Rigney pond experiences massive fish kill due to heatwave

In Rigney, Doubs, more than two tonnes of fish have died in the local pond due to extreme drought and heatwaves. The mass mortality includes various species such as catfish, carp, pike, and perch.

Local authorities reported that the water level in the second pond dropped by more than one meter, leading to a critical reduction in dissolved oxygen. Mayor Nathalie Concet has issued a municipal decree prohibiting fishing to allow the remaining aquatic population to stabilize. The local mayor described the situation as "catastrophic" and "unprecedented."

Scientific analysis indicates that such summer fish kills are often driven by the physical principle of decreased oxygen solubility: as water temperature rises, its capacity to hold dissolved oxygen decreases. This phenomenon is a growing global trend, with studies suggesting that nearly 80% of analyzed river systems have lost dissolved oxygen over the last four decades.