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The Kimberley is one of the most remote regions of Australia and is considered one of the last wilderness frontiers. Located in the far north of Western Australia between 15 and 20° south latitude, it is surrounded by the Indian Ocean to the west, Timor Sea to the north, and the Great Sandy and Tanami Deserts to the south and east.
While the Kimberley region has an area of 424,517 km², much of the area remains undeveloped and like many parts of Australia, is a region of few towns with great distances between them. Looking at a map can be deceiving because the huge size is not obvious. The Kimberley has a resident population of only around 30,000; however, wildlife is abundant and visible.
The region is distinguished by a diverse range of geographical features. From the red dune fields of the Great Sandy Desert through the rugged escarpment country to Geikie and Windjana Gorges and the Bungle Bungles to broad tidal flats, waterfalls and patches of rainforest. Many rivers flow from the high-rainfall parts of the northern plateaux to the coastline. The coastal and marine environments comprise numerous inlets, mangrove shores, bays and offshore islands. The coast is prone to large tidal variations that, together with summer river discharges, dramatically influence the coastal environment.
The Kimberley has some spectacular and significant waterways. It is home to more than 100 rivers and many more creeks and streams. They exhibit highly seasonal flow conditions as a result of being located at the southern edge of the global monsoon system, where intense and widespread rainfall results in flood flows during summer. The largest river in the Kimberley (and in Western Australia) is the Fitzroy, which has a floodplain several kilometres wide. The second largest river in the Kimberley is the Ord.
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| Kimberley 'Autobahn' - no traffic congestion here! - ©Bruce Hansen |
The Kimberley is accessible by road from Perth and Port Hedland via the Great Northern Highway, or from the Northern Territory via Darwin and Katherine. However, unless you are intentionally undertaking a trans-Australian driving adventure, it is recommended that you fly into Broome to begin your visit. Flights are available daily from all the major Australian cities. Rental vehicles of all types, including 4WDs and campervans, are available in Broome.
The Kimberley has a tropical monsoon climate characterised by two dominant seasons: The warm, dry season prevails from May to October with temperatures of 20-30° Celsius and little rainfall. The tropical wet season from November-April is marked by temperatures of 30-38° Celsius and increased rainfall. Ninety percent of the region's rainfall occurs between December and March, often in heavy downpours. Rainfall can vary drastically from year to year; it can be drought one year and torrential floods the next.
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| Cratercephalus stramineus - ©Neil Armstrong |
Parambassis gulliveri - ©Günther Schmida |
The Kimberley region of Western Australia is home to a unique assemblage of freshwater fishes. Perennial and intermittent rivers in the Kimberley provide habitat to a variety of fish, crustacean, aquatic reptiles and invertebrates. Much of the landscape is rugged, with vehicular access seasonally limited. This, together with the isolation of the region, has resulted in only limited fish surveys being conducted. No systematic survey of freshwater fishes has been concluded in the Kimberley to date; although there have been a number of separate stream surveys completed. Fish surveys have often revealed species that are new to science, or have greatly extended the ranges of the species present.
Fish species found in the Kimberley are similar to the fish fauna extending across northern Australia. However, the Kimberley is a distinctive ancient island, with quite different types of rivers to the Northern Territory and the Gulf of Carpentaria. For example, the Kimberley is the only region in Australia where the highly evolved and dispersed freshwater crayfish do not occur, apparently replaced by giant freshwater shrimps. Macrobrachium river prawns and Caridina shrimps, both of which are common across northern Australia, are present in the Kimberley.
The Kimberley freshwater fauna show a high level of endemism. This is particularly notable within the fish fauna that currently comprises about 50 species. Endemism is found within several families of fish including gudgeons (Eleotridae), grunters (Terapontidae), hardyheads (Atherinidae) and rainbowfish (Melanotaeniidae). Rainbowfish species found in the Kimberley area include Melanotaenia australis, Melanotaenia exquisita, Melanotaenia gracilis, Melanotaenia nigrans and Melanotaenia pygmaea.
