The Macquarie perch (''Macquaria australasica'') is an Australian native freshwater

fish Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs with Digit (anatomy), digits. Included in this definition are the living hagfish, lampreys, and Chondrichthyes, cartilaginous and bony fish as we ...

of the Murray-Darling river system. It is a member of the family

Percichthyidae The members of the family Percichthyidae are known as the temperate perches. They belong to the order Perciformes, the perch-like fishes. The name Percichthyidae derives from the Latin ''perca'' for perch and Ancient Greek ἰχθύς, ''ichthy ...

and is closely related to the

golden perch The golden perch (''Macquaria ambigua'') is a medium-sized, yellow or gold-coloured species of Australian freshwater fish found primarily in the Murray-Darling River system, though a subspecies is found in the Lake Eyre-Cooper Creek system, an ...

(''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 Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...

word for "southern" (''australasica'').

Description and diet

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 Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as see ...

and soft

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...

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

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chorda ...

s such as

caddisfly The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the ...

stonefly Plecoptera is an order of insects, commonly known as stoneflies. Some 3,500 species are described worldwide, with new species still being discovered. Stoneflies are found worldwide, except Antarctica. Stoneflies are believed to be one of the mos ...

and

mayfly Mayflies (also known as shadflies or fishflies in Canada and the upper Midwestern United States, as Canadian soldiers in the American Great Lakes region, and as up-winged flies in the United Kingdom) are aquatic insects belonging to the orde ...

species, with a small quantity of terrestrial

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pa ...

s taken as well.

Breeding and biology

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 Trout are species of freshwater fish belonging to the genera '' Oncorhynchus'', '' Salmo'' and '' Salvelinus'', all of the subfamily Salmoninae of the family Salmonidae. The word ''trout'' is also used as part of the name of some non-salm ...

. 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).

Range

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 Blackfish is a common name for the following species of fish, dolphins, and whales: Fish * Alaska blackfish, (''Dallia pectoralis''), an Esocidae from Alaska, Siberia and the Bering Sea islands * Black fish (''Carassioides acuminatus'') a cyprin ...

species. Macquarie perch continue a pattern found in native freshwater fish of the Murray-Darling system of specialisation into

lowland Upland and lowland are conditional descriptions of a plain based on elevation above sea level. In studies of the ecology of freshwater rivers, habitats are classified as upland or lowland. Definitions Upland and lowland are portions of p ...

and upland stream inhabitants. Macquarie perch are a speciated, more specialised upland version of the

, which is ''primarily'' a

fish. (Having said this, the ''primarily''

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 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. Location and features The river rises ...

, a tributary of the Shoalhaven. 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. There is also a translocated self-sustaining breeding population of Macquarie Perch located in the middle and upper reaches of the

Yarra River The Yarra River or historically, the Yarra Yarra River, ( Kulin languages: ''Berrern'', ''Birr-arrung'', ''Bay-ray-rung'', ''Birarang'', ''Birrarung'', and ''Wongete'') is a perennial river in south-central Victoria, Australia. The lower s ...

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.

Conservation

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 The European perch (''Perca fluviatilis''), also known as the common perch, redfin perch, big-scaled redfin, English perch, Euro perch, Eurasian perch, Eurasian river perch, Hatch, poor man’s rockfish or in Anglophone parts of Europe, simply th ...

, 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 The brown trout (''Salmo trutta'') is a European species of salmonid fish that has been widely introduced into suitable environments globally. It includes purely freshwater populations, referred to as the riverine ecotype, ''Salmo trutta'' morp ...

(''Salmo trutta'') and

rainbow trout The rainbow trout (''Oncorhynchus mykiss'') is a species of trout native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead (sometimes called "steelhead trout") is an anadromous (sea-run) form of the coast ...

(''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

fingerlings have been shown to carry significant levels of EHN virus.

References

* * * * Butcher, A.D. 1945. The food of indigenous and non-indigenous freshwater fish in Victoria, with special reference to ntroducedtrout. ''Fisheries Pamphlet 2''. Fisheries and Wildlife Department, Victoria. * Butcher, A.D. 1967. A changing aquatic fauna in a changing environment. ''IUCN Publications, New Series'' 9: 197–218. * Cadwallader, P.L. (ed.) 1977. J.O. Langtry's 1949–50 Murray River Investigations. Fisheries and Wildlife Paper. Ministry for Conservation, Victoria. * Cadwallader, P.L. 1981. Past and present distributions and translocations of the Macquarie perch ''Macquaria australasica'' (Pisces: Percichthyidae), with particular reference to Victoria. ''Proceedings of the Royal Society of Victoria'' 93: 23–30. * Cadwallader, P.L. & Eden, A.K. 1979. Observations on the food of Macquarie Perch, Macquaria australasica (Pisces: Percicthyidae) in Victoria, ''Australian Journal of Marine and Freshwater Research'' 30: 401–409. * Cadwallader, P.L. & Rogan, P.L. 1977. The Macquarie Perch, ''Macquaria australasica'' (Pisces: Percicthyidae), of Lake Eildon, ''Australian Journal of Ecology'' 2: 409–418 * McDowall, R.M. (ed.) 1996. ''Freshwater Fishes of south-eastern Australia.'' Reed Books, Sydney, Australia. * Faulks L.K., Gilligan D.M. & Beheregaray L.B. (2008). Evolution and maintenance of divergent lineages in an endangered freshwater fish, ''Macquaria australasica''. ''Conservation Genetics''. DOI 10.1007/s10592-009-9936-7. * Lintermans, M. (2006) The re-establishment of endangered Macquarie Perch Macquaria australasica in the Queanbeyan River, New South Wales, with an examination of dietary overlap with alien trout. Technical report, CRCFE, Canberra. * McKeown, K.C. 1934. Notes on the food of trout and Macquarie Perch in Australia, ''Records of the Australian Museum'' 19: 141–152. * Merrick, J.R. & Schmida, G.E. 1984. ''Australian freshwater fishes: biology and management.'' Griffin Press, Sydney, Australia. * Rhodes, J.O. 1999. ''Heads and Tales: Recollections of a Fisheries and Wildlife Officer.'' The Australian Deer Research Foundation Ltd., Melbourne. * Trueman WT (2007). Some recollections of native fish in the Murray-Darling system with special reference to the trout cod (Maccullochella macquariensis). Summary and source material for the draft publication ‘True Tales of the Trout Cod’. Native Fish Australia (Victoria) Incorporated, Doncaster, Victoria. Available online at: https://web.archive.org/web/20080721002731/http://www.nativefish.asn.au/files/Recollections_compressed.pdf * Trueman WT (2011). True Tales of the Trout Cod: River Histories of the Murray-Darling Basin. Publication No. 215/11. Murray-Darling Basin Authority, Canberra. Also available online at: https://web.archive.org/web/20130807212235/http://australianriverrestorationcentre.com.au/mdb/troutcod/ * Trueman, W. and Luker, C. 1992. Fishing Yesteryear. ''Freshwater Fishing Australia Magazine'' 17: 34–38.

External links

Sweetwater Fishing Australia - Macquarie PerchNative Fish Australia - Macquarie perch page
{{Taxonbar, from=Q3100700 Macquarie perch Murray-Darling basin Taxa named by Georges Cuvier Freshwater fish of Australia Macquarie perch