Evaluating age in Octopus vulgaris: estimation, validation and seasonal differences

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 441:141-149 (2011) - DOI: https://doi.org/10.3354/meps09399 Evaluating age in Octopus vulgaris: estimation, validation and seasonal differences Ester Canali1, Giovanna Ponte1,*, Paola Belcari2,3, Francisco Rocha4, Graziano Fiorito1 1Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy 2Dipartimento di Scienze dell’Uomo e dell’Ambiente, University of Pisa, 56126 Pisa, Italy 3London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, UK 4Department of Ecology and Animal Biology, University of Vigo, Campus of Lagoas-Marcosende, 36310 Vigo, Spain *Email: giovanna.ponte@szn.it ABSTRACT: Several internal structures have been used to estimate age in the cephalopod Octopus vulgaris, but with limited accuracy. We estimated age by investigating growth increments (rings) in the upper beaks of octopus collected between 2003 and 2010 in the Bay of Naples, Italy (Mediterranean Sea). To validate the daily periodicity of ring deposition, ‘thermal shock marking’ was for the first time applied to live octopuses fished between 2009 and 2010; this method produced a mark on the beak corresponding to the day of thermal shock, enabling us to elucidate the relationship between ring number and time elapsed (i.e. ~30 d). In addition, rings were counted in >700 preserved specimens of O. vulgaris collected between 2003 and 2009, also in the Bay of Naples. The estimated age of of these octopuses ranged from about 70 to 370 d. Specimens with similar body weights had different numbers of rings, confirming the view that body size is a not a good index of age. Additionally, the relationship between body weight and number of rings was affected by sex and season, with the distance between rings clearly correlated to seasonal temperature oscillations. Our data suggest that different cohorts of octopus exist in the Bay of Naples and that temperature has a strong influence on growth. Overall the results demonstrate that growth increments in the upper beak of O. vulgaris provide a reliable method of aging that can be applied to assessing differences in the growth patterns in wild populations, and one that provides a record of environmental influences upon an individual. KEY WORDS: Octopus · Age · Thermal marking · Upper beak · Seasonal variability Full text in pdf format PreviousNextCite this article as: Canali E, Ponte G, Belcari P, Rocha F, Fiorito G (2011) Evaluating age in Octopus vulgaris: estimation, validation and seasonal differences. Mar Ecol Prog Ser 441:141-149. https://doi.org/10.3354/meps09399 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 441. Online publication date: November 15, 2011 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2011 Inter-Research.