Age estimation is important in a management perspective, as it helps determine catch composition and stock demography. Different techniques are used for this, with the counting of growth layer groups in hard structures; teeth, ear plugs and baleen being the most widely used for marine mammals. In 2009, the Joint Scientific Working Group of the Canada and Greenland Joint Commission on Narwhal and Beluga and the NAMMCO Scientific Committee recommended that one or more workshops with the subject of obtaining standardized and accurate age estimates be convened by NAMMCO. This volume is the product of the review and two workshops resulting from this recommendation.

The workshops were held in 2011, and the first papers were published two years later, so this volume has indeed been a lengthy process. Despite this, we believe that the papers contained in this volume are still, and will continue to be, both relevant and useful for readers interested in age estimation techniques.

Enjoy!