Rapid assessment of non-indigenous species in the era of the eDNA barcoding: A Mediterranean case study
Abstract
With only a narrow opening through the Gibraltar and Suez Canals, the Mediterranean Sea is one of the
largest semi-enclosed seas. The marine flora and fauna are some of the richest in the world, relative to its
size, particularly in the coastal habitats, which are also characterized by numerous endemic species
although the introduction of non-indigenous species threatens its rich and unique biodiversity. Following
the opening of the Suez Canal, and in combination with shipping and aquaculture activities, nonindigenous
species (NIS) introduction has had measurable impacts on the Mediterranean. Lagoon ecosystems
along the French coastline, with approx. 100 NIS identified, are considered hot-spot areas for
these species. Rapid assessment sampling for sessile benthic species together with DNA barcoding is a
rapid, easy and cheap method to detect non-indigenous species. Two nearby and different ecosystems
were sampled for invertebrate species: Saint-Nazaire lagoon, a Special Protection Area within the Natura
2000 Network and Canet port, a marina in a small village. The DNA barcoding tool for species identification
was used for confirming the taxonomy. This showed that, despite the Saint-Nazaire Lagoon
classification within the Natura 2000 network, it is already contaminated with a single NIS that was
found in high densities and is clearly beginning to dominate the system. It is proposed that a rapid
assessment of the sampled environment and the DNA barcode approach are efficient and can provide
sufficient information on the new target species to be used in conservation planning and ongoing
management efforts.