Document ID: chunk:federal_register_of_legislation:F2019L00106:body:0:p40
Version: federal_register_of_legislation:F2019L00106
Segment Type: other
Provision Reference: 
Character Range: 106396–109459

Introduced fish species may impact on native species in a number of different ways such as: predation (particularly on eggs and larvae); competition for habitat and food resources; habitat degradation; spread of diseases and parasites. Interactions with introduced fish species such as trout (brown (Salmo trutta) and rainbow (Oncorhynchus mykiss)) and redfin (Perca fluviatilis) have been identified as likely causes in the decline of the Macquarie perch (Cadwallader 1978; 1996; Gilligan 2005; Lintermans 2007). Furthermore, introduced fish species may bring new parasites and diseases which could potentially threaten native species (Cadwallader & Lawrence 1990; Arthington 1991; Abramovitz 1996; Cadwallader 1996; Arthington & McKenzie 1997; Horwitz et al., 1998; Lintermans 2007). For more information on this threat refer to section 6.2.5 below. Introduced fish have also been implicated in the local extinction and altered community structure of macroinvertebrates which are major food resources for native fish (Bruton 1995, Horwitz et al., 1998, Lintermans 2007).
Stocking introduced fish species for recreational fisheries, including trout (brown and rainbow) and redfin, has occurred widely in Macquarie perch range states and territory of New South Wales, the Australian Capital Territory, Victoria and South Australia during the past 120 years (Arthington & McKenzie 1997; Lintermans 2013c). Other species which were originally introduced to Australia for acclimatisation so that they could be recreationally fished for were brook char (Salvelinus fontinalis) and Atlantic salmon (Salmo salar), tench (Tinca tinca), roach (Rutilus rutilus) and European carp (Cyprinus carpio) (Lintermans 2004).
Brown and rainbow trout were introduced and established in southeastern Australia during the second half of the 19th Century and populations have persisted, and stockings have continued to today, for over 100 years (Wilson 1879; Nicols 1882; Lake 1957; 1967; Cadwallader 1996; Arthington & McKenzie 1997; Lintermans 2004). From as early as the 1930s, observations of stomach contents from fish in New South Wales showed that both rainbow trout and brown trout preyed upon items very similar to the items which Macquarie perch prey upon, indicating the risk of competition for food resources (McKeown 1934; Butcher 1945; Butcher 1967; Cadwallader 1978). Futher, from as early as the 1940s, there were reports of brown trout eating small Macquarie perch (Butcher 1945; 1967). The dietary overlap that has been observed between Macquarie perch, European carp and rainbow trout is now well recognised (Butcher 1945; Cadwallader 1978; 1979; Jackson 1981; Battaglene 1988; Koehn & O'Connor 1990b; Lintermans 2006a).
Concern was expressed by J.O. Langtry during his 1949–1950 surveys and by others later about the ability for native fish and trout to coexist (Butcher 1967; Cadwallader 1977; Rhodes 1999) and the impacts of 'incessant' trout stocking in the Murray-Darling Basin and that little information on the composition of native fauna was available before