Revealed: The main causes of death in Norwegian farmed salmon for 2023

Matthew Wilcox

What are the main causes of death in farmed salmon?

A groundbreaking report from the Norwegian Veterinary Institute, offers for the first time a detailed categorization of the leading causes of death among farmed salmon in Norway.

Major mortality events, involving the sudden deaths of millions of fish have become increasingly common in recent years. Last year in Norway, close to 17% of farmed salmon died suddenly.

In 2023, 62.8 million salmon died in the sea phase and 37.7 million salmon in the hatchery phase – a total of 100.5 million fish.

The report unveils that infectious diseases are the predominant cause of mortality, responsible for an estimated 38% of the deaths. This insight is a result of data contributed by farming companies via the AquaCloud industry initiative.

Extent of mortality crisis revealed: More than 100 million salmon died in Norway in 2023

“Infectious diseases are an extensive problem both for the fish’s welfare and survival in the sea. There is a lot of knowledge about how the risk of infection can be reduced and there is great potential for improvement. It requires the knowledge to be put to use and translated into action in the farming industry,” wrote the Norwegian Veterinary Institute’s Edgar Brun in the preface to the report.

Injuries, often resulting from trauma, account for about 33% of the fatalities.

The report specifies other causes of mortality: physiological factors are involved in 4.5% of the cases, environmental conditions in 2.9%, and various other reasons make up the remaining 2%.

Approximately 20% of the deaths remain attributed to unknown causes, highlighting gaps in current understanding and monitoring.


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