Mitochondrial and allozyme genetics of two Tasmanian galaxiids (Galaxias auratus and G. tanycephalus, Pisces: Galaxiidae) with restricted lacustrine distributions

Abstract

Galaxias auratus and G. tanycephalus have a restricted distribution in Tasmanian highland lakes and were probably derived from a landlocked population of the diadromous G. truttaceus during the last 100,000 years. We have analysed the mitochondrial DNA and the allozyme products of 22 nuclear loci for each lake species. Four mitochondrial DNA haplotypes, defined by 40-42 six-base restriction sites, were identified amongst 26 G. auratus and three haplotypes, defined by 38-39 restriction sites, were found in six G. tanycephalus. The evolutionary genetics of reproductive isolation appears to have inflated mitochondrial but not nuclear DNA diversity between the lake species and their hypothesized progenitor, G. truttaceus. The amount of intraspecific mitochondrial and nuclear DNA diversity for G. auratus and G. tanycephalus is consistent with their having an extended and independent evolutionary history in reproductive isolation.

Crying wolf, crying foul, or crying shame: alien salmonids and a biodiversity crisis in the southern cool-temperate galaxioid fishes?

“…Southern Victoria and Tasmania have three distinctively large and stout-bodied galaxiids that probably form a closely related species-group (Ovenden and White 1990;Ovenden et al 1993), which is dealt with, below.…”

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“…The correct stock as assessment and identification of species is essential to ascertain the maximum sustainable effort of a given marine resource (Ryman and Utter, 1987;Ryman, 1991). Many stock concepts can be found in the literature (Booke, 1981;Ovenden, 1990;Carvalho and Hauser,1995), but one of the most accepted and used is "a stockist an intraspecific group of randomly mating individuals with temporal and spatial integrity" (Ihssen et al, 1981) which swathe most of the definitions given by other authors. The fish stock identification can be made efficiently by the use of highly polymorphic molecular markers (Blaber et al, 2005;Caddy and Seijo, 2005).…”

Status of galaxiid fishes in Tasmania, Australia: conservation listings, threats and management issues

“…Information available includes status and distribution (Fulton, 1990;Sanger and Fulton, 1991;Chilcott and Humphries, 1996;Crook and Sanger, 1997;Hardie, 2003;Nelson, 2004;Threatened Species Unit, 2005) and evolutionary history and genetics of the galaxiid fauna (Johnson et al, 1981(Johnson et al, , 1983White et al, 1987;Ovenden and White, 1990;Ovenden et al, 1993;Waters, 1996;Waters and White, 1997;McDowall, 1998), as well as the biology and ecology of some species (Fulton, 1982;Humphries, 1989Humphries, , 1990Sanger and Fulton, 1991;Hamr, 1992a;Hardie, 2003).…”