Radiometric Fish Age Validation

Fish ages generated from counting growth rings of otoliths can be validated by measuring the ratio of lead (Pb-210) to radium (Ra-226) in the otolith core. Lead and radium are naturally occurring elements that become incorporated into the otolith structure. Over time the radium naturally decays to lead at a predicable rate, so the ratio of lead to radium trapped in the calcified structure of the otolith can provide an estimate of fish age. The AFSC Age and Growth Program has the capability to accurately measure lead and radium and has used this technique to validate ages from northern rockfish, Pacific ocean perch, rougheye rockfish, sablefish, shortraker rockfish, shortspine thornyhead, and walleye pollock.

Last updated by Alaska Fisheries Science Center on June 18, 2018