摘要:
Australian freshwater systems are under extreme pressure from a multitude of biotic and abiotic stressors. To effectively manage native species, an understanding of biological life history, population connectivity and genetic diversity is crucial. Genetic methods can serve as useful tools not just for monitoring population health but for revealing the life histories of species. My thesis aims to analyse the genetic connectivity and genetic diversity of three coastal diadromous fish species, common galaxias (Galaxias maculatus), tupong (Pseudaphritis urvillii), and Australian grayling (Prototroctes maraena) and one inland freshwater fish species, Murray cod (Maccullochella peelii). Furthermore, I explore the extent to which molecular kinship assignments can be utilised to investigate demographic population connectivity and inform fundamental life-history characteristics of Murray cod. In Chapter 2, I investigate patterns of genetic connectivity for populations of common galaxias, tupong, and Australian grayling along the south-eastern Australian coastline. Despite sharing many similar life-history traits, each species exhibited different patterns of genetic connectivity, with patterns for common galaxias reflecting genetic panmixia, and patterns for Australian grayling and tupong reflecting different degrees of isolation- by-distance. In Chapter 3, I undertake a power analysis using simulated data and genetic data from the native fish species Macquarie perch (Macquaria australasica) and demonstrate the limitations of different types of molecular kinship assignment methods under varying scenarios, helping inform best practice kinship analysis. In Chapter 4, I use sibship-based kinship analyses of Murray cod larvae to investigate the mating strategies of Murray cod in three breeding populations across the southern Murray-Darling Basin, providing insights into yearly breeding and implications for ongoing management. In Chapter 5, I undertake an extensive study of gene f