The coastal lagoons

The Languedoc coastline is low and sandy, and contains within it a string of coastal lagoons. The largest of these is the Etang de Thau, with a surface area of more than 7,000 hectares. It is bounded by a 20-kilometre-long lido, or sand spit, which is anchored at its centre on the island town of Sète and at one end on the volcanic formation of Mont Saint-Loup (Agde). Channels – or graus – in the spit connect the brackish waters of the lagoon with the sea. This type of shore is a shifting milieu, which is today threatened by human activity and rising sea levels. Conversely, the lagoon's interior shore features an unchanging landscape of hills sculpted by an regular network of streams, which has determined the location of human settlements since the Neolithic.

On average, the Etang de Thau is about four metres deep. This is much deeper than most of the other lagoons, which serve as outlets for silt-laden coastal rivers. Its waters, which warm rapidly in springtime, are home to a rich ecosystem that is exploited to the present day. Seasonal fishing and gathering wild shellfish have given way to shellfish farming. Saltworks have been present since the medieval period. Until recently, the lack of compartmentalisation between the various lagoons made this "interior sea" a precious communication route.


Interactive document - Thau Lagoon

Thau Lagoon

A deep lagoon and an agricultural area.
© Christian Hussy, Laboratoire d'Arts Graphiques, Culture/DRAC PACA
Interactive document - The Etang de Thau

The Etang de Thau

The Etang de Thau, a rich ecosystem. Today, the increasing number of oyster beds testify to the growth of shellfish-farming, a dynamic sector for the regional economy.
© Sandra Lebrun CCNBT
Interactive document - Oyster-farming


A modern oyster farm using intensive farming techniques. Although trade in shellfish is attested to in Antiquity, we have no definitive evidence of Roman-era shellfish farms. The richness of the region allowed for widespread gathering of natural resources for both local consumption and for sale at markets.
© Sandra Lebrun CCNBT
Interactive document - The Mèze shipwreck

The Mèze shipwreck

The shipwreck at Conque des Salins in the Hérault département. The remains of the hull of a boat were found at a depth of one metre some 80 metres from the shores of the lagoon. The techniques used were consistent with those of Greco-Roman ship construction. Radiocarbon dating places the construction between 280 BCE and 70 CE.
©Marie-Pierre Jézégou Culture/DRASSM
Interactive document - The Mèze shipwreck

The Mèze shipwreck

Reconstruction of a sunken vessel at Conque des Salins, Mèze (Hérault). A study by the Department of Underwater Archaeological Research uncovered a flat-keeled barge some fifteen metres long, which shared certain characteristics of other Roman-era vessels.
© MCC - Département des recherches archéologiques sous-marines et subaquatiques / Jonathan Letuppe. Scientific director Marie-Pierre Jézégou