An index based on physico-chemical, fish (fish index), invertebrates, algae, or phytoplankton has been used to evaluate the quality of an aquatic environment. The fish community is considered as the trophic chain's ultimate integrator in the fish index.
The "rapid diagnosis" method developed by CEMAGREF in 1990 and adapted to the Algerian condition by Boudjenah in 2002 is presented in this work for the first time, and for the second time, the theoretical production evaluation method has been applied to the data collected from the bibliography.
This index's analysis helps us to position the lake's trophic level inside the range of trophic levels, including oligotrophic, mesotrophic, and eutrophic (Barbe et al, 1990).
With the help of this categorization, we can finally plan and maximize the utilization of Lake BOUKOURDANE by calculating its productivity.
Key words: rapid diagnosis, trophic index, productivity