Guðjón Atli Auðunsson, Ph.D., Project Manager from Innovation Center Iceland presents analytical research on the age estimation of common minke whales in Icelandic waters.
The study discussed is a part of a wide ranging research programme on the biology and feeding ecology of minke whales in Icelandic waters.
Good estimates of age of animals is of great importance in all aspects of wildlife research as for example management of stocks, elucidating age structure, life-history, and catch-at-age history of populations. However, it has been found difficult to determine age of common minke whales from the North Atlantic (Balaenoptera acutorostrata) by way of either earplugs or bulla tympanica in contrast to Antarctic minke whale (B. bonaerenis) and fin whales (B. physalus) for which earplugs are routinely used for age estimation. Therefore, an alternative method is needed for the common minke whales from the North Atlantic. A method based on the racemization rate of L-aspartic acid enantiomer into its D-form in lens nuclei will be described. This method has been used for several marine mammals where age estimation of animals by growth layer groups (GLGs) has been compared with age estimation by way of “Aspartic Acid Racemization” (AAR) method in order to establish a sort of calibration for other marine mammals. However, it was at first evaluated for humans for this purpose. The relationships between age and racemization for humans and fin whales together with additional information on racemization ratios at zero age have been used to estimate age of several marine mammals, e.g. bowhead whales, North Atlantic minke whales, and narwhals (Monodon monoceros). Results from studies using this method to determine the racemization rate for Antartic minke whale and the Icelandic minke and fin whales will be discussed.