Genetic structure of Octopus vulgaris (Mollusca, Cephalopoda) from the Mediterranean Sea as revealed by a microsatellite locus

An investigation of the genetic variability of Octopus vulgaris, an intensively harvested species, was carried out using a mi crosatellite locus as genetic marker. Samples from one eastern At lantic and nine Mediterranean locations were analysed. In each population, the number of alleles at locus Ov06 varied from four to seven and was 21 overall. Observed and expected heterozy-gosity values ranged from 0.310 to 0.655 and 0.506 to 0.841, re spectively. Permutation tests and the positive average value of F IS showed significant departures from the Hardy-Weinberg equilibri um, due to a deficit of heterozygotes. F ST showed high levels of genetic divergence among the populations. Genetic distance val ues ranged from 0.0004 to 7.1520. Isolation-by-distance was not evident either by the Mantel test or multidimensional scaling. Mi crosatellite results are consistent with a previous allozyme study, and suggest that the common octopus does not form a single panmictic unit in the Mediterranean. From a fishery perspective, this information leads to the conclusion that the management of O. vulgaris should be planned on a local level.