An entomological study was conducted during the construction of a small hydro-agricultural dam at Raffierkro near Bouaké, in central Côte d’Ivoire, between June 2007 and November 2009. The objective of this research was to evaluate the variation in specific diversity, abundance and nuisance of mosquitoes species in correlation with the different stages of the dam implementation. Larvae were collected using a ‘dipping’ sampling method in irrigation canals, stagnant water footprints and fish breeding ponds to determine specific diversity. Adult mosquitoes were captured on human bait over 2 to 3 consecutive nights. A total of 20,925 adult mosquitoes and 489 larvae were collected, divided into 6 genera and 21 species, with the most prevalent being Anopheles gambiae and Mansonia africana. Abundances exhibited considerable variation from one year to the next, with a marked increase during the rice-growing season, which was accompanied by a significant nuisance, particularly in localities in proximity to the dam and rice-growing facilities. This study highlights the impact of the facilities on culicid dynamics, with potential implications for disease transmission.

To assess the influence of the breeding structure on the effectiveness of sexual inversion, growth performance and economic returns of Bouaké strain of Nile tilapia Oreochromis niloticus, hormonal treatment with 17-α-méthytestosterone was performed snapped installed in concrete basin (lot I), in happa) implanted in earthen pond (lot II) and concrete basin snapped without (lot III). The success rate of sexual inversion is 100% male in the three lots. The final average weights recorded were 2,35 ± 0,24 g (lot II), 2,06 ± 0,72 g (lot I) and 1,53 ± 0,65 g (lot III). The daily growth and the specific growth rate significantly different only between the Lot II and Lot III. The survival rate, the nutrient ratio and condition factor were not affected by the farming structure. The cost of producing a fry of 5 g recorded for Lot III (19,82 ± 0,40 F CFA) was significantly (p <0,05) higher than that obtained in the lot II (14,59 ± 1,49 CFA) and to that noted in the lot I (16,12 ± 0,10 F CFA). Profitability indices are 2,4 ± 0,25 for Lot II, 2,17 ± 0,12 for Lot I and 1,76 ± 0,25 for Lot III. The best results were recorded at the happas implanted pond followed by those installed in concrete basin.