BIRD: linking the biodiversity community
Golden Perch (Macquarie ambigua) is a medium-sized potamodromous fish with an elongated, deep and laterally compressed body. They can weigh up to 23kg and measure 760mm, but are usually around 4kg and 400mm (Merrick and Schmida, 1984). While the species is also commonly known as Yellowbelly in recognition of its distinctive golden/yellow underbelly, the body colour is habitat-dependent and varies from dark green, olive and bronze (clear waters), through to yellow, gold and cream (turbid waters). The dorsal profile, in contrast to the ventral profile, is strongly convex, while the forehead profile is generally concave. Juveniles often have a more streamlined body shape and mottled appearance. M.ambigua have a well developed nuchal hump and a large mouth with a slightly protruding lower jaw. Eyes are of moderate size, lateral in position. A band of villiform teeth are found in jaws, on vomer and palatines. The body is covered with moderate-size ctenoid scale, with a single dorsal fin and rounded caudal and pectoral fins (Cadwallader and Backhouse, 1983).
Golden perch occurs naturally throughout most of the Murray-Darling river system, except at higher altitudes. It is also naturally found in the Lake Eyre and Bulloo internal drainage systems of Queensland, New South Wales and South Australia (Merrick and Schmida, 1984; Ye, 2004). The Fitzroy Basin in Central Queensland represents the northern most natural distribution of the golden perch, although the fish found in this area are now considered a morphologically and genetically distinct sub-species, M. ambigua oriens (Musyl and Keenan, 1992). Similarly, golden perch in the Lake Eyre and Dawson River drainage systems are considered to have sufficient genetic differences to be considered separate sub-species (O’ Connor et al., 2005).
In the past few decades, a hatchery industry for the large-scale production of golden perch has been developed, whereby government and private commercial hatcheries produce juvenile fish for stocking of lakes, impoundments and farm dams throughout eastern Australia (Anderson et al., 1992; Rowland, 1996). The high commercial and recreational demand for golden perch has resulted in it being introduced to areas outside of its natural range, including Green Lake near Horsham and Wannon River near Hamilton (DPI, 2007)
Like other native species in the region, including Macquaria australasica and Bidyanus bidyanus, the natural distribution range and abundance of golden perch appear to have declined since the advent of European settlement (Cadwallader and Backhouse, 1983; O’ Connor et al., 2005). According to the DPI (2007), golden perch is a “significant component of the Department’s native fish program, with considerable numbers being purchased each year from commercial fish farms to stock rivers and lakes to restore existing populations or establish new recreational fishing populations in suitable waters.” While it remains a widespread and abundant species in the lower Murray-Darling tributaries, natural population numbers for golden perch in Victoria have declined throughout their historical distribution in the past 30 years (Brumley, 1987; Baumgartner, 2007)
There is limited detailed information available regarding the specific habitat preferences of golden perch. This is most likely a consequence of the wide range of habitats in which they have been recorded throughout Victoria. In addition to rivers, estuaries and large streams, golden perch have been found in lakes and impoundments. Merrick and Schmida (1984) noted that they inhabit a wide variety of environments but are predominantly associated with lowland, warmer, turbid and slow flowing rivers. They are often found in sympatry with Murray cod, Maccullochella peelii peelii, and appear well adapted to the dynamic stream flow conditions of the Murray-Darling system (Ye, 2004; Baumgartner et al., 2006). Golden perch prefer deep pool habitats with woody debris cover, snags, undercut banks or rocky ledges (Crook, D.A, 2008, pers. comm., October 9)
Life History and Ecology
