Evaluation of Three Techniques to Age Arctic Char from Alaskan and Canadian Waters

Publisher Website
Google Scholar
Abstract
Ages of fish from three stocks of North American Arctic char Salvelinus alpinus were estimated by examination of the external surface of otoliths, burnt otolith sections, and sectioned fin rays. Anal and pectoral fins showed the best definition of opaque and translucent zones and produced similar ages. However, age estimates for both fins varied extensively from and were generally lower than ages estimated from burnt otolith sections. Age estimates from both otolith techniques were similar up to about age 8, after which burnt otolith sections yielded greater ages. Maximum ages of Alaskan fish were lower than ages of Canadian stocks from Ekalluk River and Nauyuk Lake (13, 19, and 21 years, respectively). Estimates of von Bertalanffy growth parameters from the two otolith aging techniques were different for the three stocks. Maximum ages estimated for the Alaskan and Canadian fish were similar to those presented in past studies and appear related to what has been designated the western (Alaskan) and eastern (Canadian) forms of Arctic char. We recommened that Arctic char older than about 8 years be aged by the burnt otolith section technique; a true age validation experiment remains to be conducted.