A holiday hotspot in France has lost up to 95% of its visitors following a bacterial outbreak. The Pont-L'Évêque lake in Normandy, about 15km from the English Channel, has been closed to swimmers since July 18 due to cyanobacteria, which can cause skin and digestive issues in humans, and pose a danger to animals.

On warm summer days, the lake in Calvados used to welcome around 1,500 people, but the number has plummeted to about 50, according to Romain Hamon, president of Mab Expérience, which operates the lake's leisure and catering facilities. He deemed it a "catastrophic season" in which they had lost 90% to 95% of visitors after tests showed the presence of cyanobacteria.

Paddleboarding and tubing have also been banned, as well as its floating inflatable course, which was a "driving force" for the leisure centre, according to Stéphanie Legendre, deputy managing director of the local public company, Terre d'Auge Attractivité.

Mr Hamon told LeParisien: "People are no longer staying put, and other activities have not made up for it." 

Its campsite with 240 pitches was holding up well, but it now needs to look at different avenues to keep the area afloat, such as walking, mini-golf, and marketing it as a relaxation spot. Activities such as canoeing remain.

Mr Hamon told LeParisien that he can only recall one occurrence at Pont-L'Évêque that lasted two days in 2022, but they had witnessed the phenomenon emerge over the last ten years, and even more so recently.

Cyanobacteria thrive in summer and early autumn, feeding on heat, nutrients, and calm waters, making lakes the perfect home.

It is boosted by sunlight and global warming, and at the end of August, readings were reportedly rising slightly in the 60-hectare lake.

The problem is that, to date, there are no large-scale solutions to prevent or combat this bacteria, informally known as blue green algae. The only effective products have been developed on a tiny scale for aquariums.

Cyanobacteria has taken over many lakes in the region close to the sea. Last month, decrees were issued for other lakes in Normandy alone: Lac de Brionne (Eure), Lac de Caniel (Seine-Maritime), and Lac de la Ferté-Macé (Orne).

The same happened at La Dathée, near Vire (Calvados), first because of cyanobacteria, then because of excessive surface pH levels.