Climate versus human impacts on the marine fauna of the Mediterranean Sea during the pre-industrial period

Climate and human impacts have impacted the Mediterranean ecosystem for thousands of years. Still, their evidence has been incomplete, hindering a proper assessment of the marine ecosystem’s baseline state and resources. In an attempt to disentangle these impacts, we conducted a study focused on commercially important species of marine mammals, fishes, and molluscs over the last 130,000 (130 ka) years until the Industrial Revolution (the year 1850). To assess differences within the basin, we subdivided the Mediterranean Sea into three subregions – Western, Eastern and Adriatic. Our work revealed significant climatic and anthropogenic impacts on three species: the banded-dye murex, the Atlantic bluefin tuna and the gilthead sea bream. Climate change, particularly temperature changes, influenced the abundance and body size of Atlantic bluefin tuna, while subregional differences in the stable isotopic composition of archaeological skeletal material reflected shifts in the system’s primary productivity. Human activities, particularly overexploitation, impacted the abundance of both banded-dye murex and Atlantic bluefin tuna, as well as the body size of gilthead sea bream and Atlantic bluefin tuna. These results highlight the significance of studying the relationships between climate, human activities, and marine resources in this large marine ecosystem. As well as integrating past data with contemporary data to reconstruct ecological baselines and obtain longer and more comprehensive time series of ecosystem change. Understanding the history of marine ecosystems and species-specific responses to environmental and anthropogenic disturbances is essential to ensure the development of effective present and future environmental management strategies while supporting the implementation of targeted conservation measures.