Research for how this species communicates and perceives its environment is insufficient. Like most fish, they probably use chemical and visual input as important modes of perceiving and communicating.
Perception Channels: visual ; tactile ; chemical
Predators on M. australasica include Australian bass (Macquaria novemaculeata) and the introduced species: rainbow trout (Oncorhynchus mykiss) and redfin (Perca flavescens).
Known Predators:
This species is a moderate-sized fish that is usually 25 to 40 cm in length and weighs about 1.5 kg. The coloration of Macquaria australasica varies from a dark silvery/purplish grey which looks almost black to a bluish grey or green-brown color with a ventral side that includes shades of pale white or tan with a yellow tinge on some. The fish has an elongated, deep, and laterally compressed body. Their caudal, anal and spiny dorsal fins are usually rounded. The fish have small mouths and white eyes and the irises are silver. Adult species have a humped back and also possess a rounded tail.
Range mass: 1.0 to 2.5 kg.
Average mass: 1.5 kg.
Range length: 18 to 50 cm.
Average length: 30 cm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: female larger
There has not been sufficient research on the lifespan of M. australasica, but average lifespan has been reported at 20 years with a maximum recorded age of 26 years.
Range lifespan
Status: wild: 26 (high) years.
Average lifespan
Status: wild: 20 years.
Average lifespan
Status: wild: 10 years.
This freshwater species lives in rivers and stream, preferring deep, rocky pools. (Reide, 2004). They also favor cool and clear water with slow-moving riffles or shallow running water. Macquaria australasica spawn in lakes and above holes in faster moving riffles at depths of 0 to 4 meters. (DEH, 2005).
Range depth: 0 to 4 m.
Habitat Regions: temperate ; freshwater
Aquatic Biomes: lakes and ponds; rivers and streams
Macquaria australasica is only found in Australia. (Paxton et. al., 1989). In it's native range, this species occurs in highest abundance in the Murray-Darling basin in New South Wales. Macquaria australasica was introduced in the Wannon, Barwon, and Yarra Rivers in Victoria, Australia, as well as the Nepean and Shoalhaven Rivers, in New South Wales. Within these areas, there are three different population areas that this species inhabits including; west of the Great Dividing Range, the Hawkesbury River, and the lower Shoalhaven River.
Some populations are the result of translocations, although few, healthy translocated populations remain.
Two, genetically distinct groups of Macquarie perch have been described from coastal and inland areas. Although it is likely that they represent different species, those species have not been described yet.
Biogeographic Regions: australian (Introduced , Native )
The bulk of their diet consists of aquatic invertebrates such as caddisfly, stonefly and mayfly species, with a small quantity of terrestrial insects taken as well. Adults feed at the bottom of lakes and rivers. Young are zooplanktivores, and eat water fleas, rotifers and water mites by sucking them up into their mouths. (Merrick and Schimda, 1984).
Animal Foods: insects; mollusks; aquatic or marine worms; aquatic crustaceans; zooplankton
Primary Diet: carnivore (Insectivore )
Macquarie perch are important predators in natural ecosystems, and prey to larger animals. The introduced fish species, Salmo trutta and Oncorhynchus mykiss, may compete with Macquarie perch for food.
Macquarie perch have been and are still fished for food. They are important members of native Australian freshwater ecosystems.
Positive Impacts: food
When this species is relocated to other ranges or even within its home range, diseases from other fish are sometimes spread as well, affecting other fish species and other populations of Macquarie perch.
Negative Impacts: injures humans (causes disease in humans )
The eggs of M. australasica are transparent and increase in size to a diameter of 4.0 mm. Once released, they are swept downstream and lodge in pebbles. The eggs usually hatch in 10 to 18 days in temperatures of 11 to 18°C. (Allen, 1989). The larvae then shelter in boulders and pebbles. Females grow much faster than males and are always bigger than males. The fish grow rapidly and their size is determined by the conditions of the water they live in. Age determines onset of gonadal maturation. For females, spawning begins at four years old and continues until the fish are ten years old. Female ovarian development begins earlier in the year around February to April, pauses until August and then rapidly resumes maturation to reach the gravid-gonad stage in late October or early November. For males the development of the testes remains unchanged until August and then a rapid maturation occurs that produces ripe males by October or early November just like the females. Larvae and transitioning juveniles are usually deep bodied with a laterally compressed head. The fish have 24 to 25 myomeres. The large gut in the fish is fully coiled and the gas bladder is over the midgut and small in size which makes it difficult to distinguish in transitioning juveniles. The large head is elongated like the body with a concave snout that is approximately the same length as the eye diameter. The eyes are small in larvae but become large in transitioning juveniles as well as adults. Small canine teeth are observed in both jaws in all larvae and adults.
