The clock is ticking for the Atlantic salmon, Salmo salar, of the River Itchen. Once a thriving species in this iconic chalk stream, their numbers have plummeted to the brink of collapse. In 2022, just 133 salmon returned to spawn – the lowest count in over three decades. And in 2024, only 187 returned – the third lowest ever recorded. This isn’t an isolated dip, but part of a worrying long-term trend.

In a fight to turn the tide, we have united with other leading environmental organisations to launch the Itchen Salmon Delivery Plan (ISDP) – a coordinated initiative designed to halt the decline of this species and protect the health of the River Itchen, one of England’s most important chalk streams, before it’s too late.

A fragile balance

85% of the world’s chalk streams are found in England, many of them in Hampshire, including the River Itchen, which is one of only six that still support Atlantic salmon. These rare, mineral-rich waters provide the cool, stable conditions essential for salmon to spawn and grow. However, these finely balanced ecosystems are under threat, putting the salmon’s future at risk.

Relentless threats such as over-abstraction, habitat destruction, pollution, in-migration stream barriers, climate change, and pressures associated with the marine environment have decimated their numbers. In December 2023, Atlantic salmon were officially classified as endangered in the UK on the IUCN Red List – a dire warning that without urgent intervention, the Itchen’s salmon could disappear forever.

This alarming decline is also reflected in the population’s failure to reach the Conservation Limit (CL) – the minimum number of eggs needed to keep the salmon population stable. The River Itchen hasn’t reached its CL since 2015. In 2022, returning salmon represented just 20% of the CL, and in 2024, only 37%. This indicates that the population is not just low, but biologically unsustainable without intervention.

A genetically unique species

Atlantic salmon are not just another fish; they are genetically unique and play an essential role in the river’s ecosystem.

As a keystone species, their presence supports the entire river ecosystem. When they return to spawn they transport essential marine nutrients upstream, providing food for insects, birds, and mammals. Their spawning activity helps aerate riverbed gravel, creating better conditions for other aquatic species.

Each population has evolved specific adaptations to their home river, making them uniquely suited to its environment. However, these adaptations are now under threat - nowhere is this more evident than in England’s chalk streams.

As anadromous fish, they also undergo an extraordinary transformation called smoltification, allowing them to migrate between freshwater and saltwater.

United for a lifeline

The ISDP brings together leading conservation and environmental organisation including Angling Trust, Environment Agency, Hampshire & Isle of Wight Wildlife Trust, Natural England, Southern Water, Test & Itchen Association, Wessex Rivers Trust, WildFish, and Wild Trout Trust.

This coalition will pool expertise and resources to combat the environmental threats facing salmon at every stage of their lifecycle – from river to sea and back again.

“The alarming decline of Atlantic salmon in the River Itchen has been a growing concern for Wessex Rivers Trust and our supporters for many years," said Dave Rumble, CEO of Wessex Rivers Trust. "These fish are an indicator species, and their loss would tell a dire story about the health of our rivers. The Itchen Salmon Delivery Plan is a crucial step forward, allowing different organisations to play to their strengths in tackling the many pressures our salmon face. By working together, we can ramp up meaningful action to protect and restore this iconic species.”

“Chalk stream salmon have swum in the waters of the River Itchen for thousands of years. Today, these rare fish are at a critical crossroads. Without urgent action to improve river conditions, we risk losing the salmon in the Itchen forever. We’ve come together as a coalition to save the Itchen’s salmon, but we need the public’s help. Join us in securing the future of this iconic fish,” said a spokesperson on behalf of the ISDP partnership.

Everyone can do something to help. Simply using less water at home this summer will make a difference to water levels in the river. If you are a local river user, be the eyes and ears of the river. Report illegal fishing to the police and pollution to the Environment Agency. Dog owners can help by not letting dogs into the water.

It can be difficult to know when to report and incident, but it’s important to do so to ensure it is addressed quickly and appropriately. The Trust’s guide to reporting incidents can be found here. 

Real action to reserve the decline

The ISDP Save Our Salmon is not just another conservation plan – it’s a mission to reverse a crisis. Key practical solutions include:

Restoring habitat: Improving spawning and rearing habitats to support salmon at all life stages.

Enhancing fish passage: Removing barriers that prevent salmon from migrating.

Enhancing water quality: Reducing pollution to create a cleaner, healthier river.

Managing water resources: Addressing over-abstraction to maintain natural river flows.

Strengthening fisheries enforcement: Reducing illegal fishing and poaching.

Engaging communities: Encouraging local people to get involved in protecting their river and its wildlife.

Martin De Retuerto, Director of Nature Recovery, Wilder Hampshire, at Hampshire & Isle of Wight Wildlife Trust said: “The River Itchen flows through Winnall Moors Nature Reserve, a wildlife haven in the heart of Winchester, and is testament to how nature can thrive when given the right conditions. For over a decade, Hampshire & Isle of Wight Wildlife Trust has been restoring the river and its floodplain habitats. This management work enhances the health of the river as it flows through the reserve, allowing species to return and flourish.

“Life is tenacious, and we have seen first-hand that when we improve water quality, reconnect natural river processes, and restore wetland habitats, wildlife responds. However, the decline of Atlantic salmon highlights the urgent need to continue this work. Through the Itchen Salmon Delivery Plan, we are joining forces with others who care just as deeply, to tackle the challenges facing this iconic species, which utilises vast landscapes of both sea and freshwater. Securing the future of the Atlantic Salmon also secures a healthier future for the whole river and all the life it supports.”

The time is act to now

This is not just an issue for conservationists – it’s a fight for the future of one of England’s most precious ecosystems. Local communities can play a crucial role in saving the Itchen’s salmon. Simple actions like reducing water consumption, supporting river-friendly policies, and volunteering for local conservation efforts can make a real impact.

The Itchen’s salmon are running out of time. But with decisive action, we can still change their fate.