Australian Smelt, Retropinna semoni (Weber 1895)
Australian Smelt, Retropinna semoni. Source: Gunther Schmida / http://www.guntherschmida.com.au. License: CC BY Attribution-Noncommercial-ShareAlike
A small, slender freshwater fish with a small dorsal fin set far back on the body, a small adipose fin, a forked tail and large eyes.
Australian Smelt are silvery to almost transparent, or slightly olive-brown above, silvery on the sides with a silvery-white belly. Some individuals in the northern parts of its range may have orange markings and fins.
Genetic work (Hammer et al. 2007) indicates that Retropinna semoni belongs to a species complex, and the Australian Smelt may not be as widespread and abundant as previously thought. As a result, the information presented here may refer to more than one closely-related species.
Video of Australian Smelt in the Cann River, East Gippsland, Victoria.
Australian Smelt, Retropinna semoni (Weber 1895)
More Info
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Distribution |
Endemic to coastal drainages of south-eastern Australia, from the Fitzroy River, southern Queensland, to the Murray River, South Australia, from the south-east of the main Murray Darling / Culgoa / Condamine drainage towards the main eastern divide, and from Darr River / Thompson River/Cooper Creek drainage flowing south-west to Lake Eyre. A schooling species found in slow- flowing and still fresh water habitats such as lakes, swamps and billabongs in large lowland floodplain rivers, upland rivers and streams, small coastal streams, dune systems, lakes, dams and weirs, and brackish river estuaries. Individuals shoal near the surface or around the cover of aquatic plants and woody debris. |
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Features |
Dorsal-fin rays 7-12; Anal-fin rays 12-21; Caudal-fin rays 18; Pectoral-fin rays 8-12; Pelvic-fin rays 7; Vertebrae 45 to 53 Body elongate, compressed, slender; dorsal and ventral profiles even and gradually arched; head of moderate size (19-29% SL); snout bluntly pointed; eyes large (25-36% HL); mouth terminal, of moderate size, reaching well below eyes, slightly oblique; jaw teeth fang-like, spaced in a single row; vomer, tongue, palatine and mesopterygoid bones with rows of fine teeth; gillrakers on first arch 45-55; lateral line absent; caudal peduncle long and slender; ventral keel often present, extending from behind pelvic fin to vent. Head naked, body scales cycloid, thin and delicate; scales of moderate size, 50-70 in lateral series. A single high, short-based dorsal fin positioned above the anus; small adipose fin behind dorsal; anal fin much longer than dorsal, high anteriorly, outer margin concave, origin below front of dorsal fin; caudal fin forked, lobes rounded; pectoral fins small, elongate, rounded, low on side behind head; ventral fins abdominal. Males have larger pectoral and pelvic fins, and larger nuptial tubercles on the body and head. |
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Size |
To 10 cm, commonly to 7cm. |
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Colour |
Silvery, somewhat olive above with a purplish sheen along sides, belly whitish, fins largely colourless with some dark colouring at bases. Some individuals appear orange. |
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Feeding |
Carnivore - feeds mostly on insects and microcrustaceans. |
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Biology |
The species completes its entire lifecycle in freshwater. Individuals mature in their first year and spawn between July and March. Demersal eggs are laid amongst aquatic vegetation. Fecundity may be low, although numbers of 100-1000 eggs have been reported depending on the size of the female. The eggs are spherical, transparent, strongly adhesive and demersal, 0.8mm when laid and expand to about 1mm when water hardened. Larvae hatch in around 10 days at around 4.6 mm TL. Yolk sac is completely absorbed at 2 days and fin folds are complete at 5 days. |
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Conservation |
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Remarks |
Primarily a freshwater species, although the species also inhabits brackish estuaries and inland salt lakes. Often congregates in schools of thousands, and has a distinct cucumber smell when freshly caught. |
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Etymology |
The species is named in honour of Richard Semon, who collected type specimen. |
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Species Citation |
Prototroctes semoni Weber, 1895, Zool. Stud. 5(2): 257-276. Type locality: Burnett River, Queensland. |
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Author |
Gomon, M.F. & Bray, D.J. 2024 |
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Resources |
Australian Smelt, Retropinna semoni (Weber 1895)
References
Allen, G.R., Midgley, S.H. & Allen, M. 2002. Field Guide to the Freshwater Fishes of Australia. Perth : Western Australian Museum 394 pp.
Bice, C., Lintermans, M., Scott, K. & Unmack, P. 2019. Retropinna semoni. The IUCN Red List of Threatened Species 2019: e.T123355754A123382631. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T123355754A123382631.en. Accessed on 05 March 2024.
Cadwallader, P.L. & Backhouse, G.N. 1983. A Guide to the Freshwater Fish of Victoria. Melbourne : F.D. Atkinson Government Printer 249 pp. figs.
Cashner, R.C., Hawkes,G.P., Gartside, D.F. & Marsh-Matthews E. 1999. Fishes of the Nymboida, Mann and Orara Rivers of the Clarence River Drainage, New South Wales, Australia. Proceedings of the Linnean Society of New South Wales 121: 89-100
Grant, E.M. 2002. Guide to Fishes. Redcliffe : EM Grant Pty Ltd 880 pp.
