Suivis stationnel et surfacique de l’herbier à Zostera noltei de la masse d’eau FRFT8 Bidassoa – 2013 - Bassin Hydrographique Adour-Garonne -

The new protocol, established by Auby et al. (2012) to the seagrass monitoring under the Water Framework Directive, was used in Txingudi bay (Hendaye, France). Based on 3 metrics ("taxonomy", "extension" and "density"), the quality index of the water body for the angiosperm indicator, was "medium", while it was in "good condition" in 2012. These results are explained by a sharp drop in the density observed on the monitoring station. The cartography of the species distribution showed a decrease of the total area of seagrass, particularly in the southern part of the mudflat. However, further north, small intertidal seagrass spots appeared. Atypical weather conditions in 2013 (cold, heavy spring rain) with silting of this area, could explain this situation.