Golden perch
Encyclopedia
The golden perch, Macquaria ambigua, is an Australia
n native freshwater fish
, primarily of the Murray
-Darling
river system. It is not a true perch of the genus Perca
.
The genus name Macquaria
derives from the Macquarie River
where the first species in the genus was collected. The specific name for golden perch—ambigua—may derive from Latin
form of the word 'ambiguous', which has connations : of "two or more sides", and thus refer to the strong lateral compression (narrow, deep, flanks) adult golden perch display, but more likely refers to the confusion over where the original specimen ('holotype
') was collected. (Richardson marked the specimen as having been collected from a marine environment.)
These fish are also commonly known as "Callop" (particularly in South Australia), and can easily be distinguished from Silver Perch
by a much larger mouth and pronounced hump on their head (in the latter stages of Juvenile life).
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).
–Darling
river system, but also push significant distances into upland reaches as well. In the Murray–Darling system golden perch are often found in sympatry
("together with") Murray cod
, Maccullochella peelii peelii.
The Macquaria perches, of which golden perch are one, continue the trend present in native fish genera of the Murray–Darling system of speciating into a lowland species and a specialist upland species. Golden perch, Macquaria ambigua, are the lowland species while the closely related Macquarie perch
, Macquaria australasica, is the speciated, 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 and habitat degradation/modification.
Like many Murray–Darling native fish, golden perch have crossed into eastern coastal river catchments through natural river capture events. Golden perch are found naturally in the Fitzroy–Dawson river
in central Queensland
and have also entered the internal Lake Eyre
–Cooper Creek
drainage system of Central Australia
.
Both of these separate populations are likely to be separate species due to isolation from parent 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.
ic, 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.
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).
, shrimp
, frog
s, small fish and aquatic invertebrate
s.
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.
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n native freshwater fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
, primarily of the Murray
Murray River
The Murray River is Australia's longest river. At in length, the Murray rises in the Australian Alps, draining the western side of Australia's highest mountains and, for most of its length, meanders across Australia's inland plains, forming the border between New South Wales and Victoria as it...
-Darling
Darling River
The Darling River is the third longest river in Australia, measuring from its source in northern New South Wales to its confluence with the Murray River at Wentworth, New South Wales. Including its longest contiguous tributaries it is long, making it the longest river system in Australia.The...
river system. It is not a true perch of the genus Perca
Perch
Perch is a common name for fish of the genus Perca, freshwater gamefish belonging to the family Percidae. The perch, of which there are three species in different geographical areas, lend their name to a large order of vertebrates: the Perciformes, from the Greek perke meaning spotted, and the...
.
The genus name Macquaria
Macquaria
The Macquaria genus is a genus of medium-sized, predatory native fish in the Percichthyidae family. The Macquaria genus was created by merging the old genera Plectrotripes and Macquaria and Percalates...
derives from the Macquarie River
Macquarie River
The Macquarie River is one of the main inland rivers in New South Wales. Its headwaters rise in the central highlands of New South Wales near the town of Oberon. The river travels generally northwest past the towns of Bathurst, Wellington, Dubbo, Narromine, and Warren to the Macquarie Marshes...
where the first species in the genus was collected. The specific name for golden perch—ambigua—may derive from Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
form of the word 'ambiguous', which has connations : of "two or more sides", and thus refer to the strong lateral compression (narrow, deep, flanks) adult golden perch display, but more likely refers to the confusion over where the original specimen ('holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
') was collected. (Richardson marked the specimen as having been collected from a marine environment.)
These fish are also commonly known as "Callop" (particularly in South Australia), and can easily be distinguished from Silver Perch
Silver Perch
Silver perch is a medium sized freshwater fish endemic to the Murray-Darling river system in south-eastern Australia. The scientific name comes from an aboriginal name for the species recorded by Major Mitchell on his 1832 expedition. It is not a perch, being a grunter in the family Terapontidae...
by a much larger mouth and pronounced hump on their head (in the latter stages of Juvenile life).
Description
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. Golden perch have an elongated deep body, laterally compressed, with a sizable mouth, small to moderate sized eyes and distinct curve to the forehead and "hump" above the head. The caudal fin, soft dorsal finDorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
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).
