The Australian smelt (''Retropinna semoni'') is a small,

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...

silvery freshwater

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...

found in large numbers in waters of the south eastern Australian mainland.

Distribution

The fish is endemic to Australia and widely distributed through the coastal drainages of the south eastern part of the mainland. The species is found in coastal drainages from the south east corner of

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

through

Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

to the Fitzroy River in south east

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , establishe ...

. It occurs widely in the

Murray River The Murray River (in South Australia: River Murray) (Ngarrindjeri: ''Millewa'', Yorta Yorta: ''Tongala'') is a river in Southeastern Australia. It is Australia's longest river at extent. Its tributaries include five of the next six longest ...

and its tributaries and up the Darling as far upstream as

Wilcannia Wilcannia is a small town located within the Central Darling Shire in north western New South Wales, Australia. Located on the Darling River, the town was the third largest inland port in the country during the river boat era of the mid-19th ce ...

. There are isolated populations in the Coopers Creek which drains into

Lake Eyre Lake Eyre ( ), officially known as Kati Thanda–Lake Eyre, is an endorheic lake in east-central Far North South Australia, some north of Adelaide. The shallow lake is the depocentre of the vast endorheic Lake Eyre basin, and contains th ...

and several smaller ones in north-western

and southern Queensland. Recent genetic research indicates Australian smelt stocks are composed of 5 highly genetically distinct and as yet undescribed species (Hammer ''et al.'', 2007).

Description

A small silvery fish to 75 mm total length, very occasionally to 100 mm. In Coopers Creek usually only to 50 mm. It is clear to purple-olive on the back, translucent with a silver streak along the sides, sometimes with orange highlights, and has colourless fins. Captively raised specimens will easily exceed 100mm and live for longer periods than their wild counterparts. Australian smelt (Retropinna semoni)

Habitat

Often found in large schools of thousands, this pelagic species prefers slow moving or still waters. It is often found in

billabong Billabong ( ) is an Australian term for an oxbow lake, an isolated pond left behind after a river changes course. Billabongs are usually formed when the path of a creek or river changes, leaving the former branch with a dead end. As a result ...

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...

s and

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

s at various salinity levels and in the lower reaches of

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of w ...

s and streams. Although there have been some reports of

diadromous Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousa ...

populations, this fish usually completes its entire life cycle in freshwater. They shoal near the surface and around the cover of aquatic plants and woody debris.

Diet

A carnivorous fish, the Australian smelt feeds mostly on small

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 chordate ...

s such as aquatic insects and microcrustaceans, and a variety of planktonic organisms.

Reproduction

Spawns in spring at water temperatures in excess of 15 °C. Eggs are demersal, adhesive, spherical and transparent, about 0.8 mm diameter to 1 mm when water hardened. Eggs fall to the bottom and stick to instream debris, vegetation and the substrate. Females lay between 100 and 1000 eggs. Hatching occurs at about 9 to 10 days and larvae are around 4.5 to 5 mm total length.

Importance to humans

This species has some potential as an aquarium species. Ideally suited to use as an effective

mosquito Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "li ...

predator in

pond A pond is an area filled with water, either natural or artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% emergent vegetation helps in distinguishing their ecology from ...

s in south eastern Australia, especially where

frog A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...

s are encountered. Not suitable for use in a community tank, best kept as a school of fish in a single species situation.

References

* * * Michael P. Hammer, Mark Adams, Peter J. Unmack and Keith F. Walker (2007) A rethink on Retropinna: conservation implications of new taxa and significant genetic sub-structure in Australian smelts (Pisces : Retropinnidae). ''Marine and Freshwater Research'' 58: 327–341.

External links

Australian Smelt video on Youtube

Native Fish Australia
{{Taxonbar, from=Q2207695 Australian smelt Freshwater fish of Australia Taxa named by Max Carl Wilhelm Weber Australian smelt