Lake Toho is a small freshwater lake located in southern Benin. From February to June 2024, water quality was assessed using monitoring equipment. The results indicate high levels of nutrients that could cause ecological problems such as eutrophication and the disappearance of aquatic species. Market gardening and riverside agriculture are responsible for this pollution.

The Lake Nokoué and Porto-Novo Lagoon complex represents the most important Lagoon system in Benin. It  Regarding the hydrological regime, a predominance of strictly freshwater taxa was noted during the High water period in Lake Nokoué. Furthermore, this predominance was recorded during both High and Low water periods within the Porto-Novo Lagoon. Thus, the variation of these taxa was found to be more pronounced in Lake Nokoué than in the Porto-Novo Lagoon.