The prolonged low levels and cold water earlier this year were ideal conditions for certain salmonid diseases to proliferate in rivers, especially fungal infections.
There have been sightings in the Wye, Usk and Severn of fish in distress, with the latest report from the Usk as late as 8th June.
The Environment Agency and Natural Resources Wales have issued advice to anglers and other river users on what to do if you witness fish in distress or behaving unnaturally. Examples of this could be fish lying in the shallows and not moving when approached or showing the visible signs of infection (usually white patches on their skin).
More information is also being gathered about a new disease in salmon called “Red Skin Disease”, the cause of which is unknown. The statutory authorities have also issued advice on what to do should you catch a salmon with the symptoms.