Recovering threatened freshwater fish in Australia

Concern over the decline of freshwater ecosystems has grown dramatically in recent decades, with major threats of habitat loss or modification, altered flow regimes, changed water quality, barriers to dispersal and migration of biota, and impacts of alien species (Malmqvist and Rundle 2002; Dudgeon et al. 2006). Fishes are a key concern for all of these threats; populations and species are declining globally, with additional threats to fish generated by inappropriate translocation and stocking, and overexploitation. The number of threatened freshwater fish taxa on the IUCN Redlist listed as critically endangered, endangered or vulnerable has increased from 741 in 1996–98 to 2041 in 2012 (version 2012.1; IUCN 2012). Australia has a comparatively small freshwater fish fauna of 256 currently recognised species, of which 74% are endemic (Unmack 2013). However, this species diversity is expected to rise significantly as there are increasing numbers of undescribed and/or cryptic taxa being uncovered through genetic investigations (e.g. Hammer et al. 2007; Raadik 2011). As new species are described, it is increasingly the case that many are already threatened, particularly in southern Australia, where they are often relictual populations with small geographic distributions (e.g. Raadik 2011). The first national list of Australian threatened species in 1980 recognised only 3 freshwater fish species but this has rapidly grown to the 74 species currently on national state or territory listings (Lintermans 2013a). Considerable effort and resources are devoted to recovery of threatened fish species in Australia. Of the 36 freshwater fish listed as nationally threatened, 21 species have national recovery plans, with several additional species having recovery plans in preparation, or covered under recovery plans for threatened ecological communities. To facilitate improvement in the management of recovery programs, review of past and current efforts is essential, but this has not yet occurred for freshwater fish in Australia.