Achieving global climate goals and securing future food supplies poses significant challenges, especially if efforts are limited to land-based solutions. Given that the ocean covers over 70% of the Earth’s surface and plays a critical role in CO2 sequestration, exploring ocean-based climate mitigation strategies will be essential. One promising approach is Ocean Alkalinity Enhancement (OAE), a form of marine geoengineering aimed at accelerating the ocean’s natural carbon sink, reducing atmospheric CO2 levels, and mitigating ocean acidification. However, the implications of OAE for global fisheries, which are vital for food security and livelihoods worldwide, remain underexplored. This study develops and analyzes future scenarios for global fisheries under different socioeconomic and climate trajectories, utilizing the Shared Socioeconomic Pathways (SSPs) and Representative Concentration Pathways (RCPs) framework. Specifically, we focus on three combined pathways: SSP1-2.6, SSP3-7.0, and SSP5-8.5, to explore the potential impacts of OAE implementation. Through an integrated narrative approach, we (semi-)quantify changes in key bio-economic parameters such as technological progress, fishing costs, fisheries management, marine aquaculture, and carrying capacity, providing an explorative assessment of how OAE could influence these under varying global conditions. With this approach, we contribute to the development of sector-specific and long-term interdisciplinary models that are crucial for future policy and management strategies aimed at climate change mitigation and the sustainable use of marine ecosystems. Our framework aligns with global scenarios that are being applied internationally.