Something green is stirring again in the traditionally muddy brown waters of the Humber estuary. After a successful initial pilot project, thousands of seagrass seeds are being planted in an initiative aimed at restoring 30 hectares of meadow off Spurn Point, the dramatic curving peninsula between the North Sea and the estuary which is often described as Yorkshire’s very own Land’s End.
In just over a century the seagrass meadows at Spurn have all but disappeared. Today less than 2% of an area recorded back in 1900 remains.
Contaminated water has driven this extraordinary loss of natural habitat with heavy metal pollution from nearby industries physically stunting plant growth while run-off from agricultural land has clouded the water to block sunlight reaching the submerged seagrass.
However, the tide is turning thanks to a partnership between Yorkshire Wildlife Trust, Lincolnshire Wildlife Trust and renewable energy firm Orsted.
Humber estuary seagrass: a haven for nature
Their ambitious five-year Wilder Humber programme not only seeks to restore the seagrass meadow but also re-build the estuary’s lost native oyster population and halt the decline of other precious habitats such as salt marshes and sand dunes.
Thriving seagrass meadows can be havens for nature, providing a breeding ground for juvenile fish and a feeding ground wading birds as well as absorbing carbon dioxide at a rate which is estimated to be between and two and four times faster than a rainforest.
Seagrass can also help improve water quality by removing excess nutrients, chemical contaminants and biotoxins and storing them in their tissues by absorbing them through their leaves and roots.
At Spurn, the results of the restoration project are starting to be seen.
Every year, around 40,000 seeds are collected from healthy seagrass before being cultivated in a dedicated nursery before being replanted in seed bags in carefully selected areas.
The latest batches have just been planted following what is now an annual Seagrass Festival held at The Deep aquarium in Hull where visitors created hundreds of seed bags ready for planting.
Restoring the oyster beds
Rachael Bice, chief executive of the Yorkshire Wildlife Trust, said:
“The time has come for bigger, bolder action on seascape and seagrass restoration following good results from our earlier trials.
“This pioneering programme delivered by an exciting partnership is a crucial step forward. We expect to see huge improvements to water quality and a richer marine habitat providing a better home for more birds, seals and fish across the estuary and beyond.”
The partnership’s target to reintroduce 500,000 native oysters is a bold one given the fact that a vast oyster reef that once stretched from the mouth of the Humber to the Thames estuary has all but vanished.
With the small number of surviving fragments of this biogenic reef considered too isolated and depleted to be able to recover naturally, the Humber programme is giving mother nature a helping hand.
At Spurn’s aquaculture site, juvenile oysters are held on specially-made trestle boxes placed near the shoreline after being brought from a hatchery where they have been reared. This allows them to acclimatise and grow to an optimal size before finally being released.
Once in the estuary, their filter feeding system naturally helps clean the water by removing algae, organic matter and excess nutrients as they grow.
In lockstep with renewable energy development
Funding for the programme is coming from Orsted as part of the company’s proposed Hornsea Four offshore wind farm development which was given the go-ahead by the government in July.
Dr Sarah Randall, environment manager at Orsted, said:
“Hornsea Project Four will be one of the world’s largest offshore wind farms, providing a significant source of low-carbon energy to UK homes and businesses.
“Throughout development of the offshore wind farm, we have been working alongside a range of stakeholders and the local community to ensure that the project is built sensitively and sustainably.
“We are delighted to be working with Yorkshire Wildlife Trust on this ambitious seagrass restoration project and hope that this will provide the foundation for future success and innovation.”
Dr James Wood, fishery and research manager for North Sea Wildlife Trusts, said:
“This pioneering project is a crucial step for seagrass in the Humber Estuary, and the wider marine environment.
“It’s an incredibly exciting partnership and could be the largest seagrass restoration project in the UK and Europe.
“Over time, we expect to see huge improvements to water quality, marine habitats, and related species within one of the most important conservation sites in the UK.”