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 ...

to Lake Barombi Mbo 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 ''

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.

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 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), 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-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