Document ID: chunk:federal_register_of_legislation:F2019L00106:body:0:p26
Version: federal_register_of_legislation:F2019L00106
Segment Type: other
Provision Reference: 
Character Range: 69751–72717

is becoming increasingly accepted in documenting environmental change in ecological studies. Triangulation refers to the practice of using two or more sources to verify observations, and its use is well established in the social sciences and is used by doctors when evaluating patient history (Robertson et al., 2000). Oral histories are particularly powerful for river management in Australia, in that they provide information that precedes formal agency or research institution records (Boulton et al., 2004). Trueman (2011) utilised photographs, newspaper stories and supporting accounts to verify oral recollections of lay observers (oral histories). For Macquarie perch, this historical research uncovered, and also confirmed that significant declines in the species' populations were evident by the early twentieth century in some areas, and that widespread population extinctions occurred between 1920–1960 (Trueman 2011).
The conclusions of Trueman's (2011) research for Macquarie perch are supported by the work of the "Sustainable Rivers Audit" (SRA), which undertook a systematic assessment of the health of all river ecosystems in the Murray-Darling Basin for the Murray-Darling Basin Authority. The assessment was undertaken on each of the 23 major river valleys in two reports, SRA1 using data collected between 2004–2007 and SRA2 between 2008–2010 (Davies et al., 2008; 2012). 'Rarity' scores were developed by an expert panel for each fish species based on the likelihood of a species being found at a site, using the SRA sampling methods, if the encompassing altitudinal zone is in 'Reference Condition' (i.e. that is in a 'condition that would be likely to prevail now had there been no significant human intervention in that region') (Davies et al., 2008; 2012).
By the end of the 1960s, endemic populations in New South Wales and the Australian Capital Territory were largely restricted to the upper Lachlan and Murrumbidgee river catchments, with a small population persisting in Mannus Creek in the upper Murray River catchment (Trueman 2011; Long 2017). In Victoria by the end of the 1960s, relict populations were restricted to the slopes and upland zones of the Mitta Mitta, Ovens and Goulburn-Broken river catchments (Trueman 2011).
New South Wales and the Australian Capital Territory
Only five individuals were caught in two catchment valleys, the Goulburn and the Murrumbidgee river valleys, in sampling for the Sustainable Rivers Audit of the Murray-Darling Basin between 2004–2007 (Davies et al., 2008) and 12 individuals were caught in three valleys, the Broken, the Goulburn and the Murrumbidgee, between 2008–2010 (Davies et al., 2012).
Macquarie perch were captured regularly in the Macquarie River catchment in New South Wales until the 1950s but historical research indicates that the species had disappeared and become extinct in the catchment by the 1960s (Trueman 2011). The estimate of the species' abundance in the Macquarie