Golden perch is one of the most studied fish species in the Murray-Darling basin and there is considerable information on its life history and ecology. While there is no significant sexual dimorphism between the sexes, males tend to mature at 2-3 years and 190mm in size, whereas females mature later at 4 years and at 350mm (Cadwallader and Backhouse, 1983). The reproductive cycle of golden perch is considered to be well adapted to the unpredictable environment of the Murray-Darling system, which fluctuates between extended drought and flooding (Rowland, 1996). It is generally believed that golden perch spawning occurs at night, during an extended period from spring to summer and is induced by a rise in the water level and the water temperature to between 23°C and 26°C (Cadwallader and Backhouse, 1983). This spawning model was consistent with the ‘flood-pulse’ concept, in which summer inundated areas provide suitable spawning conditions for fish (Mallen-Cooper and Stuart, 2003). Recent studies, however, have provided evidence that golden perch have a more flexible breeding strategy with spawning and recruitment occurring during both flood conditions and rising flows within river banks during the winter-spring period (Mallen-Cooper and Stuart, 2003; Roberts, D.T., 2008, pers. comm., October 7). A study by Humphries and Lake (2000) found that recruitment of golden perch larvae occurred in times of “extremely poor winter rains and low daily discharge throughout summer” and conversely, spawning did not occur in preceding years when discharge and temperature were considerably more favourable. Additionally, some of the Victorian populations of golden perch appear to spawn at temperatures around only 19°C and populations in the middle reaches of the Murray river have strong recruitment in non-flood years but poor recruitment in flood years (Mallen-Cooper and Stuart, 2003; Roberts, D.T., 2008, pers. comm., October 7). This seems to confirm that golden perch are responding to the highly variable environmental conditions by displaying opportunistic and flexible spawning behaviour and recruitment variation across their geographic distribution. Nonetheless, it is clear that alterations to natural flooding and water temperature regimes, and barriers to movement, have the potential to seriously affect the spawning behaviour and success of golden perch.
Prespawning behaviour includes substantial colour changes over a period of hours, varying levels of aggressiveness in both sexes, and courting of a female by many males near the water surface (Merrick and Schmida, 1984; Ye, 2004). Fish have been known to migrate upstream up to 2,000 km prior to spawning, at the onset of flooding, most likely to compensate for the downstream displacement of eggs, larvae and juveniles (Cadwallader and Backhouse, 1983, O’Connor et al., 2005). This upstream migration enables larvae to disperse over the floodplain and feed on the phytoplankton, zooplankton and aquatic insects which have been attracted by the nutrients released during flooding (Rowland, 1996; Collins and Anderson, 1999). The large amount of energy expended in upstream migrations is necessary to ensure that eggs and fry do not get carried into the sea (Reynolds, 1983).
The species is highly fecund with females able to produce over 500,000 eggs in a single spawning and, if conditions are favourable, there may be more than one spawning per season. Females can hold eggs at an advanced stage of development for 5 months until conditions are suitable (Cadwallader and Backhouse, 1983). In the absence of favourable conditions, females will go through the process of ovarian involution by reabsorbing their eggs (Collins and Anderson, 1999). Mature eggs are 1.1mm in diameter, spherical and amber-coloured. They swell to about 4mm and become transparent upon fertilization. They have a thin, smooth chorion which is non-adhesive and the eggs are semi-buoyant, requiring a gentle current to maintain them in the water column. Hatching occurs rapidly (within 24-33 hours at 20-30°C), larvae are able to swim and feed 96 hours after hatching and within 5 days, disperse and commence feeding on zooplankton. Golden perch complete there metamorphosis after 15-20 days at a total length of approximately 15mm (Cadwallader and Backhouse, 1984; Ye, 2004).
Golden perch are opportunistic carnivores. While they feed during the day and night, they appear to have two feeding behaviour patterns during daytime. Some individuals will remain in shaded areas or amongst weeds, grabbing prey organisms ass the pass. Other adults will move slowly over weed beds and seize prey that break cover (Merrick and Schmida, 1984). The larvae and small juveniles feed primarily on zooplankton – mainly copepods and cladocerans (Arumugam, 1990). Adult fish mainly feed on crustaceans, aquatic insect larvae, molluscs and small fish, such as European carp and goldfish (Baumgartner, 2007). Research in NSW and QLD has shown that small fish form the major part of golden perch diet in the winter, while crustaceans are the larger component in the summer. Both adult fish and larvae diet depend on flooding to provide them with readily available insects and zooplankton, respectively (Ye, 2004).
