A Gram-negative, yellow-coloured, chemoheterotrophic, non-motile, strictly aerobic, rod-shaped bacterium, designated IMCC1914(T), was isolated from coastal surface seawater of the Yellow Sea, Korea. The temperature, pH and NaCl ranges for growth were 3-37 degrees C, pH 8.0-11.0 and 0.5-4.0 %. The DNA G+C content of the strain was 38.1 mol% and the major cellular fatty acids were iso-C(15 : 1) (32.1 %), iso-C(15 : 0) (20.6 %) and iso-C(17 : 0) 3-OH (7.8 %). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain IMCC1914(T) was related most closely to Gaetbulibacter saemankumensis SMK-12(T), with a sequence similarity of 96.2 %. On the basis of phylogenetic data and several distinct phenotypic characteristics, strain IMCC1914(T) (=KCCM 42380(T) =NBRC 102040(T)) could be assigned to the genus Gaetbulibacter as the type strain of a novel species, for which the name Gaetbulibacter marinus sp. nov. is proposed. In addition, an emended description of the genus Gaetbulibacter is presented.