Implementing an EAFM requires identifying a spatial framework where ecosystems can be characterized, monitored, and reported. Within the IOTC convention area, a spatial framework of nine candidate ecoregions has been developed to support ecosystem-based planning and research, as well as the development of ecosystem-based advice products to complement single-species fisheries management advice. Building on previous ecoregion delineation efforts, this study validates the nine candidate ecoregions by evaluating their ability to demarcate areas with distinct communities of tuna and tuna-like species, as well as unique fisheries and fleets. Using IOTC and CCSBT fishery statistics datasets, we characterize core fleets, their gears, and catch composition within each ecoregion, and analyze the differences among ecoregions to assess their ecological and fisheries uniqueness to serve as a spatial framework for supporting ecosystem-based planning, research, and advice products. The findings reveal unique fleet compositions in each ecoregion, with regional fleets dominating, except in the ACE, where across-regions fleets prevail. The catch composition of the fleets also varies significantly across ecoregions, with neritic tunas and Spanish mackerels being more prominent in coastal tropical ecoregions, tropical oceanic species like skipjack and yellowfin tunas being prevalent in tropical oceanic ecoregions, while temperate oceanic species such as southern bluefin tuna and swordfish dominate in higher latitude ecoregions. While our findings highlight the unique ecological and fishery characteristics of each ecoregion, we also recommend refinements and boundary adjustments, including treating coastal areas adjacent to continental landmasses as distinct ecoregions, extending ecoregion boundaries to align with Exclusive Economic Zones (EEZs), and reclassifying areas like the northern region of the ACE and Indonesian Throughflow to improve ecological and fleets representation within each ecoregion