Phylogeography of a threatened freshwater fish (Mogurnda adspersa) in eastern Australia: conservation implications.
The southern purple spotted gudgeon is a small freshwater fish that was once common and widely distributed throughout the Murray-Darling Basin and the east coast of Australia north of Coffs Harbour. However, within the last 50 years, the Murray-Darling Basin population has declined dramatically in distribution and abundance. Only a small number of isolated remnant populations remain and it is locally extinct in many catchments. The population genetics of the species was studied to provide guidance for the development and implementation of recovery strategies for inland populations. Samples were collected from NSW and Queensland. The genetic data suggest that the inland catchments were colonised from the coast around 1.6 millions years ago. Inland populations had low genetic diversity compared to coastal populations and there was little of no gene flow between remnant inland populations. This will lead to further loss of genetic diversity and increased risk of extinction. Recovery actions should include increasing the population size as quickly as possible, translocation of individuals between populations and/or the reintroduction of genetically diverse captive bred fish into catchments where they have disappeared. However, genetic material from coastal populations should not be introduced to the Murray-Darling population. Habitat restoration adjacent to remnant populations and at potential reintroduction sites and enhancing the recruitment of the remnant populations are equally important management needs.