~ 26 ~  International Journal of Fauna and Biological Studies 2017; 4(6): 26-34 ISSN 2347-2677 IJFBS 2017; 4(6): 26-34 Received: 15-09-2017 Accepted: 17-10-2017 Alphonse Adite Laboratoire d’Ecologie et de Management des Ecosystèmes Aquatiques (LEMEA), Département de Zoologie, Faculté des Sciences et Techniques, Université d’Abomey-Calavi, BP 526 Cotonou, Bénin Ephrem C Tossavi Laboratoire d’Ecologie et de Management des Ecosystèmes Aquatiques (LEMEA), Département de Zoologie, Faculté des Sciences et Techniques, Université d’Abomey-Calavi, BP 526 Cotonou, Bénin Dossi B Esperancia Kakpo Laboratoire d’Ecologie et de Management des Ecosystèmes Aquatiques (LEMEA), Département de Zoologie, Faculté des Sciences et Techniques, Université d’Abomey-Calavi, BP 526 Cotonou, Bénin Correspondence Alphonse Adite Laboratoire d’Ecologie et de Management des Ecosystèmes Aquatiques (LEMEA), Département de Zoologie, Faculté des Sciences et Techniques, Université d’Abomey-Calavi, BP 526 Cotonou, Bénin Biodiversity, length-weight patterns and condition factors of cichlid fishes (Perciformes: Cichlidae) in brackish water and freshwater lakes of the Mono River, Southern Benin, West Africa Alphonse Adite, Ephrem C Tossavi and Dossi B Esperancia Kakpo Abstract Cichlids are the major components of the ichthyodiversity and fisheries in tropical Africa. In Southern Benin, cichlids is of great importance and made about half (49.82%) of the inland fisheries. This study assessed diversities, length-weight models and condition factors of cichlids in South-Benin in order to contribute to species conservation and management. Six (6) cichlids dominated by Sarotherodon melanotheron (72.92%), a native species and Oreochromis niloticus (20.83%), an invasive alien species were recorded in Lake Toho. Likewise, the coastal zone comprised nine (9) cichlids dominated by S. melanotheron (74.49%) and Tilapia guineensis (20.06%). In both habitats, dominant species showed isometric growth patterns. The results showed significant (p≤0.0001) variations in the condition factors across both habitats. In Benin, cichlids have a high potential in fisheries and in aquaculture. Further studies are required and should focus on bioecology, dynamics, fisheries and aquaculture in order to implement a sound community-based approach of habitat protection, conservation and valorization scheme of cichlids species. Keywords: Alien cichlid, Cichlidae, Condition factors, Conservation/Fisheries, Degradation, Isometric growth 1. Introduction In inland waters of tropical Africa, cichlids are the major components of fish biodiversity and fisheries (FAO, 1995) [1] . As reported by Leveque (1997) [2] , about 870 cichlid species belonging to 143 genera were recorded for the whole African continent. Almost all of these cichlids are concentrated in the Great Lakes of East Africa namely Lake Malawi comprising 600 cichlids, Lake Victoria with 250, and Lake Tanganyika with 185 (Fryer and Iles, 1972; Lowe McConnell, 1987; Snoeks, 2000) [3-5] . According to Moyle and Cech (1988) [6] , the major cause of cichlid speciation is that not only most species have a strong trends to forage in lake bottoms that comprise a large variety of foods, but also because of the presence of pharyngeal jaws that confer to cichlids a high ability for trophic specialization. In Southern Benin, of a total of 126 fish species known for the whole region, only nine (9) cichlid species are currently recorded. Though less speciose, cichlids consistently remain numerically the dominant species in freshwater and brackish water fisheries. Indeed, of a total annual fish production of 23,067.2 metric tons estimated for South-Benin inland waters, almost half (49.82%) were cichlids, evidencing its great fisheries and commercial importance in the Benin aquatic ecosystems (Gbaguidi et al.,1998) [7] . However, despite its potentials in fisheries and its socio-economic importance, knowledge on diversity, abundance and condition factors of cichlid fish community in the degrading environment are scant. Particularly, in the ecotonal coastal brackish water, and in Lake Toho, a freshwater floodplain lake both linked to the Mono River, very little documented research works are available on the diversity, population structure and growth models of cichlid fish fauna in these degrading aquatic habitats. However, difference in salinities, primary production, and environmental degradations of both habitats could affect the abundance and well-being of the fishes, leading to a decline of fisheries production, actually estimated at 2,506 tons and 905 tons, respectively for the coastal zone and Lake Toho. Knowledge on cichlid biodiversity and structure are badly needed for habitat protection, species conservation and valorization.