Age estimation of invasive silver carp (Hypophthalmichthys molitrix) from the Illinois River, Illinois in 2018 using seven calcified structures and multiple readers

Accurate age data is essential for modeling fish population dynamics and informing management decisions. Estimating age in cyprinid fishes like the invasive silver carp is challenging. During this study we evaluated precision and bias in age estimates of silver carp collected from the Illinois River, Illinois using seven structures: the first and second section of the ossified pectoral fin ray, the first section of the ossified dorsal fin ray, the postcleithrum, whole vertebrae, sectioned vertebrae, and lapilli otoliths. In 2018, we convened a workshop of 12 scientists to provide age estimates, identify challenges, and provide recommendations for standard methods in preparation, age estimation and to identify knowledge gaps. An additional 241 fish were aged by 3 of the experts using the dorsal spine and lapilli otolith to validate standard methods provide additional data for evaluating precision and bias in aging estimation.