Eastern Gambusia, Gambusia holbrooki Girard 1859
Male and female Eastern Gambusia, Gambusia holbrooki. Source: Gunther Schmida / http://www.guntherschmida.com.au. License: CC BY Attribution-Noncommercial-ShareAlike 3.0
In 1925, this native of North and Central America was intentionally introduced to Australia to control mosquito populations. Gambusia holbrooki is invasive on every continent except Antarctica. The species is in almost plague proportions in parts of Australia, and has had a significant impact on native fishes, invertebrates and frogs.
Identifying features: Olive-green above, sides greyish, belly silvery white; a single dorsal fin originating behind the level of the anal fin; females larger than males with a dark patch on the belly near the anus; mouth upturned, caudal peduncle long; males with long anal fin rays.
Eastern Gambusia, Gambusia holbrooki Girard 1859
More Info
|
Distribution |
Intentially released (from SE United States of America) into Australia to control mosquitoes, Eastern Gambusia are now widespread throughout much of mainland Australia, and also occur in northern Tasmania. In 1991, a population was discovered in a farm dam in the Tamar River catchment, northern Tasmania. Despite eradication attempts, the species is now appears to be established in the Tamar Valley. Eastern Gambusia prefer warm, gently flowing or still waters, and are usually found amongst aquatic vegetation near the water's edge. They inhabit lakes, dams, marshes, billabongs, aqueducts and slow-flowing streams, and are extremely tolerant of a wide range of environmental conditions. They survive in water temperatures ranging from almost freezing to 38ºC, in water bodies with very low dissolved oxygen levels and in salinities ranging from freshwater to fully marine. |
|
Features |
Dorsal-fin rays 6-8 (usually 7); Anal-fin rays 9-11 (usually 10); Vertebrae 31-33; Gill rakers 13-15 Body stout with a deep rounded belly (particularly in females, and more so when carrying a brood of young); upper surface flattened, especially the head; mouth small, upturned and protrusible, lower jaw a little longer than upper; eyes large. Large scales cover head and trunk (28-32, usually 30-31 along side); no lateral line. Dorsal fin single, sort-based, soft-rayed, positioned well back on trunk, fin high and rounded; anal fin small and rounded in females, elongate and modified into a gonopodium in males; caudal fin rounded. |
|
Size |
Females to 6 cm SL; males to 3.5 cm SL. |
|
Colour |
Generally greenish olive to brownish on back, sides grey with a bluish sheen, belly silvery; some dark speckling dorsally and on caudal fin; females with a large black blotch surrounded by a golden patch just above vent. |
|
Feeding |
Primarily carnivores - feed on a range of small freshwater invertebrates, windblown terrestrial insects, and the eggs, larvae and juveniles of native fishes and frogs. |
|
Biology |
Eastern Gambusia are live-bearers. The front rays of the male’s anal fin are modified to form a gonopodium which is used to internally fertilise eggs. Breeding occurs during the warmer months and females produce about 50 live young in each batch with up to 9 batches per year. Zane et al. (1999) found that females store sperm, and that 90% of all broods were sired by multiple males. The fertilised eggs develop inside the female, and the young are a few millimetres long when born. |
|
Remarks |
Gambusia holbrooki has been ineffective in controlling mosquitos, and is now a widespread pest species. It is highly adaptable to changing environmental conditions, and persists in most aquatic habitats, except where cool temperatures affect the reproductive cycle. Eastern Gambusia have been implicated in the decline of at least 9 fish species and more than 10 frog species in Australia. They compete with native fishes for habitat and food, and are very aggressive towards other species. |
|
Species Citation |
Gambusia holbrooki Girard 1859, Proc. Acad. Nat. Sci. Philad. 11: 62. Type locality: Palatka, Florida, Charleston, South Carolina, U.S.A. |
|
Author |
Martin F. Gomon & Dianne J. Bray |
Eastern Gambusia, Gambusia holbrooki Girard 1859
References
Allen, G.R. 1982. Inland Fishes of Western Australia. Perth : Western Australian Museum 86 pp. 6 figs 20 pls.
