Impacts of the Invading Golden Mussel Limnoperna fortunei on Zooplankton: a Mesocosm Experiment

ROJAS MOLINA FLORENCIA; JOSÉ DE PAGGI SUSANA; FRAU DIEGO

ZOOLOGICAL STUDIES

ACAD SINICA INST ZOOLOGY

Lugar: Taiwan; Año: 2012 vol. 51 p. 733 - 744

1021-5506

Invasive filter feeding mussels and clams have long been known for their profound impact on the invaded systems.  Many studies in South America have documented the interaction of the Asian mussel Limnoperna fortunei with several components of the local biota.  However, few experiments have examined in detail the effect of the mussels on zooplankton abundance and species composition.  We conducted a 72-hour experiment to assess the impact of L. fortunei on the composition and abundance of the Paraná River floodplain zooplankton using experimental mesocosms.  Three treatments with three replicates each were used in the experiment: control (without mussels) and two treatments with mussels in different concentrations.  The density of the most abundant genera of rotifers (Keratella) and cladocerans (Bosmina and Diaphanosoma) declined significantly in mollusc mesocosms compared with control.  Phytoplankton density was significantly lower in presence of the mollusc.  Mesocosms with higher mollusc concentration had lower zooplankton density than those with fewer predators.  Therefore, our results strongly suggest that Limnoperna fortunei has a negative impact on this community, affecting the abundance, composition of species and size structure.  The ability of the mussel to control the zooplankton could be explained by direct consumption or by the competition for trophic resources.