Golden perch has not been listed under the Commonwealth Environment Protection and Biodiversity Act 1999. It is, however, considered at risk from ‘changed hydrology’ and ‘salinity’ in the Victorian Midlands (ANRA, 2007).
Natural populations of the golden perch are currently listed as vulnerable under the Flora and Fauna Guarantee (FFG) Act 1988. It is also listed as one of the species in the Lowland Riverine Fish Community of the Southern Murray-Darling Basin, which is listed as a threatened ecological community under the FFG Act 1988 (DSE, 2007). Also, the golden perch is part of the Lower Murray River aquatic ecological community, recently listed as an Endangered ecological community under the NSW Threatened Species Conservation Act 1995 (NSW DPI, 2007)
Decline and Threats
While the release of fry for angling has expanded the distribution of golden perch, there has been a noticeable decline in abundance within its natural range over the past 3 decades. Cadwallader and Backhouse (1983) noted a worrying decline in the range and abundance of the species, and implicated dams and weirs for preventing upstream migrations and reducing flooding events. Similarly, Koehn and Morison (1990) recognized that despite the increase in range, due to artificial stocking and translocation, golden perch populations have been adversely affected by weirs. While the decline in golden perch is most likely a result of a combination of factors, knowledge of the specific requirements of the species allows us to make an informed assessment of these threats.
Dams and weirs are the main cause of golden perch decline throughout the Murray-Darling system. Mallen-Cooper (1994) noted that there were more than 250 dams and weirs on the major streams of the Murray-Darling system. Recent estimates confirm that the Murray-Darling system as the most regulated river system in the country, with over 3600 artificial barriers to fish movement (Crook, D.A, 2008, pers. comm., October 9). Barriers most obviously impact upon golden perch by preventing the upstream and downstream movements that are essential to potamodromous fish. Impediments to movement could isolate golden perch from specific spawning sites (O’ Conner et al., 2006) and threaten the survival of eggs, larvae and juveniles. The disappearance of natural populations of golden perch from the upper River Murray, following the construction of Hume Dam and Yarrawonga Weir has been acknowledged (Mallen-Cooper, 1992).
The direct exclusion of migratory fish from their specific habitats is only one the impacts of artificial barriers. While some low level weirs may be navigable, studies have shown that there are various lethal and sub-lethal effects of moving downstream over or through weir structures, such as abrasion, eye damage, embolism and death (O’Connor et al., 2006). Additionally, there is a reduction in the ecosystem diversity, the loss of recolonisation opportunities, angling pressure and, in the long term, a reduction in genetic diversity that can result from barriers. Barriers also obstruct and reduce the available suitable habitat for aquatic fauna. “Prevention of passage of aquatic biota as a result of the presence of instream structures” is listed as a potentially threatening process under the Flora and Fauna Guarantee Act 1988.
Alteration of temperature regimes
A corollary of dams is cold water pollution, which can adversely affect ecosystem parameters. The low level outlets on dams form cold layers completely lacking oxygen, which produce habitat areas unsuitable for fish and release de-oxygenated water into the river system (Koehn and O’Connor, 1990). This may result in localized extinctions downstream from dams as water consistently fails to reach the critical temperatures required for spawning. Although adult golden perch are known to tolerate a wide temperature and salinity range (Merrick and Schmida, 1984), their spawning and migratory behaviour is highly sensitive to appropriate temperature changes. There may also be secondary impacts of altered temperature regimes, in that it could affect metabolic growth and food availability (Koehn and O’Connor, 1990). “The alteration to the natural temperature regimes of rivers and stream” is listed as a potentially threatening process under the Flora and Fauna Guarantee Act 1988.
