Biodiversity and Community Structure of Mormyridae (Pisces: Teleostei: Osteoglossiformes) from Niger River in Northern Benin: Threats, Conservation and Valorization Perspectives

Author(s): Kayodé Nambil Adjibade, Alphonse Adite, Hamidou Arame, Rachad Sidi Imorou, Stanislas Pejanos Sonon

Mormyrid fishes are of great commercial and economic importance in the artisanal fisheries of the Niger River in Benin. We investigated species composition and community structure of this taxa in order to contribute to species management and sustainable exploitation. Mormyrid individuals were collected monthly from February 2015 to July 2016 using cast nets, gill nets and seines. Among a total of 6825 individuals collected, eleven (11) species belonging to 9 genera were inventoried. Numerically, Marcusenius senegalensis dominated the fish assemblages and made 43.74% of the mormyrid sub-community followed by Mormyrus macrophthalmus (14.87%), Hyperopisus bebe, (11.43%), Petrocephalus bovei (11.21%), Mormyrus rume (8.54%) and Hippopotamyrus pssittacus (4.69%). The Shannon-Weaver index of species diversity was moderate and reached H’=2.54. Overall, percentage occurrences (PO) of Mormyrids in the 5 selected sites ranged between 40 and 100%, with Marcusenius senegalensis (PO=100%) and Hyperopisus bebe (PO=100%) widely distributed in all 5 sites. In the Niger River, Mormyrid abundances significantly (r=0.70; P<0.01) increased with dissolved oxygen. The overexploitation and other antropogenic disturbances such as domestic uses (ditch cleanings, clothe washings, bathings), invasion of floating plants (Echhornia crassipes), sand dragging, human wastes dumping, the use of chemical fertilizers and pesticides for adjacent agriculture etc. constituted some major threats for the growth and survival of the Mormyrids in the Niger River. The results of this study will contribute to design a holistic species management scheme that includes habitat protection, species conservation and valorization.

Benin, Community Structure, Conservation, Management, Mormyrids, Niger River, Shannon-Weaver Index

