Wild Atlantic Salmon Autumn Migration
Autumn is an important time for wild Atlantic salmon. While they migrate throughout the year, this is when most return to our rivers to spawn. After months at sea, they begin their journey back to the chalk streams where their life began, completing one of nature’s most demanding life cycles. Once home, they prepare to spawn, continuing a cycle that has linked salmon to our chalk streams for thousands of years.
Each fish travels hundreds of miles, guided by a sense of smell so acute it can find the exact stretch of gravel where it hatched years before. From October through to January, salmon create nests known as redds - shallow depressions in the riverbed where eggs are laid and fertilised.
If you’re lucky, you might glimpse a salmon leaping in the river or notice signs of redds in shallow gravelly areas. Identifying redds accurately requires training and experience, but here are a few tips for observing safely:
Look for slightly lighter, clean gravel in shallow sections of the river. These are often the areas salmon have cleared for spawning.
Redds can appear as shallow, oval depressions in the gravel, sometimes with a small mound of displaced stones at the downstream end.
Observe from the bank, take notes or photos from a distance rather than trying to interact with the redd. This information can be useful for monitoring without putting salmon at risk.
These nests are essential to the species’ survival, yet they are vulnerable to disturbance. Low water levels, pollution, and even people wading or swimming through rivers can damage the delicate gravels where eggs are buried.
To protect these sensitive sites, please avoid walking or swimming in rivers between November and June, when salmon and their young are at their most vulnerable.
The Environment Agency currently conducts annual salmon redd surveys on the Test and Itchen. Reporting observations responsibly can help track salmon success without disturbing these vital habitats.
Species Under Threat
In 2023, the UK population of Atlantic salmon was officially classified as ‘Endangered’ on the IUCN Red List of Threatened Species. Pollution, water abstraction, habitat loss, and in-stream barriers are making it increasingly difficult for salmon to complete their life cycle - and climate change is making these pressures worse.
For the genetically distinct salmon of England’s chalk streams, the situation is even more urgent. This unique strain of wild Atlantic salmon has suffered catastrophic declines and now faces the risk of imminent extinction.
Where once thousands of fish returned each year to the famous Test and Itchen chalk streams, only 187 adult salmon are estimated to have returned to spawn in the River Itchen in 2024. In 2022, just 133 were recorded — the lowest number since monitoring began in 1990.
What can be done?
The Trust is collaborating with local and national organisations in an effort to save this endangered population. You can read more about
The Itchen Salmon Delivery Plan (ISDP), which was launched in April this year. Please keep an eye on your inbox and our social media for updates on other projects that are underway.
How you can help
Use water wisely. Every drop saved at home keeps more water in the river for wildlife.
Enjoy rivers responsibly. Keep to the banks during spawning season and avoid disturbing gravel beds. If you are a wild swimmer, pleased follow this
guidance.
Help us by being the eyes and ears of the river: Report any pollution or suspected pollution to the Environment Agency on 0800 80 70 60 and Southern Water on 0800 952 1001.
📷 Spot something interesting? Share your salmon sightings or photos from the riverbank by tagging @WessexRiversTrust on social media. Please avoid sharing the exact location of salmon sightings, to protect this endangered species from disturbance.
