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We 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. Betweenreader 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. RESULTSSectioned otoliths, scales, and sectioned dorsal spines were collected from 341 saugeyes varying in TL from 130 to 670 mm (Figure 1). Between-reader agreement was generally greatest for otoliths, followed by dorsal spines and scales (Figure 2). Agreement between readers varied from 96.2% to 98.0% for otoliths, and CVs for reader combinations were between 1.3% and 3.1%. No bias between readers was detected for otoliths for any age estimate combination. Agreement between readers for scale age estimates varied from 64.1% to 68.8%, and CV values ranged from 19.9% to 23.1%. Significant deviations in scale age estimates between readers occurred at young 32 KOCH ET AL.

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