Across the Global South, commercial development and technological innovations are transforming fish food systems in ways that significantly impact the livelihoods of small-scale producers and the food security of the poor. A crucial but understudied aspect of such transformations is the social relations in which fish food systems are embedded. Food system transformations change power relations and rework gendered economic roles and divisions of labour in ways that often marginalise women and other vulnerable groups. In this paper, we draw on feminist studies of gender and technology and feminist commodity chain analysis to investigate the impact of technological transformation on social relations in the ring seine fishery of Kerala, India. Kerala’s ring seine fishery specifically targets small pelagics like sardine, mackerel, and anchovies, which have been identified as important to the food security and nutrition of the poor. Since the mid-1980s, when the ring seine was first introduced to enable small-scale fishers to compete with mechanised trawlers, these fishing units have expanded both in terms of numbers and in size, largely as a result of locally-driven technological innovation and adaptation. Though traditional arrangements of labour deployment and wage sharing have remained, rising competition and differentiation between fishermen have ensued. At the same time, changes in processing, distribution, and trade have reworked women’s economic roles and position in the fishery, and questions about long-term profitability and sustainability have necessitated interventions in governance at various levels. Tracing the trajectory of technological innovation and changing social relations through the value chain, we assessed the gendered implications of fish food system transformations for livelihoods. We found that the increase in dimensions of the new gear increased both investments and operational costs of the fishing units rendering several of them uneconomical. Time-tested social norms have also changed as competition increased, which is much more pronounced between the smaller and larger fishing vessels. The traditional wage sharing pattern still remains ensuring income security for fishermen who cannot find work as crew on these fishing vessels. Women, however, have been most affected by the changes as they no longer are able to access the fish resource as earlier for engaging in post-harvest activities, such as marketing and fish drying.