. Toundji Olivier AMOUSSOU exprime également sa gratitude à l'endroit de l'Union Européenne pour lui avoir accordé une bourse complémentaire de Doctorat à travers le projet HAAGRIM (Programme de mobilité universitaire INTRA-ACP). RESUMEA l'instar du tilapia du Nil Oreochromis niloticus, Sarotherodon melanotheron, espèce caractéristique des estuaires et lagunes d'Afrique de l'Ouest est aussi un bon candidat pour la promotion de la tilapiaculture. Les informations fournies dans cette synthèse ont été recueillies à partir des articles scientifiques, des livres, des communications scientifiques, des mémoires et des rapports. Cet article expose les connaissances actuellement disponibles sur la biologie, la zootechnie et les facteurs influençant la croissance et la survie de ces deux espèces de tilapia. La position systématique, les exigences écologiques et la répartition géographique de ces deux espèces de tilapia ont été premièrement résumées. Les ressources alimentaires qu'elles valorisent (à savoir les planctons, les déchets agricoles et d'animaux, …) ainsi que leurs besoins nutritionnels et les facteurs influençant la prise alimentaire ont été ensuite exposés. Les schémas comportementaux et les facteurs associés à la reproduction et aux soins parentaux prodigués aux oeufs ont été présentés. Les caractéristiques morphologiques et les facteurs influençant leur croissance ont été également inventoriés. Enfin, les potentialités écologiques, zootechniques et économiques des tilapias ont été présentées. © 2016 International Formulae Group. All rights reserved.Mots clés: pisciculture, croissance, alimentation, amélioration génétique. AMOUSSOU et al. / Int. J. Biol. Chem. Sci. 10(4): 1869-1887, 2016 1870 Biological and zootechnical characteristics of African tilapias Oreochromis niloticus (Linnaeus, 1758) and Sarotherodon melanotheron Rüppell, 1852: a review ABSTRACT Like the Nile tilapia Oreochromis niloticus, Sarotherodon melanotheron, a typical species found in West African estuaries and lagoons, is also a good candidate for promoting tilapia farming. The information provided in this review was collected from scientific articles, books, proceedings, thesis and reports. This review presents the current knowledge on the biology, production and factors influencing the growth and survival of these two tilapia species. Their systematic positions, ecological requirements and distributions were first summarized. The food resources that they depend on (plankton, agricultural and animal wastes, ...) as well as their nutritional needs and factors influencing their food intake are then exposited. Also, their behavioral patterns and morphological features are presented. Factors influencing their growth, reproduction and parental care for eggs are also documented. Finally, the ecological, zootechnical and economic potentials of these two tilapia species were presented. T. O.

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The current research aimed at using the application of multi-factor models to support fisheries management decisions for successful resources’ conservation. The study was based on the tilapia species Coptodon guineensis, which is among the most widely exploited in Benin coastal zone. In an attempt to suggest conservation strategies, the phenotypic variability of 356 accessions of this species was assessed in relation with water salinity, and several interactions. The fish were collected through small-scale experimental fishing using cast nets and gillnets. The findings indicated that the salinity observed in the sampled rivers is due, at proportions ranging from 0.13% to 47%, to the sea surface salinity (SSS) of the Atlantic Ocean, suggesting a leading inland origin of the salinity of these rivers. The evidence also showed that the tilapia populations have been relatively adapted to the increasing water salinity of the sampled rivers. The fish species*river type and fish species*fish sex interactions had significant effects on phenotypic characteristics rather than river type*fish sex interaction. For an efficient conservation of these populations, two conservation areas (Lake Nokoué and Porto-Novo lagoon vs Lake Toho and Grand-Popo lagoon), could be considered for this tilapia species. Keywords: Aquatic salinization, population adaptation, growth parameters, interaction patterns

The Cichlid fish Sarotherodon melanotheron is typically found in West and Central African estuaries and lagoons. It represents a good candidate for promoting tilapia farming in brackish waters. Understanding the genetic diversity in its populations from the hydrographical basins of Southern Benin is primordial before designing selective breeding programs. For this purpose, 202 samples collected from four rivers of Southern Benin and were genotyped using 15 polymorphic microsatellite DNA markers. Each river was split up into three sampling sites. We found significant global linkage disequilibrium across the genome of natural populations of this tilapia species overall the loci. However, when the loci that display aberrant Wright's (F and F) were removed from the data, a linkage disequilibrium was detected for the remaining 11 loci and became compatible with the null hypothesis. Null alleles explained at least 20.58% of F variation. We found a significant isolation by distance across subsamples. Effective population size averaged 210 individuals, with a range from 36 to 517 individuals. Assuming that 79% of heterozygote deficits are explained by sib mating lead to a rough estimate of r = 0.4 of mating rate between full sibs within S. melanotheron subpopulations. The fish size correlated positively and significantly with the observed F (r = 0.58; p value = 0.04806). Reproduction system (endogamy) in S. melanotheron could explain the strong heterozygote deficit observed. Our results provide technical guidance for efficient management of this tilapia species' genetic resources for breeding programs in fresh and brackish waters.