Parasite communities in three sympatric flounders (Pleuronectiformes: Paralichthyidae): similar ecological filters driving to repeatable assemblages

ALARCOS, A.J.; TIMI, J.T.

Viña del Mar

Simposio; VIII International Symposium on Fish Parasites; 2011

Universidad de Antofagasta, Chile

The relative role of host phylogeny and ecology on parasite community structure is analyzed in 3 sympatric paralichthyids, the carcinophagous Xystreuris rasile, and the piscivorous Paralichthys isosceles and P. patagonicus, from Argentina. Due to their relatedness, inherited ecological and physiological traits and shared past histories are expected to provide certain similarity to parasite assemblages. This is our null hypothesis to focus in the effect of measurable traits (size, age and diet) across fish species, with departures of a general pattern interpreted as consequence of ecological filters preventing homogeneous infections. The % of individuals/species that host-specific parasites contributed to each component community, as well as their effect on similarity of assemblages within/across host species, showed that they were unimportant contributors to abundance, richness and similarity, being irrelevant for the repeatability within component communities and across fish species as a phylogenetically related group. To minimize the effect of variables other than diet or trophic level only trophically-transmitted unspecific parasites were included in further analyses. After controlling for fish size, congeneric fish harboured assemblages significantly different from those found in X. rasile, but similar each other because of their shared high trophic levels. Assemblages with equivalent structure, harboured by fish with different age-size relationships, showed that these variables seem to act at dissimilar rates on different features of assemblages. Indeed, age affected mainly the parasite abundance, whereas body size influenced mostly species richness. Concluding, similar ecological filters produce analogous infections across host species driving to homogeneous parasite communities.