Background. This study was initiated by the first observations of a coastal and benthic Atlantic fish species—Parablennius pilicornis (Cuvier, 1829)on the southern coasts of France.This fish has been recorded in the Mediterranean Sea since 1963, until recently colonizing its entire western part as well as the Adriatic Italian coasts. The aim of this study is to analyse and understand the dynamics of this invasion of P. pilicornisand to report its most recent sightings along theProvencal coast, France. Materials and methods. The data on the geographic distribution of P. pilicornis were either extracted from the relevant literature (majority of records) or contributed by the present authors. For the French coast, particularly the coast of Provence, the latter were data from underwater visual censuses, conducted during various studies or monitoring programs. The data were critically selected, organised, and analysed. Results. Two dispersal pathways seem to have been followed by P. pilicornis. The first follows the coast of Morocco, Algeria, and Italy. The second pathway goes through the Spanish and French coasts. The meeting point of these two ways may be located on the coast of Provance, where we lastly observed this species in 2006. The emergence of P. pilicornis in the Mediterranean Sea corresponds clearly to a marginal dispersal. Colonization of the western Mediterranean took 43 years. Conclusion. Since P. pilicornis is already present on the Italian coast of the Adriatic Sea, the colonization of the eastern Mediterranean seems imminent.Global change, including rising temperatures, seem to be a factor promoting the repartition area of this fish with tropical affinities.

Atlantic migrant, marginal dispersal, fishes, Mediterranean, establishment, ringneck blenny,Blenniidae