Seagrass planted in the River Hamble in 2025 has taken root and is beginning to thrive, marking the return of one of the UK’s most threatened marine habitats.
In April 2025, 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. Within a few months, healthy plants were growing, flowering, and producing new seed in the estuary. These early signs suggest the possible return of 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. A wasting disease outbreak in the 1930s caused widespread losses across the North Atlantic. A survey in 2023 confirmed that no seagrass beds remained in the river.
Only fragments of the extensive seagrass meadows that once thrived across the UK now remain. It is estimated that up to 92% of seagrass has been lost over the past century, with recovery limited by 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 producing new seed gives me a lot of hope.
“Seagrass restoration is not straightforward. It is slow and difficult work, and there are no guarantees. But these early signs show that the Hamble can still support seagrass and that recovery is possible when science, innovation and community support come together.”
Important habitats
Seagrass meadows provide important nursery habitats for marine life including pipefish, cuttlefish and thornback rays. They also store carbon in the seabed, making them one of the ocean’s important natural carbon sinks.
The Zostera seeds planted in April 2025 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 through the winter at the University of Portsmouth’s Institute of Marine Science.
In spring, they were planted into the Hamble’s seabed using Dispenser Injection Seeding. This technique adapts caulking guns to place seeds directly into the seabed with minimal disturbance, helping them establish.
The restoration in the Hamble forms part of wider seagrass recovery efforts across the Solent. Across Hampshire and the Isle of Wight, volunteers collected more than 58,000 seagrass seeds during 2024, supporting ongoing planting efforts to restore seagrass meadows in the region.
The work is part of the Solent Seascape Project, supported by the Endangered Landscapes & Seascapes Programme. The project brings together partners including Blue Marine Foundation, conservation organisations, researchers and local communities to restore seagrass, oyster reefs, saltmarsh and seabird nesting habitats across the Solent.
This article was originally published on the Solent Seascape Project website. For more information, visit their project page.