Macquarie perch are considered endangered in Australia, but this is not yet reflected in international conservation organizations. Macquaria australasica is threatened by predation and competition from exotic fish species, including redfin (Perca flavescens), rainbow trout (Oncorhynchus mykiss), and brown trout (Salmo trutta). They are also threatened by dams, habitat destruction, sedimentation, heavy metal pollution, and introduced diseases. Dam removal is recommended for species recovery so that migration to spawning sites can occur. Illegal fishing occurs in some areas and overfishing is considered one of the contributing factors to the rarity of this species.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: data deficient
M. australasica is in the Family Percichthyidae. Common names include: Macquarie perch, Macquarie-aborre, Macquaries barsch, mountain perch, black bream, silberauge, silvereye, and white-eye.
Breeding fish migrate upstream and gather in schools which can last for several weeks. Males nudge the female vent region which causes the release of eggs and then fertilization. Females are oviparous and mate each year. (Merrick and Schmida, 1984).
Mating System: monogamous
Spawning occurs in shallow upland streams and the fish usually migrate in order to spawn. Many fish use the same river to spawn each year. This occurs in fast-flowing water over gravel beds and the eggs stick to the gravel on the bottom of the water (demersal). (Merrick and Schmida, 1984). Females produce, on average, 32,000 eggs per kg of fish.
Male M. australasica usually mature around the age of two years old and 21 cm in length while females do not reach maturity until they are three years old and 30 cm in length.
Breeding interval: Macquari perch breed yearly.
Breeding season: Breeding occurs from the end of October through early November.
Average number of offspring: 32,000 eggs per Kg of fish.
Range gestation period: 10 to 18 days.
Average age at sexual or reproductive maturity (female): 3 years.
Average age at sexual or reproductive maturity (male): 2 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; sexual ; fertilization (External ); broadcast (group) spawning; oviparous
During spawning females remain close to the area where they laid their eggs in groups of two or four. One or two males usually accompany the females during this time to make sure that nothing happens to the eggs. After the eggs hatch the larvae travel downstream either through swimming or from the current of the stream.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Male, Female)
The Macquarie perch (Macquaria australasica) 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 (Macquaria ambigua).
The Macquarie perch derives its scientific name from the Macquarie River where the first scientifically described specimen was collected (Macquaria) and a derivation of the Latin word for "southern" (australasica).
Macquarie perch are a medium-sized fish, commonly 30–40 cm and 1.0–1.5 kg. Maximum size is about 2.5 kg and 50 cm. Their body is elongated, deep, and laterally compressed. The caudal fin, anal fin and soft dorsal fin are rounded. Spiny dorsal fin medium height and strong. Mouth and eyes are relatively small. Colouration can vary from tan to (more commonly) dark purplish-grey to black. The irises of the eyes are distinctly silver.
Macquarie perch are a relatively placid native fish species with the bulk of their diet consisting of aquatic invertebrates such as caddisfly, stonefly and mayfly species, with a small quantity of terrestrial insects taken as well.
The Macquarie perch is primarily an upland native fish and has a breeding biology clearly adapted to flowing upland rivers and streams. (For this reason, the species has proven difficult to breed artificially, as captive females do not produce ripe eggs when kept in still broodponds or tanks). Macquarie perch breed in late spring at temperatures of 15 to 16 °C, in flowing water over unsilted cobble and gravel substrate. The demersal (sinking) eggs fall into the interstices (spaces) between the gravel and cobble, where they lodge and are then protected and incubated until hatching. This is a breeding strategy similar to that used by introduced species of trout.
Macquarie perch appear to have inherited the sexual dimorphism of other Macquaria species where females reach a larger maximum size than males. Females also reach sexual maturity at older, larger sizes than males.
Limited ageing work on Macquarie perch has recorded fish to 20 years of age. Maximum age for Macquarie perch is probably similar to the maximum age recorded for the closely related golden perch (26 years).
Macquarie perch were originally found in the larger upland rivers and streams in the south-eastern corner of the Murray-Darling system, which they usually co-inhabited with trout cod and one or both of the blackfish species.
