Sfax

Sfax is usually introduced as Tunisia's second city. A more revealing description is that it is the country's processing back room. At just 8 metres above sea level, the municipality had 273,506 residents in the 2024 census, close to the GeoNames figure but far smaller than the economic territory it serves. Standard summaries mention the medina and the port. The harder fact is that Sfax specialises in turning central and southern Tunisia's raw output into tradable goods: the local chamber of commerce counts 346 olive mills and 63 exporting companies, while Britannica still describes the city as the main outlet for the phosphate belt and a major fishing port.

The scale of that processing role shows up in the commodity numbers. In the 2025-26 olive campaign, regional officials estimated the Sfax governorate's harvest at 515,000 tonnes of olives. The same chamber of commerce says the region's eight fishing ports produce more than 18,000 tonnes of seafood, about 18% of national output, and 10,000 tonnes are exported, equal to 60% of Tunisian seafood exports. Sfax does not live primarily by attracting visitors or ministries. It lives by concentrating mills, cold storage, exporters, port facilities, and trading know-how in one coastal strip.

That concentration also explains why the city spent decades treating its shoreline as expendable. The Union for the Mediterranean's Taparura project aims to convert 420 hectares of former phosphate coast into a mixed-use district and reconnect Sfax to the sea. This is resource allocation under pressure: waterfront land that could have gone to housing or leisure was assigned instead to phosphate handling, industrial waste, and export logistics. Network effects made the choice self-reinforcing. Once processors, freight agents, and buyers were clustered in Sfax, more producers routed their goods through the same node.

The closest biological analogue is the leaf-cutter ant. Leaf-cutters do not eat the leaves they carry; they haul material inward, process it, and maintain separate waste systems so the colony does not poison itself. Sfax works the same way. Source-sink dynamics pull olives, fish, and mineral flows toward the port, while niche construction keeps rebuilding the physical system that makes that throughput possible.