Résumé
Several authors, with estimated abundance index, attempted to study the dynamic of Sardinella populations in relation with to their environment fluctuations in West African region. However, this relationship still poorly understood because of the complexity and difficulty to estimate this abundance index that depends on a variable difficult to identify, the fishing effort from artisanal fisheries. This study is a contribution to better understand the link between the variability of environmental conditions and the dynamic of Sardinella aurita and Sardinella maderensis in Senegalese waters using generalized additive model. Recruitment data of these two species estimated from the virtual population analysis model, sea surface temperature, coastal upwelling index, wind speed, surface chlorophyll concentration and north Atlantic oscillation index within 2004-2013 period were used. Our results showed that recruitment of these two small pelagic species are closely linked to changes in the climatic variables tested. However, variables playing the most critical roles differ from one species to another. For the S. aurita, the index of coastal upwelling is the most important factor, while for S. maderensis is the SST which plays the leading role. This study also reveals the existence of temperature, intensity of upwelling, wind speed, concentration of chlorophyll-a and north Atlantic oscillation index thresholds above or below which Sardinella recruitment success is low.