Catch per Unit Effort and yields as indicators of exploited fish communities: application to two West African reservoirs

International audienceTwo indicators of fish exploitation, catch per unit effort (CPUE) and yield per unit area, were used with surveys of small-scale fishery landings to compare two African reservoirs that differ in their level of fish exploitation, being high for Selingue Reservoir and low for Manantali Reservoir, both located in West Africa. The heavy exploitation in Selingue Reservoir induced a decline in catches per fishing trip (9.5 kg trip−1), whereas the catch remained high at Manantali Reservoir (17.0 kg trip−1). Moreover, the annual fish yield per unit area was lower for Manantali Reservoir (19 kg ha−1) than for Selingue Reservoir (79 kg ha−1). There was no relationship between the Morphoedaphic Index and catches for the two reservoirs. Rather, only the fishing effort and annual water-level variations defined the reservoir fish yields. Based on the results of the present study, it appears that CPUE and fish yield per unit area represent simple and robust indicators for describing the impacts of fishing intensity in aquatic ecosystems