Abstract: As essential auxiliary tools in tropical tuna purse seine fisheries, fish aggregating devices (FADs) improve fishing efficiency significantly, but result in incidental catch of large number of juvenile bigeye (Thunnus obesus) and yellowfin tuna (T. albacares), posing threats to the stock sustainability. In order to scientifically manage FADs purse seine fisheries and mitigate their negative impacts on tropical tuna resources, we applied the Spatio-Temporal Generalized Additive Mixed Model (st-GAMM) to standardize the catches per unit of fishing effort (CPUE) of bigeye tuna and yellowfin tuna, and then estimated the spatio-temporal dynamics of abundances, based on the operational data of FADs of the European purse seine fleet in the Eastern Atlantic Ocean from 2011−2022. The results indicate a persistent decline in bigeye tuna abundance since 2016, whereas yellowfin tuna abundance remained relatively stable. Both species showed aggregated distributions around the equatorial region, but bigeye tuna were more concentrated in the western equatorial area, while yellowfin tuna were dominant in the eastern equatorial waters, particularly in the Gulf of Guinea. Additionally, high abundance of bigeye tuna was observed in the Cape Verde and St. Helena regions, and yellowfin tuna exhibited high abundance along the Angolan coast. The CPUE for both species exhibited similar dome-shaped responses to sea surface temperature and dissolved oxygen, with inflection points at approximately 21   ℃ and 225  mg·L⁻¹, respectively. Bigeye tuna CPUE showed a V-shaped response to mixed layer depth (MLD), with an inflection at 30 m, while yellowfin tuna CPUE was negatively correlated with MLD.