Age Estimation And Growth Layer Patterns In Teeth Of Crabeater Seals: A Comparison Of Techniques

Age estimation of marine mammals provides important information about ecological and life history parameters. Counting growth layer groups (GLGs) in the dentine and cementum of teeth is the most common technique for age estimation in pinnipeds. In this study, we used acid-etched canines (n= 38) and decalcified stained postcanine sections (n= 40) to calibrate readings in mummified crabeater seals (Lobodon carcinophaga). A subsample of this group received a prior cleaning treatment of boiling the teeth with hydrogen peroxide (H2O2). Ages ranged from 0 to 31 years. Dentine from canines and cementum from postcanines showed higher estimated ages (maximum 31 years) than dentine from postcanines (maximum 24 years), mainly in those teeth that did not receive prior treatment. Boiling with H(2)O(2)has shown to affect cementum structure and, thus, results in underestimated ages, but dentine did not seem to be affected. The results presented here showed that ages can be estimated for the crabeater seal regardless of which tooth/tissue or method is used, at least for seals <13 years old. However, nontreated, stained thin sections of postcanine teeth are recommended because more reliable age estimations in older crabeater seals are obtained.