Reproductive cycle and sexual maturation of the musky octopus Eledone moschata (Cephalopoda: Octopodidae) in the northern and central Adriatic Sea

Length-weight relationships, sex ratio, maturity patterns, reproductive Outputs, fecundity and spawning period of the Musky octopus Eledone moschata (Lamarck, 1798) in the northern and central Adriatic Sea are presented for the first time. Samples were collected oil a monthly basis by commercial bottom trawls between October 2001 and June 2003. A total of 1552 specimens were analysed (779 males, 764 females, 9 undetermined). The overall sex ratio was close to 1: 1, but during summer males were dominant. Length-weight relationships calculated for each sex and the whole sample showed negative allometric growth (b<3). The allometric coefficient in maturing and mature individuals revealed isometric growth (b=3). The length at 50% maturity showed that males mature at smaller sizes than females. The mean total fecundity was 310 +/- 60, with a mean oocyte length and width of 9.39 +/- 1.99 mm and 2.57 +/- 0.72 mm respectively. The number of spermatophores ranged from 45 to 287 with a mean length of 17.71 +/- 3.27 mm. The maturity indices used to analyse the maturation process showed that the pattern of seasonal change had the lowest values in Summer for both sexes. The results indicate that in the Adriatic Sea E. moschata has an extended reproductive season that starts in autumn and ends in spring, with spawning peaks between January and April.