Golden perch are medium-sized fish, commonly 30–40cm and 1–2kg in rivers. Fish from rivers are smaller and somewhat streamlined — fish in man-made impoundments are much deeper-bodied and show much greater average and maximum sizes. In rivers, has been recorded to 9kg, in impoundments to 15kg. A 24-kg fish caught from Kow Swamp, Victoria in the early 1900s, and labelled and sold as a "Murray perch", is often referred to as the largest recorded golden perch, but this record is doubtful — this record grossly exceeds all other size records for golden perch, and the specimen in question is far more likely to have been a Murray cod (Maccullochella peelii), which grow to far larger sizes than golden perch.
Golden perch have an elongated, deep but laterally compressed body, with a sizeable mouth, small to moderate-sized eyes, a distinct curve to the forehead, and a distinct "hump" above the head. The opercula or gill covers possess a small, flat spine sharp enough to cut unwary fishermen's fingers. The caudal fin, soft dorsal fin, and anal fin are rounded. The spiny dorsal fin is short to moderate in length and strong. Golden perch vary from in colour from pale silvery-gold (turbid waters) to deep yellow/gold or bronze-black (very clear waters).
A wild golden perch from an upland river: Note the much leaner, slimmer shape of wild specimens and the intense golden colouration.
Taxonomy
The genus name Macquaria derives from the Macquarie River, where the first species in the genus, the Macquarie perch (M. australasica), was collected. However, the genus name Macquaria was applied to golden perch much later. The naturalist Richardson actually named golden perch Datnia ambigua and applied the specific name ambigua (Latin for "doubtful") to the species because, as he states in his species description, he could not decide in which of two genera to place it, Dules (now Kuhlia species) or Datnia (now various Terapontidae species):
“I have had much doubt as to whether this fish should be placed in the genus Dules, or Datnia. It agrees with the group of Dules that has two opercular points, in the number of dorsal rays, and in the presence of palatine teeth, but in general habit it is more like Datnia, strongly resembling it in the strength of its dorsal and anal spines, and in the number of rays in the anal. The only two specimens [8.5 and 14 inches standard length] I had the opportunity of examining are dried, and are both mutilated in the caudal fin, so that I am unable to describe the form of that member, and can give no anatomical details.”
This choice of specific name was unwittingly appropriate. Golden perch are neither a khulid nor a terapontid, and Richardson also erroneously stated the golden perch's habitat was "Western Australia", when in fact the species is not found in that state. (This error was corrected, presumably by Richardson himself, in at least one reprint of the publication in question.)
Range
Golden perch are native primarily to lowland reaches of the Murray–Darling River system, but also extend far into slope habitats and occasionally even lower upland reaches. In the Murray–Darling system golden perch are often found in sympatry with Murray cod.
The Macquaria perches, of which golden perch are one, continue the trend present in Murray–Darling native fish genera of diversification into more generalist lowland species and more specialist upland species. Golden perch, M. ambigua, represent the lowland species, while the closely related Macquarie perch, M. australasica, is the more specialised upland species which used to inhabit the upland reaches of the southern Murray–Darling basin, although this endangered species has now been almost wholly displaced by introduced trout species, dams, and associated effects such as cold-water pollution, and habitat degradation/modification.
Like many Murray–Darling native fish, golden perch have crossed river catchments through natural river capture/connection events. Golden perch are found naturally in the Fitzroy–Dawson River in central Queensland and the internal Lake Eyre–Cooper Creek drainage system of Central Australia. The fish has also been successfully introduced to other river systems in the Northern Territory, Queensland, and New South Wales, confusing studies of the natural range.[4] Introductions into Western Australia have been unsuccessful.
Both of these separate populations are at least subspecies, possibly separate species, due to isolation from Murray–Darling populations, genetic drift, and natural selection. The taxonomy of golden perch has not been updated to reflect this, although the term Macquaria ambigua oriens, denoting subspecies status, has recently appeared in literature discussing the Fitzroy–Dawson population. Some research[5] indicates the Fitzroy River population is the ancestral golden perch population.
