Document ID: chunk:federal_register_of_legislation:F2019L00106:body:0:p42
Version: federal_register_of_legislation:F2019L00106
Segment Type: other
Provision Reference: 
Character Range: 111800–114696

commissioned in Australia into the physical examination or DNA-assays of trout gut contents in the few remaining locations where Macquarie perch still co-occur. Research commenced into this approach (MacDonald et al., 2014) but ceased as a result of a lack of funding.
Redfin are a fast-breeding, voracious predatory fish introduced to mainland Australia in the 1860s originating from stock from the United Kingdom (Weatherley 1963b; Weatherley 1977; Cadwallader & Backhouse 1983; Lintermans 2007). The species is now widely distributed through the southern part of the Murray-Darling Basin, being restricted to water temperatures less than 31°C (Weatherley 1963a; 1963b; 1977). The species can live in a wide variety of habitats, but generally prefer still or slow-flowing waters such as lakes, dams, billabongs, swamps and slower moving streams and rivers (NSW DPI 2017). Redfin are known to prey on many small and juvenile native species (Clunie et al., 2002). Direct predation on trout cod juveniles was reported by undertaking gut analysis of redfin from Seven Creeks (Kearns et al., 2012a, cited in ARI pers. comm., 2017), where a population of Macquarie perch also occurs. Cadwallader & Rogan (1977) noted the appearance of redfin in Lake Eildon, Victoria attributed predation on juvenile Macquarie perch by redfin as a contributing factor to their decline. In the Australian Capital Territory, the decline of Macquarie perch in the Murrumbidgee River is closely correlated with the increase in redfin (ACT Gov. pers. comm., 2017). Redfin were first discovered in the Lachlan River above Lake Wyangala in 2005, and since have proliferated the entire length of the upper Lachlan River (Pearce 2013). The remnant population which occurred in the Lachlan River is now extinct (NSW DPI pers. comm., 2017). A recent laboratory study did show that Macquarie perch are able to recognise and respond to the threat of predation posed by redfin (Brown & Morgan 2015). Victoria's largest population of Macquarie perch occurs in Lake Dartmouth where no redfin occur as yet (ARI pers. comm., 2017).
European carp were first introduced into Australia as early as the 1860s, but these strains showed no signs of spreading (Shearer & Mulley 1978). The 'Boolarra strain' was imported illegally into Victoria from Germany in the 1950s, and in the 1960s was illegally introduced into watercourses in the Murray-Darling Basin and quickly spread throughout (Rhodes 1999; Koehn et al., 2000). European carp now dominate freshwater systems across the Murray-Darling Basin, and it has become the most abundant large freshwater fish in southeastern Australia (Koehn 2005; Davies et al., 2012). European carp disturb native fish habitats by raising turbidity and destroying submergent macrophytes (Roberts et al., 1995; Roberts & Sainty 1996; Villizi et al., 2014). European carp larvae feed upon similar prey items