Benthic habitat mapping on the Basque continental shelf (SE Bay of Biscay) and its application to the European Marine Strategy Framework Directive

• Benthic habitat map of 2300 km2 of the Basque continental shelf was produced.
• Benthic habitats were classified according to the European Nature Information System (EUNIS).
• Thirteen new EUNIS types are proposed and described.
• Seafloor mapping is relevant information within the European Marine Strategy Framework Directive.

Benthic habitats on the Basque continental shelf were mapped based on multibeam echosounder surveys, grab sampling, video surveys and oceanographic monitoring. A total area of 2302 km2 was classified according to the European Nature Information System (EUNIS) hierarchical classification. Almost 50% of the area corresponded to rock and other hard substrata and the other 50% corresponded to soft bottoms. The biotic composition of several areas was significantly different from the EUNIS habitat classes described previously; therefore, we propose a total of 13 new classes. The habitat mapping has contributed to improving the knowledge and application of several criteria and indicators used to assess environmental status in the European Marine Strategy Framework Directive in relation to the biological diversity descriptors, such as non-indigenous species and seafloor integrity. It is also useful for other descriptors and for developing the sampling design.