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Vol. 51 No. 6, 2012
Impacts of the Invading Golden Mussel Limnoperna fortunei on Zooplankton: A Mesocosm
Experiment
Florencia
Rojas Molina1,*, Susana José de Paggi1,2, and
Diego Frau1
1Instituto
Nacional de Limnología (INALI, Universidad Nacional del Litoral,
Consejo Nacional de Investigaciones Científicas y Técnicas), Ciudad
Universitaria, Paraje El Pozo S/N, Santa Fe 3000, Argentina
2Escuela
de Sanidad, Facultad de Bioquímica y Ciencias Biológicas, Universidad
Nacional del Litoral, Ciudad Universitaria, Paraje El Pozo S/N, Santa
Fe 3000, Argentina
Florencia Rojas Molina, Susana José de Paggi, and
Diego Frau (2012)
Invasive filter-feeding mussels and clams are well-known for profoundly
impacting the invaded systems. Many studies in South America
documented interactions 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 abundances and the species composition. We conducted
a 72-h experiment to assess the impacts of L. fortunei on the
composition and abundance of Paraná River floodplain zooplankton using
experimental mesocosms. Three treatments with 3 replicates each
were used in the experiment: control (without mussels) and 2 treatments
with mussels at different concentrations. Densities of the most
abundant genera of rotifers (Keratella)
and cladocerans (Bosmina and Diaphanosoma)
significantly declined in mollusc-containing mesocosms compared to the
control. Phytoplankton density was significantly lower in the
presence of the mollusc. Mesocosms with higher mollusc
concentrations had lower zooplankton densities than those with fewer
predators. Therefore, our results strongly suggest that L. fortunei
has negative impacts on this community, affecting the abundance and
composition of species, and the size structure. The ability of
the mussel to control the zooplankton can be explained by its direct
consumption or by competition for trophic resources.
Key words: Suspension-feeding bivalves,
Phytoplankton, Rotifera, Cladocera.
*Correspondence: Fax: 54-342-4511645.
E-mail:frojasmolina@inali.unl.edu.ar
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