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

Abstract

1. Fish of the family Galaxiidae are restricted to the southern hemisphere where they occupy a diverse array of habitats ranging from over 2000m in elevation to sea level. Some species are diadromous and, hence, freshwater, estuarine and marine habitats are used during their life-cycle; other species complete their entire life-cycles in freshwater environments. 2. Tasmania has a diverse galaxiid fauna that accounts for 64% of native freshwater fish species found on the island. The Tasmanian galaxiid fauna is characterized by high species richness (5 genera and 16 species), endemism (11 species), restricted distributions, and non-diadromous life histories (11 species). 3. The galaxiid fauna of Tasmania has significant conservation status with 69% of species considered ‘threatened’. The conservation status of the fauna is recognized at State, national and international levels. 4. The key threats to galaxiids in Tasmania are exotic species, hydrological manipulations, restricted distributions, general habitat degradation and exploitation of stocks. 5. Although work has recently been undertaken to conserve and manage Tasmanian galaxiid populations, the fauna is still thought to be imperilled. Knowledge gaps that need to be addressed include the biology and ecology of most species (e.g. reproductive biology, life histories, habitat use and requirements) and impacts of habitat manipulations, as well as mechanisms and impacts of interactions with exotic species. Techniques to monitor accurately the status of galaxiid species and their populations need to be developed and the coexistence of some galaxiids with introduced salmonids should also be examined.