État écologique des eaux littorales en 2015, selon la Directive Cadre sur l’eau

The Water Framework Directive (WFD) defines two types of coastal water bodies: coastal water bodies and transitional water bodies.

In 2015, 44% of 273 coastal water bodies are in good or very good ecological status (or potential): 51% of 179 coastal water bodies and 30% of 94 transitional water bodies. The share of coastal and transitional waters in moderate ecological status is respectively 36% and 27%.

Coastal water bodies in poor or bad ecological status account for approximately 22%. This concerns 12% of coastal water bodies and 42% of transitional water bodies. Only 1% of coastal waters and 2% of transitional waters are in unknown ecological status.

In 2015, more than one in two coastal water bodies (51%) and one in four transitional water bodies (30%) are in good or very good ecological status (potential). For all surface water bodies (11,414), across all water categories (rivers, lakes, lagoons, estuaries, and coastal seas), the share in good or very good ecological status is 44%.

Conversely, 12% of coastal water bodies and more than one-third of transitional water bodies (42%) are in poor to bad ecological status. The number of transitional water bodies in unknown status (insufficient information to assign a status) at the national level declined significantly between the last two state assessments (2013 status report and 2015 evaluation), dropping from 10% to 2%.

In 2015, the ecological status assessment presents a medium or high confidence level for 52.6% of surface water bodies, across all water categories (AFB).

• The Water Framework Directive recommends working at the level of "river basin districts." In total, 14 river basin districts are established in France: 9 in mainland and 5 for overseas, one per overseas department. In mainland France, only 6 districts have coastal exposure. • The ecological status (or potential) of water bodies varies from one district to another. In mainland France, the share of coastal waters in good or very good ecological status (potential) is generally higher than that of waters in poor or bad status. • In Adour-Garonne, 100% of coastal waters are in very good and good ecological status. In the Loire and Seine districts, the share of water bodies in this category remains high, with 72% of coastal water bodies in the Loire district and 63% in the Seine district. The share is lower in Continental Mediterranean (59%), Réunion (58%), Corsica (57%), and Mayotte (41%). • Nineteen coastal water bodies are in poor status. These are: • Côte de Nacre Est in Calvados (Seine district); • Petite rade de Marseille (Continental Mediterranean district); • five water bodies in the Loire district: fond de baie de Saint-Brieuc, baie de Douarnenez, baie de Douarnenez (coast), baie de concarneau, and Nord Sables-d'Olonne; • six water bodies in Martinique: baie de la Trinité, baie du Marin, littoral du François au Vauclin, fond ouest de la baie du Robert, baie du Galion, and Nord baie de Fort de France; • four water bodies in Guadeloupe: côte Ouest de Basse Terre, pointe du Vieux-Fort - Sainte-Marie, Petit Cul-de-Sac Marin, and Port Louis-Pointe Madame (Grand Cul de Sac marin); • two water bodies in the Mayotte archipelago: Mamoudzou – Dzaoudzi (Coastal) and Pamandzi – Ajangoua – Bandrélé (Coastal). • Two coastal water bodies are in bad status: one in the Escaut district (Gris Nez – Slack in Pas-de-Calais) and the other in the Loire district (baie de Lannion, in Brittany).

• For most districts, the situation of transitional water bodies is less favorable than that of coastal water bodies. Thus, the share of transitional water bodies in poor or bad ecological status is generally higher than that of water bodies in good or very good status, except for the Loire district where 60% of transitional water bodies are in good or very good status. • Twenty-nine transitional water bodies are in poor ecological status, namely: • baie de Somme (Escaut district); • étang d'Urbino and étang de Palu in Corsica; • estuaire de Seine aval; • eight estuaries in the Adour-Garonne district: estuaire Adour amont and aval, estuaire Bidassoa, estuaire Gironde aval and amont, Estuaire Fluvial Dordogne, and Estuaire Fluvial Garonne amont and aval; • rivières de pont-l'abbé and de Vannes (Loire district); • ten water bodies in the Mediterranean district: étang de Campignol in the Narbonnais lagoon complex, étangs Palavasiens east and west, Narbonnais Grazel/Mateille complex, Petite Camargue Medart, Grand Bagnas, Petite Camargue Marette, Petite Camargue Scamandre - Charnier, Camargue la Palissade, and étang de Berre Vaine; • five of nine water bodies in French Guiana: Sinnamary, Kourou, Cayenne, Mahury, and Maroni. • Furthermore, 10 transitional water bodies are in bad ecological status: • six water bodies in the Mediterranean district (Canet, Vendres, étang de l'Or, étang du Ponant, étang de Berre Grand Etang, and étang de Berre Bolmon); • one in Corsica (étang de Biguglia); • two in the Seine district (estuaire de Seine amont and moyen); one in Martinique (étang de Salines).

Water body classifications result from a multi-criteria analysis covering biological quality elements (phytoplankton, macroalgae, angiosperms...), physico-chemical (nutrients, oxygen, temperature...), and hydromorphological elements. The parameters monitored differ for coastal and transitional water bodies and are not monitored uniformly across all water bodies given local context.

For coastal water bodies, the relevant biological quality elements (BQE) to monitor are: phytoplankton, macroalgae (except for French Guiana), angiosperms (except for French Guiana and Réunion), and benthic invertebrates. Regarding transitional water bodies, the relevant BQE are: phytoplankton (except for French Guiana), macroalgae (only for North Sea, English Channel, and Atlantic water bodies), angiosperms (only for North Sea, English Channel, and Atlantic water bodies), macrophytes (only for Mediterranean water bodies), benthic invertebrates (except for French Guiana and Martinique), and fish (except for Martinique).

In 2015, when biological quality elements are documented, macroalgae and angiosperms are the main causes of coastal water body status classification as moderate, poor, or bad. For transitional waters, these are macrophytes, phytoplankton, macroalgae, and fish.

Among the physico-chemical parameters evaluated and documented, nitrogen and phosphorus are the main elements responsible for the degradation of transitional water body status. For nitrogen, this concerns 20 of 108 reported coastal water bodies and 14 of 41 reported transitional water bodies. 13 of 14 reported transitional water bodies are in moderate, poor, or bad status for phosphorus.

Ecological status of coastal water bodies in 2015

Ecological status of transitional water bodies in 2015

Authors: Service de l'Observation et des Statistiques (SDES), Agence française pour la biodiversité (AFB).