1. Aboubacar A, Humphrey S. (2007). Atlas Bassin du Niger. Autorité du bassin du Niger, ABN, Niamey.
2. Adite A, Imorou toko I and Gbankoto A. (2013). Fish Assemblages in the Degraded Mangrove Ecosystems of the Coastal Zone, Benin, West Africa : Implications for Ecosystem Restoration and Resources Conservation. Journal of Environmental Protection 4: 1461–1475.
3. Adjibade KN, Adite A, Arame H, Sidi Imorou R and Sonon SP. (2019). The fish fauna of the Mormyridae (Pisces: Teleostei: Osteoglossiformes) from the Niger River at Malanville town, Northern Benin. In press.
4. Ajibade WA, Ayodele IA and Agbede SA. (2008). Water quality parameters in the major rivers of Kainji. African Journal of Environmental Science and Technology 2: 185–196.
5. Barbault R. (2000). Ecologie générale : Structure et fonctionnement de la biosphère. 5ème édition, Dunod, Paris. 326 p.
6. Blache J, Milton F, Stauch A, Iltis A and Loubens G. (1964). Les poissons du bassin du Tchad et du bassin adjacent du Mayo-Kebbi. Etude Systématique et Biologique. Mémoire Orstom, 4, 483 p.
7. ter Braak CJF. (1989). CANOCO - An extension of Decorana to analyze species-environment relationships. Hydrobiologia 184: 169–170.
8. Daget J. (1960). Report on the Kainji dam project (Fisheries). C. R. 4eme collogue sur l’hydrobiologie et pêches en eau douce; Fort-Lamy, CCTA/CSA n° 76: 69-76.
9. Daget J and Iltis A. (1965). Poissons de la Côte d'Ivoire (eaux douces et saumâtres). Mémoire Institut Français d'Afrique Noire, 74: 385p.
10. Gbaguidi HMAG, Adite A and Sossoukpe E. (2016). Ecology and Fish Biodiversity of Man-Made Lakes of Southern Benin (West Africa): Implications for Species Conservation and Fisheries Management. Journal of Environmental Protection 7: 874–894.
11. Hauber ME. (2011). Description and Improvement of the ‘Whedo’‐ Aquaculture ‐ System in Malanville (North of Benin). Dissertation Zur Erlangung Des, Naturwissenschaftlichen Doktorgrades Der Bayerischen Julius‐Maximilians‐Universtität Würzburg. 203p.
12. Hazoume RUS, Chikou A, Koudenoukpo CZ, Adite A, Bonou CA and Mensah GA. (2017). Length-weight relationships of 30 species of fish of the river Sô in Benin (West Africa). International Journal of Fisheries and Aquatic Studies 5: 514–519.
13. Hopkins CD, Lavoué S and Sullivan JP. (2007). Mormyridae. In: Stiassny MLJ, Teugels GG, Hopkins CD, editors. Poissons d’eaux douces et saumâtres de basse Guinée, Ouest de l’Afrique centrale. IRD Éditions, Volume 1, Paris, 220–334.
14. Jackson AT. (2012). Fish assemblage and food web structure in whedos (shallow floodplain habitats) of the Ouémé River, West. Master of Science Thesis, Texas A&M University, USA, 101p.
15. Kisekelwa T, Boden G, Snoeks J and Vreven E. (2016). Marcusenius kaninginii, a new species of elephantfish from the Lowa River basin, Democratic Republic of the Congo (Osteoglossiformes: Mormyridae). Ichthyological Exploration of Freshwaters 26: 341-352.
16. Koba G. (2005). Les pratiques de pêches dans le Fleuve Niger au Benin et leurs impacts sur la faune ichtyologique. Mémoire de DEA en Gestion de l'Environnement. Université d’Abomey-Calavi. 73p.
17. Kramer B. (2013). Differentiation in morphology and electrical signalling in four species of para- and sympatric Marcusenius (Teleostei : Mormyridae) from Côte d’ Ivoire, West Africa. Marine and Freshwater Behaviour and Physiology 46: 105–133.
18. Laë R, Williams S, Morand P, Mikolasek O. 2004. Review of the present state of the environment, fish stocks and fisheries of the river Niger (West Africa). In: Proceedings of the Second International Symposium on the Management of Large Rivers for Fisheries: Sustaining livelihoods and biodiversity in the new millenium. Vol. I. Ed. by Welcomme R. and T. Petr. Rome: FAO, 199-277. (RAP Publication, 16) International symposium on the management of large river for fisheries. 2, Phnom Penh, Cambodge, 11 Février 2003/14 Février 2003. ftp://ftp.fao.org/docrep/fao/007/AD525e/ad525e09.pdf
19. Laleye PA, Chikou A, Philippart J-C, Teugels GG and Vandewalle P. (2004). Etude de la diversité ichtyologique du bassin du fleuve Ouémé au Bénin (Afrique de l’Ouest). Cybium 28: 329–339.
20. Lavoué S, Arnegard ME, Sullivan JP and Hopkins CD. (2008). Petrocephalus of Odzala offer insights into evolutionary patterns of signal diversification in the Mormyridae, a family of weakly electrogenic fishes from Africa. Journal of Physiology - Paris 102: 322–339.
21. Legendre P and Legendre L. (1998). Numerical ecology. Second English edition. Elsevier Science BV, Amsterdam, 853p.
22. Lemoalle J. 2006. La diversité des milieux aquatiques. In: Les poissons des eaux continentales africaines: Diversité, écologie, utilisation par l’homme, Lévêque C, Paugy D (eds). IRD Éditions, Paris, 573p.
23. Lévêque C, Balian E V and Martens K. (2005). An assessment of animal species diversity in continental waters. Hydrobiologia 542: 39–67.
24. Liu W, Zhao E, Kuo Y and Jang C. (2017). Identifying the relationships between trophic states and their driving factors in the Shihmen Reservoir, Taiwan. Limnologica 64:38-45. http://dx.doi.org/10.1016/j.limno.2017.04.004.
25. Lowe-McConnell RH. (1969). Speciation in tropical freshwater fishes. Biological Journal of the Linnean society 1: 51–75.
26. Margalef R. (1968). "Perspective in Ecological Theory" University of Chicago Press, Chicago.
27. Moller P. (1995). Electric Fishes: History and Behaviour. Fish & Fisheries Series, Chapman&Hall, London, NewYork, 584 p.
28. Montchowui E, Chikou A and Philippe MK. (2008). Biodiversité et structure des communautés de poissons du lac Hlan au Bénin. International Journal of Biological and Chemical Sciences 2: 196–206.
29. Morgan GA, Griego OV and Gloeckner G. (2001). SPSS for Windows: An introduction to use and interpretation in research, Lawrence Erlbaum Associates, Publishers, Mahwah, New Jersey.
30. Moritz T, Laleye PA, Koba G and Linsenmair KE. (2006). An annotated list of fish from the River Niger at Malanville, Benin, with notes on the local fisheries. Verhandlung der Gesellschaft für Ichthyologie 5: 95–110.
31. Murphy BR and Willis DW. (1996). Fisheries techniques. American Fisheries Society Bethesda, Maryland.
32. Nelson JS. (2006). Fishes of the World. John Wiley and Sons, New York, NY, USA, Fourth edition. 601p.
33. Nwani CD, Eyo JE, Udeh EF. (2006). Food and feeding habits of Campylomormyrus tamandua in Anambra river, Nigeria. Animal Research International 3: 410–414.
34. Paugy D, Lévêque C and Teugels GG. (2003). Poissons d’eaux douces et saumâtres de l’Afrique de l’Ouest [The fresh and brackishwater fishes of west Africa]. Volume 1 and 2, IRD Editions, Paris.
35. PDC Malanville. (2006). Monographie de la commune de Malanville. Mission de Decentralisation. Programme d'Appui au Demarrage des Communes. Afrique Conseil. Cotonou. 48p.
36. R Core Team. (2013) A Language and Environment for Statistical Computing (R Foundation for Statistical Computing, Vienna.
37. Rich M, Sullivan JP and Hopkins CD. (2017). Rediscovery and description of Paramormyrops sphekodes (Sauvage, 1879) and a new cryptic Paramormyrops (Mormyridae : Osteoglossiformes) from the Ogooué River of Gabon using morphometrics, DNA sequencing and electrophysiology. Zoological Journal of the Linnean Society, 180: 613-646.
38. Schreck CB and Moyle PB. (1990). Methods for Fish Biology. American Fisheries Society, Bethesa, Maryland.
39. Schugardt C and Kirschbaum F. (2004). Control of gonadal maturation and regression by experimental variation of environmental factors in the mormyrid fish, Mormyrus rume proboscirostris. Environmental Biology of Fishes 70: 227–233.
40. Shannon CE and Weaver W. (1963). The mathematical theory of communication. University of Illinois Press, Urbana.
41. Sidi Imorou R, Adite A, Adjibade KN, Arame H, Sonon PS and Abou Y. (2019). Fish biodiversity and community structure of the Okpara stream from the Oueme River, Benin, West Africa. In press.
42. Swann L. (1997). A fish farmer’s guide to understanding water quality. Aquaculture Extension, Illinois-Indiana Sea Grant Program.
43. Van Thielen R, Hounkpe C, Dagba L and Agon G. (1987). Guide de détermination des Poissons et Crustacés des Lagunes et Lacs du Bas-Bénin. Direction des Pêches, Cotonou, Bénin.