The aim is to create a comprehensive coverage of the species in the eastern Atlantic from 26°N to the North Pole, the Mid Atlantic Ridge and the Mediterranean and Baltic Seas. The database lists the species currently accepted as valid, its basionym, (the original reference where the specific name was introduced) and all synonyms and questionable synonyms known to the CLEMAM editor. Subsequent references to the species are not exhaustive; these include references to the species, using the valid name, or one of its synonyms or combinations, and misidentifications. Page references are given for all entries registered after 1995, and are being completed gradually for the initial batch, where only a statement of the name, author and date of publication were given.