Hi Anastasiya,

You could read:

• Rodríguez-Domínguez, A., C. Rosas, I. Méndez-Loeza and U. Markaida. 2013. Validation of growth increments in stylets, beaks and lenses as ageing tools in Octopus maya. Journal of Experimental Marine Biology and Ecology. Vol. 449: 194-199. (available in ResearchGate).
• Cárdenas, E.R.B., S.M. Correa, R. Contreras Guzman, N. Barahona, F. Briceño, M.J. Villegas and R. Paredes. 2011. Eye Lens Structure of the Octopus Enteroctopus megalocyathus: Evidence of Growth. Journal of Shellfish Research. Vol. 30 (2): 199-204. (online free-available).

Good luck!

Alba

Good luck'

Franz

We tried validating growth increments from lenses of Octopus maya of known age as described in the paper above (Rodríguez-Domínguez, et al. 2013).  Preparation is costly and time consuming. Growth increments are regularly spaced and easy to see, but the perifery of the lens was often damaged by the slide and increments could not be easily counted there. We always counted much more growth increments than the actual life span of the octopus in days. We concluded they are not suitable for growth studies.

Hope you have better luck than us if you try...

Unai