Cape galaxias

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Cape galaxias
Galaxias zebratus.jpg
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Galaxiiformes
Family: Galaxiidae
Genus: Galaxias
Species:
G. zebratus
Binomial name
Galaxias zebratus
(Castelnau, 1861) [2]
Synonyms

Cobitis punctiferCastelnau, 1861
Cobitis zebrataCastelnau, 1861
Galaxias capensisSteindachner, 1894
Galaxias dubiusGilchrist & Thompson, 1917

Contents

The Cape galaxias (Galaxias zebratus) is a species of freshwater fish of the family Galaxiidae.

It is a small fish, rarely larger than 6 cm, that inhabits clear streams, rivers and ponds of South Africa. It shares the same habitat as imported trout and bass species and has been identified as prey. [3] The numbers of this relatively delicate fish have declined around Cape Town. Although in South Africa it was at one time classified as near threatened, in Australia species of the same genus were driven to extinction by competing salmonids and other introduced species of fish. [4] It is now classified as "Data Deficient" on the grounds that the taxonomic status of the species complex is unclear. [1]

Description

The Cape galaxias is a small slender fish with a cylindrical body and no scales. It has a single dorsal fin with 9 to 13 soft rays set well back on the body and just above the anal fin which has a similar number of rays. It is silvery in colour and the internal organs can be seen through the skin. [5]

Distribution and habitat

Genus Galaxias is restricted to the Southern Hemisphere and the Cape galaxias is unique because it is the only species of the genus found in the African continent.

It is endemic to the Western Cape region in South Africa and the first specimen caught by scientists was captured in the Cape Flats area in 1861. For a long time it was believed that the distribution of this fish species was restricted to the Western Cape, within an area ranging between the Keurbooms River and the Olifants River. However, since 1995 it has been also found in the Krom River as well as in the Gamtoos River system of the Eastern Cape. [6] Some of the taxa in the complex are found in clear mountain streams with low dissolved mineral levels but others seem to prefer lowland streams that can be turbid and have high levels of dissolved minerals. [1]

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Olifants River (Western Cape) River in the Western Cape, South Africa

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Gamtoos River River in the Eastern Cape, South Africa

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Berg River River in the Western Cape, South Africa

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Freshwater mullet Species of fish

The freshwater mullet is a species of fish in the family Mugilidae. It is endemic to South Africa.

Kouga River River in the Eastern Cape, South Africa

The Kouga River originates near Uniondale, Eastern Cape, South Africa, and flows eastward, where it joins the Groot River to form the Gamtoos just past the Kouga Dam. Its main tributary is the Baviaanskloof River, which joins its left bank before the dam.

Keurbooms River River in the Western Cape, South Africa

The Keurbooms River is a river in the Western Cape Province in South Africa. The river has its sources south of Uniondale in the Langkloof and flows in a roughly southeastern direction. It passes De Vlugt and the Prince Alfred Pass, flowing along the northern side of the R340 road then it turns south. After crossing the N2 road, it flows into the Indian Ocean through the Keurbooms Estuary, located close to the coastal town of Plettenberg Bay.

Krom River River in the Eastern Cape, South Africa

Krom River or Kromme River is a river in the Eastern Cape Province in South Africa. The river flows into the Indian Ocean through an estuary on the north side of St Francis Bay, west of Port Elizabeth. The Krom river flows in an ESE direction and is approximately 109 km long with a catchment area of 1,085 km2.

Galaxias supremus, the Kosciuszko galaxias, is a galaxiid of the genus Galaxias, a member of the Mountain Galaxias species complex group of freshwater fish, found in Australia.

Galaxias tantangara, the stocky galaxias, is a galaxiid of the genus Galaxias, a member of the Mountain Galaxias species complex group of freshwater fish, found in Australia.

Galaxias terenasus, the roundsnout galaxias, is a galaxiid of the genus Galaxias, a member of the Mountain Galaxias species complex group of freshwater fish, found in Australia.

References

  1. 1 2 3 Swartz, E.; Impson, D.; Cambray, J. (2007). "Galaxias zebratus". IUCN Red List of Threatened Species . 2007: e.T8816A12934076. doi: 10.2305/IUCN.UK.2007.RLTS.T8816A12934076.en . Retrieved 19 November 2021.
  2. Froese, Rainer and Pauly, Daniel, eds. (2006). "Galaxias zebratus" in FishBase. June 2006 version.
  3. Woodford, D. J.; Impson, N. D. (2004). "A preliminary assessment of the impact of alien rainbow trout (Oncorhynchus mykiss) on indigenous fishes of the upper Berg River, Western Cape Province, South Africa]". African Journal of Aquatic Science. 29 (1): 107–111. doi:10.2989/16085910409503799. Archived from the original on 31 December 2013.
  4. "Biodiversity, Alien trout, and the So what attitude" [ permanent dead link ]
  5. "Galaxias zebratus (Castelnau, 1861): Cape galaxius". FishBase. Retrieved 2013-12-29.
  6. Freshwater Ichthyology - The Cape galaxias Galaxias zebratus [ permanent dead link ]