''Galaxias mungadhan'', the Dargo galaxias, is a

galaxiid The Galaxiidae are a family of mostly small freshwater fish in the Southern Hemisphere. The majority live in Southern Australia or New Zealand, but some are found in South Africa, southern South America, Lord Howe Island, New Caledonia, and the ...

of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Galaxias ''Galaxias'' is a genus of small freshwater fish in the family (biology), family Galaxiidae, and are frequently referred to as the galaxiids. These highly adaptable fish are typically found at temperate latitudes across the Southern Hemisphere. ...

'', a member of the

Mountain Galaxias ''Galaxias olidus'', the mountain galaxias, is a species of freshwater galaxiid fish widely found in southeastern Australia. Description As for other members of the species complex, although ''Galaxias olidus'' exhibits a greater range of charac ...

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

group of freshwater fish, found in

Victoria, Australia Victoria is a state in southeastern Australia. It is the second-smallest state with a land area of , the second most populated state (after New South Wales) with a population of over 6.5 million, and the most densely populated state in Au ...

Description

Similar to other members of the mountain galaxias species complex with a long, tubular body, commonly in length, maximum recorded . Head medium sized noticeably wider than deep. Back surface of body flattened behind the

pectoral 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 ...

s. Mouth at the tip of the snout angling back and down. Front of upper lip about level with the middle of the eye with the rearmost end of the mouth reaching about one third the way back from the leading edge of the eye.

Dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...

and anal fins short and rounded, usually of equal length. Pectoral fins low on body, longish and paddle-shaped, about 20 percent longer than the

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

s which in turn are positioned about midway along and low on the body. Tail fin medium length with low but well developed flanges extending from the fin to a position just behind the rear end of the

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 se ...

. The Shaw galaxias is generally dark brown overall, darker above the lateral line, becoming brown on the belly. The base colour is overlain with irregular somewhat diffuse blotches, more concentrated above the lateral line. The sides of the trunk have a moderately wide band of gold spots or flecks extending from behind the nape to about even with the dorsal fin, but sometimes extending as far forward as the head and snout. The head is diffusely covered with a scattering of small gold flecks. Extending from behind the pectoral fins to the

caudal peduncle 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 ...

is a diffuse band of gold spots generally below the lateral line and most prominent on the rear end of the fish.

Distribution

Restricted to a section above a natural barrier, of a tributary of the Dargo River within the Mitchell River system in

Gippsland Gippsland is a rural region that makes up the southeastern part of Victoria, Australia, mostly comprising the coastal plains to the rainward (southern) side of the Victorian Alps (the southernmost section of the Great Dividing Range). It covers ...

. Believed to have historically been present throughout the upper Dargo River catchment prior to the introduction of brown trout.

Habitat

The stream the Dargo galaxias has been recorded from is a clear, cool alpine creek surrounded by a grassy plain. The creek is small, averaging in width and in depth, and made up mainly of riffles and pools with the pools averaging deep. Often covered with snow for periods in winter. Bottom of stream is mainly bedrock and a few boulders with small amounts of pebble, gravel, sand and clay. Cover mostly rock and some overhanging alpine grasses.

Lifecycle/Reproduction

Confined to freshwater for its entire lifecycle, ''Galaxias mungadhan'' is the only native fish recorded within its current range. Spawning time is unknown and is possibly different from year to year depending on conditions, however gonads of adults collected during mid April 2008 were at an advanced stage of development consistent with a winter/spring spawning season. Collection of juvenile fish, presumed young of the year, of various lengths at different times suggest an extended spawning season from late winter to spring. Able to withstand very cold water less than .

Utility to humans

Not an angling target due to small size and conservation status.

Conservation status and measures

Critically endangered, protected under the ''

Victorian Flora and Fauna Guarantee Act 1988 The ''Flora and Fauna Guarantee Act 1988'', also known as the ''FFG Act'', is an act of the Victorian Government designed to protect species, genetic material and habitats, to prevent extinction and allow maximum genetic diversity within the Au ...

''.

Post 2019–2020 fires

Staff from the Arthur Rylah Institute in February 2020 travelled to the

Dargo River The Dargo River is a perennial river of the Mitchell River catchment, located in the Alpine and East Gippsland regions of the Australian state of Victoria. Features and location The Dargo River rises below Mount Higginbotham, part of the Grea ...

near

Mount Hotham Mount Hotham is a mountain located in the Victorian Alps of the Great Dividing Range, in the Australian state of Victoria. The mountain is located approximately north east of Melbourne, from Sydney, and from Adelaide by road. The nearest m ...

and captured about 200 Dargo galaxias to be brought into captivity as an

insurance population Translocation in wildlife conservation is the capture, transport and release or introduction of species, habitats or other ecological material (such as soil) from one location to another. It contrasts with reintroduction, a term which is gener ...

while the ash and debris from the 2019–2020 bushfires in Australia moved through the system. The ash and debris causes low dissolved oxygen and can clog the gills of the fish. The intention was to return the fish to the stream once the water is again clear and riparian vegetation has recovered, probably after about four months.

References

{{Taxonbar, from=Q85762537 mungadhan Taxa named by Tarmo Ain Raadik Fish described in 2014 Freshwater fish of Australia