Comparative Genomics Analysis of Isolated from Lumpfish () in Newfoundland Reveal Novel Chromosomal Organizations.

is a Gram-negative marine pathogen causative agent of vibriosis in a wide range of hosts, including invertebrates and teleosts. Lumpfish (), a native fish of the North Atlantic Ocean, is utilized as cleaner fish to control sea lice () infestations in the Atlantic salmon () aquaculture industry. is one of the most frequent bacterial pathogens affecting lumpfish. Here, we described the phenotype and genomic characteristics of strain J360 isolated from infected cultured lumpfish in Newfoundland, Canada. Koch's postulates determined in naïve lumpfish showed lethal acute vibriosis in lumpfish. The J360 genome was shown to be composed of two chromosomes and two plasmids with a total genome size of 4.56 Mb with 44.85% G + C content. Phylogenetic and comparative analyses showed that J360 is closely related to strain VIB43, isolated in Scotland, with a 99.8% genome identity. Differences in the genomic organization were identified and associated with insertion sequence elements (ISs). Additionally, J360 does not possess a pJM1-like plasmid, typically present in virulent isolates from the Pacific Ocean, suggesting that acquisition of this extrachromosomal element and the virulence of J360 or other Atlantic isolates could increase.