Otolith reading as a tool for stock identification

Abstract A method is presented for using otolith readings to identify stocks, and a refined statistical analysis of age/length keys is proposed based on 95% probability ellipses of log-log plots. Three case studies are given: (1) an application for the identification of the red-mullet stock in the central Mediterranean; (2) an approach for the identification of stock units of anchovies in the Adriatic Sea; (3) an “ab contrario” proof of the validity of the approach on hake in the central Mediterranean. The final discussion deals mainly with the justification of methods used. Evidence of independent circulation of water masses as gathered from oceanographic mesoscale studies seems to parallel preliminary evidence of unit fish stocks from statistical treatment of age-length relations.