Document ID: chunk:federal_register_of_legislation:F2019L00106:body:0:p46
Version: federal_register_of_legislation:F2019L00106
Segment Type: other
Provision Reference: 
Character Range: 122774–125629

these natural flow and temperature patterns (Walker 1985; Kingsford 2000; Lintermans 2013c).
Flow in the coastal rivers of New South Wales where the Macquarie perch occurs, is generally more consistent however altered flow regimes as a result of large dams and impoundments also have a major impact on Macquarie perch ecology. River regulation has resulted in changes in the size of flows; seasonality of flow patterns; frequency and duration of floods; timing, variability and predictability of flows; rates of rise and fall of water levels; and surface and subsurface water levels (Walker 1985; Kingsford 2000; Lintermans 2013c).
A study surveying sites in the Yarra River detected only very low spawning and recruitment indicators in 2008/09, and this apparent failure in this season was linked to the low flow conditons in the river (King & Mahoney 2009). However, a recent study on five Victorian populations of Macquarie perch (in the Yarra River, Lake Dartmouth, King Parrot Creek, Hughes Creek and Seven Creeks) found lower levels of recruitment in years where there was higher discharge in the months of November and December (Tonkin et al., 2017b). The November-December period corresponds with the core egg and larval period for the species (Tonkin et al., 2017b). Therefore, it may be important for regulators to avoid sudden, sharp increases in discharge during the spawning period for Macquarie perch.
By the end of the 1970s all of the major river catchments in New South Wales, the Australian Capital Territory and Victoria where the Macquarie perch occurs were regulated with large dams to store and control the flow of water for primary resources and domestic supply. The regulation of water flow by the operation of in-stream structures generally reduces the flow of water downstream and reduces the frequency and magnitude of natural flooding (Walker 1985; ASEC 2001; NSW FSC 2002; Magilligan et al., 2003). Water is delivered to users who depend on reliable and predictable water supplies often at the expense of the ecological needs of fish communities.
Remnant populations of Macquarie perch in the Murray-Darling Basin generally occur either in and/or above impoundments or in unaltered catchments. Reduced flows caused by drought and water extraction may impact by reducing size of key refuge pools in streams and access to key riffle habitats which are important for spawning. Fish surveys in lower Hughes Creek found Macquarie perch in poor condition and displaying signs of severe stress as a direct result of low flows (Kearns 2009, cited in Lintermans et al., 2014). Consequently, 32 adult fish were translocated to Victorina Government hatchery facilities and then re-released into Hughes Creek when water quality had improved (Lintermans et al., 2014).
The exceptions are small populations of Macquarie perch below Cordeaux