Individual populations of Atlantic salmon (Salmo salar, Annex II Habitats Directive) differ between each other in terms of various morphological and genetic characteristics, depending on the river basins they originate from. This species reproduces in fresh water after spending 1 to 3 years at sea, where it grows to its full size. The Loire/Allier basin population is the last one in western Europe to have the characteristics indispensable for migrating nearly 1000 km in fresh water. Its numbers fell from several thousand to a few hundred between 1988 and 1995 (population estimated to be 100.000 at the end of the 18th century). This population is therefore threatened with extinction, since the number of mature fish returning to the spawning grounds (between 300 and 500 a year) is far below the minimum threshold estimated for the Gartempe/Allier axis (2.400 mature breading fish). This decline has been caused by physical (dams) and chemical (pollution, silting) obstacles to the migration of the fish and the degradation of their vital habitats (spawning grounds, nurseries).
The project aims to increase the size of the population on the Allier and Gartempe axis until there is a viable stock which no longer requires artificial support. This will be done using eggs, hatchlings and young salmon produced by the Chanteuges salmon-breeding farm. This installation, which went into operation in 2001, us remarkable for its ability to produce young salmon using techniques inspired by those developed in Quebec. The goal is to have around 1.500 breeding fish in the spawning grounds by the end of the LIFE-Nature project and 2.500 after the salmon farm has been operating for 6 years (start of 2007). At the same time, improving the conditions for surmounting obstacles (carried out parallel to LIFE: reducing pollution, removing dams, building salmon ladders) and measures to preserve spawning grounds (management plan, regulatory protection) must make it possible to preserve and make accessible 1.000 spawning grounds on the Allier and its tributaries and the Gartempe. Awareness-raising measures are also planned (CD-ROM, Internet site, etc) as well as a colloquium at the end of the project to recapitulate its results.