Hammer, M.P., Adams, M. & Foster, R. 2012. Update to the catalogue of South Australian freshwater fishes (Petromyzontida & Actinopterygii). Zootaxa 3593: 59–74
Hammer, M.P., Adams, M., Unmack, P.J. & Walker, K. 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(4): 327–341 http://dx.doi.org/10.1071/MF05258
Humphries, P., Serafini, L.G. & King, A.J. 2002. River regulation and fish larvae: variation through space and time. Freshwater Biology 47: 1307–1331.
Kuiter, R.H. 2018. Pictorial guide to Victoria's freshwater fishes. E-version Part 1. Aquatic Photographics, Seaford, Victoria, Australia, 110 pp.
Lake, J.S. 1978. Australian Freshwater Fishes. Melbourne : Thomas Nelson 160 pp. 140 figs.
Leggett, R. & Merrick, J.R. 1987. Australian Native Fishes for Aquariums. Artarmon : J.R. Merrick Publications 241 pp. 142 figs.
Leigh, S.J. 2002. Aspects of the Life-History and Population Biology of the Australian Smelt, Retropinna semoni (Weber 1895) (Salmoniformes: Retropinnidae) for a Lower Murray River Population. Unpubl. B Sc (Hons) thesis, University of Adelaide.
Lintermans, M. 2023. Fishes of the Murray-Darling Basin. Ed. 2. Canberra : Murray-Darling Basin Commission 157 pp.
Mallen-Cooper, M. 1994. How high can a fish jump? New Scientist 142 (1921): 32–37.
McCulloch, A.R. 1920. Studies in Australian fishes, No. 6. Records of the Australian Museum 13(2): 41-71 figs 1-3 pls 10-14
McDowall, R.M. 1979. Fishes of the family Retropinnidae (Pisces : Salmoniformes): A taxonomic revision and synopsis. Journal of the Royal Society of New Zealand 9(1): 85-121 figs 1-11
McDowall, R.M. 1994. Families Retropinnidae, Prototroctidae, Galaxiidae. pp. 232-239 figs 207-212 in Gomon, M.F., Glover, C.J.M. & Kuiter, R.H (eds). The Fishes of Australia's South Coast. Adelaide : State Printer 992 pp. 810 figs.
McDowall, R.M., in McDowall, R.M. (ed.) 1996. Freshwater Fishes of South-eastern Australia. Sydney : Reed Books 247 pp.
Merrick, J.R. & Schmida, G.E. 1984. Australian Freshwater Fishes Biology and Management. Sydney : J.R. Merrick 409 pp. figs 280 col. figs.
Milton, D.A. & Arthington, A.H. 1985. Reproductive strategy and growth of the Australian smelt, Retropinna semoni (Weber) (Pisces: Retropinnidae), and the olive perchlet, Ambassis nigripinnis (De Vis) (Pisces: Ambassidae), in Brisbane, south-eastern Queensland. Australian Journal of Marine and Freshwater Research 36(3): 329–341.
Moffat, D. & Voller, J. 2002. Fish and Fish Habitat of the Queensland Murray-Darling Basin. Department of Primary Industries, Queensland.
Ogilby, J.D. 1908. New or little known fishes in the Queensland Museum. Annals of the Queensland Museum 9(1): 3-41. (described as Jenynsella weatherilli, type locality Enoggera Creek, southern Queensland)
Pusey, B.J., Kennard, M.J. & Arthington, A.H. 2004. Freshwater Fishes of North-Eastern Australia. CSIRO Publishing, Collingwood, Victoria.
Pusey, B.J., Kennard, M.J. & Bird, J. 2000. Fishes of the dune fields of Cape Flattery, northern Queensland and other dune systems in north-eastern Australia. Ichthyological Explorations of Freshwater 11(1): 65-74
Raadik, T.A. 1992. Distribution of freshwater fishes in east Gippsland, Victoria, 1967–1991. Proceedings of the Royal Society of Victoria 104: 1-22
Raadik, T.A. 2008. Family Retropinnidae. pp. 214-216 in Gomon, M.F., Bray, D.J. & Kuiter, R.H. (eds). Fishes of Australia's Southern Coast. Sydney : Reed New Holland 928 pp. (Populations in southern Australia treated as a distinct species - Retropinna sp. 1)
Stokell, G. 1941. A revision of the genus Retropinna. Records of the Canterbury Museum 4(7): 361-372 fig. 1 pls 55-57 (described as Retropinna victoriae, type locality Victoria, Australia).
Unmack, P.J., Adams, M., Hammer, M.P., Johnson, J.B., et al. 2021. Plotting for change: an analytical framework to aid decisions on which lineages are candidate species in phylogenomic species discovery, Biological Journal of the Linnean Society 135(1): 117–137, https://doi.org/10.1093/biolinnean/blab095
Wager, R. & Unmack, P.J. 2000. Fishes of the Lake Eyre Catchment of Central Australia. Brisbane : Department of Primary Industries and Queensland Fisheries Service 88 pp.
Weber, M. 1895. Fische von Ambon, Java, Thursday Island dem Burnett-Fluss und von der Süd-Küste von Neu-Guinea. Zoological Studies 5(2): 257-276 1 fig. See ref at BHL
Wedderburn, S. & Hammer, M. 2003. The Lower Lakes Fish Inventory: Distribution and Conservation of Freshwater Fishes of the Ramsar Convention Wetland at the Terminus of the Murray-Darling Basin, South Australia. Native Fish Australia (SA) Inc., Adelaide. 38 pp.
