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Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)


Wildlife and Fisheries Science

First Advisor

David W. Willis


chromatography, walleye, oxtetracycline


Oxytetracycline (OTC) is used to chemically mark calcified structures in walleye Stizostedion vitreum fry and fingerlings. Current visual methods for detection of these marks are subjective, and biologists are unable to quantify the amount of OTC in a sample. The goal of this study was to determine if high pressure liquid chromatography (HPLC) is a feasible and superior alternative for detecting and quantifying OTC in otoliths of fry-marked and spines of fingerlingmarked walleyes. Study objectives were to validate methodology of extraction of OTC from calcified tissue, detect and quantify extracted OTC using HPLC, and determine a cost comparison of current visual detection methods and detection using HPLC. Walleye fry and fingerlings were marked with OTC at 700 ppm for 6 h. Methods that currently exist for extraction of OTC from edible tissue were assessed and modified to extract OTC from calcified tissue. Extraction and detection of OTC from otoliths of fry-marked walleyes using HPLC was largely unsuccessful. Visual methods of detecting OTC in walleye otoliths were found to be highly variable among viewers. Extraction and detection of OTC from fingerling-marked walleye dorsal spines using HPLC was 100% accurate. Visual detection rates of OTC in dorsal spines were variable and similar to those of other researchers. High pressure liquid chromatography detection was more expensive than visual methods, but fewer samples may be needed because of increased accuracy, which may reduce the cost of HPLC analysis. Costs needed to train viewers and purchase and maintain visual detection equipment were not included in this study, but should be considered when comparing methods.

Library of Congress Subject Headings

Walleye (Fish) -- Marking
High performance liquid chromatography


Includes bibliographical references (page 44-46)



Number of Pages



South Dakota State University


Copyright © 2002 Michael J. Hawkins. All rights reserved.