Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences

Salinity may cause fragmentation of hardyhead (Teleostei: Atherinidae) populations in the River Murray, Australia

Scotte D. Wedderburn A C , Keith F. Walker A and Brenton P. Zampatti B

A School of Earth & Environmental Sciences DX650 312, The University of Adelaide, SA 5005, Australia.

B SARDI Aquatic Sciences, PO Box 120, Henley Beach, SA 5022, Australia.

C Corresponding author. Email:

Marine and Freshwater Research 59(3) 254-258
Submitted: 31 October 2007  Accepted: 28 February 2008   Published: 30 April 2008


Salinisation in lowland areas of the Murray–Darling Basin, Australia, has had noticeable effects on fish. The endangered endemic Murray hardyhead Craterocephalus fluviatilis is distributed patchily and confined mainly to saline waters (0.4–20 g L–1), whereas the unspecked hardyhead C. stercusmuscarum fulvus has a more continuous distribution but is absent from high salinities (>10). Osmoregulation was compared in these two congeners and an estuarine atherinid, the small-mouth hardyhead Atherinosoma microstoma, over a wide salinity range (0.03–85). All three species are euryhaline, although the osmoregulatory ability of C. s. fulvus falters above ~35 salinity. In low salinity (<1), C. fluviatilis is a better osmoregulator than A. microstoma, but both species tolerate hypersaline conditions (85). These data imply a physiological reason for the predominance of C. fluviatilis in inland saline waters, but the reasons for its absence from freshwater habitats (<0.4) remain unclear. The findings have implications for other freshwater fish, especially populations of closely related species, subjected to the effects of salinisation or other stressors.

Additional keywords: Atherinosoma, Craterocephalus, endangered species, osmoregulation, salinity tolerance.


Altinok I.Grizzle J. M.2001Effects of low salinities on Flavobacterium columnare infection of euryhaline and freshwater stenohaline fish.Journal of Fish Diseases24361367doi:10.1046/J.1365-2761.2001.00306.X

Bamber R. N.Henderson P. A.1988Pre-adaptive plasticity in atherinids and the estuarine seat of teleost evolution.Journal of Fish Biology331723doi:10.1111/J.1095-8649.1988.TB05554.X

Bettoli P. W.Morris J. E.1991Changes in the abundance of two atherinid species after aquatic vegetation removal.Transactions of the American Fisheries Society1209097doi:10.1577/1548-8659(1991)120<0090:CITAOT>2.3.CO;2

Cataldi E.Mandich A.Ozzimo A.Cataudella S.2005The interrelationships between stress and osmoregulation in a euryhaline fish, Oreochromis mossambicus.Journal of Applied Ichthyology21229231doi:10.1111/J.1439-0426.2005.00634.X

Chessman B. C.Williams W. D.1974Distribution of fish in inland saline waters in Victoria, Australia.Australian Journal of Marine and Freshwater Research25167172doi:10.1071/MF9740167

Clavero M.Blanco-Garrido F.Prenda J.2007Population and microhabitat effects of interspecific interactions on the endangered Andalusian toothcarp (Aphanius baeticus).Environmental Biology of Fishes78173182doi:10.1007/S10641-006-9088-2

Davenport J.Sayer M. D. J.1993Physiological determinants of distribution in fish.Journal of Fish Biology43A121145

Duncan J. R.Lockwood J. L.2001Extinction in a field of bullets: a search for the causes in the decline of the world’s freshwater fishes.Biological Conservation10297105

Echelle A. A.Echelle A. F.Hill L. G.1972Interspecific interactions and limiting factors of abundance and distribution in the Red River pupfish, Cyprinodon rubrofluviatilis.American Midland Naturalist88109130doi:10.2307/2424492

Febry R.Lutz P.1987Energy partitioning in fish: activity-related cost of osmoregulation in a euryhaline cichlid.The Journal of Experimental Biology1286385

Frankham R.1996Relationship of genetic variation to population size in wildlife.Conservation Biology1015001508

Gill H. S.Potter I. C.1993Spatial segregation amongst goby species within an Australian estuary, with a comparison of the diets and salinity tolerance of the two most abundant species.Marine Biology117515526

Goss K. F.2003Environmental flows, river salinity and biodiversity conservation: managing trade-offs in the Murray-Darling basin.Australian Journal of Botany51619625

