2012/714 Use of next generation DNA technologies for revealing the genetic impact of fisheries restocking and ranching

By Jonathan Sandoval-Castillo, Nick Robinson, Lachlan Strain, Anthony Hart and Luciano Beheregaray

Several initiatives by the Australian Seafood CRC’s Future Harvest theme involve some form of stocking or enhancement of fisheries. In Western Australia, populations of Roe’s Abalone (Haliotis roei) are currently being restocked after the occurrence of a catastrophic mortality event, while stock enhancement of Greenlip Abalone (Haliotis laevigata) is also occurring. Translocation of undersized Southern Rocklobster from deep to shallow water locations and ranching of Sea Cucumbers is also occurring. In all such cases there is a need to understand the population genetic dynamics of stocked populations and the extent of genetic interactions of stocked with wild populations. Important considerations are the genetic health of individuals used as breeders, genetic structuring of source populations for restocking, effective population size (i.e. effective number of breeders), effects on inbreeding or loss of genetic diversity, recruitment and geographic spread. Molecular markers can be used to investigate these effects and guide the stocking. Genomic technologies such as Genotyping-By-Sequencing (GBS) are rapidly developing and becoming less expensive and more useful to apply than traditional genetic approaches. Therefore, this project employed a post-doctoral researcher with the following objectives:

1. Develop new expertise and transfer genomic approaches, currently used for commercially important species of the Northern hemisphere, to benefit the fisheries or aquaculture of key commercial species in Australia

2. Generate and use genomic data to analyse changes and patterns in functionally relevant genetic diversity (i.e. variation related to fitness) with restocking and ranching and advise on management strategies for the species concerned

3. Develop expertise in genetic management associated with enhancement and related interventions

The overall benefit of this project was to create genetically healthy/sustainable restocked populations, improve returns from ranching while having minimal impact on natural populations and maintain healthy fisheries.

Genomic sequencing techniques were developed and found to be effective for both Roe’s Abalone and Greenlip Abalone. Three genetically distinct groups of Roe’s Abalone and five genetically distinct groups of Greenlip Abalone were defined and each of these groups showed high connectivity. This information will inform management approaches to the restocking of Roe’s abalone and contribute to the stock enhancement of Greenlip Abalone in Western Australia.