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. They 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.
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.
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.