Golden perch

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Golden perch
Golden perch.JPG
A large, stocked, female golden perch caught from an impoundment. The fishing lure is still in its mouth.
Conservation status
Not evaluated (IUCN 3.1)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Percichthyidae
Genus: Macquaria
Species: M. ambigua
Binomial name
Macquaria ambigua
(J. Richardson, 1845)
Synonyms
  • Datnia ambigua J. Richardson, 1845
  • Plectroplites ambiguus (J. Richardson, 1845)
  • Ctenolates macquariensis Günther, 1871
  • Dules auratus Castelnau, 1872
  • Dules flavescens Castelnau, 1875
For a fictional inn from J. R. R. Tolkien's legendarium, see The Golden Perch.

The golden perch, Macquaria ambigua, is a medium-sized, yellow or gold-coloured Australian freshwater fish species. It is found primarily in the Murray-Darling river system, though a sub-species is found in the Lake Eyre-Coopers Creek system, and another sub-species, suspected to be ancestral to all other populations, is found in the Fitzroy River system in Queensland. Golden perch are not a true perch of the genus Perca, but a member of the Percichthyidae (temperate perches) family.

This relatively widespread and widely-stocked species is an important angling fish in Australia.

Other common names for golden perch are "goldens", “yellowbelly” and "callop", the latter generally used only in South Australia.

Description[edit]

Golden perch are medium sized fish, commonly 30–40 cm and 1–2 kg 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 9 kg, in impoundments to 15 kg. 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 sizable 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[edit]

The genus name Macquaria derives from the Macquarie River where the first species in the Macquaria genus (Macquarie perch, Macquaria 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 which of two genera to place it in, 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[edit]

Golden perch are native primarily to lowland reaches of the MurrayDarling 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 ("together 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, Macquaria ambigua, represent the lowland species while the closely related Macquarie perch, Macquaria 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 EyreCooper Creek drainage system of Central Australia.

Both of these separate populations are at least sub-species, 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 sub-species status, has recently appeared in literature discussing the Fitzroy–Dawson population. Recent research (Faulks et al., 2010) indicates the Fitzroy River population is the ancestral golden perch population.

Reproduction and biology[edit]

In the Murray River, wild male golden perch generally reach sexual maturity at 3 years of age and 32.5 cm in length, and wild female golden perch at 4 years of age and 40 cm in length (Mallen-Cooper & Stuart, 2003). The latter fact is a concern given that minimum size limits for the species are currently less than 40 cm.

Originally temperatures of close to 24 degrees Celsius were considered necessary for golden perch to spawn (Lake, 1967) but as with all Murray-Darling fish species it has become apparent that their "required" spawning temperature is flexible and that they can and do spawn at somewhat lower temperatures (as low as 20 degrees Celsius) (Koehn & Harrington, 2005). Golden perch have a flexible breeding strategy but generally need 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 to 2.4 kg producing approximately half a million eggs per spawning event with fish above 2.5 kg producing well in excess of this number.[1] The eggs are generally planktonic, and hatch fairly quickly (24 to 36 hours) (Lake, 1967; Rowland, 1996).

Like other Macquaria species, sexual dimorphism is present, with females reaching much larger maximum sizes than males. Females also reach sexual maturity at older, larger sizes than males.

Very long migrations are part of the golden perch's ecology, particularly preceding spawning. Adult fish have been recorded migrating more than 1,000 km when flood conditions allow passage over weirs and other man-made obstructions (Reynolds, 1983). Smaller migrations are important in the ecology of juvenile fish (Mallen-Cooper & Stuart, 2003). The evidence suggests that before European settlement, vast shoals of golden perch roamed the entire lowland and slope reaches of the 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 — Lintermans, 2007) 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 degrees Celsius, and unusually high salinity limits for a freshwater fish, up to 33 parts per thousand (ppt) (Merrick & Schmida, 1984; McDowall, 1996).

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 (Mallen-Cooper & Stuart, 2003).

Diet[edit]

Golden perch are predators, taking yabbies, shrimp, frogs, small fish and aquatic invertebrates.

Angling[edit]

Generally a very good angling species (though renowned for being "moody"), golden perch are fished for throughout their range. Baits include small yabbies and shrimp, with yabbies around 5–6 cm being a favourite bait. Strikes on bait can often be timid but can sometimes be a "smash and grab" affair. Golden perch will take a wide variety of lures. Deep diving plug lures are favoured, though spinnerbaits and vibration lures like "Jackalls" can also be successful. A strike from a golden perch on a lure is often aggressive and they have a powerful fighting style with strong beats of their tail. They are generally not known to take surface lures, although some exceptions occur.

Conservation[edit]

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. Golden perch are extremely migratory and migration appears to have been important in maintaining populations over the length of rivers, particularly the upper reaches.

Recreational harvest of the species is suspected to be significant.

Weirs are proving to be a more significant threat to golden perch than first thought, with a recent studying proving that about 90% of golden perch larvae passing through undershot weirs are killed (Baumgartner et al., 2006).

The species is however bred in hatcheries in large numbers and stocked. Concerns over genetic diversity issues are growing however.

References[edit]

  1. ^ Koehn & O'Connor (1990). Biological Information for Management of Freshwater Fish in Victoria. Melbourne: Department of Conservation & Environment. p. 72. ISBN 0-7306-0590-6. 
  • 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: 187–191
  • 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
  • Froese, Rainer and Pauly, Daniel, eds. (2005). "Macquaria ambigua" in FishBase. 10 2005 version.
  • 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 Zoology 53: 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 Research 18: 137–153.
  • Lintermans M (2007). Fishes of the Murray-Darling Basin: An introductory guide. Murray-Darling Basin Commission, Canberra.
  • "Macquaria ambigua". Integrated Taxonomic Information System. Retrieved 11 March 2006. 
  • 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.
  • 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.
  • 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.
  • 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 Research 47: 233–242.

External links[edit]