Can science save the River Itchen?

The Environment Agency (EA) has launched a critical study into the state of salmon on the River Itchen, one of just six chalkstreams in England still supporting the endangered species. The project focuses on improving fish passage past barriers and restoring degraded sections of the lower river near Southampton.

In 2022, only 133 salmon returned to the Itchen to spawn, the lowest figure since records began in 1990 and just 20% of the conservation limit, according to the Test & Itchen Association.

A river under threat

Jackie Mellan, EA project manager, explained the urgency of the situation:

“The Itchen has really changed in the past 10 years – salmon are at significant risk of extinction, the sea level has risen, and climate change makes floods and low flows more extreme.”

One of the biggest challenges lies at barriers such as Woodmill sluice, where sudden changes in water velocity cause smolts to hesitate and bunch up, leaving them vulnerable to predators. Part of the river has also “breached,” with water spilling into the floodplain through Riverside Park and bypassing the main channel.

Study to inform action and community involvement

The EA study, due for completion in October, will explore options such as river habitat restoration, improved fish passage, and ways to engage local communities in conservation efforts.

This research forms part of the wider Itchen Salmon Delivery Plan, which brings together conservation organisations and government agencies to address the decline of wild salmon on the Itchen.

Protecting this iconic chalkstream and its salmon population is seen as a crucial test of how science, restoration and community action can work together to save endangered river species.