A large dataset on bacterial contamination of shellfish in France, 1989-2023: which taxons are most contaminated?

This study aims at comparing bacterial contamination level between shellfish species monitored as part of surveillance network in France. Using 35 years of monitoring data (1989-2023), we compared faecal indicator bacteria loads across taxa sampled simultaneously at the same sites. Analysis of 2428 taxon pairs revealed significant differences in faecal indicator bacteria concentrations between species, with burrowing bivalves (Cerastoderma edule, Ruditapes sp.) accumulating more bacteria than non-burrowing species. Contamination levels followed the gradient: C. edule = Ruditapes sp. > Mytilus sp. > Magallana gigas. These findings resolve inconsistencies in previous studies and provide robust evidence for the designation of sentinel species.