Evaluation of Removal and Sectioning Locations of Dorsal Spines and Pectoral Fin Rays for Estimating Age of Common Carp

Understanding age distributions and dynamic rate functions are critical components of effective management of fish populations.  As such, the accuracy and precision of rate function estimates depends on reliable estimates of fish age. Pectoral fin rays of common carp Cyprinus carpio have been previously compared to otolith (i.e., asteriscus) age—a validated structure.  Age estimates are commonly derived from both fin rays and dorsal spines of common carp, but dorsal spines have not been compared to otoliths.  In October 2012, common carp were sampled using electrofishing and experimental gill nets from Crane Creek Reservoir (n = 121) and Lake Lowell (n = 88) in southwestern Idaho.  We compared dorsal spines, pectoral fin rays, and otoliths to determine the efficacy of different structures for estimating age.  In addition, we evaluated the precision of age estimates from different sectioning locations of dorsal spines and pectoral fin rays.  We compared the precision and readability of age estimates from a location where structure removal from a live fish would occur and at 25, 50, and 75 percent of the total structure length.  This research will provide insight on the efficiency of dorsal fin spines and pectoral fin rays as non-lethal alternatives for obtaining age information from common carp.