Understanding the reproductive biology of a species is an important means of determining the renewal capacity of natural stocks, especially in the case of heavily exploited species. It is a fundamental element in supporting the implementation of management measures. Here, we studied the bloody cockle (S. senilis) in the Sine-Saloum, with the aim of describing its seasonal and spatial reproductive cycle. S. senilis reproduction was studied over an annual cycle at two sites chosen for their contrasting situations along the upstream-downstream gradient. The dataset contains the results of biometric measurements (individual height and weight) and gonad histological analyses (maturation stage, reproductive investment) of a pool of bloody cockles (Senilia Senilis; n = 200) individuals maintained in-situ in an experimental caging and sampled throughout the year in the Sine Saloum inverse estuary (Senegal), between March 2021 and March 2022. The reproduction being asynchronous, each stage of maturation for a given individual is represented by its percentage ratio to the total surface area of the gonad. The reproductive investment represents the surface area occupied by the gonad, all stages combined, over the total surface area of the body section.