This dataset is based on the MSFD marine regions and sub-regions dataset. As indicated in the abstract, it has been defined as the marine waters surrounding the EU countries whose outer limit is defined by the 200 NM boundary from the coast (possibly coinciding with formally recognised EEZ boundaries) or the equidistance (in cases of opposite neighbouring EU countries), or by the presence of a boundary defined by an agreed treaty. Given no formal boundary of this map exists and since this limit coincides with the boundary of the maritime area (water column) submitted by EU Member States under MSFD, this dataset was based on a MSFD Region/Subregion boundary shapefile assembled in 2020 by ETC/ICM and harmonised with the Coastline and European seas layers. The derived dataset includes following EU MSFD regions/subregions:

• Adriatic Sea.

• Aegean-Levantine Sea.

• Baltic Sea.

• Bay of Biscay and the Iberian Coast.

• Black Sea.

• Celtic Seas.

• Greater North Sea, incl. the Kattegat and the English Channel.

• Ionian Sea and the Central Mediterranean Sea.

• Macaronesia.

• Western Mediterranean Sea.

The topological errors (gaps & overlaps) have been removed from the dataset.