Understanding patterns shaping marine species connectivity is essential for effective management of marine resources and the development of conservation strategies. Yet, incorporating connectivity into marine spatial planning remains challenging due to the complex dynamics linking species’ dispersal and environmental variability. For instance, detailed information on spawning grounds is often lacking, complicating the identification of connectivity pathways. Further, the effects of climate change on the structure and strength of marine connectivity are still not fully understood.

In this study, we reconstructed and analysed the larval connectivity of European hake (Merluccius merluccius), a commercially important species in the Mediterranean Sea, focusing on the Adriatic and western Ionian basins. We employed a Lagrangian particle-tracking approach combined with network analysis to assess spatial and temporal connectivity patterns across different timeframes and climate scenarios, specifically under Representative Concentration Pathways RCP4.5 and RCP8.5. Community detection methods were used to identify potential sub-populations, revealing biologically meaningful management units.

Our results show that, despite the increase in seawater temperatures under moderate and extreme scenarios, connectivity metrics and the spatial structure of communities remain broadly consistent, supporting their application as stable indicators for conservation planning. However, climate-induced shifts in biological and physical parameters, such as increased larval transport speeds and a shortened dispersal period—likely driven by temperature-dependent metabolic responses—may lead to more polarised and vulnerable sub-population structures in future conditions. Finally, we classified network nodes based on their connectivity roles, reflecting their structural importance within and between communities. These findings, together with the persistence of community boundaries across scenarios, offer a robust foundation for spatially explicit management aimed at enhancing population resilience under both current and projected climate scenarios.