French marine heatwave threatens coast ecosystems and fisheries

Record marine heatwaves across France’s Atlantic and Mediterranean coasts have caused a dramatic decline in marine biodiversity and put coastal fisheries at risk. Researchers from Ifremer described the event as the most severe since 1960, noting massive mortality of species such as red gorgonians, kelp forests, and the sea snail bulot. In the Bay of Granville, bulot catches have fallen about 80 % since 2017, endangering a fishery that supports 10,000‑20,000 jobs nationwide. Similar temperature spikes were recorded in the Mediterranean, with a June record of 24.34 °C.

In Le Croisic, scientists emphasized the ecological role of the sea‑weed line (laisse de mer) as a nutrient source for microorganisms and crustaceans, urging protective management to preserve these habitats against pollution and mechanical disturbance. The combined loss of habitat and increased temperatures threatens both marine life and the coastal economies that depend on them.