Precision of Three Structures for Saugeye Age Estimation

Abstract

AbstractWe evaluated the precision of age estimates obtained from sagittal otoliths, scales, and dorsal fin spines from 341 saugeyes (Walleye Sander vitreus × Sauger S. canadensis) collected from six Kansas reservoirs. Between‐reader agreement was greatest for otoliths, followed by dorsal spines and then scales. Coefficient of variation (CV) values for between‐reader comparisons were 1.3–3.1% for otoliths and 13.8–18.2% for dorsal spines. Between‐reader comparisons for scales were the most variable, with CV estimates between 19.9% and 23.1%. Age estimates from otoliths aligned with age estimates from scales more often than with estimates from dorsal spines, although age estimate comparisons between structures were generally variable. Between‐reader agreement for scales and dorsal spines decreased with increasing estimated age; however, agreement for otoliths generally remained high (i.e., >80%) through age 10. Given greater precision relative to other structures, we recommend the use of sectioned otoliths to estimate ages of saugeyes, especially when sacrificing the fish is not a concern.