It is subject to very strong tidal currents and great care is needed when navigating the estuary by any size or type of boat.

[5] Within the estuary between the Pointe de Grave at the seaward end and the Bec d'Ambès are a series of small islands.

In 2006, the Conseil General decided to make the island a ZPENS (zone de pre-emption espace naturel sensible).

The Île Sans Nom which appeared in 2009 following Cyclone Klaus lies around 1 mile (1.6 km) east of Cordouan Lighthouse.

[6] In December 1942, during the Second World War, Operation Frankton took place with the goal of destroying ships moored at the docks in Bordeaux.

On arrival they would attach timed limpet mines to the docked cargo ships and escape overland to Spain.