Final report
If abalone can be accurately aged, this would be a fundamental tool for more effective management of abalone fisheries. Several authors have proposed ageing abalone by grinding or cutting abalone shells, and counting the shell layers deposited beneath the spire. Other authors have cast doubt on this method. What is uncertain is how reliable these age estimates are. To construct useful models to assess and manage abalone stocks, it is important to know the accuracy of the data on which the model is based. Furthermore, it is labour intensive to collect age data, and if these data are very inaccurate, then resources are wasted in collecting it.
This project aimed to find out how reliable and accurate the ageing method was, by investigating the timing and the periodicity of layer formation in abalone shells. It seemed possible that the ageing method might work reasonably in some areas, but not in others. Thus we planned to repeat the work at many places in the hope that we could predict where ageing would be useful for managing the blacklip and greenlip abalone fisheries of Victoria, Tasmania, New South Wales and South Australia.