This marine bacterium is a rod-shaped, unipolar-flagellated, Gram-negative, non-pigmented. It is aerobic and has an oxydative metabolism. This is an unvalid species. The taxonomic position of this bacterium is not clear. The phenotypic characteristics are very similar to the biochemical features reported for Vibrio agarlyticus (Cataldi, 1940). Based on the report of Vibrio agarlyticus as incertae sedis (Buchanan and Gibbons, 1974), and the fact that the strain GJ1B has not a fermentative metabolism and displays a G+C content below 50%, we have called it Alteromonas agarlyticus (Potin at al., 1993), Then Alteromonas agarilytica according the latin rules. Alteromonas agarilytica is deposed at the DSMZ collection number DSM 12513.