Validity of Otoliths and Pectoral Spines for Estimating Ages of Channel Catfish

Basal recess and articulating process sections of pectoral spines are often used to estimate the age of channel catfish Ictalurus punctatus. However, identification of annuli in pectoral spine sections can be difficult. We developed and validated a method for estimating the age of channel catfish by using sagittal otoliths. We also validated a new method using pectoral spines in which a single cut is made through the dorsal and anterior processes (hereafter termed cut spines) and annuli are enhanced with side illumination. Age estimates from otoliths and cut spines were compared with age estimates from traditional articulating process sections of pectoral spines for channel catfish of known ages (1–4). Age estimates by the three methods were correct for more than 90% of fish after two experienced readers independently estimated ages and resolved disagreements by mutual examination. Otoliths were more accurate and less variable in estimating age. Otolith age estimates were always within 1 year and, after mutual examination of the structures in question, 97% of the assigned ages agreed with known age. The accuracy of cut spines and articulating process sections after mutual examination was similar; however, the cut‐spine method was simpler than preparing articulating process sections. Otolith annuli were more distinguishable than pectoral spine annuli and were validated for age‐1–4 channel catfish. Therefore, we recommend using otoliths to estimate the age of channel catfish.