Relations entre la nourriture disponible et la reproduction de mollusques en milieu estuarien : variabilité temporelle de la colonne d'eau

The study of the trophic relations needs to collect data which can best represent the variability of the populations of molluscan and the parameters of the water. For the water, the main parameters which play a role on the production of molluscan in an estuarine area are the temperature, the seston, and the phytoplanctonic biomass. For the temperature is proposed to sample only twice a month. At the contrary for seston variations which are very large on a tidal cycle and correlated with the currents and the waves, it is necessary to take in count this variability. For the phytoplancton, the annual cycle is well characterized, but the variability at a station is depending on the caracteristic of each water masses. The authors suggest that a sampling strategy in a tidal cycle is necessary to study trophic relations between plankton and benthos.