Life on the edge: Mesolithic population size and viability on Malta.

Recent discoveries in Malta and Tunisia provocatively point to a possible web of Mesolithic/Epipalaeolithic sea crossings, encounters, and exchanges that linked continents long before the age of the sail. Determining whether such connections were singular events or sustained episodes is therefore critical to illuminate the scale and character of early seafaring. Here, we model how patterns of sea-level change impacted land connectivity between Sicily and Malta and predict potential population sizes through time from the Last Glacial Maximum to evaluate whether Mesolithic hunter-gatherers could have persisted on Malta, or if sustained connections would have been required. To achieve this, we use reconstructions of sea-level change and modern bathymetric models to evaluate changes in land size areas and connectivity. We calculate net primary productivity values for a high-resolution paleoclimate dataset, which we translate to population density by comparisons to ethnographic datasets. Finally, we calculate changes in estimated population sizes through time for Malta and Sicily, as well as minimum distances of sea voyages. Our results show that following disconnection from Sicily, Malta would have been unable to support a viable, persistent forager population, including for the minimum 1000-year timespan of the Maltese Mesolithic record. As a result, only repeated, long-distance sea voyaging can explain the longevity of Mesolithic occupations of Malta, opening up the possibility that other south-central Mediterranean islands were reached and explaining the presence of European hunter-gatherer ancestry in North Africa.