Diversité piscicole et paramètres démographiques des principales espèces de poisson du réservoir de Samandeni, Burkina Faso

Abstract

La gestion de la pêcherie du réservoir de Samandeni au Burkina Faso, nouvellement mise en eau en 2017 nécessite des informations fiables qui sont pour l’instant éparses, insuffisantes voire inexistantes. Ce travail vise à combler ce gap à travers une analyse de la diversité, des paramètres de croissance et d’exploitabilité de la faune piscicole de ce réservoir. Pour ce faire, les poissons ont été échantillonnés au filet maillant et épervier entre avril 2018 et janvier 2019. Les espèces ont été identifiées et chaque poisson a été pesé puis mesuré. Au total 39 espèces ont été recensées et regroupées en 29 genres et 14 familles. Les familles les plus représentées sont Cichlidae, Mormyridae et Mochokidae. Les espèces dominantes sont Sarotherodon galilaeus Siluranodon auratus, Schilbe intermedius, Coptodon zillii et Oreochromis niloticus. L'étude suggère que les poissons et cet écosystème aquatique sont dans de bonnes conditions. Les résultats de cette étude contribueront à mieux planifier la gestion de cette nouvelle pêcherie et constitueront une base pour comprendre les changements futurs.

Growth, Population Parameters and Stock Status of <i>Sarotherodon galilaeus</i> in Samandeni Reservoir, Burkina Faso

“…We noted that the estimated Z-value in the present study was much larger than those of [21] in lakes Doukon and Togbadji, Benin (Z = 2.21 yrs −1 ) and [22] in the Golinga and Bontanga reservoirs in northern Ghana (2.64 and 2.03 yrs −1 ). On the contrary, mortality in this study remains comparatively lower than that obtained by [6] in the same reservoir and for the same species before its opening to fishing. In this study, the value of natural mortality (M) was recorded at 1.36 yrs −1 , resulting in an instantaneous fishing mortality coefficient (F) of 1.68 yrs −1 .…”

“…A comparative analysis of the fish population parameter estimates for different settings is provided in 2 and Table 3), the asymptotic length values reported in the present study were found to be comparatively higher than those obtained by [21] in two lakes in Benin and [22] in the Botanga reservoirs, Tono and Golinga in northern Ghana. Similarly, the present study reported higher growth constants than [6] and [8]. On the contrary, the asymptotic length estimated in the present study was lower than the estimates documented by other studies such as [6] and [8].…”

“…Similarly, the present study reported higher growth constants than [6] and [8]. On the contrary, the asymptotic length estimated in the present study was lower than the estimates documented by other studies such as [6] and [8]. Many studies have documented differences in the growth of a given species in different geographic areas [23] [24], and differences may be due to habitat heterogeneity and genetic diversity and fishing pressure [25] [26].…”

“…This difference in mortality rates could be explained by the different sampling methods and fishing effort from one reservoir to another. Indeed, [6] evaluated mortality based on experimental fishing while in the present study the sampling was realized on caught fish from commercial fishermen that use fishing methods and gear other than those in experimental fishing. Comparatively, the fishing mortality in the present study was relatively higher than the estimated natural mortality, which, according to [28] should not exceed this mortality during the exploited phase of the stock, suggesting that the assessed population of S. galilaeus is more prone to fishing activities than naturally induced morality situation such as predation, competition, diseases and old age.…”

“…Indeed, it is an abundant fish in the reservoir where it is part of the main commercial catch [5]. In addition, a study conducted before the reservoir was opened to fishing showed S. galilaeus to be one of the most abundant fish species in this ecosystem [6]. Despite its considerable economic value, only one study was conducted on the biology of this species in Samandeni Reservoir prior to its exploitation [7].…”