Comunidad de moluscos asociados al mejillón verde <i>Perna viridis</i> (Mollusca: Bivalvia) y sus relaciones tróficas en la costa norte de la Península de Araya, Estado Sucre, Venezuela

Abstract

Mollusc communities associated with the green mussel Perna viridis (Mollusca: Bivalvia) and their trophic relations on the north coast of Araya Peninsula, Sucre State, Venezuela. Perna viridis (Linné, 1758) is an Indo-Pacific bivalve of the intertidal zone that has invaded several ecosystems of the north coast of the Sucre State, Venezuela. Bimonthly samplings were carried out between October 1997 and August 1998 to study the mollusc communities associated with this species and their trophic relationships. Studies were conducted on a naturally-occuring bank of mussels two meters deep on the north coast of the peninsula of Araya (10°40’N - 48°63’W). Sample organisms were collected withing areas defined by a quadrat of 0.25 m2, and were identified to the species level using taxonomic keys that also included bibliographic identification of trophic level. A total of 1 235 individuals of P. viridis were collected, along with 3 163 specimens of associated species belonging to the phylum Mollusca, including bivalves, gastropods and polyplacophora. The associated mollusc organisms represented 50 species corresponding to 10 orders and 24 families, including 25 gastropod species, 22 bivalves and three polyplacophorans. With regard to trophic level 40% of the 50 species were suspensivores, 26% carnivores, 24% herbivores and the residual 10% represented two categories (suspensivore-detritivore, herbivore-suspensivore). Of the suspensivores the most common were: Perna perna, Musculus lateralis, Crassostrea rhizophorae and Ostrea equestris. The carnivore group was dominated by the three species of the Family Columbellidae, Mitrella lunata, Anachis obesa and Nitidella ocellata. The group of herbivores was dominated by two members of the family Fisurellidae, Diodora cayenensis and D. minuta. Two species of suspensivore-detritívore and three species of herbivore-suspensivore were also found in the genus Crepidula. The high percentage of suspensivores was thought indicative, inside this ecosystem, that there is probably a higher degree of nutritious fractions available to this group. Rev. Biol. Trop. 54 (Suppl. 3): 135-144. Epub 2007 Jan. 15.