In 1995, the gulf of Morbihan was not showing on the whole a pronounced level of eutrophication, but has nonetheless three sites of green algae proliferation: the Auray river estuary, the branches of the Vannes and Séné estuary, as well as the outlet of the Noyalo's estuary. Only these last two sectors show algal developments that are "abnormal" and that can be linked to a specific phenomenon of eutrophication (Ulva green tide in the Rosvellec-Séné sector, Monostroma green tide in the Saint Armel-Tascon sector). In the spring of 1995, the observations made on the foreshores of the Gulf of Morbihan, excluding the islands, made it possible to estimate an algal biomass of between 2,000 and 6,000 tons. |