Determining the age of sharks is difficult. A reliable independent method of validating age estimates is needed, apart from relying on tag return data. The success of radiometric analysis for bony fish overseas and in Australia suggested that it would be worth trying the method on sharks.

Four species were chosen for this study, school shark Galeorhinus galeus, white­spotted dogfish Squalus acanthias, and two deepwater sharks golden dogfish Centroscymnus crepidater and the southern dogfish Centrophorus uyato.

The project has been successful in fulfilling the objectives of the study, and importantly the method looks very promising to offer an alternate method of ageing and a validation tool. The results of this study point to further development of this method for sharks, including analysing vertebrae from tag-­return individuals which have been at liberty for many years.