Macquarie perch continue a pattern found in native freshwater fish of the Murray-Darling system of specialisation into lowland and upland stream inhabitants. Macquarie perch are a speciated, more specialised upland version of the golden perch, which is primarily a lowland fish. (Having said this, the primarily lowland golden perch, being highly adaptable species, did extend into upland habitats) in some situations.
Macquarie perch are found in the eastern coastal Shoalhaven and Hawkesbury-Nepean river systems as well as the Murray-Darling Basin, indicating that, as with some other native fish genera in south-eastern Australia, Macquarie perch have managed to cross the Great Dividing Range through natural river capture/connection events. Genetic research now indicates the Shoalhaven River population was the ancestral Macquarie perch population and colonised the Hawkesbury-Nepean system ~2 million years ago, and the Hawkesbury-Nepean population then colonised the Murray-Darling Basin – possibly through a "wet divide" in the Breadalbane Plains region, ~657,000 years ago (Faulks et al., 2008).
Major differences between the eastern coastal populations and the Murray-Darling population are that the eastern coastal populations display a far smaller average and maximum size (15 and 20 cm respectively) and are reported to have one less vertebra than the Murray-Darling species. Recent evidence suggest the Shoalhaven population is now extinct after a rapid decline due to damming of their habitat and subsequent encroachment of legally and illegally stocked fish species. The Hawkesbury-Nepean population appears to be threatened by introduced trout and other exotic fish, river damming and regulation, siltation, and urban encroachment, but does not appear to be as threatened as the Murray-Darling species. Information on this page relates primarily to the Murray-Darling population.
There is a translocated population in the Mongarlowe River, a tributary of the Shoalhaven.[3][4][5] It is thought that this population descends from fish from the Murray-Darling Basin and not the eastern sub-species native to other parts of the Shoalhaven catchment. In recent years, this population seems to be in decline and may be doomed to local extinction.[5]
There is also a translocated self-sustaining breeding population of Macquarie Perch located in the middle and upper reaches of the Yarra River on the outskirts of Melbourne. They highest numbers are found lowest reaches, which also support a mix of translocated native and introduced fish including trout. In this stretch however no fish species is particularly dominant, and introduced trout are not numerous.
Murray-Darling Macquarie perch are now listed as endangered on state and Commonwealth listings. Gross overfishing by anglers, habitat degradation through siltation, and regulation of flow and "thermal pollution" by dams have all been major causes of decline. A mysterious but endemic disease called Epizootic Haemotopoeitic Necrosis virus (EHN virus), now vectored by introduced redfin perch, has been proven to be fatal to Macquarie perch, and may have contributed to the decline of some populations of Macquarie perch in upland impoundments. What has become clear however is that total domination of the Macquarie perch's upland habitats by introduced brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) have also been a major cause of decline. Indeed, Macquarie perch populations have failed in significant stretches of relatively pristine upland river that offer excellent habitat, are not silted, dammed or overfished, and where there are no possible explanations for their demise except introduced trout species. Dietary studies have documented significant overlap between the diet of Macquarie perch and introduced trout species, and anglers have observed predation of Macquarie perch juveniles by introduced trout species. Several publications in the 1940s through to the 1960s by the director of the Victorian Fisheries and Game Department (A.D.Butcher) documents predation on juvenile trout cod, Macquarie perch and other upland native fish species by introduced trout species, and major dietary overlaps. Recent research (Lintermans, 2006) records dietary overlaps that are significant by scientific criteria between Macquarie perch and introduced trout species.
Over the last 20 or 30 years, the last few remaining Macquarie perch populations in upland habitats have faltered. All of these populations appear to be in extinction vortices and may disappear completely over the next several decades.
Macquarie perch have proved difficult but not impossible to breed. However, no Australian government agency is breeding Macquarie perch in significant numbers, and some government agencies are stocking upland habitats containing remnant Macquarie perch populations with introduced trout species. Not only do these stockings threaten Macquarie perch by competition and predation, but rainbow trout fingerlings have been shown to carry significant levels of EHN virus.
{{cite web}}: CS1 maint: url-status (link) The Macquarie perch (Macquaria australasica) 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 (Macquaria ambigua).
The Macquarie perch derives its scientific name from the Macquarie River where the first scientifically described specimen was collected (Macquaria) and a derivation of the Latin word for "southern" (australasica).
