Variation in distribution of Corbicula species (Mollusca, Bivalvia, Corbiculide) after 25 years in the Río de la Plata, Argentina

RESHAID, Y; CAO, L.; BREA, F.; ORTIZ BLANCHE, M.; TORRES, S; G.DARRIGRAN

ZOOLOGIA (CURITIBA)

SOC BRASILEIRA ZOOLOGIA

Año: 2017

1984-4670

In 1981, Corbicula fluminea (Müller, 1774) and C. largillierti (Philippi, 1844) were recorded at the Río de la PlataRiver. During the 1980?s, C. largillierti was found on a continuous fringe in the shore of that river, while C. fluminea was onlyfound North of Buenos Aires? harbor. Ten years later, C. fluminea spread to Punta Indio, while C. largillierti remained restrictedto tributary streams. The density and size frequency distribution of both species were compared with previous data fromsamples performed in the same area in 1985?1989. The aim of this research was to determine whether the densities of bothspecies decreased; whether C. fluminea is still more abundant than C. largillierti; and whether the size frequency distributionsindicate different population structures from those observed in the end of the 1980?s. Nine localities from the river shore weresampled, and each individual was identified and measured. The size of C. fluminea varied between 2 and 39 mm, showing thehighest frequency of individuals between 20 and 25 mm; furthermore the density decreased 90% in 2015/2016. No specimensof C. largillierti were found. In conclusion, the populations of Corbicula inhabiting the Río de la Plata River are retracting.