The oyster industries now require breeding programs to focus on quality and market appeal, to increase competitiveness alongside imported and alternative products.
This project will look for preliminary evidence of sensory variation between standard and selectively bred oysters sufficient to warrant further investigation. At least, it is necessary to ensure that selection within the oyster breeding programs does not diminish marketability characteristics.
Spawning and associated reduction in marketability is often at variance with demand for table oysters , and the possibility of selecting for lines with slower/faster maturation or which have an extended reproductive peak would provide growers with better control.
There have been suggestions that selected broodstock are more difficult to condition. This must be investigated to avoid what could become a serious future limitation of the breeding programs.
The Economic Weights Model developed in FRDC 2006/227 identified the time required to reach suitable shell size and the time required to reach a suitable market condition as traits under different genetic control. The model needs refinement by determining the relationship between the two traits. In order to accurately put economic weights on growth time and condition time it is important to measure this relationship for both Pacific and SRO.
Near Infra-red Spectroscopy (NIRS) offers the ability to perform a wide range of otherwise expensive biochemical measures of condition rapidly and cost efficiently.
Mortality is a serious, ongoing problem for Pacific oysters, particularly in SA and not confined to ASI stock. While the syndrome is undefined, there is evidence that susceptibility differs between ASI lines and that the difference is partly genetic (Ryan – unpublished; Pierre Boudry).
This project seeks to develop selection methods to enhance reproductive conditioning, marketability and survival and to develop oyster families which increasingly display these features.