INFLUENCE OF TIDAL ADVECTION ON THE LARVA L DISTRIBUTION OF POLYCHAETE ANNELIDS IN THE CHANNELS FROM ARCACHON BAY

This study shows the influence of tidal currents on the temporal chang es of a multispecific larval population of polychaete annelids from th ree stations located in the mouth of Arcachon Bay (southwest French At lantic coast). Plankton samples taken during several tides revealed th e existence of two larval contingents of different origins through the channels: one arises from the ocean, the latter originates from the i nner bay. Their density and diversity were estimated: the absence of f ollowing dispersion towards the ocean of larvae originating from the B ay was demonstrated. This work allowed to report for the first time th e presence of Microspio atlantica larvae in the inner bay.