The site, locality 45198 Purkholmen, is operated by SalMar Oppdrett AS for the production of Atlantic salmon.
The suspicion follows positive PCR test results from samples taken at the site, according to the Norwegian Food Safety Authority (Mattilsynet). SalMar notified the regulator of the suspected outbreak on 13 May.
Mattilsynet said it will secure additional samples for analysis by the Norwegian Veterinary Institute to confirm whether ISA is present.
Restrictions have been imposed on the site to limit the risk of disease spread, including a ban on moving fish without special permission.
If the diagnosis is confirmed, the regulator may order the site, or parts of the site, to be emptied.
Mattilsynet said a restriction zone would also be established if the outbreak is confirmed. Such zones typically include both protection and surveillance areas and may extend around 10–20 kilometres from affected sites, depending on local conditions including currents, site locations and distance between facilities.
The suspected case has been published on BarentsWatch’s interactive disease map.