Blue-green algae, which may form a scum on the water, can produce toxins. Harmful Algae Blooms producing these toxins can kill wild animals, farm livestock and domestic pets; in humans, they can cause rashes after skin contact and illness if swallowed. Not all blue-green algae blooms and scums are toxic but you cannot tell which are/are not just by looking at them. It is therefore best to assume that they are harmful if swallowed and a skin rash may result from contact.
Canoeists, windsurfers and swimmers who have swum through algal scum or who have swallowed it have suffered from skin rashes, eye irritation, vomiting, diarrhoea and pains in muscles and joints. Illnesses can be severe, particularly where affected water has been swallowed. These, so far as we are aware, have not led to long-term effects or death but, in some cases, the illnesses were severe. Anglers are thought to be at lesser risk than the above as direct contact with the water is very limited but they must however take precautions.
Do not eat drink or smoke unless you have thoroughly cleaned your hands first
Although algal scum is not always harmful, avoid contact with it and the water close to it.
Use anti-bacterial wipes after contact with fish/water/nets and remember to take them home for disposal.
If it is windy any scum will accumulate on the shoreline – it is safest to fish with the wind over your back not facing the wind.
Make sure your nets are thoroughly clean and dry after use.
Essentially the more likely you are to come into direct contact the greater the risk of effects of exposure. Symptoms of those affected could easily be confused with a range of other illnesses so it is important to be aware of the risk of blue-green algae as a contributory factor. The basic principle to be born in mind is that anglers should understand the risks and best practices to minimise that risk. If anglers of sufficient maturity understand and accept the dangers involved and decide that they wish to continue to fish at their own risk, they may do so unless the water has been specifically closed to angling.