Atlantic salmon  (Salmo salar)

Historically the Atlantic salmon could be found throughout the North Atlantic in a range spreading from Quebec to Connecticut in the west and from the Arctic Circle to Portugal in the east. In the last 30 years however, the salmon population has suffered a devastating decline with catches falling by more than 80 percent. Today many populations are teetering on the brink of extinction or have already been lost, and it is believed that Atlantic salmon numbers are only reasonably healthy in four countries; Norway, Ireland, Iceland and Scotland. Across the UK, populations in nearly 50 percent of salmon rivers are at risk and over 30 percent are endangered.

Adult Atlantic salmon are found in the open ocean at depths between 2 to 10 metres. They return to freshwater to spawn in the streams in which they themselves were born, often only returning to pristine river systems. This makes them a useful indicator species of a river's quality.