Socio-economic and Climate Change Effects on Fishing Yields and Farming in the Mono River Basin : Case Study of Toho Lake

Abstract

Fisheries and aquaculture play an important role in western African sub-region countries. Even if its contribution to GDP is not so important compare to agriculture, decrease in productivity affect communities living along water bodies. In the view to better understand how, this study proposes to assess the socio-economic and climate change effects on fishing yields and fishing farming at the level of lake Toho in the Mono river basin. Rainfall and temperature data were collected and analysed with Excel. Thus, simple random sampling method was used to select 95 fishermen in Athiémé, Lokossa and Houéyogbé villages around this lake. Many packages from R were used and Chi-2 homogeneity test was performed to analyse changes in fishermen profile and fishing yields variations. The results show an unstable rainfall pattern particularly associated with an upward trend over the target period (1985-2015) and an upward trend in observed temperatures. This increase is conducive to productivity because during high water periods, fish take advantage of high water to reproduce, and the depth of the lakes does not favour fishing. The same is true for temperature. In fact, most fish reproduce well at temperatures between 27°C and 28°C. As fish reproduction is not systematically synonymous with increased productivity, we are witnessing a drop in productivity linked to the disappearance of certain species, due to the non-discharge of the Mono River into the lake since the construction of the dam, the drop in catch quantities linked to the reduction in the size of the fish and the fishing techniques and gear that are not conducive to the sustainability of fishery resources. Furthermore, the study showed through surveys conducted among fishermen that they perceive the decline in fishery resources and the manifestations of climate change and propose measures to cope with this decline and then to satisfy the needs of their families, which vary according to their membership of a socio-ethnic group, their age category, their level of education and the number of years spent fishing on the lake. Among the measures proposed are fish farming, changes in fishing techniques and gear, and the practice of rituals. Fish farming is one of the measures that the study deems effective and sustainable for the management and improvement of the lake's resources and the socio-economic situation of the communities living there.