Reproduction and biology
In the Murray River, wild male golden perch generally reach sexual maturity at 3 years of age and 32.5cm in length, and wild female golden perch at 4 years of age and 40cm in length.[6] The latter fact is a concern given that minimum size limits for the species are currently less than 40cm, at 30cm.
Originally, temperatures close to 24°C were considered necessary for golden perch to spawn,[7] but as with all Murray-Darling fish species, multiple field studies have shown that their "required" spawning temperature is flexible and that they can and do spawn at lower temperatures.[8] In the Barmah Forests region of the Murray River, for instance, fertilised drifting golden perch eggs have been netted in water temperatures as low as 16.9 degrees Celsius (full range 16.9 to 24.7 degrees).[9] Golden perch have a flexible breeding strategy but generally (but not always) require a spring or summer flood or "fresh" (temporary, within-channel increase in flow) to stimulate spawning. Like some other primarily lowland native fish species of the Murray–Darling river system, these floods or freshes appear to be necessary for good survival and recruitment of spawned fish. Very small freshes appear to be sufficient for some spawning and recruitment, however.
Golden perch are highly fecund; females between 2.2 and 2.4kg produce about half a million eggs per spawning event, with fish above 2.5kg producing well in excess of this number.[10] The eggs are generally planktonic, and hatch fairly quickly (24 to 36 hours).[11]
Like other Macquaria species, sexual dimorphism is present, with females reaching much larger maximum sizes than males. Females also reach sexual maturity at older ages and larger sizes than males.
Very long migrations are part of the golden perch's ecology, particularly preceding spawning. Adult fish have been recorded migrating well over 1,000km when flood conditions allow passage over weirs and other man-made obstructions.[12] Smaller migrations are important in the ecology and dispersal of juvenile fish.[13] The evidence suggests that before European settlement, huge shoals of golden perch roamed the entire lowland and slope reaches of the vast Murray-Darling River system, unimpeded. Thus, the gradual loss of fish passage through the numerous dams, weirs, locks, and other barriers (estimated at 4,000 in the Murray-Darling system[14]) now present has had severe impacts on the species. Some major weirs have been remediated to provide fish passage, however.
Golden perch have unusually broad temperature limits, from 4 to 37°C, and unusually high salinity limits for a freshwater fish, up to 33 parts per thousand.[15][16]
Golden perch continue the trend, among many native fish of southeast Australia, of being very long-lived. Longevity is a survival strategy in the often challenging Australian environment which ensures that most adults participate in at least one exceptional spawning and recruitment event. These events are often linked to unusually wet La Niña years and may only occur every one or two decades. Maximum recorded age is 26 years.[13]
Generally a very good angling species (though renowned for being "moody"), golden perch are fished throughout their range. Baits include small yabbies and shrimp, as well as various types of deeper-running lures. Recreational harvest of the species is suspected to be significant.
Conservation
Wild populations have declined significantly, and a number of populations lost in upper reaches of rivers, due to dams and weirs blocking migration, mitigating floods and freshes, regulating flows, and releasing unnaturally cold water ("thermal pollution"), all of which interfere with migration, spawning, and recruitment. They are listed under the Victorian Flora and Fauna Guarantee Act 1988 and classified as "Vulnerable" for management purposes.[4] Golden perch are extremely migratory and migration appears to have been important in maintaining populations over the length of rivers, particularly the upper reaches.
Weirs are proving to be a more significant threat to golden perch than first thought, with a 2006 study showing that about 90% of golden perch larvae passing through undershot weirs are killed.[17] The species is bred in hatcheries, though, in large numbers, and stocked. Concerns over genetic diversity issues are growing.
