Large and otherwise healthy fish are most prone the CMS. Photo: Trygve T Poppe.

CMS is a growing problem in salmon farming

A conference on cooperation for the exchange of knowledge about the viral diseases pancreas disease (PD), cardiomyopathy syndrome (CMS) and heart and skeletal muscle inflammation (HSMI), was held for the first time digitally at the end of April. As for the previous conference in Dublin 2019, one of the main features is that CMS, a severe heart disease that primarily affects large salmon, is increasing in importance.

The Trination conference was opened with an update from the three regions - Norway, Scotland and Ireland.

A common feature of the three areas is that CMS is increasing and leads to large biological and economic losses. Hilde Sindre, a senior fish health researcher with the Norwegian Veterinary Institute, stated that CMS is now one of the most serious viral diseases in Norwegian salmon farming (see figure). In addition to the fact that the number of outbreaks is increasing, the severity of the outbreaks is also increasing. They come earlier and the losses are bigger.

About the Trination

  • Established in 2005 to increase the knowledge base by jointly disseminating new results about PD
  • The agenda has now been extended to include CMS and HSMI
  • Meeting place for academia, fish farmers, suppliers of fish health-related products and services and authorities 
  • No participation fee at the meetings; the event is funded by sponsorship funds from public institutions and private companies
  • The next meeting is scheduled for Scotland (Edinburgh) in the spring of 2022
  • This year’s Trination conference was held for the first time as a digital conference on April 21 and 22. There was a record turnout of 260 participants.

Earlier outbreaks

Similar conditions were reported from Ireland. Fish vet Susie Mitchell emphasised the fact that they see outbreaks of fish earlier in the production, and that the disease is then more acute.

In contrast to CMS, very different experiences with HSMI were reported. In Scotland, there have been only two registered outbreaks since 2019 and in Ireland, clinical HSMI has been detected only once, in 2015, despite the presence of the PRV virus. In Norway, the disease is detected along the entire coast.

PD is present in all three areas, but there are different virus variants that are detected; mainly SAV1 in Ireland, but also SAV4 where average mortality showed a downward trend in the period 2013-2019. In Norway, SAV2 and SAV3 are detected in two different geographical areas. Hilde Sindre pointed out that in the Fish Health Report, PD is mentioned as the biggest reason for reduced growth.

Presentations from this year’s conference are available on the Trination website.