EVALUATION OF THE DEGREE OF ORGANIC POLLU TION IN A MEGATIDAL ENVIRONMENT USING AN ANNELID POLLUTION INDEX

The effects of organic pollution have been estimated on the French coa st of the western Channel (Saint-Malo Bay) using specific biotic indic es and biological indicators. Although the environmental (megatidal) c onditions differ greatly from those in the Mediterranean Sea where thi s method was first employed, the results obtained have revealed a stru ctural imbalance between annelid communities on rocky and on soft bott oms. The areas in this region affected by organic discharges have also been delimited. Our evaluation shows that this method can usefully be extended to much wider fields than has so far been supposed.