Kimberley - known Rainbowfish distribution sites. Absence of species from other areas reflects a lack of sampling, rather than absence as many suitable habitats have never been sampled. |
Melanotaenia australis have a wide distribution across northern Australia ranging from the Ashburton River in the Pilbara to the Adelaide River in the Northern Territory. Melanotaenia australis show considerable variation in morphology across its known distribution. Recent genetic studies have shown that there is a high level of genetic divergence existing within the east Kimberley, and a very high genetic difference between the Pilbara and east Kimberley populations of Melanotaenia australis. These studies suggest that there maybe more than one species in the Melanotaenia australis complex. However the taxonomy of Melanotaenia australis is still incomplete.
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| Bindoola Creek - ©Franz-Peter Muellenholz |
Melanotaenia exquisita were first discovered in the King George River. Another population was found in Bindoola Creek, a small stream that flows into the Cambridge Gulf in the far north-eastern area of the Kimberley. No doubt other populations will be found in areas still uncollected in the future. Preliminary genetic studies of Melanotaenia exquisita from Bindoola Creek have shown some clear differences from other known populations.
Melanotaenia gracilis are so far only known from the Drysdale River drainage and nearby Carson River (a tributary of the King Edward River), about 140 km west northwest of Wyndham. Most collections have taken place in the Drysdale River.
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| Melanotaenia nigrans [Pago Creek] - ©Bruce Hansen |
Melanotaenia nigrans have so far only been collected in Dominic and Pago creeks; however, they probably occur elsewhere. Dominic and Pago creeks are small isolated streams between the Drysdale and King Edward Rivers. Unlike other nigrans varieties, they have a row of reddish-orange dots below the black stripe and may prove to be genetically different.
Melanotaenia pygmaea are known only from two small tributaries of the Prince Regent River; Cascade Creek and Youwanjela Creek. There are nine major tributaries of the Prince Regent River, originating 11-32 km from their junctions with the river. Upper reaches and creeks are mainly seasonal, with some small permanent pools.
Two freshwater fishes, Melanotaenia pygmaea and Hypseleotris ejuncida, are endemic to the Prince Regent River system. Two others, Leiopotherapon macrolepis and Hypseleotris regalis, are endemic to the site and nearby Roe River system. Another species, Hannia greenwayi, is known only from the site and the Hann River system (50 km south-east). Mogurnda oligolepis is also found in the Prince Regent River system.
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| Mitchell River |
The Mitchell River, flowing northwards, drains into Walmsley Bay and Admiralty Gulf, carving gorges and waterfalls into the underlying sandstone, particularly along the margins of the Mitchell Plateau. The Mitchell River is about 350 km north-east of Derby, 270 km north-west of Wyndham. The creeks and upper reaches of the Mitchell River are seasonal; the entrenched lower reaches are permanent or near permanent. At least ten species of freshwater fish occur which include Melanotaenia australis. The system is the only known habitat of the Mitchell Gudgeon (Kimberleyeleotris hutchinsi).
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| Drysdale River - ©Franz-Peter Muellenholz |
Twenty-six species of freshwater fish have been recorded from the Drysdale River and its tributaries with at least nineteen of these found in the Drysdale River itself. Three fish species are possibly endemic to the Drysdale River: The Drysdale Hardyhead (Craterocephalus helenae), the Drysdale Grunter (Syncomistes rastellus) and the Drysdale Gudgeon (Kimberleyeleotris notata). Mogurnda oligolepis, endemic to the Kimberley region has also been collected from the Drysdale River system.
The Ord River contains nearly 50 species of freshwater fishes (mainly catfishes, grunters and gudgeons). Melanotaenia australis, Craterocephalus stramineus, Craterocephalus stercusmuscarum, Glossogobius sp.2, Hypseleotris compressa, Kurtus gulliveri, Parambassis gulliveri and the freshwater sawfish (Pristis microdon) occur in the Ord River system.
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| King Edward River |
In 2004 thirty sites on the King Edward and Carson Rivers were sampled for fish. A total of 24 fish species were recorded in the catchment including Melanotaenia australis, Hephaestus jenkinsi, Hephaestus epirrhinos, Mogurnda oligolepis, Craterocephalus lentigenosus, Syncomistes butleri and Hypseleotris ejuncida.
