Key words: Murray- Darling Basin, fish, genetic diversity, genetic resources, Native Fish Strategy.
The Native Fish Strategy aims to rebuild all fish stocks within the Murray-Darling Basin (MDB) to 60 percent of pre-European settlement levels within 50 years. To achieve this target, management responses would be assisted by an understanding of the underlying genetic diversity of species. Many species have genetically distinct populations. For example, Murray Cod (Macculochella peelii) are known to have little genetic difference throughout most of the southern range of the MDB, however, several populations (Lachlan, Macquarie and Gwydir catchments) were found to be genetically distinct.
Maintaining genetic diversity is critical to species and ecosystem resilience, particularly in the face of changing environmental conditions. Despite the explicit recognition within legislation that genetic diversity is a key component of biodiversity, until now there remains no consistent or practical guidelines for the management of these resources.
Project objectives and methods: The objectives of this project were to create a resource able to be used to guide the management of genetic diversity within the Basin.
- Review current genetic management practices across the MDB;
- Review the current knowledge base for genetic structure within native fish species in the MDB and identify knowledge gaps;
- Hold an international workshop to define the level of genetic management required to maintain distinct evolutionary significance of native fishes within the MDB;
- Suggest a consistent approach to the management of genetic resources for native fish in the MDB.
A survey of fisheries agencies was conducted to identify current genetic management protocols for hatchery management, restocking, translocations, conservation captive breeding programs, fish rescues and interventions and the monitoring of threatened species. Protocols for the collection, preservation and storage of genetic material (e.g. fin clips, biopsy material, scales, bones, cryopreserved sperm, etc.) were also identified.
Previous and contemporary genetic research of MDB species was reviewed to highlight and map inferred genetic boundaries within the Basin. All available published and unpublished molecular data were compiled to assist in determining genetic structuring, ecologically sustainable units and management units. Strengths, weaknesses and implications of these data were considered, knowledge gaps highlighted and methods for addressing these gaps were discussed.
A workshop was held to determine what level of genetic management is appropriate for fish in the MDB and bring together experts to present the latest thinking on defining conservation units, to help inform development of a framework for prioritising and managing evolutionary distinction. Review findings and workshop outputs were then used to inform development of guidelines for management of genetic diversity in Australian native fish within the MDB which includes:
- a review of current genetic issues and management practices across the MDB;
- a review of the genetic structuring for native fish and crustacean species in the MDB including knowledge gaps;
- guidelines and recommendations for genetic management within the MDB;
- a genetic management template for fish stocking; and,
- recommendations from the Management of Genetic Resources for Fish and Crustaceans in the Murray-Darling Basin workshop.
Findings and recommendations: Available data on genetic subdivision for 65 fish and crustacean species across the MDB were reviewed and discussed in the context of management for these species. This review highlighted significant genetic differences between populations of native fish and crustaceans within the Basin. These genetically different populations potentially contain unique evolutionary heritage that will require specific approaches to manage.
A number of recommendations were provided from this project:
- Populations that are defined as distinct genetic management units should be treated as unique populations with limited transfer of individuals between units (Figs 1 and 2).
- Information provided through this project should be used to develop a unified approach to the management of genetic diversity within the MDB.
- The substantial knowledge gaps for species with insufficient genetic data (outlined in species profiles) should be addressed to allow the identification of genetic management units for the MDB.
- Adequate stocking and hatchery genetic protocols should be adhered to for all breeding programs within the MDB.
Stakeholders and Funding bodies: This project was funded through the Murray-Darling Basin Authority’s Native Fish Strategy.
Contacts: Dr Andy Moore, Department of Agriculture Fisheries and Forestry. Tel: + 61 2 6272 3090, Email: email@example.com.