Although the incident happened several months ago, the company has only been able to calculate the figure now, after harvesting and counting the remaining fish.
The escaped fish had an average weight of about 4kg, Norway’s Fisheries Directorate said in a press release.
Monitoring of rivers
The Directorate ordered environmental monitoring of 13 rivers in October following the escape on September 3 from the giant cage, which can hold a million fish and is moored off the coast of Frøya in Trøndelag, central Norway.
Initial investigations indicated that the structure tilted due to water coming in through a hatch in a tank system, a supportive part of a sliding bulkhead which was inside the cage. The closure had been opened for inspection the day before and left open by mistake.
A few metres of the net were up to 18cms under water for a short period of time, allowing fish to escape.
In accordance with procedures, a total of 1.2 kilometres of nets were placed on in the sea on the day of the incident, and the next morning 12 salmon were caught in these nets, something which SalMar said at the time underlined that only a small number of fish came out of the cage before the tilt was corrected.
Minimise the risk
“So far we’ve recaptured 69 salmon around the cage, which indicates that the incident had a limited effect, but we take this seriously,” said chief executive Olav-Andreas Ervik in September.
Speaking at the Seafood Days conference in the Norwegian village of Hell, Ervik said there had been good growth and low mortality, but that the company regretted the escape.
“When it first happens, it is important to learn a lesson from that, and make sure that we minimise the risk that something like that will happen again,” he said.
SalMar is taking a further step towards open sea farming with the “Smart Fish Farm” development concept with MariCulture AS, which SalMar has bought a controlling stake in.
The cage, which is designed to handle waves of up to 30 metres in the open sea, can accommodate three million salmon.