Continuous, confident and rigorous process of compilation and analysis of fishing information (landing statistics and stock assessment) are rare in developing countries like Colombia; particularly in case of the artisanal fisheries. However, such information is required for the appropriate management of the fishing resources. In this situation, the ecological knowledge that fishermen have acquired generationally or during their fishing trips, can be used as an alternative, but must be gathered, systematized, compared and verified. In this context, 17 meetings were carried out between December 2007 and December 2008 to register the ecological knowledge of 209 artisanal fishermen from 18 settlements. Fishermen perceptions around temporary changes of catches and individual lengths, as well as management strategies with higher consensus, were analyzed. Fishermen agree in a total catch decline between 1997 and 2003. Maximum lengths of Megalops atlanticus, Trichiurus lepturus y Scomberomorus cavalla would decrease in more than 50 % in the last 12 years. In addition, fishermen suggest a modernization of the fleet and the fulfillment of the legislation as required strategies to assure their activity. Management strategies should include fishermen in the decision process to be effective. The co-management can promote a consensus thru the enforcement of the actors involved in the activity. Recognizing the local ecological knowledge can be a first step in the region.