Artisanal fisheries are fundamental to riverine socioecological systems, yet fishing communities remain underrepresented in environmental governance and decision-making. This gap constrains the incorporation of local knowledge into environmental decision-making and may reduce the effectiveness of governance strategies for addressing complex socioecological challenges. This study analyzes the socio-environmental characteristics of artisanal fisheries in the lower Magdalena River estuarine zone (Colombia) and discusses their implications for water governance and monitoring systems. Using a mixed-methods integrative design, we combined a PRISMA-guided literature review with a structured survey of 43 community members in the strategic territory of Bocas de Cenizas–Ciénaga de Mallorquín. The results reveal strong livelihood dependence on aquatic ecosystems, increasing environmental pressures, and limited institutional coordination. Respondents reported clear perceptions of environmental degradation, including declines in fish availability, vegetation cover, and water quality. Crucially, local actors possess detailed experiential knowledge of these transformations and show favorable conditions for participatory engagement. The integrative analysis indicates that artisanal fishers are not merely vulnerable populations, but key environmental observers whose knowledge can enhance adaptive and inclusive water governance. The findings identify a specific monitoring gap in the lower Magdalena estuarine zone: the environmental changes most consistently perceived by local actors—including declining fish availability, deteriorating water conditions, vegetation loss, and shoreline erosion—are directly linked to livelihood dependence but remain weakly connected to formal governance processes. These locally observed variables provide a context-specific basis for developing integrated socioecological and hydroenvironmental monitoring systems that combine conventional scientific indicators with community-based observations, thereby improving the territorial relevance of environmental information for water governance and decision-making.