Guo R.Mather P. B.Capra M. F.1995Salinity tolerance and osmoregulation in the silver perch, Bidyanus bidyanus Mitchell (Teraponidae), an endemic Australian freshwater teleost.Marine and Freshwater Research46947952doi:10.1071/MF9950947

Hart B. T.Bailey P.Edwards R.Hortle K.James K. R.McMahon A.Meredith C.Swadling K.1991A review of the salt sensitivity of the Australian freshwater biota.Hydrobiologia210105144

Hobbs R. J.Mooney H. A.1998Broadening the extinction debate: population deletions and additions in California and Western Australia.Conservation Biology12271283

IUCN (2007). 2007 IUCN Red List of Threatened Species. Available at Accessed 31 August 2007.

Kinne O.1964The effects of temperature and salinity on marine and brackish water animals: II. Salinity and temperature salinity combinations.Oceanography and Marine Biology Annual Review2281339

Kipriyanova L. M.Yermolaeva N. I.Bezmaternykh D. M.Dvurechenskaya S. Y.Mitrofanova E. Y.2007Changes in the biota of Chany Lake along a salinity gradient.Hydrobiologia5768393

Kwak S. N.Baeck G. W.Klumpp D. W.2005Comparative feeding ecology of two sympatric greenling species, Hexagrammos otakii and Hexagrammos agrammus in eelgrass Zostera marina beds.Environmental Biology of Fishes74129140doi:10.1007/S10641-005-7429-1

Lloyd L. N. (1987). Ecology and distribution of the small native fish of the lower River Murray, South Australia and their interactions with the exotic mosquitofish, Gambusia affinis holbrooki. MSc Thesis, University of Adelaide.

Lucas M. C., and Baras E. (2001). ‘Migration of Freshwater Fishes.’ (Blackwell Science: Oxford.)

Lui L. C.1969Salinity tolerance and osmoregulation of Taeniomembras microstomus (Gunther, 1861) (Pisces: Mugiliformes: Atherinidae) from Australian salt lakes.Australian Journal of Marine and Freshwater Research20157162doi:10.1071/MF9690157

Mackay N., Hillman T. J., and Rolls J. (1988). ‘Water Quality of the River Murray: Review of Monitoring 1978 to 1986.’ (Murray-Darling Basin Commission: Canberra.)

Molsher R. L.Geddes M. C.Paton D. C.1994Population and reproductive ecology of the small-mouthed hardyhead Atherinosoma microstoma (Günther) (Pisces: Atherinidae) along a salinity gradient in the Coorong, South Australia.Transactions of the Royal Society of South Australia118207216

Moyle P. B.Williams J. E.1990Biodiversity loss in the temperate zone: decline of the native fish fauna of California.Conservation Biology4275284

Nordlie F. G.Walsh S. J.1989Adaptive radiation in osmotic regulatory patterns among three species of cyprinodontids (Teleostei: Atherinomorpha).Physiological Zoology6212031218

Prince J. D.Potter I. C.Lenanton R. C. J.Loneragan N. R.1982Segregation and feeding of atherinid species (Teleostei) in south-western Australian estuaries.Australian Journal of Marine and Freshwater Research33865880

Rogowski D. L.Stockwell C. A.2006Parasites and salinity: costly tradeoffs in a threatened species.Oecologia146615622doi:10.1007/S00442-005-0218-XPubmed Abstract

Sheldon, A. L. (1988). Conservation of stream fishes: patterns of diversity, rarity and risk. Conservation Biology 2, 149–156.

Valentine D. W.Miller R.1969Osmoregulation in the California killifish, Fundulus parvipinnis.California Fish and Game582025

Walker K. F. (1992). A semi-arid lowland river: the River Murray, Australia. In ‘The Rivers Handbook’. (Eds P. A. Calow and G. E. Petts.) pp. 472–492. (Blackwell Scientific: Oxford.)

Wedderburn S. D.Walker K. F.Zampatti B. P.2007Habitat separation of Craterocephalus (Atherinidae) species and populations in off-channel areas of the lower River Murray, Australia.Ecology of Freshwater Fish16442449

Williams M. D.Williams W. D.1991Salinity tolerance of four species of fish from the Murray-Darling Basin River System.Hydrobiologia210145160

Zwick P.1992Stream habitat fragmentation – a threat to biodiversity.Biodiversity and Conservation18097

Export Citation