Rapid assessment of non-indigenous species in the era of the eDNA barcoding: A Mediterranean case study

International audienceWith only a narrow opening through the Gibraltar and Suez Canals, the Mediterranean Sea is one of thelargest semi-enclosed seas. The marine flora and fauna are some of the richest in the world, relative to itssize, particularly in the coastal habitats, which are also characterized by numerous endemic speciesalthough the introduction of non-indigenous species threatens its rich and unique biodiversity. Followingthe opening of the Suez Canal, and in combination with shipping and aquaculture activities, nonindigenousspecies (NIS) introduction has had measurable impacts on the Mediterranean. Lagoon ecosystemsalong the French coastline, with approx. 100 NIS identified, are considered hot-spot areas forthese species. Rapid assessment sampling for sessile benthic species together with DNA barcoding is arapid, easy and cheap method to detect non-indigenous species. Two nearby and different ecosystemswere sampled for invertebrate species: Saint-Nazaire lagoon, a Special Protection Area within the Natura2000 Network and Canet port, a marina in a small village. The DNA barcoding tool for species identificationwas used for confirming the taxonomy. This showed that, despite the Saint-Nazaire Lagoonclassification within the Natura 2000 network, it is already contaminated with a single NIS that wasfound in high densities and is clearly beginning to dominate the system. It is proposed that a rapidassessment of the sampled environment and the DNA barcode approach are efficient and can providesufficient information on the new target species to be used in conservation planning and ongoingmanagement efforts