There is limited documentation on the status and dynamics of fished marine shelled mollusc species in many countries. Some of the challenges are due to obscure documentation of species, extensive unregulated and unrecorded fishing and unawareness of drivers behind declining stocks. The lack of understanding makes it difficult to formulate effective management plans. Here, we assess the fishers’ perceptions on changes in abundance of targeted marine shelled mollusc species and status of associated fished habitats. We interviewed 132 marine shelled mollusc gleaners (fishing by walking) at five sites in coastal Kenya. We established that a multispecies marine shelled mollusc fishery is present in Kenya and that this fishery is conducted by both women and men. We distinguished 158 different shelled mollusc species being targeted. The gleaners perceived a temporal decline of gleaned species. The main causes for the decline were perceived to be overfishing of shells, elevated sea-surface temperature and habitat destruction. The more experienced gleaners perceived a greater decline indicating a baseline shift in perceptions. Our findings suggest that local ecological knowledge is useful to understand historic changes in fisheries lacking long-term scientific data. Furthermore, it highlights the potential benefits of a collaboration between ecologists and gleaners to improve our understanding of the status and dynamics of fishing of marine shelled molluscs as well as other types of fishing.