Fish community assemblages in relation to environmental variables in the Lefini River, middle Congo River basin (Republic of Congo)
How to cite: Ibala Zamba, A., Vreven, E., Mamonekene, V., & Snoeks, J. (2019). Fish community assemblages in relation to environmental variables in the Lefini River, middle Congo River basin (Republic of Congo). Cybium, 43(1): 83-95. https://doi.org/10.26028/CYBIUM/2019-431-008
This study, one of the few ecological investigations of fishes recently performed in Africa, was undertaken in the Lefini River basin, a large right bank affluent of the Congo River in the Republic of Congo. The study area comprised 12 ecological stations, spread along 103 km of the river. Each station was sampled eight times over a two-year period, with fishing following standardized methods utilizing five monofilament gill nets of 10, 12, 15, 20 and 30 mm mesh size. Eighteen environment variables were also measured at each station. A total of 8,698 specimens, including 84 species belonging to 51 genera, 21 families, was reported. Redundancy Analysis with forward selection coupled with Monte Carlo permutation tests identified three variables (temperature, canopy closure, and canopy height) as accounting for 36.9% of the total variance (p < 0.05). The contribution of the two first axes was significant (F = 1,56; p = 0.02). Fish populations are distributed according to five habitat types: pool with fringing grasses; river bank with grass; forest with high canopy coverage 60.0-67.0%; forest with mean canopy coverage 33.0-48.0%; and forest with low canopy coverage 24.0%. The index of species richness “S” showed the grassy habitat to be the least diversified but overall, the high value of H’ (2.64-3.24) and R (0.73-0.83) indices in all stations, indicates that the examined stretch of the Lefini basin is in good ecological health.