COMPARISON OF AGE-DETERMINATION TECHNIQUES FOR KNOWN-AGE CAPE FUR SEALS

Known-age teeth were used to validate age determination techniques for the Cape fur seal (Arctocephalus pusillus pusillus). Thin sectioning and staining of decalcified teeth produced the poorest age estimates. For etched half canines, only upper canines could be used to estimate age with good results, and coating improved the accuracy. Scanning ele ctron microscopy produced poor accuracy in age estimation. External ri dges reflected age accurately only in younger age classes and should o nly be used to verify counts of internal growth layer groups, or when rapid, preliminary estimates of age are necessary. This study has high lighted the importance of comparing different age determination techni ques and validating such techniques with known-age animals. The reliab ility with which age can be estimated for the Cape fur seal has also b een improved.