Filtration rates of the invasive pest bivalve Limnoperna fortunei as a function of size and temperature
FRANCISCO SYLVESTER; JIMENA DORADO; DEMETRIO BOLTOVSKOY; ANGELA JUAREZ; DANIEL CATALDO
Año: 2005 vol. 534 p. 71 - 71
Clearance rates of Limnoperna fortunei (Bivalvia) were investigated in laboratory experiments using monocultures of the alga Chlorella vulgaris. Experimental conditions included two mollusc sizes (15 and 23 mm), and three water temperatures (15, 20 and 25 ºC) covering the normal seasonal range in the lower Paraná river and Río de la Plata estuary. Filtration rates obtained were, for the larger mussels: 9.9, 13.1 and 17.7 ml mg tissue dry weight-1 h-1 at 15, 20 and 25ºC, respectively; and for the smaller ones: 17.7, 20.8 and 29.5 ml mg-1 h-1. Differences between sizes and between temperatures (except 15 vs. 20ºC) were statistically significant. In absolute terms larger animals have higher clearance rates, but as a function of body mass smaller individuals feed more actively. Within the range of experimental values used, filtration rates were positively associated with water temperature. These clearance rates (125350 ml individual-1 h-1) are among the highest reported for suspension feeding bivalves, including the invasive species Dreissena polymorpha, D. bugensis and Corbicula fluminea. High filtration rates, associated with thevery high densities of this mollusc in the Paraná watershed (up to over 200,000 ind m2) suggest that its environmental impact may be swiftly changing ecological conditions in the areas colonized.