Multi-generational evaluation of genetic diversity and parentage in captive southern pygmy perch (Nannoperca australis)
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Maintaining genetic diversity within captive breeding populations is a key challenge for conservation managers. We applied a multi-generational genetic approach to the captive breeding program of an endangered Australian freshwater fish, the southern pygmy perch (Nannoperca australis). During previous work, fish from the lower Murray-Darling Basin were rescued before drought exacerbated by irrigation resulted in local extinction. This endemic lineage of the species was captive-bred in genetically designed groups, and equal numbers of F1 individuals were reintroduced to the wild with the return of favourable habitat. Here, we implemented a contingency plan by continuing the genetic-based captive breeding in the event that a self-sustaining wild population was not established. F1 individuals were available as putative breeders from the subset of groups that produced an excess of fish in the original restoration program. We used microsatellite-based parentage analyses of these F1 fish to form breeding groups that minimized inbreeding. We assessed their subsequent parental contribution to F2 individuals and the maintenance of genetic diversity. We found skewed parental contribution to F2 individuals, yet minimal loss of genetic diversity from their parents. However, the diversity was substantially less than that of the original rescued population. We attribute this to the unavoidable use of F1 individuals from a limited number of the original breeding groups. Alternative genetic sources for supplementation or reintroduction should be assessed to determine their suitability. The genetic fate of the captive-bred population highlights the strong need to integrate DNA-based tools for monitoring and adaptive management of captive breeding programs.
KeywordsRestoration genetics Pedigree Kinship Relatedness Fish Biodiversity extinction
We thank the many people who helped with or supported the genetic captive breeding program, especially S. Westergaard, H. Mahon, A. Hall, N. Whiterod, A. Watt, C. Bice, B. Zampatti, and A. Frears. Financial support was provided by the Australian Research Council (LP100200409 to L.B.B., J.O.H. and M Adams; FT130101068 to L.B.B.). We thank the Flinders University component of FT130101068 for providing the salary for C.R.M.A. Additional support was received by Department of Environment, Water and Natural Resources SA, SA Museum, SA Murray Darling NRMB, PIRSA Fisheries, and Native Fish Australia SA. This work was conducted under approval from the Flinders University Animal Welfare Committee (approval E313).
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