Freshwater ecosystems are increasingly threatened by anthropogenic pressures, yet their monitoring still relies heavily on invasive or lethal sampling of aquatic organisms. This thesis evaluates the potential of keratinized tissues (fish scales and turtle shells) as non-invasive bioindicators of water quality in Algerian wetlands, with emphasis on Ramsar-listed sites and dam reservoirs. A comprehensive literature review highlights the ecological importance of wetlands, the role of fish and turtles as sentinel species, and the limitations of conventional biomonitoring methods. The work then examines the physicochemical properties of keratinized tissues, their capacity for long-term contaminant accumulation, and their logistical advantages, including durability, low degradation, and ease of preservation. By integrating case studies and regional environmental challenges, the thesis proposes a framework for incorporating fish scales and turtle shells into existing biomonitoring programs. This approach enhances ethical sampling, reduces pressure on vulnerable species, and provides a reliable, cost-effective tool for assessing aquatic pollution in North African freshwater ecosystems.