It’s widely known the existent relation between the development of artisanal fisheries and the traditional knowledge of fishermen. However, there are few studies concerning this aspect, given the difficulties in establishing the agreement that a group of persons have about one theme and who are the most competent fishermen. The present article shows the results of two case studies developed with artisanal fishermen of four landing sites of San Andres Island, applying the Cultural Consensus Analysis developed by Romney et al. (1986), a method based in mathematical, anthropological and sicometric analysis, that enables the evaluation of the group’s consensus from individual answers to a series of questions or propositions, taking into account, besides the majority’s answers, the level of competence of the interviewed. The first case was directed towards evaluating the perception about historic evolution of the fishery; 25 fishermen were interviewed about the catch and effort tendencies in the past 10 years, obtaining a higher consensus score (PC = 0.74). For the second case, 42 fishermen were interviewed with questions related to the spatial and temporal dynamics of targeted species of the fishery, giving as a result that fishermen share one basic knowledge (Competence average score PC = 0.55), although some differences existed in the consensus and level of competence between the different landing sites. The application of this method resulted to be the most convenient for this kind of communities and is established as a potential tool for future works about the development and management of fisheries.