Angling
Generally a very good angling species, golden perch are fished for Australia-wide. The best baits include small yabbies and shrimp, with yabbies being a favourite and larger ones around 5 or 6cm can produce great fish. Fish of around 1-5kg are common but 4 or 5 kilogram fish are sometimes rare, the will grow to around 75cm and 23kg which is the largest ever recorded. If using yabbies for bait you will generally feel one bite, which will be the fish trying to take the yabbies' claws off, then the fish with come and swallow the yabby. Golden perch can provide an excellent fight because of their large paddle like tail.Range
It is native primarily to lowland reaches of the MurrayMurray River
The Murray River is Australia's longest river. At in length, the Murray rises in the Australian Alps, draining the western side of Australia's highest mountains and, for most of its length, meanders across Australia's inland plains, forming the border between New South Wales and Victoria as it...
–Darling
Darling River
The Darling River is the third longest river in Australia, measuring from its source in northern New South Wales to its confluence with the Murray River at Wentworth, New South Wales. Including its longest contiguous tributaries it is long, making it the longest river system in Australia.The...
river system, but also push significant distances into upland reaches as well. In the Murray–Darling system golden perch are often found in sympatry
Sympatry
In biology, two species or populations are considered sympatric when they exist in the same geographic area and thus regularly encounter one another. An initially-interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation...
("together with") Murray cod
Murray Cod
The Murray cod is a large Australian predatory freshwater fish of the Maccullochella genus and the Percichthyidae family. Although the species is a called cod in the vernacular, it is not related to the northern hemisphere marine cod species...
, Maccullochella peelii peelii.
The Macquaria perches, of which golden perch are one, continue the trend present in native fish genera of the Murray–Darling system of speciating into a lowland species and a specialist upland species. Golden perch, Macquaria ambigua, are the lowland species while the closely related Macquarie perch
Macquarie perch
The Macquarie perch is an Australian native freshwater fish of the Murray-Darling river system. It is a member of the Percichthyidae family and is closely related to the golden perch ....
, Macquaria australasica, is the speciated, 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 and habitat degradation/modification.
Like many Murray–Darling native fish, golden perch have crossed into eastern coastal river catchments through natural river capture events. Golden perch are found naturally in the Fitzroy–Dawson river
Fitzroy River (Queensland)
The Fitzroy River lies in Queensland, Australia. Its catchment covers an area of 142,665 square kilometres, making it the largest river catchment flowing to the eastern coast of Australia. The river is formed by the joining of the Mackenzie and Dawson rivers at Duaringa. The catchment stretches...
in central Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
and have also entered the internal Lake Eyre
Lake Eyre
Lake Eyre is the lowest point in Australia, at approximately below sea level, and, on the rare occasions that it fills, it is the largest lake in Australia and 18th largest in the world...
–Cooper Creek
Cooper Creek
Cooper Creek is one of the most famous and yet least visited rivers in Australia. It is sometimes known as the Barcoo River from one of its tributaries and is one of three major Queensland river systems that flow into the Lake Eyre Basin...
drainage system of Central Australia
Central Australia
Central Australia/Alice Springs Region is one of the five regions in the Northern Territory. The term Central Australia is used to describe an area centred on Alice Springs in Australia. It is sometimes referred to as Centralia; likewise the people of the area are sometimes called Centralians...
.
Both of these separate populations are likely to be separate species due to isolation from parent 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.
Reproduction and biology
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" 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. 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. The eggs are generally planktonPlankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
ic, and hatch fairly quickly (24 to 36 hours) (Lake, 1967; Rowland, 1996).
Like other Macquaria
Macquaria
The Macquaria genus is a genus of medium-sized, predatory native fish in the Percichthyidae family. The Macquaria genus was created by merging the old genera Plectrotripes and Macquaria and Percalates...
species, sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
is present, with females reaching much larger maximum sizes than males. Females also reach sexual maturity at older, larger sizes than males.
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
La Niña
La Niña is a coupled ocean-atmosphere phenomenon that is the counterpart of El Niño as part of the broader El Niño-Southern Oscillation climate pattern. During a period of La Niña, the sea surface temperature across the equatorial Eastern Central Pacific Ocean will be lower than normal by 3–5 °C...
years and may only occur every one or two decades. Maximum recorded age is 26 years (Mallen-Cooper & Stuart, 2003).
Diet
Golden perch are predators, taking yabbiesCherax
Cherax is the largest and most widespread genus of fully and partially aquatic crayfish in the Southern Hemisphere. Its members may be found in lakes, rivers and streams across most of Australia and New Guinea. In Australia the many species of Cherax are commonly known as yabbies...
, shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
, frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...
s, small fish and aquatic invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s.
Conservation
Wild populations have declined significantly, especially 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 in some reaches of river, usually the upper reaches.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.