New insight into the genetic structure of an iconic species: the spiny lobster, Palinurus elephas

The spiny lobster, Palinurus elephas (Fabricius 1787) is both a key economic resource and a coastal marine species of conservation concern in the Mediterranean Sea, primarily due to overfishing. To enhance biological understanding and support the integration of fisheries management with conservation efforts, a genetic study was conducted on populations around Corsica (France, Mediterranean Sea). A total of 85 individuals were collected from five sampling sites around the island, in collaboration with local fishermen’s associations. These individuals were genotyped at 21 microsatellite loci. An additional 15 specimens from the Atlantic coast (Brittany, France) were included as an outgroup. Genetic analyses revealed low levels of differentiation among Corsican samples, with no evidence of geographic genetic structuring or isolation by distance around the island. Unexpectedly, the Atlantic population showed no pronounced genetic divergence from the Mediterranean populations. However, a significant overall deviation from panmixia was detected. Variation partitioning of redundancy analyses suggest that this pattern is likely driven by irregular annual recruitment events originating from multiple breeding aggregations, resulting in subtle genetic differentiation among locations and year classes.