We issued this advice in July 2022. With the very warm weather in June, we are re-issuing it now:
The very hot weather means some rivers and lakes are now very warm. Even though thunderstorms and heavy rain might lift the water level, water temperatures can remain high. High water temperature means low oxygen concentrations, which is bad news for fish and especially cold water fish like salmon, trout and grayling.
The issue of high water temperatures is exacerbated by poor water quality, especially organic pollution (sewage and slurry, for example) which can reduce oxygen levels.
Once the water temperature reaches 20 – 21C, our native brown trout start to struggle and even best practice catch and release can result in unintended mortality. Take the temperature of the water before you fish and if it is at or around 20C, it is better not to fish.
If you would like to know more about the effect of temperature on trout and salmon, click here.