A psychrophilic bacterium, designated strain HJ039(T), was isolated from a marine sponge collected in the East Sea of Korea (also known as the Sea of Japan). Cells were Gram-negative, motile and rod-shaped (1.8-3.54 microm x 0.27-0.73 microm). Growth was observed between 5 and 26 degrees C (optimum 15 degrees C), at pH 5.0-8.5 (optimum pH 6.0-6.5) and in the presence of 0-6.0 % NaCl (optimum 2.0 %). The 16S rRNA gene sequence of strain HJ039(T) showed high levels of similarity (93.7-95.4 %) with members of the genus Shewanella, especially with Shewanella gaetbuli TF-27(T) (95.2 %), Shewanella decolorationis S12(T) (94.9 %), Shewanella putrefaciens LMG 26268(T) (94.6 %), Shewanella hafniensis P010(T) (94.6 %), Shewanella algae ATCC 51192(T) (94.5 %) and Shewanella kaireitica c931(T) (94.5 %). However, phylogenetic analysis revealed that strain HJ039(T) shared a phyletic line with S. algae and Shewanella amazonensis. The major respiratory quinone was Q-8. The DNA G+C content was 52.8 mol%. The major fatty acids were i-13 : 0 (8.5 %), 15 : 0 (4.2 %), i-15 : 0 (23.2 %), i-15 : 1 (7.9 %), 16 : 0 (8.7 %), 16 : 1omega7 (21.0 %) and 17 : 1omega8 (6.4 %). From this polyphasic taxonomic evidence, strain HJ039(T) is considered to represent a novel species of the genus Shewanella, for which the name Shewanella spongiae sp. nov. is proposed. The type strain is HJ039(T) (=KCCM 42304(T)=JCM 13830(T)).