The dikume (''Konia dikume'') is a critically endangered species of fish in the family

Cichlidae Cichlids are fish from the family Cichlidae in the order Cichliformes. Cichlids were traditionally classed in a suborder, the Labroidei, along with the wrasses ( Labridae), in the order Perciformes, but molecular studies have contradicted thi ...

. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Lake Barombi Mbo Lake Barombi Mbo or Barombi-ma-Mbu is a lake near Kumba in the Southwest Region of Cameroon. It is located in the Cameroon volcanic chain, and is the largest volcanic lake in this region. It is one of the oldest radiocarbon-dated lakes in Afri ...

in western

Cameroon Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west-central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; the C ...

Description

The dikume is a silvery coloured fish with faint vertical barring. It grow to a maximum length of 11.2 cm. The most distinguishing feature of this species is that when freshly caught the capillaries swell with blood, particularly at the base of the fins, and oozes out to stain the fishes otherwise silvery skin.

Distribution and habitat

It is endemic to Lake Barombi Mbo, a volcanic crater lake with a diameter of just 3 miles in western Cameroon where only the top 40 metres contains enough dissolved oxygen to sustain vertebrate life.

Habits

The dikume is an invertebrate feeder which specialises in feeding on the larvae of the

mosquito Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "li ...

Chaoborus ''Chaoborus'' is a genus of midges in the family Chaoboridae. The larvae are known as glassworms because they are transparent. They can be found commonly in lakes all over the world and can be up to . The adults are sometimes called phantom midg ...

spp''. To reach this food source the dikumbe must spend time in water that is so deep that it is deoxygenated, the high levels of

hemoglobin Hemoglobin (haemoglobin BrE) (from the Greek word αἷμα, ''haîma'' 'blood' + Latin ''globus'' 'ball, sphere' + ''-in'') (), abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythrocyte ...

in its blood are an adaptation that allow it to store oxygen so that it can visit the deeper, deoxygenated parts of the lake. Like the other cichlids endemic to Lake Barombi Mbo the dikume is a

mouthbrooder Mouthbrooding, also known as oral incubation and buccal incubation, is the care given by some groups of animals to their offspring by holding them in the mouth of the parent for extended periods of time. Although mouthbrooding is performed by a va ...

Threats

It is threatened because of

pollution Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...

and

sedimentation Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the ...

due to human activities. It is potentially also threatened by large emissions of

carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...

(CO₂) from the lake's bottom (compare

Lake Nyos Lake Nyos ( ) is a crater lake in the Region of Cameroon, located about northwest of Yaoundé, the capital. Nyos is a deep lake high on the flank of an inactive volcano in the Oku volcanic plain along the Cameroon line of volcanic activity ...

), although studies indicate that Barombo Mbo lacks excess amounts of this gas.Freeth, S.J.; C.O. Ofoegbu; and K.M. Onuoha (1992). Natural Hazards in West and Central Africa, pp. 50—51. As well as water abstraction to supply the growing town of Kumba and the introduction of non-native species. However, at the moment, there are no introduced fish species on Lake Barombi Mbo and commercial fishing is banned.

Taxonomy

Lake Barombi Mbo is home to a "species flock" of cichlids with fourteen species, of which twelve are endemic. They all appear to be descended from a common

tilapia Tilapia ( ) is the common name for nearly a hundred species of cichlid fish from the coelotilapine, coptodonine, heterotilapine, oreochromine, pelmatolapiine, and tilapiine tribes (formerly all were "Tilapiini"), with the economically most ...

-like ancestor and the dikume is one of the more specialised of them.

References

{{Taxonbar, from=Q304664 Dikume Fish of Cameroon Endemic fauna of Cameroon Cichlid fish of Africa Fish of Lake Barombi Mbo Fish described in 1972 Taxonomy articles created by Polbot