Related Research Articles
The Murray cod is a large Australian predatory freshwater fish of the genus Maccullochella in the family Percichthyidae. Although the species is called a cod in the vernacular, it is not related to the Northern Hemisphere marine cod (Gadus) species. The Murray cod is an important part of Australia's vertebrate wildlife—as an apex predator in the Murray-Darling River system—and also significant in Australia's human culture. The Murray cod is the largest exclusively freshwater fish in Australia, and one of the largest in the world. Other common names for Murray cod include cod, greenfish, goodoo, Mary River cod, Murray perch, ponde, pondi and Queensland freshwater cod.
The eastern freshwater cod, also known as the eastern cod or Clarence River cod, is a large predatory freshwater fish of the genus Maccullochella and the family Percichthyidae, that occur in the coastal Clarence River system of north-eastern New South Wales. Eastern freshwater cod are closely related to the Murray cod of the Murray-Darling River system, and are considered an icon of the Clarence River system.
The trout cod or bluenose cod, is a large predatory freshwater fish of the genus Maccullochella and the family Percichthyidae, closely related to the Murray cod. It was originally widespread in the south-east corner of the Murray-Darling river system in Australia, but is now an endangered species.
The members of the family Percichthyidae are known as the temperate perches. They belong to the order Perciformes, the perch-like fishes.
The Macquarie perch is an Australian native freshwater fish of the Murray-Darling river system. It is a member of the family Percichthyidae and is closely related to the golden perch.
The Australian bass is a small- to medium-sized species of primarily freshwater fish found in coastal rivers and streams along the east coast of Australia. A member of the genus Macquaria from the family Percichthyidae, the Australian bass is an important member of the native fish assemblages found in east coast river systems. It is a native predatory fish and an extremely popular game fish species among anglers. The species was simply called perch in most coastal rivers where it was caught until the 1960s, when the name "Australian bass" started to gain popularity.
The estuary perch is a species of temperate perch endemic to south-eastern Australia, where it prefers brackish waters such as lower tidal reaches of coastal lakes, rivers, and streams.
The river blackfish is a freshwater fish endemic to the temperate waters of south-eastern Australia. It is found from southern Queensland through to central Victoria, including in the Murray-Darling river system. It is also found in some eastern and southern flowing coastal rivers. Found primarily in upland and "midland" habitats, though early records of fish fauna suggest it was originally far more extensively distributed and was found in some lowland habitats as well. Originally, river blackfish co-inhabited many of its lowland and "midland" habitats with species such as Murray cod and golden perch, and its upland habitats with species such as trout cod and Macquarie perch. It is a popular angling fish in some parts of its range.
The two-spined blackfish is a species of temperate perch endemic to Australia.
The western carp gudgeon is one of several carp gudgeon species. Carp gudgeons are very small perciform fish found in the Australian Murray-Darling River system, mainly in lowland environments, but some have been observed in upland environments. They are often found in small creeks, as well as billabongs and the edges of larger rivers. They prefer water 1 to 2 m deep with aquatic weed and structure provided by rocks or sunken timber.
The Mary River cod is a species of temperate perch native to the coastal Mary River system of southern Queensland, Australia. Mary River cod are one of Australia's most endangered freshwater fishes and are notable for being the most northerly of the four Maccullochella cods found or once found in coastal river systems of eastern Australia.
The Brisbane River cod was a unique form of Maccullochella cod that occurred naturally in the Brisbane River system, an east coast river system in south east Queensland, Australia. The Brisbane River Cod was known as the Bumgur by the Jinibara people centred in the Kilcoy region and the junction of the Stanley and Brisbane Rivers. Their exact taxonomic status is not known, but based on several genetic studies it is suspected that Brisbane River Cod were a species intermediate between eastern freshwater cod of the Clarence River and Richmond River systems in northern New South Wales and Mary River cod of the Mary River in southern Queensland.
Maccullochella is a genus of large Australian predatory freshwater fish within the family Percichthyidae. The genus Maccullochella was named after an early Australian fish researcher with the surname McCulloch.
