|Scientific Name:||Redigobius bikolanus|
|Species Authority:||(Herre, 1927)|
Vaimosa bikolana Herre, 1927
|Taxonomic Notes:||This species has recently been reviewed by Larson (2010); it is possible that this is a species-complex. A genetic and morphological study covering all habitat types and geographic localities may help to clarify if there are cryptic species within R. bikolanus.|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Reviewer/s:||Hoese, D. & Keith, P.|
At present, this widespread species appears to have stable populations in suitable habitat and can be locally common. It is listed as Least Concern. The possibility still exists that there are cryptic species within Redigobius bikolanus; taxonomic work on this remains to be undertaken.
|Range Description:||This species is widespread, occurring from the Comores to Samoa (Larson 2010).|
Native:Australia; Cambodia; Comoros; Cook Islands; Fiji; Indonesia; Japan; Madagascar; Malaysia; Mauritius; Micronesia, Federated States of; New Caledonia; Northern Mariana Islands; Palau; Papua New Guinea; Philippines; Samoa; Seychelles; South Africa; Sri Lanka; Taiwan, Province of China; Vanuatu
|Range Map:||Click here to open the map viewer and explore range.|
There is some abundance data for populations in northern Queensland (Australia), which show the species to be patchily distributed; it may be common in some streams but less so in others (Pusey et al. 2004). Its highest abundance and density was in the Johnstone River.
Rayner et al. (2008 and 2009), discussed changes in community structure and dietary habits of fishes in the seasonally flooding Mulgrave River, Queensland, finding that the species formed a significant part of a gobioid-dominant fish assemblage during the dry season (when flows were lower).
|Habitat and Ecology:||
This species is found in fresh and brackish waters, in rivers, small streams, estuaries and mangroves, and has been recorded 120 kilometres upstream in pure freshwater in New Guinea and 160 kilometres upstream in the Fitzroy River, Queensland (Allen 1991, Larson 2010, Pusey et al. 2004). Pusey et al. (2004) give details of habitat/microhabitat types and use for north Queensland rivers, indicating that the species prefers low flow streams, where cover (leaf litter and woody debris) is plentiful. As individuals have been found in lakes and the upper reaches of rivers and above obstructions such as the Fitzroy barrage, it appears that individuals can breed in freshwater. The species has bred in freshwater in captivity (Leggett and Merrick 1987).
|Major Threat(s):||There are currently no known major threats to this species. Potential threats include damage to coastal rivers and mangrove habitats through habitat degradation and destruction. Some populations may be more at risk (e.g. Philippines, Singapore) due to development and clearing. The species may be sought after for the aquarium trade.|
|Conservation Actions:||In Australia this species is listed as Non-threatened (Wager and Jackson 1993), as its preferred habitats are relatively stable and a number of waterways in which it occurs are in protected areas. Further taxonomic work is required as there is a possibility that there are cryptic species within this species.|
Allen, G.R. 1991. Field guide to the freshwater fishes of New Guinea. Christensen Research Institute, Madang, Papua New Guinea.
Allen, G.R., Midgley, S.H. and Allen, M. 2002. Field guide to the Freshwater Fishes of Australia. Western Australian Museum, Perth.
Chen, I.S. and Fang, L.S. 1999. The freshwater and estuarine Fishes of Taiwan. National Museum of Marine Biology and Aquarium, Taiwan.
Donaldson, T.J. and Myers, R.F. 2002. Insular freshwater fish faunas of Micronesia: patterns of species richness and similarity. Environmental Biology of Fishes 65: 139-149.
Hoese, D.F., Bray, D.J., Paxton, J.R. and Allen, G.R. 2006. Fishes. In: P.L. Beesley and A. Wells (eds), Zoological Catalogue of Australia, pp. 2178. Australian Biological Resources Study and Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia.
IUCN. 2012. IUCN Red List of Threatened Species (ver. 2012.2). Available at: http://www.iucnredlist.org. (Accessed: 17 October 2012).
Larson, H.K. 2010. A review of the gobiid fish genus Redigobius (Teleostei: Gobionellinae), with descriptions of two species. Ichthyological Exploration of Freshwaters 21(2): 123-191.
Leggett, R. and Merrick, J.R. 1987. Australian natives fishes for aquariums. J.R. Merrick Publications, Artamon, New South Wales.
Merrick, J.R. and Schmida, G.E. 1984. Australian freshwater fishes. Biology and Management. Griffin Press, Ltd., Netley, Australia.
Monks, N. (editor). 2006. Brackish-water fishes. An aquarist's guide to identification, care and husbandry. T.F.H. Publications, Inc., Neptune City, New Jersey.
Pusey, B., Kennard, M. and Arthington, A. 2004. Freshwater Fishes of North-Eastern Australia. Csiro Publishing, Colingwood, Victoria.
Rayner, T. S, Pusey, B.J. and Pearson, R.G. 2009. Spatio-temporal dynamics of fish feeding in the lower Mulgrave River, north-eastern Queensland: the influence of seasonal flooding, instream productivity and invertebrate abundance. Marine and Freshwater Research 60: 97-111.
Rayner, T. S, Pusey, B.J. & Pearson, R.G. 2008. Seasonal flooding, instream habitat structure and fish assemblages in the Mulgrave River, north-east Queensland: towards a new conceptual framework for understanding fish-habitat dynamics in small tropical rivers. Marine and Freshwater Research 59: 97-116.
Wager, R. and Jackson, P. 1993. The action plan for Australian freshwater fishes. Australian Nature Conservation Agency, Canberra, A.C.T.
|Citation:||Larson, H. 2012. Redigobius bikolanus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 19 May 2013.|
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