Allen, G.R., Midgley, S.H. & Allen, M. 2002. Field Guide to the Freshwater Fishes of Australia. Perth : Western Australian Museum 394 pp.
Ayres, R.M., Pettigrove, V.J. & Hoffmann, A.A. 2010. Low diversity and high levels of population genetic structuring in introduced eastern mosquitofish (Gambusia holbrooki) in the greater Melbourne area, Australia. Biological Invasions 12: 3727–3744.
Ayres, R.M., Pettigrove, V.J. & Hoffmann, A.A. 2013. Genetic structure and diversity of introduced eastern mosquitofish (Gambusia holbrooki) in south-eastern Australia. Marine and Freshwater Research 63: 1206–1214.
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
Corfield, J., Diggles, B., Jubb, C., McDowall, R.M., Moore, A., Richards, A. & Rowe, D.K. 2008. Review of the impacts of introduced ornamental fish species that have established wild populations in Australia. Prepared for the Australian Government Department of the Environment, Water, Heritage and the Arts. 277 pp.
Dove, A.D.M. 2000. Richness patterns in the parasite communities of exotic poeciliid fishes. Parasitology 120(6): 609-623.
Dove, A.D.M., T.H. Cribb, S.P. Mockler & M. Lintermans. 1997. The Asian fish tapeworm, Bothriocephalus acheilognathi, in Australian freshwater fishes. Marine and Freshwater Research 48(2) 181 - 183
Girard, C.F. 1859. Ichthyological notices. Proceedings of the Academy of Natural Sciences, Philadelphia 11: 56-58
Grant, E.M. 1975. Guide to Fishes. Brisbane : Queensland Government, Co-ordinator General’s Department 640 pp.
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.
Harris, J.H. 2013. 11. Fishes from elsewhere. pp. 259-282 in Humphries, P. & Walker, K. (eds). Ecology of Australian Freshwater Fishes. Collingwood, Victoria : CSIRO Publishing 423 pp.
Hitchcock, G., Finn, M.A., Burrows, D.W., & Johnson, J.W. 2012. Fishes from fresh and brackish waters of islands in Torres Strait, far north Queensland. Memoirs of the Queensland Museum 56(1): 14-24
Johnson, J. 1993. Fishes of the Brisbane River. Fishes of Sahul, Journal of the Australian New Guinea Fishes Association 8(1): 347-352.
Larson, H.K., Williams, R.S. & Hammer, M.P. 2013. An annotated checklist of the fishes of the Northern Territory, Australia. Zootaxa 3696(1): 1-293
Lloyd, L.N. & Tomasov, J.F. 1985. Taxonomic status of the mosquito fish, Gambusia affinis (Poeciliidae), in Australia. Australian Journal of Marine and Freshwater Research 36: 447-451 fig. 1
McDowall, R.M. (ed.) 1980. Freshwater Fishes of South-eastern Australia. Sydney : A.H. & A.W. Reed 208 pp., figs, 32 pls.
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.
Morgan, D.L., Gill, H.S., Maddern, M.G. & Beatty, S.J. 2004. Distribution and impacts of introduced freshwater fishes in Western Australia. New Zealand Journal of Marine and Freshwater Research 38: 511-523.
Morgan, D.L., Gill, H.S. & Potter, I.C. 1998. Distribution, identification and biology of freshwater fishes in south-western Australia. Records of the Western Australian Museum, Supplement 56: 1-97.
Prokop, F. 2002. Australian Fish Guide. Croydon South, Victoria : Australian Fishing Network 256 pp.
Smith, B.B. & Hammer, M. 2006. Mapping the current distribution of native and exotic fishes within the South Australian Murray Darling Basin. Final Report to PIRSA Rural Solutions (Animal and Plant Control Board). Primary Industries and Resources South Australia, SARDI Aquatic Sciences, Adelaide. 60 pp.
Unmack, P.J. 2001. Fish persistence and fluvial geomorphology in central Australia. Journal of Arid Environments 49: 653-669.
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.
Webb, A.C. 2007. Status of non-native freshwater fishes in tropical northern Queensland, including establishment success, rates of spread, range and introduction pathways. Journal and Proceedings of the Royal Society of New South Wales 140: 63–78.
