Is stress in farmed salmon an important factor for Saprolegniosis?

Is stress in farmed salmon an important factor for Saprolegniosis?

Elanco logoMarine Harvest logoSupervisors:

Full time PhD student:

  • Max Beckmann

Fish displaying saprolegniosis symptomsSaprolegnia is a eukaryotic microorganism with an evolved pathogenic lifestyle and is endemic to all fresh water habitats around the world. Due to their filamentous hyphal structures oomycetes are often described as fungal-like microorganisms. Saprolegnia parasitica in particular causes devastating infections of fresh water fish leading to the disease called Saprolegniosis. Salmon farmers often report Saprolegnia infections during the fresh water phase after common practices such as grading of the pre-smolt stock.

The occurrence of Saprolegniosis after the vaccination against diseases such as Infectious Pancreatic Necrosis (IPN) and Furunculosis has in recent years caused huge economic losses due to Saprolegnia related deaths.

Symptoms of Saprolegniosis are reported by farm managers to appear approximately 8-12 days post vaccination if not treated preventatively.

I am investigating which impact stress has on the susceptibility of farmed salmon after the routine vaccination against viral and bacterial diseases of salmon pre-smolts as well as the prevalence of Saprolegnia species/strains around Scottish salmon farms.

We are aiming to distinguish between two key factors of the vaccination procedure which are;

  1. stress, due to the physical processing of the fish and
  2. the immune modulatory effect of the vaccine itself.

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