SOCIO-ECONOMIC IMPACTS OF MORPHOLOGICAL DYNAMICS INDICATORS AND ECOLOGICAL CHANGE IN THE FISHERIES OF LAKE NOKOUÉ (SOUTH BENIN)

Lake Nokoué is experiencing serious environmental problems which threaten its existence and contribute to the reduction of goods and services for the beneficiary population. The objective of this study is to understand the dynamics of ecological factors and their impacts on the biocenosis. This study is based on bathymetric data collected in 11 stations on the lake following seasonal sampling from February 2017 to January 2018 and from March 2019 to February 2020. Documentary research, field surveys, interview guides, a camera digital and labeled sachets are the tools and materials used for data collection from 120 households. In addition, images from aerial and satellite photographs of the LANDSAT type (TM and ETM) were used to assess the dynamics of the acadjas of Lake Nokoué. The results were analyzed with the FPEIR model. The results show that from 2000 to 2020 Lake Nokoué experienced an increase in the number of acadja which went from 667 to 1417 or 47.07% followed by a decrease in its depth from West to East of the order of 0.5m. The factors favorable to the filling of Lake Nokoué are according to 70% of the population surveyed: the flood and its solid inputs, the proliferation of water hyacinth in the rainy season and its degeneration in the dry season, the erosion of the banks, the intrusion of marine water and stations with high human and economic densities (implantation and decomposition of acadja, agricultural activities, etc.). These internal and external factors contribute to the morphological dynamics of Lake Nokoué, thus hindering the socio-economic development of populations dependent on Lake Nokoué. Faced with this situation, measures have been proposed for better management of this ecosystem, which is essential to the survival of its population.