Recruitment in golden perch is strongly influenced by river regulation as spawning is initiated by rises in water level. River regulation, in particular irrigation discharges, often reverses natural flows, resulting in high flows during summer and low flows during winter. Natural fluctuations in water levels and seasonal flooding are also reduced (Koehn and O’Connor, 1990). This altered water flow affects the ability of fish to spawn and their adult movement patterns. River regulation may also alter the quality and availability of floodplain habitats, which are essential as a food source and nursery for fry and juveniles. Reduced flooding also decreases the chance to flush out sediment and areas of poor water quality, while sudden reductions in water levels can leave fish and/or eggs stranded above the water level (Koehn and O’Connor, 1990). “The alteration to the natural flow regimes of rivers and streams” is listed as a potentially threatening process under the Flora and Fauna Guarantee Act 1988.
Unlike some other native fish species, golden perch are not particularly susceptible to predation from introduced species, such as Brown trout. They are, however, vulnerable to competition from other top-order predatory introduced species. The species of most concern is the redfin or English perch (Perca fluviatilis) which has been known to compete with golden perch for food and space (Cadwallader and Backhouse, 1984; Arthington and McKenzie, 1997). The interaction of other introduced fish species with golden perch is less, but it is known that Carp, Roach and Goldfish have an overlapping diet with golden perch (Koehn and O’Connor, 1990). It is likely that trout, redfin and carp also compete with golden perch for habitat space and predate upon their eggs and larvae.
Introduced species also have the adverse effect of introducing pathogens and diseases and negatively affecting the surrounding habitat. Carp, in particular, has been known to damage habitat by uprooting plants, increase sedimentation and turbidity and destabilize banks (O’Dwyer, C., 2008, pers. comm., October 20). Mosquito fish, also widespread in Victoria, can alter the trophic structure of a habitat by feeding upon a number of aquatic insects and larvae (Arthington and McKenzie, 1997). “The introduction of live fish into waters outside their natural range within a Victorian catchment after 1770” is listed as a potentially threatening process under the Flora and Fauna Guarantee Act 1988.
Loss of riparian and aquatic vegetation
Riparian vegetation is crucial to freshwater ecosystems. It acts as a buffer from surrounding activities and provides habitat, shade, nutrients and additional food in the form of terrestrial invertebrates (Koehn and O’Connor, 1990). Many riparian vegetation zones in Victoria have been cleared and resulted in increased runoff and erosion, loss of protective cover from predation and high water velocity, as well as a valuable nursery habitat for larvae and juveniles (Mallen-Cooper, 1992). There is little detailed information on the importance of specific riparian vegetation to golden perch but Gehrke (1990) suggested golden perch larvae are closely associated with river red gum leaf litter. Similarly, a decline in aquatic vegetation is detrimental to both adult and juvenile fish. Aquatic vegetation provides a complex habitat and food source, and the loss of aquatic vegetation has been implicated in the decline of many native freshwater fish (Mallen-Cooper, 1992). “Removal of wood debris from Victorian streams” and “Degradation of native riparian vegetation along Victorian rivers and streams” are listed as potentially threatening processes under the Flora and Fauna Guarantee Act 1988.
Stocking and Translocation
Golden perch has been stocked and translocated widely across parts of Australia and outside of its natural range. This has been done for commercial (farming) and recreational purposes. Inappropriate breeding and stocking programs, however, are likely to severely impact upon golden perch populations in the long-term. There is a crucial need to ensure that breeding programs maximize the genetic composition of stocks. There is already ample evidence that new sub-species of golden perch have emerged in VIC, NSW and QLD which needs further investigation to ensure genetic diversity and integrity (Musyl and Keenan, 1992; O’Connor et al., 2005).
Existing Conservation Measures
Golden perch has only recently been listed as vulnerable under the FFG Act 1988. That listing is specific to natural populations only and there is no listing under the EPBC Act 1999. Consequently, there has been no specific management or action taken to conserve golden perch populations, despite warnings of their decline over the past three decades (Cadwallader and Backhouse, 1983).
The golden perch is part of a larger ecological community, however, which has been the target of conservation measures. It is also found in sympatry with Murray Cod, which is involved in an active management plan (Lintermans and Phillips, 2005). Protection of Murray Cod and its associated habitat has undoubtedly benefited golden perch as well.
