species (IUCN) status. This species of sturgeon can reach a length of , weigh up to and can reach an age of 100 years. Previously found on most coasts of Europe, it has now become so rare that they only breed in the Garonne river basin in France. Conservation projects are under way to save this fish from extinction via species reintroduction from aquaculture, with the first releases having been made in 1995. Towns along the river Aran Valley (Spain): Vielha, Bossòst Haute-Garonne (31): Saint-Gaudens, Muret, Toulouse Tarn-et-Garonne (82): Castelsarrasin Lot-et-Garonne (47): Agen, Marmande, Aiguillon Gironde (33): Langon, Bordeaux Main tributaries Following the flow of the river, from source to mouth: Pique Ourse Neste Salat Volp Arize Louge Ariège Touch Hers-Mort Save Gimone Tarn Arrats Barguelonne Auroue Séoune Gers Baïse Lot Avance Dropt Ciron Gat mort Devèze Jalle de Blanquefort Navigation The Garonne plays an important role in inland shipping. The river not only allows seagoing vessels to reach the port of Bordeaux but also forms part of the Canal des Deux Mers, linking the Mediterranean Sea and the Atlantic Ocean. From the ocean, ships pass through the Gironde estuary up to the mouth of the Garonne (to the right of the Dordogne when sailing upstream). Ships continue on the tidal river Garonne up to the Pont de Pierre (stone bridge) in Bordeaux. Inland vessels continue upstream to Castets-en-Dorthe, where the Canal de Garonne joins the river. Prior to the building of the Canal lateral à la Garonne, between 1838 and 1856, shallow-draught boats used the Garonne itself as far as Toulouse. However, navigation on the upper river was very uncertain, and this stretch of the river is no longer considered navigable. Instead the lateral canal takes boats through 53 locks to the town of Toulouse, where the canal meets the Canal du Midi. Hydrography The upstream part of the river, upstream from Toulouse depends primarily on snow and snow melt. The lower/downstream part is rain fed as well as its main tributaries. The Garonne also feeds several channels/canals: The Saint-Martory canal – Saint-Martory water intake takes 10 m3/s from the river; The canal latéral à la Garonne – with the water intake in Toulouse by the Brienne canal. SANDRE assigns to the Garonne a hydrographic identity number 0 --- 00000 and the generic code O --- 000014,15. Floods A flood of the Garonne in 1930 broke the dike in