A guide to the interpretation of sea trout scales

Abstract

The overall purpose of this guide is to provide a manualfor the collection and interpretation of sea trout scales. Abrief introduction considers the advantages anddisadvantages of using scales to determine age and growth.To ensure that scales are interpreted in a consistentmanner, all major terms are defined and a standard systemfor age notation is proposed. The methodology for thecollection, mounting and interpretation of scales isdescribed in detail, and this is followed by a section on the back-calculation of lengths at different ages. Each topic is discussed critically. The final part of this guide is an atlas illustrating scales from a wide range of sea trout and including not only excellent "type-scales" but also difficult and impossible scales.