Using Pectoral Spines and Otoliths for Estimating Ages of Channel Catfish and Effects on Estimating Population Parameters

Accurate and precise age estimates are required to correctly estimate fish population metrics such as age, growth, mortality, and recruitment. Channel catfish (Ictalurus punctatus) are commonly aged using the lapilli otolith or the articular process of the pectoral spine. Many fisheries managers prefer to use pectoral spines because the process does not require the sacrifice of the fish, but this method may produce biased age estimates. To com- pare precision of the two methods, we used pectoral spines and lapilli otoliths to age 649 channel catfish collected from five Oklahoma impoundments during 2018 to 2020. Additionally, we compared von Bertalanffy growth parameters and mortality estimates derived using our pectoral spine and otolith age estimates. Finally, we compared processing times for both structures. Agreement and precision between readers were higher with otoliths (percent agreement = 80%–82.6%; mean CV = 1.5%–4.4%; average percent error = 2.1%–9.3%) than with spines (percent agreement = 37%–50.5%; mean CV = 8.5%–15.1%; average percent error = 12%–21.3%). Reader-specific bias was not observed in otolith age estimates but was observed in spine age es- timates in fish ≥7 years old. Age-bias plots comparing consensus ages between structures indicated that using spines overestimated ages of younger fish but underestimated ages of fish age 6 and older. Due to low sample size in three of the five reservoirs, growth parameters and mortality were only cal- culated for Carl Blackwell and Meeker reservoirs. Disparities in aging precision between the two methods resulted in differences in estimates of growth parameters and mortality from Carl Blackwell but not Meeker. Further, processing spines was three times more labor intensive than processing otoliths. Our results indicate that use of spines produces imprecise age estimates for channel catfish and may result in biased growth estimates. However, managers may be able to use spines to estimate ages of channel catfish in short-lived populations where older fish are rare or nonexistent.

Publication date
Starting page
Ending page