Common diseases
Please report any sightings of diseased fish to SLRT and/or Fisheries Management Scotland.
There are a number of diseases that can impact wild salmonids, but the distribution and transfer of disease between fish is not fully understood. Therefore, it is important to report sightings of any potentially diseased fish to relevant fisheries organisations. In Scotland, three of the most common diseases are Red Vent Syndrome, Red Skin Disease and Saprolegnia. More information can be found below.
Red Skin Disease (RSD) presents as a red ‘rash’, bleeding and/or ulceration on the skin of Atlantic salmon. Damage can be found along the underside of the fish and can be seen most commonly on fresh-run salmon that are entering the freshwater environment.
Red Vent Syndrome (RVS) presents as an inflamed, swollen bleeding vent on fish. Fish that are most at risk are individuals that have spent at least one winter in the marine environment, with both sexes being affected. Few cases have been observed in sea trout, with the majority of affected individuals being wild Atlantic salmon. There have been no reported cases of RVS in farmed Atlantic salmon.
Saprolegnia is a naturally occurring fungal condition that affects both wild and farmed salmonids. It presents as a cotton wool-like coating on the body of the fish, that can progress into open lesions and skin infections.
