Seagrass begins to flourish in the Hamble for the first time in almost 100 years

Seagrass seed planted earlier this year in the River Hamble has taken root and is beginning to thrive, marking a historic return for one of the UK’s most threatened marine habitats.

In April, as part of the Solent Seascape Project, Hampshire & Isle of Wight Wildlife Trust’s marine team planted more than 2,000 seagrass seeds using innovative methods. Just a few months later, healthy plants are now growing, flowering, and producing new seed in the estuary – the first signs of a potential comeback for a habitat lost from the Hamble since the late 1920s and 1930s.

Historic meadows

Seagrass once stretched from Southampton Water up the Hamble to Bursledon, until a wasting disease outbreak in the 1930s caused widespread loss across the whole North Atlantic area. A survey in 2023 found no remaining beds.

Only fragments of vast seagrass meadows that once thrived across the UK now remain – up to 92% of seagrass has been lost over the past century and recovery limited due to pollution, dredging, boat anchoring and coastal development.

Tim Ferrero, Senior Specialist, Marine Conservation, at Hampshire & Isle of Wight Wildlife Trust, said: “Standing in the Hamble and seeing seagrass growing again was a truly emotional moment for me. This river hasn’t seen seagrass for almost a century – but now, for the first time in living memory, it’s back. To witness those tiny shoots flowering and even producing new seed gives me so much hope.”

“Seagrass restoration is not straightforward – it’s slow, difficult work, and there are no guarantees. But to see these early signs proves that the Hamble can still support seagrass, and that we really can bring this forgotten habitat back. It shows what’s possible when we combine science, innovation, and the dedication of volunteers who give their time to help restore our seas. This really feels like a tipping point in our journey towards the restoration of the Solent Seascape.”

Important habitats

Seagrass meadows are vital nursery habitats for marine life including pipefish, cuttlefish and thornback rays. They can also capture carbon, burying it down in the seabed and making them one of the most important natural solutions to the climate crisis.

The Zostera seeds planted in April were collected in autumn 2024 from intertidal meadows in Langstone Harbour, at Farlington, Portsmouth, with the help of Solent Seagrass Champion volunteers. The seeds were sorted and stored safely through the winter at the University of Portsmouth’s Institute of Marine Science. The seeds were then planted into the Hamble’s seabed using Dispenser Injection Seeding – a technique that adapts DIY caulking guns to place seeds directly into the seabed with minimal disturbance, giving them the best chance to establish.

Tim added: “When you imagine what the Hamble might once have been like – clear waters with seagrass streaming in the tide, alive with fish and wildlife – it makes you realise how much we’ve lost. Seeing seagrass return reminds me that we don’t have to just accept those losses as permanent. We can change the story of our seas, and the Hamble is showing us that recovery is possible.”

This effort is one small part of a bigger movement to restore seagrass across the Solent. Across Hampshire and the Isle of Wight, hundreds of dedicated volunteers have helped collect more than 58,000 seagrass seeds this year alone, with the aim of planting the seeds in coming seasons and ultimately restoring seagrass meadows as vibrant, self-sustaining ecosystems that benefit people, nature, and the climate.

The restoration in the Hamble is part of the Solent Seagrass Restoration Project, and the Solent Seascape Project, which brings together partners including Blue Marine Foundation, conservationists, researchers, and the local community to restore seagrass, oyster reefs, saltmarsh and seabird nesting habitats across the Solent’s seascape.