Some 47,000 salmon are estimated to have escaped from a farm owned by Alsaker Fjordbruk in southwestern Norway in February, reported the newspaper Bergens Tidende (BT).
The incident is the fifth escape of salmon reported from five separate farms so far this year.
The escape was reported in February but authorities have only now gotten a clear overview over the number of salmon that have escaped.
The cage affected held 103,000 farmed salmon, of an average weight of 2.2 kilos.
The farm is located in Alfjorden, between Stavanger and Bergen on the southwestern coast of Norway.
Alsaker experienced another escape only last week, said BT, this time from a site slightly further north, between Bomlo and Stord.
A representative at the company told the newspaper they had not identified the cause of the accident yet.