<p>Understanding how demographic indicators intersect with the continuity of labor in traditional livelihoods is particularly urgent for subsistence-based sectors. Small-scale fisheries (SSF), which sustain food security and income for millions worldwide, are especially sensitive to demographic transitions. In this study, we analyzed the national registry of Brazilian small-scale fishers—comprising over 1.8 million individuals—to evaluate the generational renewal dynamics of the largest SSF population in the Americas. Our results reveal a widespread aging trend across the sector, with marked regional asymmetries. Along the north–south gradient, younger people are more prevalent in less economically developed regions, whereas older fishers tend to dominate more developed areas. Additionally, younger fisher populations are concentrated in regions with higher educational attainment and literacy yet paradoxically associated with lower income brackets. Conversely, regions with older fisher populations tend to show lower literacy and schooling levels. To quantify intergenerational risks, we developed and applied renewal indices that consistently demonstrated a declining capacity for age-based replenishment in the sector. These findings suggest that the aging trajectory of this population, if left unaddressed, may jeopardize the long-term continuity of small-scale fisheries. We discuss potential structural drivers behind this trend and urge policymakers to recognize the temporal and silent nature of this demographic risk. By leveraging the largest dataset of its kind, this study offers a replicable framework to assess generational sustainability in SSF and highlights aging as a critical, yet often overlooked, threat to the future of this essential livelihood.</p>