Evolution of Aquatic Biota: Tigerfishes and others
The Principal Literature on Africa's tigerfishes is in the Bibliography - Downloadable pdfs - appended bottom of this page
Graphical Abstract [Right] of a Recent Published Study - The Numbered Events link speciation events in Tigerfishes (ages in million of years, Ma) to episodes of tectonism, where uplift and faulting focused along Africa's Rift zones reconfigured drainage basins over the past ~11 Ma
"I have stated heretofore in print, and am still ready to maintain my pronouncement, that the tigerfish of Africa is the fiercest fish that swims. Let others hold forth as advocates for the mako shark, the barracuda, the piranha of the Amazon, or the bluefish of the Atlantic.
To them I say, ' 'Pish and tush!' "
Nearly 300 Tigerfishes genotyped from 17 African countries...
In 2000, I initiated field collecting and the planning of a detailed study of Africa's tigerfishes, the predatory, freshwater characiformes of the genus Hydrocynus. This has developed into a collaborative Pan-African study, not least thanks to the fine work by Sarah Goodier for her MSc under the auspices of the Africa Earth Observatory Network (then at UCT until closed down in 2011). Nearly 300 fishes have been sampled from a total of 23 principal rivers within 15 geographically isolated drainage basins in West, East and Central Africa. These represent a total of 17 African countries: from Mali and The Gambia to Kenya and Ethiopia and south to South Africa and Mozambique.
Initial genotyping was carried out in Colleen O'Ryan's Population Genetics Laboratory, Dept of Molecular and Cell Biology, at UCT. An expanded survey and detailed analyses continue under auspices of AEON's Geoecodynamics Research Hub, Stellenbosch University
This tigerfish research is part of integrated research on wetlands biodiversity. The biological insights continuing to be obtained dovetail with efforts to decipher the geological intricacies of an evolutionary narrative. Integral to Geoecodynamics Research, the evolution of Hydrocynus aims to reconstruct details of drainage evolution across tropical Africa, with a focus on deciphering recent events in the Kalahari Epeirogeny. These phylogeographic studies of fishes build on the synthesis published by Skelton (1994). My close association with the Southern African Institute for Aquatic Biodiversity (SAIAB) is a key component with this research on tigerfishes and other fishes in the Zambezi and Congo basins. Additional biotic indicators of landscape evolution are being studied, including lechwe antelopes. The latter focus has entailed a detailed review of lechwe taxonomy (including the description of the Upemba lechwe, Kobus anselli as new to science).
The inaugural publication on tigerfish evolution is published in PLoS One. An overview of the project (Cotterill and Goodier 2009) summarizes the described diversity of Hydrocynus,and also places the phylogeographic aspects of the research into the context of drainage evolution.
Aspects of fieldwork along the Bas Congo river were filmed for a National Geographic documentary, which highlights the Goliath Tigerfish, Hydrocynus goliath. This documentary also highlights the unique hydrology and remarkable fish fauna of the Bas Congo. See recent studies by Markert et al. BMC Evolutionary Biology 2010, 10:149, and results of velocity mapping that reveal the unique bathymetry and hydrodynamics of the 150m deep channel of the Bulu reach of the Bas Congo (Jackson et al. 2009).
The recent study of rheophilic [rapid-loving] Cichlid Fishes by Schwarzer et al (2011) employed a Geoecodynamics methodology - gene trees and molecular clocks - to estimate that the Bas Congo began to incise the western rim of Africa in the late Miocene. Geoecodynamics undergirded the reconstruction of where and when ancestral lineages of Steatocranus and Nanochromis underwent adaptive radiations in the spectacular rapids of the Bas Congo, and so testifies to when the river incised deep gorges across the Crystal Mountains. This geobiological estimate of the age of Earth's deepest river agrees with available geological reconstructions. The study exploited the high fidelity of these little fishes to fast-flowing rapids - their "torrential aquatic habitats", which they have tracked through space and time.
Portrait of a large specimen ofGoliath Tigerfish, Hydrocynus goliath
netted by local fishermen on the
Upper Kwango River, southern
Congo basin in 2007 (Photo Mike de Wit)
Map. The principal drainage systems and localities of key relevance to tigerfish biogeography and associated research. Distributional lacunae depicted in yellow denote lakes and rivers where tigerfish do not occur. The distribution of Tanzanian Tigerfish, Hydrocynus tanzaniae is highlighted for the Rufiji-Ruaha drainage system (White). Although Hydrocynus are listed as occurring in the Rovuma drainage system (Green), the identity of these fish, if present, awaits elucidation.