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| Fitzroy River |
The Fitzroy River is a major floodplain system with a catchment area of over 95,000km². The upper catchment of about 45,000km² (upstream of Fitzroy Crossing) can be divided into the catchments of the Margaret and Fitzroy rivers. Near the town of Fitzroy Crossing many smaller rivers and creeks radiate from the main channel and have varying degrees of ephemerality depending on the rainfall zone. Downstream of Fitzroy Crossing lies the river floodplain, which extends some 300 km to the coast, and includes the tributaries of Christmas, Mt Hardman, Mt Wynne and Geegully creeks. The main tributaries of the upper Fitzroy include the Hann, Adcock, Louisa and Little Fitzroy rivers, while those of the Margaret include the Mary, Leopold, O'Donnell, Gidden, Little Gold and Laura rivers
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| Mogurnda oligolepis - ©Neil Armstrong |
In 2004 forty-four species of freshwater fish were recorded in the Fitzroy catchment. These included Melanotaenia australis, Toxotes kimberleyensis, Mogurnda oligolepis, Craterocephalus lentigenosus, Craterocephalus stramineus, Hypseleotris kimberleyensis, Pristis clavata and Pristis microdon.
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| Ondinea purpurea - ©Bruce Hansen |
Wetlands in the Kimberley generally are seasonal unless water supply is abundant enough to maintain levels during the dry season or created artificially such as Lake Kununurra and Lake Argyle. Many aquatic species have adapted to the seasonal drying out of wetlands.
Many river systems in the Kimberley region have not been adequately surveyed for aquatic plants. However, a large number of aquatic and wetland plants are present including the genera Aponogeton, Baumea, Blyxa, Ceratophyllum, Ceratopteris, Chara, Eriocaulon, Glossostigma, Hydrilla, Ipomoea, Limnophila, Marsilea, Myriophyllum, Najas, Nymphaea, Nymphoides, Potamogeton, Rotala, Triglochin, Utricularia and Vallisneria.
Examples are Aponogeton kimberleyensis, Aponogeton euryspermus, Bacopa floribunda, Blyxa aubertii, Ceratopteris thalictroides, Eclipta platyglossa, Eriocaulon setaceum, Glossostigma drummondii, Hydrilla verticillata, Lemna aequinoctialis, Limnophila australis, Limnophila brownii, Limnophila chinensis, Limnophila fragrans, Ludwigia octovalvis, Ludwigia perennis, Myriophyllum callitrichoides, Myriophyllum costatum, Myriophyllum crispatum, Myriophyllum filiforme, Myriophyllum trachycarpum, Myriophyllum verrucosum, Nymphaea hastifolia, Nymphaea immutabilis, Nymphaea immutabilis subsp. immutabilis, Nymphaea macrosperma, Nymphaea violacea, Nymphoides aurantiaca, Nymphoides beaglensis, Nymphoides crenata, Nymphoides disperma, Nymphoides indica, Nymphoides minima, Nymphoides quadriloba, Ondinea purpurea subsp. petaloidea, Ondinea purpurea subsp. purpurea, Pistia stratiotes, Pogostemon stellatus, Potamogeton crispus, Potamogeton javanicus, Potamogeton tepperi, Potamogeton tricarinatus, Rotala diandra, Rotala mexicana, Rotala occultiflora, Vallisneria annua, Vallisneria nana, Vallisneria triptera and many, many others.
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| Malaccotristicha australis (Tristicha trifaria) - ©Bruce Hansen |
Aquatic plants include a population of Malaccotristicha australis (Tristicha trifaria), an unusual aquatic that grows in fast flowing water in the Mitchell Falls area. Another interesting plant found at Mitchell Falls is Aldrovanda vesiculosa. This is a carnivorous plant, which has whorls of spoke-like leaves but no roots. It floats on water, and flowers at the nodes rise above the water to enable pollination to take place. This is a rather unique aquatic plant that can best be described as an aquatic Venus Fly Trap. The plant has a similar structure to aquatic Utricularia, however instead of producing bladders to trap prey, a jaw like trap is produced. The traps have sensitive trigger hairs, that when touched by would be prey, cause it to close.
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| Aldrovanda vesiculosa - ©Dave Wilson |
© Copyright Adrian R. Tappin
Created 17 February, 2001
Updated 30 August, 2005
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