[Genetic studies of relationship between Mediterranean and Atlantic populations of loggerhead turtle Caretta caretta with mitochondrial marker]. / Etude génétique des relations entre les populations méditerranéenne et atlantique d'une tortue marine (Caretta caretta) à l'aide d'un marqueur mitochondrial.

The loggerhead turtle Caretta caretta is an endangered species in the Mediterranean. Therefore, the definition of the Mediterranean population, and their relationships to the Atlantic population is of fundamental importance. For this purpose, we have sequenced a portion of the mitochondrial cytochrome b gene to generate genetic markers. Results indicate that the Mediterranean nesting female population is genetically isolated from the Atlantic nesting female population, but loggerhead turtles of Atlantic origin were found in the West Mediterranean basin. This entry of Atlantic loggerheads in the Mediterranean confirms earlier speculations and presents special conservation problems. The Spanish swordfish longline fishery which incidentally captures large numbers of loggerheads in the West Mediterranean basin has therefore an impact on the Atlantic population. These data demonstrate the international nature of marine turtle conservation.