Atlantic salmon Salmo salar

Atlantic salmon can be very large fish, growing over a metre in length. They are found in the cleanest rivers, mostly in the north and west. They spend most of their lives out at sea, famously returning to spawn in the same stretch of river or stream in which they hatched. Adult salmon are much larger than trout; they are silvery with a few dark spots on the back and may have a pinkish flush to the belly. Mature males may develop a hooked lower jaw, or kype, in the breeding season.


Atlantic salmon travel upstream from November to February, often jumping over weirs and waterfalls to get to the gravelly-bottomed headwaters where they prefer to breed. Once they have reached their breeding grounds, the females dig depressions, known as redds, in the gravel and eggs and sperm are released simultaneously into the water. The juveniles will stay in freshwater for up to six years, after which they migrate back to the sea – morphological changes allowing them to survive in saltwater. Salmon are predators, feeding on invertebrates and small fish as juveniles, and squid and fish in the sea.


  • Length: 1.2-1.5m
  • Weight: up to 40kg
  • Average Lifespan: 4-10 years


Classified as Lower Risk/Least Concern on the IUCN Red List. Classified as a Priority Species in the UK Biodiversity Action Plan.


Found in rivers in Wales, Scotland and northern and southwest England.

When to see

January – December


  • Known as the ‘King of the Fish’, the Atlantic salmon is able to clear seemingly insurmountable obstacles during its journey to spawn: from waterfalls to weirs, Atlantic salmon have been known to leap vertical obstacles over 3 metres tall.
  • It is unclear how they navigate to the breeding grounds of their own birth but it is thought smell is important in freshwater and the Earth’s magnetic field plays a part when they are at sea.

Common name

Atlantic salmon

Species name

Salmo salar

IUCN Red List status


When to see in Scotland

January – December

Where to see in Scotland

Rivers throughout Scotland, particularly in the Tweed and the Tay. Atlantic salmon are not regularly spotted on Scottish Wildlife Trust reserves, but they have been seen at Montrose Basin and Ben Mor Coigach.

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