ABSTRACT
The production of pseudo-faeces in the natural environment is a function of the density of particles in the water. It varies over the course of a day in relation to tidal currents, although faeces are produced continuously. According to Heral et al, this biodeposition is the best indication of seston present in sea water. With the exception of species which are carnivorous, saprophytic or living symbiotically with algae or bacteria, most bivalves are microphagous and feed on particles which are deposited on the surface of the sea bed or in suspension in sea water. Most of the commercially important species of bivalve molluscs feed on plankton. Dissolved organic substances or lipid droplets may be absorbed directly by the epithelium of larvae or adults. Many studies have demonstrated the existence of active transfer in the mantle and the gills, while certain carbohydrates present in sea water stimulate the rate of pumping and particle retention.
