Healthy Fish are Productive Fish

In the fast-evolving world of aquaculture, fish health is central to both operational success and long-term sustainability. When animal welfare is the priority of farmers, profitability follows, however disease and stress from environmental changes create many ever-shifting challenges to pre-existing management strategies. Diseases, like Cardiomyopathy Syndrome (CMS), that are years away from developing market-ready vaccines, must rely solely on careful biosecurity and surveillance practices to reduce the impact of disease through early detection.

Cardiomyopathy Syndrome (CMS) is a viral disease primarily affecting Atlantic salmon during the seawater grow-out phase. While Scotland and Canada have placed strict biosecurity measures against CMS and have been fortunate to avoid major outbreaks, Norway continues to see CMS as a major contributor to harvest losses. This virus causes inflammation and degeneration of the heart muscle, leading to weakened cardiac function, increased vulnerability to secondary stressors, and, ultimately, elevated mortality — often in the critical final months before harvest.

Early detection of CMS has proven difficult, as clinical signs often emerge suddenly and at a stage where intervention options are limited. Consequences for producers are therefore significant: by the time CMS is visible to farmers, the damage is already done.

Routine structured health surveillance programs are proving essential. Detecting subclinical signs early gives producers critical time to adjust farm management strategies before major losses occur. This, combined with integrating health monitoring data and environmental parameters such as temperature, biomass density and oxygen levels, allows farms to spot patterns and predict elevated CMS risk periods. Prediction empowers producers to proactively adjust feeding regimes, handling schedules, and stocking densities to reduce stress.Farm teams that conduct scenario planning for potential health events are better prepared to respond quickly and effectively in the event of disease.

While good biosecurity, health management and surveillance should be standard procedure on farms to mitigate disease and allow for early detection, we should not stop there. Reservoirs of disease remain in areas with low CMS-related losses, resulting in trickling mortality and profitability losses, as well as potentially triggering an arms race between pre-existing management strategies and pathogen adaptation. Research on other preventative measures, such as vaccines or genetic breeding, should therefore remain an industry priority with prevention, rather than detection, as the end goal of collaborative research with industry partners, Onda believes producers fighting against CMS will see a brighter future.