Lake Bermin

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Lake Bermin
Coordinates 5°09′30″N 9°38′0″E / 5.15833°N 9.63333°E / 5.15833; 9.63333Coordinates: 5°09′30″N 9°38′0″E / 5.15833°N 9.63333°E / 5.15833; 9.63333
Lake type Crater lake
Primary inflows None
Primary outflows Cross River system
Basin countries Cameroon
Surface area

144 acres (58 ha)[1]
or

280 acres (110 ha)[2]
Max. depth 15 m (49 ft)[2]

Lake Bermin (sometimes spelled Bemin or Beme) is a small lake in the volcanic chain in the Southwest Region of Cameroon. It is a volcanic lake with a diameter of about 700 m (2,300 ft)[3] and a crater rim that rises to a height of about 46 m (150 ft).[1] This highly isolated lake is roughly circular in shape, lacks an inflow, but has an outflow into the Cross River system.[4]

Biology[edit]

Despite its very small size, it supports nine endemic species of tilapiine cichlid fishes (C. bakossiorum, C. bemini, C. bythobates, C. flava, C. gutturosa, C. imbriferna, C. snyderae, C. spongotroktis, and C. thysi).[1] This number of endemic fishes per area is the highest recorded anywhere.[5] Early genetic evidence suggested that these probably were the result of sympatric speciation.[4] Later studies indicate a level of secondary gene flow between the Bermin cichlids and Cross River C. guineensis, although it is unclear if this facilitated speciation among the former group.[3] All the Bermin cichlids are critically endangered by pollution and sedimentation from human activities, and potentially also by large emissions of carbon dioxide (CO2) from the lake's bottom (compare Lake Nyos),[6][7][8] although Bermin is too shallow to contain very high amounts of this gas.[2]

See also[edit]

References[edit]

  1. ^ a b c Dickinson, C. (2005). The Tilapia of Lake Bernin, Cameroon. Modern Aquarium -Greater City A.S. (NY): 15-16
  2. ^ a b c Freeth, S.J.; C.O. Ofoegbu; and K.M. Onuoha (1992). Natural Hazards in West and Central Africa, pp. 50—52. ISBN 978-3-663-05239-5
  3. ^ a b Martin; Cutler; Friel; Touokong; Coop; and Wainwright (2015). Complex histories of repeated gene flow in Cameroon crater lake cichlids cast doubt on one of the clearest examples of sympatric speciation. Evolution 69-6: 1406–1422. doi:10.1111/evo.12674
  4. ^ a b Schliewen, U.K., Tautz, D., and Pääbo, S. (1994). Sympatric speciation suggested by monophyly of crater lake cichlids. Nature 368(6472): 629-632.
  5. ^ Freshwater Ecoregions of the World (2008). Western Equatorial Crater Lakes.
  6. ^ Moelants, T. (2009). "Tilapia bakossiorum". IUCN Red List of Threatened Species. Version 2010.4. International Union for Conservation of Nature. Retrieved 29 April 2011. 
  7. ^ Moelants, T. (2009). "Tilapia gutturosa". IUCN Red List of Threatened Species. Version 2010.4. International Union for Conservation of Nature. Retrieved 29 April 2011. 
  8. ^ Moelants, T. (2009). "Tilapia thysi". IUCN Red List of Threatened Species. Version 2010.4. International Union for Conservation of Nature. Retrieved 29 April 2011.