BIOGEOGRAPHICAL RELATIONSHIPS OF THE EEL PARASITE ANGUILLICOLA CRASSUS REVEALED BY RANDOM AMPLIFIED POLYMORPHIC DNA MARKERS (RAPDS)

The introduction and the rapid expansion of the nematode Anguillicola crassus in Europe in the early 80’s is one of the causes of the decrease of the European eel, Anguilla anguilla, populations. The aims of this work were to study, using RAPD markers, the genetic diversity and the population relationships between 16 populations of Anguillicola crassus originating from Europe (11 populations coming from the Mediterranean Sea or facing the Atlantic Ocean), Morocco, Japan (the original region of the parasite) and the USA (the most recently invaded place). Overall, 7 primers were useful and 32 reproducible bands showed polymorphism. Our results revealed a significant population differentiation between populations coming from the Mediterranean Sea and the other populations. We did not find a significant relationship between the genetic and the geographic distances suggesting multiple events of introduction. This was confirmed by the significant relationship found between the geographical distance and the dates of introduction. We also discuss the origin of the parasite in North America.