Long-term dynamics of three benthic Ampelisca (Crustacea-Amphipoda) populations from the Bay of Morlaix (western English Channel) related to their disappearance after the 'Amoco Cadiz' oil spill

Many studies have dealt with the effects of the 'Amoco Cadiz' wreck. In par ticular, they describe the influence of the oil spill on the benthic popula tions dynamics off northern Brittany coasts (western English Channel). Seve ral mechanisms have been proposed to explain how communities have recolonis ed the area during these last 20 yr. In this paper, we focus on the dynamic s of the Pierre Noire Ampelisca populations which constitute the dominant p art of the total fine sand Abra alba community. We propose a discrete popul ation dynamics model that takes into account the sea temperature, the amoun t of pollutant and competition. The model permits the simulation of long te rm changes in abundance for each of the more abundant Ampelisca species. It provides a tool for testing assumptions and for understanding the differen t processes occurring during recolonisation.