Assessing Trophic Status of Lake Guidimouni (Niger) Using Secchi Depth (SD) and Fish Communities

Determining the ecological conditions of lentic ecosystems using different parameters of the ecosystems is a relevant approache in water quality evaluating. The aim of this study was to examine the trophic state of lake Guidimouni according to Carlson system, OECD criteria and fish communities using data collected during 2 seasons. The Secchi depth values chanced from 0,95 m to 0,5 m respectively during the dry and wet season. Six (6) fish species belonging to 6 genera were identifed at lake Guidimouni. With regard to water quality, lake Guidimouni was eutrophic according to Carlson system during the 2 seasons, while it showed hypertrophic status according to OECD criteria. In accordance of fish communities, the lake Guidimouni showed a moderate ecological status. These results provide supplementary data about the lake's water quality and could help decision makers on the preservation of this important aquatic ecosystem.