Precision of Five Structures for Estimating Age of Common Carp

Abstract

AbstractOtoliths (asteriscus) have been validated as an accurate structure for estimating age of common carp Cyprinus carpio. However, extraction and processing of common carp otoliths are time consuming and require sacrifice of fish. Therefore, we analyzed age estimation precision of four alternative structures relative to otolith age for 139 common carp collected from five eastern South Dakota lakes. All common carp were collected using daytime electrofishing. Each fish was assigned an identification number and measured to the nearest millimeter total length, after which aging structures were removed. Age was estimated from scales, vertebrae, opercles, pectoral fin rays, and asteriscus otoliths by methods similar to those recommended by previous researchers. Relative to otolith age, average percent error was 6.8% for scales, 15.4% for vertebrae, 9.9% for opercles, and 1.2% for pectoral fin rays. Compared with all other structures, ages from pectoral fin ray sections were nearly as precise as otoliths through age 13 (lowest average percent error); however, fin rays consistently underestimated the ages of fish older than 13 years. In most cases, pectoral fin ray ages matched otolith ages, thereby providing similar age estimates. We conclude that pectoral fin rays provide a precise, economical, and nonlethal alternative for estimating common carp age structure. Accuracy of common carp ages estimated from pectoral fin rays still requires evaluation.