1.9 19.7 7.7 20 6.8 6.5 Cap ellina longicollis Cap ella equilib a Cap ella scau a Cap ella e ucosa Deu ella enenosa Pa acap ella pusilla Abundance pe sample: P - p esen (1-10 indi iduals) Co - common (11-100 indi iduals) Ab - abundan (101-1,000 indi iduals) Su - supe abundan (> 1,000 indi iduals) DISTRIBUTION OF LITTORAL CAPRELLIDS FROM CHILE 312 APPENDIX 1 De ailed in o ma ion abou de ached buoys ound o he Paci ic coas o Chile: (Cq) Coquimbo; (Ca) Calde a; sampling olumes di e ed due o logis ic easons (e.g., leng h o ope s ill a ached o buoys) In o mación de allada de boyas desp endidas encon adas al en e de la cos a Pací ico de Chile: (Cq) Coquimbo; (Ca) Calde a; olumenes de mues eo di ie en po azones logís icas (e.g., la go de la cue da aun ichado a las boyas) Coquimbo Calde a Cq1 Cq2-b Cq2- Cq3 Cq4 Cq5 Cq6 Ca1 Ca2-b Ca2- Sample ype Buoy Buoy Rope (7m) Buoy Buoy Buoy Buoy Buoy Buoy Rope (12m) Volume (1000 cm 3 ) 11 21.5 11 11 11 11 11 21.5 Su ace a ea (100 cm 3 ) 23.8 37.4 23.8 23.8 23.8 23.8 23.8 37.4 La i ude 29 o 49’23” 29 o 47’06” 29 o 58’38” 30 o 03’56” 30 o 13’00” 29 o 37’59” 27 o 01’23” 27 o 05’45” .. Longi ude 71 o 26’39” 71 o 27’44” 71 o 24’59” 71 o 40’55” 71 o 42’35” 71 o 31’33” 70 o 56’55” 71 o 00’15” .. Dis ance om sho e (km) 12.5 11.8 1.9 19.7 7.7 20 6.8 6.5 Sampling da e 11 June 2002 11 June 2002 12 June 2002 12 June 2002 12 June 2002 24 June 2002 9 Feb ua y 2002 9 Feb ua y 2002 .. Sampling olume (l) 0.5 0.5 1.0 1.0 0.5 0.5 0.1 0.5 1.3 Buoy en i ely/pa ially sc aped En i e Pa ial En i e En i e En i e En i e En i e En i e Pa ial Pa ial O he epibio a Ul a sp. B yozoa spp. Ul a spp., B yozoa spp., B yozoa spp. B yozoa spp. Ul a spp. Hyd ozoa spp. Hyd ozoa spp. Hyd ozoa spp. B yozoa spp., B yozoa spp Ul a spp., Ul a spp., Ascidia spp. Bugula Bugula ne i ina, ne i ina,Ascidia spp. Ascidia spp. Pyu a chilensis THIEL ET AL.