The authority, responsible for oversight of fish health and biosafety in Norway's aquaculture sector, identified several "recurring issues" across all audited companies.
SalMar is the first of Norway's big salmon firms to be audited in the wake of last year's fish mortality crisis - with "non-conformities" found in the company's management of fish health.
"We believe that improvement at the system level means improvement for as many animals as possible," said Bård Skjelstad, Director of Aquaculture at the Norwegian Food Safety Authority.