French mussel production drops by 25% amid heatwaves

French mussel production has dropped by approximately 25% due to heatwaves and drought. Industry professionals report that rising temperatures and lack of rainfall have disrupted the nutritional balance for the shellfish. According to Fabrice Pernet, a researcher at Ifremer, warmer waters cause mussels to consume more energy, while decreased rainfall prevents essential nutrients from reaching the water, leading to a scarcity of phytoplankton.

In certain regions, the impact is even more severe. In the Bay of Saint-Brieuc, some producers have reported losses between 60% and 75% due to a combination of warming, ocean acidification, and massive sea spider attacks. Ocean acidification, caused by dissolved CO2, is making the water more corrosive, which complicates the growth of calcifying organisms like mussels and oysters. Producers note that mussels are becoming increasingly smaller, a trend observed over the last several years.