The objective of this project was to develop novel biological tags for penaeid prawns.  The impetus for this research was the growing interest in Australia in the potential for stock-enhancement of penaeid fisheries with hatchery reared juveniles.  In any stock- enhancement program some means of differentiating between introduced and wild prawns is needed to monitor the effectiveness of the program.  Many different types of tags have been used in fisheries, but none are suitable for penaeid reseeding.  For prawns, the tags would ideally be: able to mark individuals at all life history stages; unique to the local population; inexpensive and quick to apply and detect; either transmissible or non-transmissible to subsequent generations; and harmless to both the prawn and consumer (Rothlisberg and Preston 1992).  This project examined whether novel chemical and genetic tags could meet these criteria and hence provide a means of monitoring the success of prawn stock-enhancement programs.

The results of the study showed that novel chemical and genetic techniques could be effectively used to tag prawns.  Neither type of type of tag meet all the desired criteria but each would be well suited for different purposes in stock-enhancement trials.  Chemical element tags would provide a cost-effective means of monitoring the fate of small prawns during the first few weeks after their release in pilot-scale stock-enhancement trials.  If the pilot trials were successful, genetic tags could then be used in subsequent full-scale releases of permanently identified prawns. Genetic tags would also be required to monitor and maintain the genetic diversity of the enhanced populations.