Off Falmouth Bay, between Swanpool and Pendennis Castle, a stretch of seafloor that once supported thriving seagrass meadows and native oyster beds has spent decades diminished by dredging, pollution and disease. This July, the Ocean Conservation Trust (OCT) and Cornwall Wildlife Trust (CWT) launched Mor Nature — Cornish for "sea nature" — a three-year, £1.8 million project aiming to restore 10 hectares of seagrass meadow while rebuilding native oyster populations across the wider Fal and Helford Special Area of Conservation. It's billed as the UK's largest-ever seagrass restoration project, and unlike most single-species efforts, it's deliberately going after seagrass and oysters together.
21,000 seagrass seedlings, grown over a single winter, are now going back into the seabed off Cornwall.
The groundwork was laid well before launch day. Over the past winter, OCT's team cultivated more than 21,000 seagrass seedlings at its National Seagrass Nursery, building on protection work the trust started at this same stretch of coast back in 2022, when it placed marker buoys across three zones to safeguard more than 20 hectares of existing meadow. Divers are now working those seedlings into the seabed in Falmouth Bay, while CWT leads the parallel push to reintroduce native oysters — a species that filters water, stabilizes sediment and once anchored the local fishing economy.
Rebuilding Two Habitats at Once
"We're not simply planting seagrass; Mor Nature represents the holistic cultivation of an entire underwater garden, nurturing the relationships between interdependent species and habitats that will allow a plethora of marine life to thrive," said Andy Cameron, Conservation Project Manager at the Ocean Conservation Trust. Dr Dan Barrios-O'Neill, Head of Marine Conservation at Cornwall Wildlife Trust, framed the oyster half of the project the same way: "Native oysters were once a defining feature of Cornwall's seas, creating thriving underwater habitats that supported wildlife, fisheries and coastal communities. Through Mor Nature, we have an opportunity to restore not only oyster populations, but the ecological functions they provide."
Ten hectares is a small fraction of what Cornwall's coastline has lost over the past century, and seagrass restoration is notoriously slow — transplanted meadows can take years to establish and remain vulnerable to storms, disease and marine heatwaves before they're self-sustaining. But by pairing seagrass with oyster reef restoration in the same water, Mor Nature is betting that rebuilding two interdependent habitats at once gives both a better shot at actually taking hold, rather than replanting one species into a seabed still missing the other.
Read the full original reporting at Oceanographic Magazine →
Image credit: Zostera marina, the native UK seagrass species being restored in Cornwall