The Atlantic salmon, Salmo salar, is listed in annexes II and V of the European Union's Habitats Directive as a species of importance to the UK. Historically, the species was widely distributed in all countries whose rivers enter the North Atlantic. However, its current distribution has been restricted by anthropogenic effects, particularly man-made barriers to movement and deterioration in water quality due to urban expansion and changes in agricultural practices. Consequently, the Atlantic salmon has declined or become locally extinct in many of the larger navigable rivers such as the River Rhine, and industrial rivers such as the Mersey.
The current distribution ranges from Portugal to North America. It includes rivers in Spain, France, the United Kingdom, Ireland, Norway, Sweden, Finland and other countries draining into the Baltic, Iceland, Greenland, some Canadian provinces, and the north-east USA.
The Atlantic salmon is widespread in the British Isles and can be found in most suitable river systems not affected by poor water quality or barriers to upstream migration. Virtually all Scottish rivers, except some lowland ones, are important for salmon. In England, the salmon is absent from eastern and southern regions. The main distribution gap in England and Wales is from rivers entering the sea between the Yorkshire Esk and the Itchen in Hampshire.
Recent improvements in water quality
have allowed the species to return to some rivers from which they have
been absent for most of the last century, such as the River Clyde and
River Taff. In addition, several previously grossly polluted waterways
such as the Mersey and Trent may soon be able to sustain populations.
Salmon have been re-introduced to the Thames, but the population is at
present being maintained by stocking, and completion of the life cycle
has yet to be demonstrated.
Ecology of the Atlantic Salmon
Monitoring the Atlantic Salmon
