The identification of key resource users and patterns of depletion alongside ecological data are presented for a small-scale traditional invertebrate fishery in south-western Madagascar. Men, women and children undertake the fishery in the Anakao region at different phases of the tide and for different purposes. Invertebrate harvest data from June to September 2000 estimated that more than 34 taxa were caught and were dominated by holothurians destined for export and molluscs for local consumption. Crustacea formed a small component of the fishery despite a high diversity and abundance of many potentially edible species. Although there was slight spatial variation in number of species caught and their relative importance to the fishery, Chicoreus ramosus, Fasciolaria trapezium and Octopus vulgaris were generally most heavily targeted and were amongst the most abundant in the catch. There were several indications of over-exploitation of invertebrate stocks, including the absence of many large bodied species, low abundance of high yield species, greater catch effort needed for high yield taxa, and higher diversity of targeted species (including many low yield taxa) at sites of higher human habitation.