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.
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
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
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.
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 )
Macquarie perch have been and are still fished for food. They are important members of native Australian freshwater ecosystems.
Positive Impacts: food
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.
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 )
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 )
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
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 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
Predators on M. australasica include Australian bass (Macquaria novemaculeata) and the introduced species: rainbow trout (Oncorhynchus mykiss) and redfin (Perca flavescens).
Known Predators:
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)
