Age Determination of Sockeye (Oncorhynchus nerka) and Chum (O. keta) Salmon from Examination of Pectoral Fin Rays

Abstract

Ages of adult sockeye and chum salmon were estimated from examination of the second anterior pectoral fin ray, and were compared with estimates from their scales or otoliths. For sockeye, only the ocean age could be estimated. Freshwater annual rings could not be distinguished on their fin rays even though they were present on their scales or otoliths. In general, the three methods provided the same estimates of ocean age. Agreement of estimates of ocean age by one to five readers ranged from 78.9 to 98.8%. For chum salmon, the scale and fin ray methods generally provided the same estimates of total age. Agreement of estimates of total age by one or two readers ranged from 73.8 to 99.3%.