Utility and Precision of Four Hard Structures Used to Estimate Age of Spotted, Shortnose, and Longnose Gars

In Illinois waterways, recreational angling for gars has become more popular in recent years; however, a fundamental understanding of population dynamics for effective management and conservation is lacking. Age data is essential for describing population dynamics, but few studies identify ideal hard structures for use in estimating gar ages. We collected Spotted, Shortnose, and Longnose Gars from five Illinois watersheds to assess the utility and precision of pectoral fin rays, branchiostegal rays, otoliths, and cleithra for age estimation. Pectoral fin rays generated the highest between-reader precision, followed by branchiostegal rays for all three species. Otoliths provided comparable between-reader precision to other hard structures for Spotted and Shortnose Gars, however, they produced significantly lower precision compared to pectoral fin rays and branchiostegal rays for Longnose Gars. Our results suggest pectoral fin rays are most useful for estimating ages of Spotted, Shortnose, and Longnose Gars because they are non-lethal, yield high between-reader precision, and show minimal age bias.