Ecological Status of Atlantic Salmon (Salmo Salar L.) in France: Need for an Ecosystemic Approach

Abstract

Atlantic salmon (Salmo salar L.) is, in France, a totemic species and a symbol of the quality of aquatic environment. Formerly, very abundant in numerous river basins entering the Channel or the Atlantic coast, this species, unfortunately, is declining since the beginning of the 20th century and particularly after the end of the 2nd World War. Presently, this anadromous fish migrates on 40 river systems located between the Belgium border and the Spanish one. Salmon is mainly exploited by rod anglers but there still exists a professional fishery in the Adour-Gaves basin (located in the South-West part of France) where salmon catches are allowed with drift net. In all other estuaries and coastal waters where they are not prohibited, salmon catches by (professional) fishermen remain incidental and very few. Commercial salmon fishing, whether targeted or accidental, is strictly regulated in France, including a fishing licensing regime specific to diadromous fish species.” The total catch is currently estimated to 10 metric tons around 3000 fish. The decline of Atlantic salmon in France is due to multiple anthropogenic pressures that have affected the size and the quality of its freshwater habitat during the 20th century such as: edification of dams on a great number of rivers for energy production or for agricultural and domestic purposes; increase of the water pollution with a degradation of the quality of the spawning areas; impediments to free migration due to an insufficient number of fish ladders or non effective fishways that prevent salmon to reach safely and rapidly their spawning areas. The final result is a large decrease of productivity of salmon stocks in most part of French salmon rivers and some difficulties to maintain a professional or leisure exploitation. Despite the ban of salmon catch in large river systems such as the Loire, Gironde, Seine, Garonne, Dordogne basins and the drastic decrease of the number of salmon fishers (presently less than 3000 for anglers and less than 30 for professional fishers), managers have some great difficulties to rebuild the population. Most of restoration programs failed due to a too fragmented approach without a global view of salmon needs; fishing regulations without improvement of salmon environment have limited effects on the stock restoration if the main cause of decline is the decrease of the quality of salmon habitat. So, the future of Atlantic salmon in France lies in the implementation of an ecosystemic approach in order to have perennial and significant effects on the abundance of this population. The examples of restoration programs undertaken in the Adour-Gaves basin or in small river systems such as the Elorn river in Brittany confirm the need for management plans including not only fishing regulations but also improvement of salmon environment. On the Adour-Gaves river system for example, a restoration program including regulation of fishery, improvement of the free migration of individuals for a better access to the best spawning areas located in the upper course of the salmon tributaries, has given significant results on the stock abundance and on the percentage of large spawners in the population.