1. Lake Chamo, SW Ethiopia; 2. Murchison Falls. 3. L. Edward. 4. L. Kivu. 5. L. Victoria. 6. L. Tanganyika. 7. L. Rukwa. 8. L. Malawi. 9. Kapachira Falls on Shire river. 10. Save-Runde. 11. Pongola. 12. Upper Kafue. 13. Okavango Delta. 14. Kunene.. 15. Cuanza. 16. Chutes Tembo on Upper Kwango River. 17. Kinshasa. The patchwork of great lakes delineates the East African Rift System.
Comparison of Sahelian Tigerfish, Hydrocynus
brevis (Top) and Nile Tigerfish, H. forskahli (Bottom).
(Photo D Neumann)
Photo Mosaic: Kinsuka Rapids, Bas Congo
Sampling in the Congo Basin: a small affluent on the Kwango river.
(Photo D. Tweddle)
Publications and Related References
Goodier, S.A.M., Cotterill, F.P.D., O'Ryan, C., Skelton, P.H and de Wit, M.J., 2011. Phylogeny of African tigerfish (Genus Hydrocynus) reveals palaeogeographic signatures of linked Neogene geotectonic events. PloS ONE 6(12): e28775. doi:10.1371/journal.pone.0028775 PDF Tigerfishes and Geologists Press Release Graphical Abstract
Cotterill, F. P. D. & de Wit, M. J. 2011. Geoecodynamics and the Kalahari Epeirogeny: linking its genomic record, tree of life and palimpsest into a unified narrative of landscape evolution. S. Afr. J. Geol. 114: 493-518. PDF
Cotterill, F. P. D. & S. A. Goodier (2009) How many tigerfish species? Genetic insights into the evolution of Africa's Tigerfish and the taxonomic status of Tanzanian Hydrocynus. African Fisherman 20 (6): 37-41. PDF
Bell-Cross, G. (1966) Preliminary observations on Hydrocynus vittatus in the Upper Zambezi river system. Fish Res. Bull. Zamb. 4 : 21-27 PDF
Brewster, B. (1986) A review of the genus Hydrocynus Cuvier 1819 (Teleostei, Characiformes). Bull. Brit. Mus. nat. Hist. (Zool.) 50 (3): 163-206. PDF
Gillet, H. (translated by L. J. McCormick) (1949) Goliath. In: B. Vesey Fitzgerald. Game Fishes of the World. pp. 358-365. PDF
Gregory, W.K. (1936) The structure and development of the complex symphysial hinge joint in the mandible of Hydrocyon lineatus Bleeker, a characin fish. Proc. zool. Soc. Lond. 1936: 975-984. PDF
Jackson, P.R., K.A. Oberg, N. Gardiner & J. Shelton (2009) Velocity mapping in the Lower Congo River: A first look at the unique bathymetry and hydrodynamics of Bulu Reach, West Central Africa. in: Proceedings of the IAHR Symposium on River Coastal and Estuarine Morphodynamics 6:1007-1014. PDF
Jackson, P. N. B. (1961) The impact of predation, especially by tiger-fish (Hydrocyon vittatus Cast.) on African freshwater fishes. Proc. Zool. Soc. Lond. 136: 603-622 PDF
Jackson, P. N. B. (1986) Fish of the Zambezi system. In: B. R. Davies and K. F. Walker. Ecology of River Systems. Dr W. Junk Publishers, Dordrecht, The Netherlands. pp. 269-288. PDF
Kenmuir, D. H. S. (1973) The ecology of the Tigerfish Hydrocynus vittatus Castelnau, in Lake Kariba. Occ. Pap. Nat. Mus. Rhod. Nat. Sci. 5B(3):115-170 PDF
Lewis, D. S. C. (1974) The food and feeding habits of Hydrocynus forskahlii Cuvier and Hydrocynus brevis Gunther in Lake Kainji, Nigeria. J. Fish Biol. 6: 349-363 PDF
McCormick, L. J. (1949) Tigerfish. In: B. Vesey Fitzgerald. Game Fishes of the World. pp. 349-357. PDF
Schwarzer J, Misof B, Ifuta SN, Schliewen UK, (2011) Time and Origin of Cichlid Colonization of the Lower Congo Rapids. PLoS ONE 6(7):e22380. doi:10.1371/journal.pone.0022380 PDF
Skelton, P. H. (1994) Diversity and distribution of freshwater fishes in east and southern Africa. Ann. Mus. r. Afr. Centr., Zool. 275:95-131. PDF
Winemiller, K. O. & Kelso-Winemiller, L. C. (1994) Comparative ecology of the African pike, Hepsetus odoe, and tigerfish, Hydrocynus forskahlii, in the Zambezi River floodplain. J. Fish Biol. 45 (2):211-225. PDF