Brussels: Prolonged drought and successive heat waves are rapidly drying up waterways and transforming aquatic ecosystems in southern France, with some fish species disappearing while others adapt to warmer conditions, Franceinfo reported Saturday. Rivers and streams across the Languedoc and Roussillon regions have experienced falling water levels, sharply reduced flows, and rising temperatures over the past two months.

According to Anadolu Agency, the French Office for Biodiversity's Onde monitoring network reported that 16% of rivers nationwide were dry by the end of June, with another 10% having "invisible" flows. The proportion of dried-up waterways reached a record 22% in the southern Aude department. Mediterranean departments have been particularly affected, with 10% to 20% of waterways drying up during summer, compared with a nationwide average of 5% to 10%.

Adrien Arazo, director of the Aude Fishing Federation, expressed concern over the drying up of certain waterways during this time of year, noting that two months of summer remain. Critical conditions have been recorded in the Montagne Noire and Corbieres areas, particularly in the upper Aude Valley.

Despite heavy winter rainfall, an unusually dry and hot spring followed by an early, prolonged heat wave caused smaller waterways to lose water more rapidly through increased evaporation. The report noted that cold-water species, such as brown trout and common bullhead, are expected to decline as water temperatures rise, while species like chub, barbel, gudgeon, and invasive American crayfish could benefit from the changing conditions.

The French Office for Biodiversity highlighted that naturally low water levels are often worsened by human activities, including irrigation and drinking water withdrawals. Authorities have imposed varying water-use restrictions based on watershed conditions, groundwater levels, and weather forecasts. Arazo warned that rivers already suffering from low flows and reduced oxygen levels faced an increasing risk of drying up, posing a real risk to aquatic biodiversity.

Ecological Transition Minister Monique Barbut announced that water restrictions are in effect across all 99 departments of metropolitan France as an "exceptional" and "very worrying" drought grips the country. A total of 206 prefectural orders restricting water use have been issued, marking the highest number recorded since at least 2013.