We evaluated the precision among age estimates obtained from sagittal otolith crosssections, whole-view sagittal otoliths, and scales from a sample of 95 walleye (Sander vitreus). Precision was evaluated by comparing age estimates between two readers, and the consistency of estimates from one reader among hard structures. Agreement between readers was greatest for otolith cross-sections (91.6%) compared to whole-view otoliths (52.6%), and scales (34.7%). Agreement between structures was greatest for whole-view otoliths and scales for reader one 34.7% and reader two 37.9%. Using scales and wholeview otoliths, both readers tended to under-estimate the age of older fish compared to age estimated with the otolith cross-sections. Agreement between age estimates made with scales and otolith cross-sections was 23.2% for reader one and 34.7% for reader two. Agreement between age estimates made with whole-view and otolith cross-sections was 32.6% for reader one and 37.9% for reader two. Due to the greatest precision in age estimates we recommend the use of cross-sectioned sagittal otoliths for estimating the age of walleye. If the sample is restricted to fish age-4 and younger and time efficiency is a priority, whole-view otoliths can be used to obtain precise age estimates.
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1 September 2018
Precision of Age Estimates Using Three Different Aging Methods for Walleye (Sander vitreus) in Cedar Bluff Reservoir, Kansas
Weston L. Fleming,
William J. Stark
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