Predominant bacteria associated with black rockcod (Notothenia coriiceps, Richardson 1844) from King George Island, Antarctica

The present study isolated bacteria from black rockcod Notothenia coriiceps (Richardson, 1844) to determine if the relative proximity of salmon farms to natural habitats has resulted in the spread of known salmon pathogens. For this, bacteria were isolated from 60 N. coriiceps collected from seven sites along Fildes Bay, Antarctica (62°12'S, 58°57'W). Bacterial cultures were obtained from the kidney, liver, and spleen. The predominant bacterium of each culture was 16S rRNA gene sequenced, with 35 isolates obtained from 14 specimens. The predominant genera were Pseudomonas (9), Psychrobacter (7), and Staphylococcus (7), followed by Sporosarcina (4), and Bacillus (3). Notably, the Aliivibrio sp. (99.85% similarity with A. logei) and Chryseobacterium scophthalmus isolates were found and subsequently used to challenge rainbow trout (Oncorhynchus mykiss) and fine flounder (Paralichthys adspersus) species, which showed no clinical signs of disease nor death. Although kidney and skin lesion isolates were recovered (10 and 8 isolates, respectively), N. coriiceps challenges are needed to assess real infection risks. To our knowledge, this is the first description of these bacterial microorganisms from N. coriiceps.