Thirty years' progress in age determination of squid using statoliths

Abstract

The discovery thirty years ago of daily growth increments in squid statoliths and the development of statolith ageing techniques gave new insight into squid age, growth and metabolism. The techniques have shown that the majority of recent coleoid cephalopods live in the ‘fast lane’, growing rapidly and completing their life cycles in a year or less. Surprisingly, these useful approaches to the study of age and growth in squid have not gained much momentum. Only approximately an eighth of more than 300 squid species have had their basic age assessed and described. Two dozen species are subject to continuing arguments about which increments to consider as daily growth increments. This paper outlines major problems encountered during age determination of squid and suggests ways to improve the techniques and make them applicable to a wider spectrum of species.