FILTRATION-RATE, USING A NEW INDIRECT TECHNIQUE, IN 13 SPECIES OF SUSPENSION-FEEDING BIVALVES

A method for determining filtration rates in undisturbed suspension-feeding bivalves is described. Concentrations of particulate matter in the water collected in the inhalant (Ci) and exhalant (Ce) currents were estimated with an electronic particle counter. The clearance was calculated as {Mathematical expression}, where Fl=flow rate through the tube collecting exhalant water. Only above critical levels of water flow (Fl) were clearances representative of filtration rates. At 10° to 13°C, the filtration rates (F, 1 h-1) within one or two orders of magnitude of dry weight (w, g), in Cardium echinatum L., C. edule L., Mytilus edulis L., Modiolus modiolus (L.) and Arctica islandica (L.) followed the allometric equations: 4.22 w0.62, 11.60 w0.70, 7.45 w0.66, 6.00 w0.75 and 5.55 w0.62, respectively. Five species of bivalves [Spisula subtruncata (da Costa), Hiatella striata (Fleuriau), Cultellus pellucidus (Pennant), Mya arenaria L. and Venerupis pullastra (Montagu)] filtered with the same rates as individuals of Cardium echinatum and A. islandica of equivalent soft weight. In Pecten furtivus and P. opercularis filtration rates were about twice the rates measured in individuals of Mytilus edulis of comparable body weight. The gill area in M. edulis increases with size at the same rate as the filtration rate. © 1979 Springer-Verlag.