The mountain galaxias species complex is a group of freshwater Galaxiid fish found all over southeast Australia. Chordates ( Phylum Chordata) are a group of Animals that includes the Vertebrates together with several closely related Invertebrates The Actinopterygii (the plural form of Actinopterygius) comprise the class of the ray-finned fishes. Osmeriformes is an order of Ray-finned fish that includes various kinds of Smelts Noodlefishes and the odd-looking Barreleyes The The Galaxiids are a family of mostly small freshwater Fish. Representatives occur throughout the southern hemisphere including South Africa, South America Galaxiinae is a subfamily of fishes It contains four genera Albrecht Karl Ludwig Gotthilf Günther FRS (also Albert Charles Lewis Gotthilf Gunther) October 3, 1830 – February 1 The Galaxiids are a family of mostly small freshwater Fish. Representatives occur throughout the southern hemisphere including South Africa, South America Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two For a topic outline on this subject see List of basic Australia topics. They form a cryptic species complex. In Biology, a cryptic species complex is a group of Species which satisfy the biological definition of species that is they are reproductively isolated from each

Classification

These fish were originally designated as a single species, Galaxias olidus, despite:

• occupying a very wide geographic range;
• occupying a range of different habitats, from headwater rivulets at 1,800 metres on the flank of Australia's highest mountain (Mount Kosciuszko) to large "midland" rivers and streams (or in other words rivers and streams at the upland/lowland transition, which may be extensive in Australia);
• displaying a wide range of body forms and colouration. Mount Kosciuszko is a Mountain located in the Snowy Mountains in Kosciuszko National Park. In studies of the Ecology of Freshwater Rivers habitats are classified as upland and lowland. In studies of the Ecology of Freshwater Rivers habitats are classified as upland and lowland.

Ongoing research is now revealing they are a species complex. In recognition of this, the mountain galaxias species complex has been referred to as Galaxias spp. , although the designation Galaxias olidus will probably remain with one of the species in the complex. The mountain galaxias species complex also incorporates the barred galaxias (Galaxias fuscus) whose status as a distinct species was debated but is now more or less confirmed.

A specimen of the mountain galaxias species complex, caught in an upland stream on a tiny barbless wet fly. This population has since been destroyed by an illegal stocking of exotic trout.

Range

The mountain galaxias species complex occupies a vast geographical range. They are found from southern Queensland to the Adelaide Hills in South Australia, and while occurring widely in the Murray-Darling river system, are also found in eastern and southern coastal systems as well. Queensland is a state of Australia, occupying the north-eastern corner of the mainland continent The Adelaide Hills are part of the Mount Lofty Ranges, east of the city of Adelaide in the state of South Australia. South Australia is a state of Australia in the southern central part of the country The Murray River, or River Murray and sometimes informally referred to as the "Mighty Murray" is Australia 's largest River. The Darling River is the third longest river in Australia, flowing 1390 km from northern New South Wales to its confluence with the Murray River at It is not clear how much of their coastal distribution is due to natural river capture events (although it is certain much of it is) and how much of it may be due to migration, for many mountain galaxias species have the ability to "climb" natural migration barriers with modified pelvic fin structures. Stream capture, river capture, or stream piracy is a geomorphological phenomenon occurring when a stream or river Drainage system or

Within the Murray-Darling system the mountain galaxias species complex continues the trend of specialisation into upland and lowland habitats, with mountain galaxias species found in upland habitats, and the Flathead Galaxias found in lowland habitats. In studies of the Ecology of Freshwater Rivers habitats are classified as upland and lowland. In studies of the Ecology of Freshwater Rivers habitats are classified as upland and lowland. In studies of the Ecology of Freshwater Rivers habitats are classified as upland and lowland. The flathead galaxias, Galaxias rostratus, is a freshwater fish found in lowland rivers and streams and associated billabongs backwaters etc of the southern Murray-Darling In studies of the Ecology of Freshwater Rivers habitats are classified as upland and lowland. Though mountain galaxias species stray down to the upland/lowland transition zone in some river, mountain galaxias species are largely upland species. Indeed, they are the upland specialists, found in the smallest of streams and at higher altitudes in Australia than any other freshwater fish, as high in fact as streams go. There has been some fascinating micro-niche partitioning amongst the Galaxiids in upland Murray-Darling habitats, this being one of the causes of the species complex we have today.

Conservation

The distribution of mountain galaxias species has been massively fragmented by the introduction of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss). The brown trout ( Salmo trutta morpha fario and S trutta morpha lacustris) and the sea trout ( S The rainbow trout ( Oncorhynchus mykiss) is a species of Salmonid native to tributaries of the Pacific Ocean in Asia and North America Mountain galaxias have — with the exception of one remarkable newly discovered species that lives in water too fast for introduced trout — shown a complete inability to live with introduced trout species in upland habitats due to competition and predation, and extremely serious predation on mountain galaxias species by introduced trout has been documented. There have been countless localised extinctions of mountain galaxias species populations due to introduced trout, and this is continuing to occur with illegal trout stockings. These issues are widely recognised and documented in the scientific literature.

Many mountain galaxias populations, possibly undescribed species or subspecies, face extinction, and many other populations, also possibly undescribed species or subspecies, have been alreay been permanently lost.

References

• Galaxias olidus (TSN 623458). Integrated Taxonomic Information System. Integrated Taxonomic Information System ( ITIS) is a partnership designed to provide consistent and reliable information on the Taxonomy of biological Species Retrieved on 11 March 2006. Events 1425 BC - Thutmose III, Pharaoh of Egypt, dies (according to the Low Chronology of the 18th Dynasty Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar.
• "Galaxias olidus". FishBase. FishBase is a comprehensive Database of information about Fish. Ed. Ranier Froese and Daniel Pauly. 10 2005 version. N. p. : FishBase, 2005.
• McDowall, R. M. (2006) Crying wolf, crying foul, or crying shame: alien salmonids and a biodiversity crisis in the southern cool-temperate galaxioid fishes? Rev Fish Biol Fisheries 16: 233–422.

External links

• Native Fish Australia - Mountain Galaxias page