Radiographs are used to age archaeologically recovered vertebrae of Pacific salmon (<i>Oncorhynchus</i> sp.). In application, the method provides an explanation for observed size variability in vertebrae from the site of Namu, on the central coast of British Columbia. The results also provide a means for assessing the species and seasonality of the Namu salmon fishery and demonstrate a consistency in fishing patterns during 4000 years of site occupation. -- AATA