ISA outbreaks continue in Norway

Lerøy and SalMar are the latest producers to report suspicions of ISA, while cases appear to be spreading up and down the Norwegian Sea coast.
Aquaculture facility in Norway.

Aquaculture facility in Norway. The Norwegian Food Safety Authority continues to receive notifications of new cases of infectious salmon anaemia along the coast.

Photo: Norwegian Food Safety Authority (Mattilsynet).

Last week, WeAreAquaculture reported that Måsøval was the latest Norwegian salmon farmer affected by a suspected outbreak of infectious salmon anemia (ISA). One week later, ISA outbreaks continue in Norway and Lerøy and SalMar join this list that already included, in addition to Måsøval, others such as Sjøtroll Havbruk and Nordlaks Havbruk.

According to the Norwegian aquaculture monitoring site BarentsWatch, then there were 14 farming locations having suspected or confirmed cases of the disease, now this figure has increased to 19 and, a glance at the map (the purple dots, click on '"Gå til tjenesten" to see the full map) shows that the cases are spread all along the Norwegian Sea coast.

Lerøy and SalMar, the latest producers to report suspicions

Of the new cases reported to the Norwegian Food Safety Authority (Mattilsynet), the first was last May 28 when Lerøy Seafood - its subsidiary Lerøy Vest Sjø AS - reported findings compatible with ISA in fish at location 24735 Gulholmen, in the municipality of Bjørnafjorden, Vestland County. The suspicion was based on the results of analyses carried out after sampling fish at the site.

Two days later, on May 30, SalMar - its subsidiary SalMar Oppdrett AS - did the same for fish at the maritime site 10839 Store Kufjord in the municipality of Alta in Finnmark County. In its case, the suspicion was based on positive PCR samples and histological changes in samples taken in connection with the disease investigation.

As usual, the Norwegian Food Safety Authority announced the immediate inspection of the marine sites to take follow-up samples so that the Veterinary Institute can confirm the diagnosis.

Incidents that can be very costly for farming companies

The infectious salmon anaemia is a serious and contagious viral disease affecting salmonids, so pending confirmation and to prevent the spread of the infection, Mattilsynet has imposed restrictions on the affected sites. This restriction zone includes a protection zone and a monitoring zone, with limitations on traffic in the area surrounding the site, and a ban on moving fish without a special permit.

Mattilsynet may even order the site to be emptied if suspicions are confirmed, as, according to Norwegian regulations, when an ISA outbreak is confirmed, this is usually associated with the immediate harvesting or culling of affected fish.

These incidents can be very costly for the farming companies involved, disrupting harvesting plans and price achievement – harvestable fish are usually reclassified as 'production fish' -, as well as increasing operating costs for the affected sites.

It should be noted that, in the wake of Norway's 'production fish' crisis following the high mortality rates recorded last year, the Norwegian Food Safety Authority decided to carry out a series of high-profile audits in six of the country's largest aquaculture companies to oversight the welfare and health of their fish.

So far, the results of three companies have been published - you can see here the results of the audits of SalMar, Mowi, and Lerøy Seafood - and the common denominator for all of them is that Mattilsynet has found non-conformities, deviations, or points for improvement concerning biosecurity and fish welfare.

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