Factors Determining Quality of Oxytetracycline Marks in Fingerling Walleye Otoliths
This study examined factors which can affect the quality of fluorescent oxytetracycline (OTC) marks on walleye (Stizostedion vitreum) otoliths. A 1 -time exposure to a strong ultraviolet (UV) light source, such as is done when viewing under a UV microscope, significantly decreased mean OTC mark qualities from an initial value of 2.8 (3.0 is maximum and 0.0 is no mark) to <1.0 3 months following the initial examination. Mark intensity continued to decrease over time (<0.5 after 6 months, 0.3 after 12 months). Otoliths that were stored in an unlit environment consistently had higher...
