Vulnerability of microcrustaceans to predation by the invasive filter-feeding mussel Limnoperna fortunei (Dunker)

ROJAS MOLINA FLORENCIA; JOSÉ DE PAGGI SUSANA; BOLTOVSKOY DEMETRIO

Mar del Plata

Congreso; BIOLIEF 2011 2nd World Conference on Biological Invasions and Ecosystem Functioning; 2011

BIOLIEF 2011

Freshwater ecosystems worldwide are increasingly impaired by multiple stressors, among which invasion by exotic species is one of the most detrimental. Populations of introduced bivalves have increased dramatically and strong effects on native ecosystems have been documented. Limnoperna fortunei is an Asian mussel introduced in South America around 1990. One of the most important impacts of this successful invader is probably its grazing on the plankton. In the current study we evaluate the vulnerability of several planktonic microcrustaceans from the Paraná River floodplain to predation by adult L. fortunei. We conducted seven two-hour laboratory feeding experiments where the bivalves were offered zooplanktonic cladocerans and copepods differing in overall body shape, size and locomotive abilities. Ingestion and clearance rates for each taxon were estimated. Our results suggest that, in addition to detritus and phytoplankton, microcrustaceans are a potentially important food item for this invasive mollusc. Larger mussels can predate on organisms up to 1,100 μm in size. Differences in the suceptibility of various zooplankton organisms to bivalve grazing may lead to modifications in zooplanktonic size and species structure. L. fortunei is capable of consuming larger zooplankton than Dreissena polymorpha, the European and North American invasive mussel.