SalMar opted to cull 1.4 million fry after mass mortality at hatchery
Fish were potentially compromised in suspected disinfectant poisoning that killed 574,000
Disinfectant residues are suspected of causing the deaths of nearly 574,000 salmon fry in a SalMar hatchery in Norway, an incident that has led to a decision to cull another 1.4 million fish.
The salmon farmer reported the incident to the Norwegian Food Safety Authority (Mattilsynet) on January 14, after significant mortality and gill problems were registered in several tanks at Salmar Settefisk’s recirculating aquaculture system (RAS) facility in Jøvika near Stonglandseidet, northern Norway, according to documents seen by news website Folkebladet.
On January 17, it was reported that 573,776 fry weighing 5-9 grams had died. The incident started in tanks 1-3 and later spread to tanks 6-10. In one of the tanks, 100% mortality was reported, with 162,140 dead fish.
Peracetic acid
The company suspects that residues of peracetic acid-based disinfectant in a pipe to a backup oxygen cone may have contaminated water supplied to tanks 1-3. According to the company, the pipe has now been flushed, and the risk should be removed. At the same time, it is stated that other possible causes are still being assessed.
“Our hypothesis is that residues from disinfectants are the reason we had this incident, and of course that is not something that should happen. To be precise, this is most likely disinfectants in the water after washing down in a department before the fish were moved in,” Anders J Fjellheim, SalMar’s executive vice president of farming, told LandbasedAQ Norway.
We have chosen to cull 1,400,000 fry due to an uncertain prognosis, to ensure fish welfare.
He said that the scope of the incident includes both mortality and culling of fry.
“We have had a mortality of approximately 573,000 fry. In addition, we have chosen to cull 1,400,000 fry due to an uncertain prognosis, to ensure fish welfare,” said Fjellheim.
Measures taken
A number of measures were implemented by the fish farming company to limit further losses.
“Among other things, we increased water exchange, increased oxygen levels and implemented several measures to optimise the water environment. At the same time, we started a broad causal analysis to rule out or confirm our hypotheses. This has been a large and comprehensive effort,” says the executive.
Will the incident affect further operations or deliveries from the facility?
“The consequence is that we have chosen to remove the fish group in its entirety. But this has no consequences for our stocking plan in 2026,” Fjellheim told LandbasedAQ.
Mattilsynet has requested a further explanation of the incident and updated mortality figures.
LandbasedAQ has contacted Mattilsynet for comments and will update the matter on an ongoing basis.