Maximum age of the common octopus (Octopus vulgaris) in its natural habitat and stress marks by using beaks of spent individuals

Beaks have been used for ageing cephalopods, mainly in octopods where statoliths are not suitable for ageing. Recently it has been validated the daily deposition of beak increments in Octopus vulgaris (Cuvier, 1797) both, in the internal lateral wall surfaces (LWS) (Canali et al., 2011; Perales-Raya et al., under review) and also in the rostrum sagittal sections (RSS) (Perales-Raya et al., under review). LWS is more accurate for estimation of absolute age because RSS seem to underestimate the absolute ages due to tip erosion of the beak during feeding (Perales-Raya et al., 2010). However, RSS have recently shown in captive individuals the deposition of stress marks (checks) related to induced events such as capture, confinement, thermal changes and the handling during chemical marking (Perales-Raya et al., under review). This is the first study of beaks as life recorders of environmental stress in the wild