There has also been recognition of the processes that threaten golden perch and other native fish populations. Action statements have been compiled for “Prevention of passage of aquatic biota by instream structures” (No.129) and “Introduction of live fish into waters within Victorian river catchments” (NO.190). As a result, there have been a number of management actions undertaken and proposed that are likely to benefit golden perch:
• The provision of fishways to provide fish passage. While the first fishways built in the country were considered inadequate, the current vertical-slot design has proven more efficacious. The State Fishway Program, established by the Victorian Government in 1997, has been responsible for monitoring the impact of weirs and fishways. The Murray-Darling Basin Commission “Hume to the sea” program has aimed at modifying existing in-stream structures which are considered barriers to fish migration (MDBC, 2007).
• The Native Fish Management Strategy for the Murray Darling Basin has proposed that altered flow regulation practices to enhance restoration of native fish populations should be given high priority.
• The Fisheries Act 1995 gives powers to specifically protect fish habitat and there has been increasing recognition of the threats posed by introduced species. A variety of species (including carp and mosquitofish) are listed as noxious under the Fisheries Act 1995 and penalties apply for possession of live specimens. There are also strict requirements for permits to stock non-native fish, such as Brown trout.
• A variety of methods were trialed to eradicate Carp from Victorian waters, including poisoning and fine-mesh screens (O’ Dwyer, 2008, pers. comm., October 20). A national management strategy for physical removal of Carp has been implemented since 2000 (MDBC, 2000). Its goals are to: prevent spread of carp, reduce impact of cap to acceptable levels, promote environmentally and socially acceptable applications of carp eradication and control programs, improve community understanding of carp impacts, and promote cost efficient use of public resources in carp eradication and control programs.
Long term objective
Maintain and increase Golden perch numbers throughout their natural range.
Objectives of this Action Statement
- Establish the extent and density of populations at least 8 sites in Victoria to provide baseline data for management actions.
- Ensure the provision of suitable fishways and modifications to weirs.
- Ensure that the required and recommended steps are being undertaken to improve habitat and water quality.
- Determine viability of increasing the number of populations and individuals in northern parts of Victoria.
Intended Management Actions
Objective 1 Establish the extent and density of populations at least 8 sites in Victoria to provide baseline data for management actions.
1. Undertake surveys of areas where extant populations are known to occur to determine status of species in these areas.
Target: Develop a standardized methodology for sampling within 6 months – 1 year. Conduct surveys in historical and current range of species to provide useful data within 3 years.
Responsibility: DSE (Biodiversity and Natural Resources Division), DSE (Arthur Rylah Institute), DPI (Fisheries Victoria)
2. Monitor selected sites to determine impact of management changes on golden perch population.
Target: Using standardized methodology, monitor population structure in at least 8 sites within 5 years.
Responsibility: DSE (Biodiversity and Natural Resources Division), DPI (Fisheries Victoria)
Objective 2: Ensure the provision of suitable fishways and modifications to dams and weirs
3. Monitor movement and spawning patterns significant populations of Golden perch under the DSE Fishways program.
Target: Employ radio-tracking to monitor the movement patterns of adult golden perch around fishways. Assess relative spawning and recruitment levels of Golden perch between fishways.
Responsibility: DSE (Water Sector Group)
4. Develop a priority list of dams for remediation works to reduce impact of cold water pollution. Develop a priority list of weirs for modifications to incorporate vertical-slot fishways where cost-effective.
Target: Develop lists within a year and liaise with relevant water authorities to facilitate remediation works.
Responsibility: DSE (Water Sector Group), State Water authorities
5. Recommend against construction of further weirs, particularly undershot weirs, in fragile sections of the Murray-Darling river system.
Target: Liaise immediately with water authorities and state government planning authorities to determine inappropriate areas for barrier construction.
Responsibility: DSE (Water Sector group), DSE (Arthur Rylah Institute)
Objective 3: Ensure that the required and recommended steps are being undertaken to improve habitat and water quality.
6. Implement recommendations identified in existing flow management plans and ensure that those in development and planning phase incorporate consideration of all species that are dependent on water level rises for spawning.
