Document ID: chunk:federal_register_of_legislation:F2019L00106:body:0:p36
Version: federal_register_of_legislation:F2019L00106
Segment Type: other
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Character Range: 95530–98472

to Australian streams each year (NLWRA 2001). Increased levels of sediment can adversely affect many aspects of freshwater ecosystems by reducing water quality, modifying the morphology, ecology and physical form of streams and altering the physical, physiological and behavioural responses of aquatic flora and fauna (Boulton & Brock 1999; Lintermans 2013c).
Catastrophic bushfires are of particular concern to remaining Macquarie perch populations. Direct impacts of bushfire on freshwater environments are increased temperatures (Hitt 2003), increased pH (Cushing Jr. & Olson 1963) and increases in nutrients from smoke and ash inputs (Bayley et al., 1992; Earl & Blinn 2003). A study in Montana recorded water temperature rises of nearly 10°C caused by a high-severity wildfire (Hitt 2003). pH increased in a stream in Washington State from 7.8 to 11.1 with temperature increase immediately following weed burning on its banks (Cushing Jr. & Olson 1963). Potassium, and phosphorus and nitrogen compounds such as ammonium, nitrate, soluble reactive phosphorus, all increase in concentration within streams immediately following a fire (Bayley et al., 1992; Earl & Blinn 2003). Mortalities of freshwater fish from these direct impacts following bushfire have been generally confined to smaller order streams, such as the ones which Macquarie perch are known to inhabit (Cushing Jr. & Olson, 1963; Lyon & O'Connor 2008). It is considered that Macquarie perch in King Parrot Creek were heavily impacted by the Black Sunday Bushfires in 2009 where more than half the King Parrot Creek catchment was burnt (Kearns 2009, cited in. ARI pers. comm., 2017). The Goodradigbee River population disappeard following a major bushfire and subsequent large rainfall event in the late-1990s/early-2000s (NSW DPI pers. comm., 2017).
A secondary, or indirect, impact following bushfire is the increased sediment load (often referred to as a 'sediment slug') which can follow rainfall events and subsequent run-off from recently burnt ground and is often widespread (Benda et al., 2003; Meyer & Pierce 2003; Smith et al., 2011; Goode et al., 2012). A sediment slug following large bushfires in 2003 in the southern Murray-Darling Basin had major negative impacts to freshwater fish in streams in the region, including native fish (Lyon & O'Connor 2008), and while no Macquarie perch were sampled in the study despite being known from surveyed catchments, it is plausible that the species also was negatively affected as recorded for other native species in the study. In the Australian Capital Territory, the 2003 fires and subsequent rainfall caused the mortality of Macquarie perch in the 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