Timing of First Annulus Formation in White Sucker Otoliths

The purpose of this study was to document the time of formation for the first two otolith annuli for White Sucker Catostomus commersoni. Young-of-the-year and age-1 individuals were sampled monthly from a population in the White River drainage of the Missouri Ozarks. The formation of a single annual opaque region during the months of June-September of the first 2 years of life was documented using edge analysis, whereby the progression of otolith annulus formation is followed throughout the year in the population. The documentation that the first annulus was formed within the first 6 months following birth provides for more accurate and precise age estimations than previously available for this species