Authorities in Vendée and Finistère have imposed a ban on shellfish collection due to the harmful proliferation of the toxic algae Pseudo-nitzschia australis.

This toxic algae, which produces a severe amnesic toxin, is currently spreading along the coasts of Vendée and Finistère.

The ban comes just before a four-day period of spring tides, which typically attracts recreational shellfish harvesters.

These significant low tides, occurring from March 29 to April 1, 2025, are ideal for shellfish gathering, prompting authorities to issue warnings.

On March 27, 2025, the prefecture of Loire-Atlantique issued a decree prohibiting all shellfish fishing, collection, transportation, storage, and commercialization in the department.

This prohibition extends to certain zones in neighboring regions, including Baie de Bourgneuf and the west coast of Noirmoutier Island.

Environmental factors such as rising temperatures, sunlight, and agricultural runoff contribute to the seasonal bloom of these harmful microalgae.

Public authorities are urging recreational fishers to exercise caution and to consult the responsible shellfish gathering website for the latest information on prohibitions.

For details on the prohibitions and safety information regarding shellfish collection, the public is advised to check the website https://www.pecheapied-responsable.fr.

Symptoms from consuming contaminated shellfish can appear between 15 minutes and 48 hours post-consumption, and cooking does not eliminate the toxins.

Ingesting contaminated shellfish can lead to gastrointestinal symptoms followed by severe neurological disorders, including disorientation and memory loss.

The toxic algae has been monitored in France since 1998, with an increase in contamination instances following its identification in Canada in 1987, which resulted in hospitalizations and deaths.