Document ID: chunk:federal_register_of_legislation:F2019L00106:body:0:p53
Version: federal_register_of_legislation:F2019L00106
Segment Type: other
Provision Reference: 
Character Range: 141464–144489

risk of gut-hooking compared to other methods such as artificial lure or fly. Conversely, there is good evidence to suggest that if fish are mouth hooked, handled carefully and returned to the water promptly they are likely to survive.
Illegal fishing is likely to remove mature adult fish from the population. At a genetic level, it is possible that persistent selective removal of larger individuals ('trophy fish') from a population will cause an evolutionary shift in population characteristics with smaller size at maturity being an advantage and hence becoming the dominant phenotype (Conover & Munch 2002). High levels of illegal fishing may constitute negative impacts to the species.

6.2.7 Chemical water pollution
Chemical water pollution can be derived from point source and non-point sources and may be derived from sources such as run-off from agricultural, rural and industrial development, and acid mine drainage. Water pollution is related to land use; the development of intensive agriculture, mining, rural industries and urban development have contributed to water pollution across the Murray-Darling Basin and in the eastern catchments where Macquarie perch occur (MDBC 2003).
For many of the extant populations, pollution is probably of low risk given that the populations exist within national parks, wilderness areas and nature reserves such as the Lake Dartmouth and Mitta Mitta River, Buffalo River and Cotter River populations in the Murray-Darling Basin and populations in Webbs Creek, Colo, Grose, Kowmung rivers, Wongawilli Creek, Cordeaux and Cataract rivers in the Hawkesbury-Nepean system. Conversely, some remaining populations of Macquarie perch exist adjacent to land use types where there are livestock grazing, production and plantation forestry, perennial horticulture of vine and tree fruits, irrigated modified pastures and grazing modified pastures. These include populations in King Parrot Creek, Yea River, Holland's and Hughes , Murrumbidgee River, Adjungbilly and Mannus creeks, Lachlan and Abercrombie rivers in the Murray-Darling Basin and the populations in the Mongarlowe and Cox's rivers Hawkesbury-Nepean system.
A further source of pollution threatening the recovery of some Macquarie perch populations includes mining and domestic effluent disposal. In particular, Macquarie perch in the Hawkesbury-Nepean system are at risk from current, proposed and past mining activities (NSW DoP 2008). Effluent from underground coal mining is saline and acidic and subsidence caused by longwall mining cracks river beds and releases iron flock from ground water. Disused and historic mine sites are a source of acid mine drainage and heavy metal contaminants (NSW DoP 2008). The population of Macquarie perch in the Molonglo River is likely to have been removed (along with all other fish species) through heavy metal contamination from the collapses of the Captains Flat Mine tailings dam between the 1930s–1940s (Lintermans 2002).
Pollution has the potential to affect all aspects