Document ID: chunk:federal_register_of_legislation:F2019L00106:body:0:p37
Version: federal_register_of_legislation:F2019L00106
Segment Type: other
Provision Reference: 
Character Range: 98205–101091

Murrumbidgee and Cotter rivers (Carey et al., 2003). Following the 2009 Black Saturday Bushfires in Victoria, Macquarie perch individuals were captured from King Parrot Creek and translocated to the Snobs Creek Hatchery to protect them from the sediment slugs (Kearns 2009; Kearns et al., 2012a, both cited in ARI pers. comm., 2017; Kearns et al., 2012b; Lintermans et al., 2014). There was concern that the fires, which burnt up to the water edge of King Parrot Creek across half the catchment, would cause a sediment slug, amongst other direct and indirect effects, to form in King Parrot Creek (Kearns et al., 2012b). At the time of rescuing fish so that they could be translocated, signs of physical stress were evident with fish kills documented as likely the result of reduced water quality (Kearns 2009 cited in ARI pers. comm., 2017). It appears that Macquarie perch do not spawn evenly across habitats (Tonkin et al., 2016a) and have preference for specific sites within King Parrot Creek (Kearns et al., 2012b). Sedimentation, loss of riparian vegetation and bank erosion are all evident in King Parrot Creek, and for recovery of the species to occur, protection of spawning habitats will be greatly assisted if there is focussed action on riparian restoration and bank stabilisation to reduce sediment loads into this waterway (Kearns et al., 2012b).
Gravel beds are important habitat areas for Macquarie perch spawning, feeding and as refuge areas for juvenile fish (Lintermans 2007). Berkman & Rabeni (1987) found that fish species requiring clean cobble/gravel in riffle zones for spawning declined as fine sedimentation of substrates increased. For Salmonid species which rely on cobble/gravel for spawning, fine sediment was also found to impair the gas exchange of developing eggs by adhering to the surface of the egg (Chapman 1988). Overseas studies have found high concentrations of fine sediment increases exposure of fish to predators and physical disturbance through destruction of shelter, physical structures and hiding places, for example smothering of aquatic macrophytes (Brookes 1986; Mol & Ouboter 2004).
Deposited coarse sediment can fill deep holes, create barriers and alter stream morphology leading to wider, shallower profiles. Infilling of deep holes removes thermal refuges that many Australian native fish species, such as the Macquarie perch, rely upon during the summer and autumn months, and reduces their ability to withstand drought events (Cadwallader 1978; Coats et al., 1985). Furthermore, the nutrients and toxic substances attached to sediment particles also pose a threat to Australian native fish species (Cadwallader 1978; 1979; Lintermans 1991a; ACT Gov 1999; Horner 2000; Burton et al., 2004). Silt and clay particles can absorb, transport and store metal contaminants (Stone & Droppo 1994) so that deposited sediments act as a sink