Podocnemis sextuberculata is cited as “vulnerable” on the International Union for Conservation of Nature Red List due to a decline in its population as a result of the intensive exploitation pressure throughout its range. Understanding the effects of environmental characteristics and human activities on turtle populations is essential to improve current conservation programs. We analyzed the abundance of Podocnemis sextuberculata in the lower Amazon, where a management experiment is under way, by comparing neighboring areas with and without community-based management (CBM) initiatives. In addition, we analyzed the influence of environmental variables on the species' abundance. Abundance was measured by captures per unit effort expressed in number of individuals (CPUEN) and biomass (CPUEB). The effects of CBM and environmental variables were tested by General Linear Model analysis. A total of 354 individuals were captured, 321 in the areas under CBM and 33 in areas without CBM. CPUEN and CPUEB were strongly correlated, and their values were about 10-fold higher in the areas carrying out CBM initiatives. The variable that best explained variation in CPUEN and CPUEB was CBM. Distance between the sampling point and the nearest nesting beach and river level also influenced capture rates. Results clearly show that local fishing restrictions can have a positive influence on turtle populations.