Open Access Repository

Assessing the validity of stylets as ageing tools in Octopus pallidus


Downloads per month over past year

Doubleday, ZA, Semmens, JM, Pecl, GT and Jackson, GD 2006 , 'Assessing the validity of stylets as ageing tools in Octopus pallidus' , Journal of Experimental Marine Biology and Ecology, vol. 338, no. 1 , pp. 35-42 , doi: 10.1016/j.jembe.2006.06.027.

[img] PDF
offprint.pdf | Request a copy
Full text restricted
Available under University of Tasmania Standard License.


A method to age octopus was determined through the quantification of growth increments within the stylet structure (highly
reduced internal shells). To validate the periodicity of the increments, stylets were analysed from known-age laboratory-raised
Octopus pallidus. The animals, which ranged from 3 to 8 months old, were exposed either to a simulated natural or to constant
temperature regime. Transverse stylet sections were embedded in thermo-plastic cement and ground until a thin section was
achieved. A pre-hatch region and first post-hatch increment was identified in the stylet microstructure. The number of increments,
across all ages and temperature treatments, was in remarkably close agreement to age (number of days), clearly demonstrating that
stylet increments are deposited daily throughout the lifecycle of O. pallidus. Morphometric analyses of the stylet indicated that
increments were laid down regularly during stylet growth and that stylets grew in concert with body size, further supporting daily
periodicity. This study successfully validates daily increments in stylets and thus demonstrate a method to age octopus, therefore,
potentially having critical implications for future octopus research and the effective management of stocks worldwide.

Item Type: Article
Authors/Creators:Doubleday, ZA and Semmens, JM and Pecl, GT and Jackson, GD
Keywords: Age validation; Cephalopod; Growth; Octopus; Octopus pallidus; Stylets
Journal or Publication Title: Journal of Experimental Marine Biology and Ecology
DOI / ID Number: 10.1016/j.jembe.2006.06.027
Additional Information:

The definitive version is available at

Item Statistics: View statistics for this item

Actions (login required)

Item Control Page Item Control Page