Biological variation in Eledone cirrhosa (Cephalopoda:Octopoda): simultaneous comparison of North Sea and Mediterranean populations

Reproductive maturity and morphometric characteristics were compared for two samples of the octopus Eledone cirrhosa from geographically widely separated sites, Aberdeen, Scotland (320) and Banyuls, France (285).At the two locations the collecting period was synchronized (13 months) and laboratory procedures standardized. In both samples the sex ratio was strongly biased to females, which were about twice the body size of the males. Both sexes were significantly larger in the northern population. Analysis of a limited selection of morphometric characters (mantle, arms, brain and body weight) showed significant differences, but these were insufficient to confirm any divergence in body shape between the two populations