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Document Type

Research

Keywords

freshwater drum, otolith, aging methods, Mississippi River

Abstract

A comparative aging study was conducted using scales and otoliths from 123 freshwater drum collected in Pool 14 of the Mississippi River. Two independent readings by 2 investigators resulted in full agreement on ages assigned using otoliths, but only 64% agreement using the scale method. A final age was determined for the remaining scale samples based on the most commonly assigned age. However, there was no agreement on assigned ages for 12% of the scales examined. Otoliths were validated as an accurate method for aging freshwater drum by age frequency histograms for 3 consecutive years. The marked 3-year periodicity in appearance of strong year-classes allowed these strong year-classes to be followed through successive years of study providing a check on the reliability of this aging method. Scales were concluded to be only 61% reliable for aging freshwater drum. The observed trend indicated that assigned ages using scales were commonly overestimated for fish age 9 and younger and underestimated for older fish.

Publication Date

June 1984

Journal Title

Proceedings of the Iowa Academy of Science

Volume

91

Issue

2

First Page

49

Last Page

51

Copyright

© Copyright 1984 by the Iowa Academy of Science, Inc.

Language

EN

File Format

application/pdf

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