Summary

The continuation of an otherwise very successful 10 year breeding program to produce fast growing disease resistant Sydney rock oysters depends on whether we can overcome diseases that affect larval and juvenile oysters. The objective of this project has been to systematically overcome these diseases. The following five complimentary strategies have been adopted to do this:

1. Appraisal of all existing information including in-house hatchery records and reports of previous disease outbreaks.
2. Pathological examination of diseased larvae and spat as a means of identifying possible infective agents.
3. Experimental investigations of:

• possible causes
• factors suspected of decreasing or increasing the likelihood of disease outbreaks
• effectiveness of disease control and prevention practices.

1. Determination and adoption of optimal rearing conditions for larvae.
2. Use of probiotic agents to provide more favourable and stable environments within hatchery rearing systems. This strategy is currently being addressed in a 3 year collaborative project with the University of Technology, Sydney.