The silver perch is a medium-sized freshwater fish of the family Terapontidae endemic to the Murray-Darling river system in south-eastern Australia.
Galaxias olidus, the mountain galaxias, is a species of freshwater galaxiid fish widely found in southeastern Australia.
Scottsdale Reserve is a 1,328-hectare (3,280-acre) nature reserve on the Murrumbidgee River in south-central New South Wales, Australia. It is 79 kilometres (49 mi) south of Canberra, and 4 kilometres (2.5 mi) north of Bredbo. It is owned and managed by Bush Heritage Australia (BHA), which purchased it in 2006. The purchase was supportive of projects aiming to connect existing fragmented remnant habitat such as K2C. Since the 1870s up until 2006, the land was used for agriculture – primarily sheep grazing with some minor cropping. A significant component of the Reserve has been cleared of native vegetation.
The Mongarlowe River is a perennial river of the Shoalhaven catchment located in the Southern Tablelands region of New South Wales, Australia. It was also known as Little River, during the 19th century.
The New South Wales Central Murray Forests lie on the floodplain of the Murray River in the Riverina region of south-central New South Wales, Australia. On 20 May 2003 the forests were recognised as a wetland site of international importance (RS1291) by designation under the Ramsar Convention on Wetlands.
The southern pygmy perch, also known as the Tasmanian pygmy perch, is a species of freshwater ray-finned fish, a temperate perch from the family Percichthyidae which is native to south-eastern Australia and Tasmania.
The Nocoleche Nature Reserve is a conservation area in New South Wales on the Paroo River located 20 kilometres south of the town of Wanaaring, New South Wales. It was created in 1979, and has an area of 711.08 km².
↑ Faulks LK, Gilligan DM and Beheregaray LB (2010). Clarifying an ambiguous evolutionary history: range-wide phylogeography of an Australian freshwater fish, the golden perch (Macquaria ambigua). Journal of Biogeography. doi:10.1111/j.1365-2699.2010.02304.x
↑ 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 Applications19: 697–719.
↑ Koehn & O'Connor (1990). Biological Information for Management of Freshwater Fish in Victoria. Melbourne: Department of Conservation & Environment. p.72. ISBN0-7306-0590-6.
↑ Reynolds LM (1983). Migration patterns of five fish species in the Murray-Darling River system. Australian Journal of Marine and Freshwater Research 34: 857–871.
↑ Lintermans M (2007). Fishes of the Murray-Darling Basin: An introductory guide. Murray-Darling Basin Commission, Canberra.
↑ Merrick JR & Schmida GE (1984). Australian Freshwater Fishes: Biology and Management. J. Merrick, North Ryde, New South Wales.
↑ McDowall RM (ed.) (1996). Freshwater Fishes of South-eastern Australia. Second Edition. Reed Books, Sydney.
↑ 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 Research57: 187–191
King AJ, Tonkin Z and Mahoney J (2008). Environmental flow enhances native fish spawning
and recruitment in the Murray River, Australia. River Research and Applications. DOI: 10.1002/rra.1209
Koehn, J. D. and Harrington, D. J. (2005). Collection and distribution of early life stages of the Murray cod (Maccullochella peelii peelii) in a regulated river. Australian Journal of Zoology53: 137–144.
Lake, J.S. (1967). Rearing experiments with five species of Australian freshwater fishes. I. Inducement to spawning. Australian Journal of Marine and Freshwater Research18: 137–153.
Lintermans M (2007). Fishes of the Murray-Darling Basin: An introductory guide. Murray-Darling Basin Commission, Canberra.
Richardson, John. Ichthyology of the voyage of H.M.S. Erebus & Terror, under the command of Captain Sir James Clark Ross, R.N., F.R.S. LONDON: M.DCCC.XLIV—M.DCCC.XLVIII [1844–1848]. Longman, Brown, Green and Longmans.
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 and Freshwater Research47: 233–242.
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