The European Register of Marine Species (ERMS) is an authoritative taxonomic list of species occurring in the European marine environment, defined as up to the strandline or splash zone above the high tide mark and down to 0.5 (psu, ppt) salinity in estuaries. The register is actively maintained and daily updated in the framework of the MarBEF EU Network of Excellence by a board of taxonomic editors, which are world experts on the taxonomy of their relevant taxa. It is anticipated that the Register will become a standard reference (and technological tool) for marine biodiversity training, research and management in Europe. ERMS is served from a relational database. The most recent version of the data will always be available through this search interface. At regular intervals, a snapshot of the database will be archived; these archive copies will be kept available through the ERMS web site.