DISTRIBUTIONAND PREVALENCEOF 15SPECIESOF EPIBIONT PERITRICHCILIA TESONTHECRAYFISH CAMBARELLUS PATZCUARENSIS VILLALOBOS,1943 IN LAKEPÁTZCUARO, MICHOACÁN, MEXICO

BY

ROSAURA MAYÉN-ESTRADA 1/ andMA. ANTONIETAALADRO-LUBEL Laboratoriode Protozoología, Departamento de Biología, Facultad de Ciencias, UNAM, Ap.Postal 70-374, C.P .04510,Mexico, D.F .,Mexico

ABSTRACT

Thegoal of the present study was to know the distribution and prevalence of ciliated Protozoa attachedto the exoskeleton and gills of thecrayŽ sh, Cambarelluspatzcuarensis .Samplesof crayŽ sh weretaken at twosites in Pá tzcuaro Lake, Michoacá n, Mexico.Fifteen species of ciliatedProtozoa (peritrichs)were found attached as epibiontson the crayŽ sh. Their distribution and prevalence on 14 bodyparts of the basibiont is presented.Community structures were analysed using Jaccard’ s index andprincipal component analysis. The results showed that the gills had no similaritywith respect tothe other body parts as regards peritrich attachment. The pereiopods and the uropods were the bodyparts with the highest species richness, the gills had the lowest. Cothurniavariabilis is the only specieswith a highdegree of speciŽcity to the body region to which it isattached(gills). Of the 15 speciesfound, only one has been reported exclusively as an epibionton crustaceans.

RESUMEN

El objetivodel presente trabajo fue conocer la distribució n yfrecuenciade especies de proto- zoariosciliados adheridos al exoesqueleto y branquiasdel acocil Cambarelluspatzcuarensis . Las muestrasde crustá ceos fueron recolectadas en dos sitios del lago de Pá tzcuaro, Michoacá n, Mé x- ico.Se presentala distribución yfrecuenciade 15 especiesde protozoarios ciliados (peritricos) en 14regionesdel cuerpo del basibionte. La estructura de lascomunidades fue analizada utilizando el índicede similitudde Jaccard y elaná lisis de componentesprincipales. Los resultados muestran que lasbranquias no tuvieronninguna similitud con el resto de las regiones del cuerpo. Los pereió podos ylosuró podos mostraron una alta riqueza especí Ž ca,y lasbranquias la menor. Cothurniavariabilis fuela ú nicaespecie con un alto grado de especiŽ cidad respecto a laregió n delcuerpo donde se adhiere(branquias). De las 15 especies de ciliados, solamente una ha sidoregistrada exclusivamente comoepibionte de crustá ceos.

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c KoninklijkeBrill NV ,Leiden,2002 Crustaceana 74(11): 1213-1224 ° 1214 R.MAYÉN-ESTRADA &M.A.ALADRO-LUBEL

INTRODUCTION Crustaceans serve as hosts tosymbiotic, commensal,parasitic, andpathogenic representatives ofall major taxa ofthe Protozoa(Couch, 1983). The exoskeleton ofcrustaceans providessuitable organicsubstrates formany species ofepibiont ciliates, especially suctorians, chonotrichs,and peritrichs (Fenchel,1965; Morado &Small, 1995;Ferná ndez-Leborans & Tato-Porto,2000). Theimpact ofthe populationsor communities ofciliated Protozoaon their hosts has beenconsidered both without repercussion (Foster et al., 1978),or in relation with some damageto their hosts, like some impairment ofswimming efŽciency ofthe host(Henebry & Ridgeway,1979;Evans et al., 1979).The epibionts appearedto beinvolved in mortality ofpond-reared shrimps (Overstreet, 1973) orin reducingsubitaneous egg production and naupliar and adult survival,and, for heavilyinfested females, attachment ofthese ciliates mayblock the genital pore (Weissman et al., 1993).Lightner (1991) reported that the genera Zoothamnium , Epistylis, and Vorticella,whenabundant on the surface ofthe gills ofpenaeid shrimp,can cause hypoxiaand death. Thedecapod, Cambarelluspatzcuarensis Villalobos, 1943,an inhabitant ofthe bottomof Lake Pá tzcuaro, Michoacá n, Mexico, belongs to the family Cambaridae Hobbs,1942, subfamily Cambarellinae Laguarda,1961 (cf. Hobbs, 1988). This crayŽsh constitutes animportant link in the ecological websand it represents aconsiderablebiomass forŽ sh nutrition.Although several species ofciliated Protozoahave been reported attached to the surface ofthis decapod(Mayé n- Estrada &Aladro-Lubel,1998, 2000, 2001), the studies ofciliate epibionts of crayŽsh in wild conditionsare yet scarce (López-Ochoterena & Ochoa-Gasca, 1971;Matthes &Guhl,1973; Lahser, 1976). The goal of the present studywas to knowthe distribution andprevalence of 15species ofciliated Protozoa(peritrichs) attached to the exoskeletonand gills of Cambarelluspatzcuarensis .

MATERIALS AND METHODS ThecrayŽ sh werecollected at twosites in LakePá tzcuaro, Michoacá n, Mexico (19±320 to 19±410N 101±320 to 101±430W):Espíritu, located onthe eastern shore ofthe lake,and Jará cuaro on the western shore(Mayé n-Estrada & Aladro- Lubel,1998). Fourteen samples wereobtained during 1990-1992, and one in 1994,using a 5mm mesh net.One part ofeach sample was Žxedwith 5% formaldehydefor staining procedures,and with 1%glutaraldehyde for standard scanningelectron microscopy(Postek et al., 1980);the otherpart was maintained alive in the laboratory,in aquariawith oxygensupply. We examined 174 decapods, 109from Espí ritu and65 from Jará cuaro. Fourteen body parts wereconsidered: