Validating Aging Structures in Asian Carp from the Lagrange Reach of the Illinois River and Known-Age Asian Carp from China [poster]

Silver carp (Hypophthalmichthys molitrix) and bighead carp (Hypophthalmichthys nobilis) have invaded much of the lower Mississippi River and its tributaries. Although fish age is routinely used to inform management decisions, aging structures for bighead and silver carp have not been validated against known-age fish to ensure accuracy and utility. We used known-age fish reared in Chinese aquaculture and collected from the LaGrange Reach of the Illinois River tracked annually from a strong 2014-year class to validate aging structures from bighead carp and silver carp. We removed vertebrae, lapillus otoliths, pectoral spines, and postcleithra from each individual. Each structure was sectioned and prepared accordingly. Annuli were counted and each annulus measured from the focus using Leica S8APO Stereoscope and measuring software to determine back-calculated growth. By using both field and aquaculture reared individuals, we are able to validate several Asian carp aging structures and determine the most reliable structure for age, back-calculated age, and growth estimates.