Target: Liaise with all relevant Water authorities to establish lines of communication within 1 year, regarding relevant streamflow management plans.
Responsibility: DSE (Water Sector Group), Catchment Management authorities, Water authorities.
7. Implement riparian and instream habitat restoration plans. Ensure habitat protection is a key management objective through Victorian freshwater regions.
Target: Identify key habitat requirements for entire life cycle for golden perch (and associated native fish species) within 1 year.
Responsibility: DSE (Biodiversity and Natural Resources Division)
Objective 4: Determine viability of increasing the number of populations and individuals in northern parts of Victoria.
8. Assess feasibility of reintroduction within northern areas and develop a reintroduction plan. Issues to be addressed include site selection, numbers to be reintroduced, genetic considerations, threat management and monitoring.
Target: Develop a reintroduction plan within 3 years.
Responsibility: DSE (Biodiversity and Natural Resources Division)
9. Monitor significant golden perch population numbers to determine the status of current populations, nature of threats and assess the viability of populations for future reintroduction plans.
Target: Compile an extensive database of approximate population numbers of stocks of golden perch in Victorian rivers and lakes within 5 years.
Responsibility: DSE (Arthur Rylah Institute), DSE (Biodiversity and Natural Resources Division)
The current status of Golden perch populations is of concern and management actions should be undertaken at the earliest date, to prevent further decline in abundance. The examples of Macquarie perch and Silver perch (which are listed as Endangered and Critically Endangered, respectively), should be instructive. It should also be clear that implementation of recovery plans for those species will assist with the conservation of golden perch and vice versa.
Anderson, J.R., Morison, A.K. and Ray, D.J. (1992) Validation of the use of thin-sectioned otholiths for determining the age and growth of Golden perch, Macquaria ambigua, in the Lower Murray-Darling Basin, Australia. Australian Journal of Marine and Freshwater Research 43: 1103-1128
Arthington, A.H. and McKenzie, F. (1997) Review of impacts of displaced/introduced fauna associated with inland waters, Australia: State of the Environment Technical Paper Series (Inland Waters), Department of the Environment, Canberra.
Arumugam, P.T. (1990) A continuous flow-chamber to study prey preferences of Golden perch (Macquaria ambigua Richardson) larvae. Hydrobiologia 190: 247-251
Australian Natural Resources Atlas (2007) Biodiversity Assessment –Victorian Midlands. Available: http://www.anra.gov.au/topics/vegetation/assessment/vic/ibra-vm-species-threats.html [Accessed: 20 September, 2008]
Baumgartner, L.J., Reynoldson, N. and Gilligan, D.M. (2006) Mortality of larval Murray cod (Maccullochella peelii peelii) and golden perch (Macquaria ambigua) associated with passage through two types of low-head weirs. Marine and Freshwater Research 57(2): 187-191
Baumgartner, L.J. (2007) Diet and feeding habits of predatory fishes upstream and downstream of a low-level weir. Journal of Fish Biology 70: 879-894.
Brumley, A.R. (1987) Past and present distribution of golden perch Macquaria ambigua (Pisces: Percichtyidae) in Victoria, with reference to releases of hatchery-produced fry. Proceedings of the Royal Society of Victoria 99: 111-116
Cadwallader, P.L. and Backhouse, G.N. (1983) A guide to the freshwater fish of Victoria. Victorian Government Printing Office, Melbourne.
Collins, A.L. and Anderson, T.A. (1999) The role of food availability in regulating reproductive development in female golden perch. Journal of Fish Biology 55: 94-104
DPI (2007) Information Notes – Freshwater Fish of Victoria: Golden Perch. Available: http://www.dpi.vic.gov.au/dpi/index.htm [Accessed: 10 October, 2008]
DSE (2007) Advisory List of Threatened Vertebrate Fauna in Victoria – 2007. Department of Sustainability and Environment, East Melbourne
Gehrke, P.C. (1990) Clinotactic responses of larval Silver perch and Golden perch to simulated environmental gradients. Australian Journal of Marine and Freshwater Research 41: 523-528
Humphries, P. and Lake, P.S, (2000) Fish larvae and the management of regulated rivers. Regulated Rivers: Research & Management 16: 421-432.
