Six species have been described in the Aliivibrio genus, that was first described in 2007. Aliiv. salmonicida is pathogenic to fish, but other species are symbionts of marine organisms or isolated from seawater, often at low temperatures. A better knowledge of the psychrotrophic marine bacteria is badly required.

The aim of the study was to characterize bacteria that had been isolated from five species of fish and from seawater at low temperatures.

A total of 149 isolates and 15 reference type strains were subjected to AFLP. The 16S rRNA gene of 20 representative isolates were sequenced. Two strains, representative of two distinct Aliivibrio groups, were subjected to sequencing of five housekeeping loci. All strains were subjected to biochemical tests as well.

Using AFLP, sixty-six strains clustered in five distinct groups that each contained type strains of known Aliivibrio species, Aliiv. logei or Aliiv. wodanis, or a strain identified as Allivibrio sp. according to 16S rRNA gene sequencing. Two groups, A and B, consisted of 13 respective 25 isolates. Sequencing of five housekeeping genes of two representative strains of the two groups revealed that they belong to distinct species not yet described.