Oral Presentation Australian Society for Fish Biology & Australian Freshwater Sciences Society Conference 2026

Improving conservation through genetic rescue: a case study on the Southern Pygmy Perch (145468)

Joyshri Sarker 1 , Peter Unmack 1 , Chris Brauer 2 , Luciano Beheregaray 2 , Chris Lamin 3 , Peter Rose 4 , Dianne Gleeson 1 , Elise Furlan 1
  1. Institute of Applied Ecology, University of Canberra, Bruce, ACT, Australia
  2. College of Science and Engineering , Flinders University, Adelaide, South Australia, Australia
  3. Middle Creek Farm, Stratford, Victoria, Australia
  4. North Central Catchment Management Authority, Huntly, Victoria, Australia

Abstract:

Genetic rescue provides a promising approach for improving the genetic health and long-term persistence of small, isolated populations that have experienced genetic drift, inbreeding, and loss of genetic diversity. By introducing individuals from genetically distinct source populations, genetic rescue can restore genetic variation, reduce inbreeding, and potentially increase the capacity of threatened populations to adapt to future environmental challenges. However, successful genetic rescue requires an understanding of the existing genetic condition of populations and the consequences of mixing individuals from different genetic backgrounds. In this study, we assess the current genetic status of wild and translocated populations of Australian freshwater fish, Southern Pygmy Perch (Nannoperca australis) by examining genetic diversity, population structure, inbreeding and allelic richness. The species is currently threatened within the Murray–Darling Basin (MDB), highlighting the need for targeted conservation actions to protect and manage remaining populations. Therefore, we investigate whether strategic mixing of genetically distinct populations can enhance genetic diversity and improve the effectiveness of genetic rescue in this species, as a conservation management action. Fin clips were collected from 10 wild and 7 translocated populations within MDB, including F1 individuals from newly established mixed-source population founded using individuals from Victorian and South Australian populations. Mitochondrial DNA Cytochrome b sequences and genome-wide single nucleotide polymorphism (SNP) data were used to characterize genetic variation and evaluate population genetic patterns. We hypothesize that mixed-source populations will retain higher levels of genetic diversity and lower inbreeding compared with populations established from a single source. The results of this study will improve our understanding of the role of genetic rescue in threatened freshwater fishes and provide valuable guidance for genetically informed translocation strategies for the conservation of Southern Pygmy Perch and other species.