Koehn, J,D. and O’Connor, W.G. (1990) Threats to Victorian native freshwater fish. The Victorian Naturalist 107(1): 5-12
Koehn, J.D. and Morison, A.K. (1990) A review of the conservation status of native freshwater fish in Victoria. The Victorian Naturalist 107(1): 13-25
Lintermans, M. and Phillips B. (eds) (2005) Management of Murray Cod in the Murray-Darling Basin: Statement, recommendations and supporting papers. Proceedings of a workshop held in Canberra ACT, 3–4 June 2004. Murray-Darling Basin Commission, Canberra.
Lintermans, M. (2007) Fishes of the Murray-Darling Basin: An introductory guide. Murray-Darling Ministerial Council, ACT
Mallen-Cooper, M. 1992. Habitat changes and declines of freshwater fish in Australia: What is the evidence and do we need more? In: Hancock, D.A. (ed.) ‘Sustainable Fisheries through sustaining fish habitat’ Australian Society for Fish Biology Workshop, Victor Harbor, SA. 12-13 August. Bureau of Resource Sciences Proceedings AGPS, Canberra. Pp. 118-123.
Mallen-Cooper, M. (1994) Swimming ability of Adult Golden perch, Macquaria ambigua, and Adult Silver perch, Bidyanus bidyanus, in an experimental vertical-slot fishway. Australian Journal of Marine and Freshwater Research 45: 191-198
Mallen-Cooper, M. and I. G. Stuart (2003) Age, growth and non-flood recruitment of two potamodromous fishes in a large semi-arid/temperate river system. River Research and Applications 19: 697–719.
MDBC (2007) Native Fish Strategy: Building Fish Freeways. Murray Darling Basin Comission, Canberra. Available: http://thelivingmurray.mdbc.gov.au/__data/page/195/fishways_web.pdf [Accessed: October 10, 2008]
Merrick, J.R. and Schmida, G.E. (1984) Australian freshwater fishes: biology and management. North Ryde, NSW.
Musyl, M.K. and Keenan, C.P. (1992) Population genetics and zoogeography of Australian freshwater golden perch, Macquaria ambigua (Richardson 1845) (Teleostei: Percichthyidae), and electrophoretic identification of a new species from the Lake Eyre basin. Australian Journal of Marine and Freshwater Research 43: 1585-1601.
NSW DPI (2007) Endangered ecological communities in NSW: Lower Murray river aquatic ecological community. Available: http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0009/171549/Lower-Murray-River-aquatic-ecological-community.pdf [Accessed: 10 October, 2008]
O’Connor, J.P., O’Mahony, D.J. and O’Mahony, J.M. (2005) Movements of Macquaria ambigua, in the Murray River, south-eastern Australia. Journal of Fish Biology 66: 392-403.
O’Connor, J.P., O’Mahony, D.J., O’Mahony, J.M., and Glenane T.J. (2006) Some impacts of low and medium head weirs on downstream fish movement in the Murray– Darling Basin in Southeastern Australia. Ecology of Freshwater Fish. 15: 419–427
Reynolds, L.F. (1983) Migration patterns of five fish species in the Murray-Darling river system. Australian Journal of Marine and Freshwater Research 34: 857-871
Rowland, S.J. (1996) Development of techniques for the large-scale rearing of the larvae of the Australian freshwater fish golden perch, Macquaria ambigua (Richardson, 1845). Marine & Freshwater Research 47: 233-242.
Ye, Qifeng (2004) Golden Perch (Macquaria ambigua) – Fishery Assessment Report to PIRSA Fisheries (Publication No. RD04/0167). South Australian Research and Development Institute. Available: http://www.sardi.sa.gov.au/pages/aquatic/pub/iwee/rd04_0167.pdf [Accessed: 05 October, 2008]
Information and research compiled by Taimur Siddiqi, Postgraduate student at the University of Melbourne (October 22, 2008)