Sur la disparition progressive de Laminaria digitata sur les côtes du Calvados (France)

Abstract

In comparison with results from 1983–1988, when a cartographic study was made on the distribution of the Laminariales and of Sargassum muticum in Lower Normandy (France), we note, on the Calvados coast, a regression of Laminaria digitata which has almost disappeared on the Grandcamp rocks. On the contrary, the growth of the populations of Sargassum muticum is very spectacular at Grandcamp; in summer, 80 % of the substratum in the lower parts of the intertidal zone and in the subtidal are covered by this species.