Abstract
Thin sections of fin rays were used to estimate the age of walleye pollock (T. chalcogramma), Pacific cod (G. macrocephalus) and albacore (T. alalunga). Because the number of methods of determining the age of fish is limited, it is advised that investigators develop a facility for the fin-ray method so that the best aging method for a stock of fish can be selected. Use of several methods also helps in estimating the accuracy of age determinations in the absence of a validation procedure that is applicable to all age-groups in a population.