This study analyzes the effects of three aspects of artisanal fishing that occurred due to the construction of the Cachoeira Caldeirão dam in a community in the middle stretch of the Araguari River. Interviews were carried out with fishermen, questionnaires were applied, and field observations were made. According to fishermen, subsistence artisanal fishing for family consumption and commercial sale in Porto Grande suffered negatively after the dam, especially with the reduction of its fishing territory, limited between physical barriers and legal barriers. This scenario is aggravated by the reduction of active fishermen in fishing activities and an alteration in the fishing dynamics which poses an imminent risk to artisanal fishing, and this may cause fishing activities to disappear in a few years in the municipality of Porto Grande.