A seafloor survey of seagrass – the essential habitat for seahorses – is to be conducted over the summer in Studland Bay by a team from the University of Southampton.
This comes as a voluntary ban on boats dropping anchor within the southern end of Studland Bay is to be extended on Wednesday 1st June 2022, to help protect the seagrass from being uprooted.
A spiny seahorse surrounded by seagrass in Studland Bay
Important habitat for seahorses
The seagrass meadows that grow on the seabed in Studland, form an important habitat for seahorses as well as fish including sea bass and sea bream.
Scientists say they may also play an important role in reducing the impact of coastal erosion within the bay.
Research shows that seagrass reduces the energy of waves and tidal currents and traps nutrients and particles of sand that would otherwise get washed away, with even their roots helping to bind sediment together, making it harder to erode.
When boats drop anchor or use a traditional buoy, the chains can scour the seabed, uprooting seagrass.
Seagrass is one of the world’s most threatened ecosystems
However seagrass is one of the world’s most threatened ecosystems and partly to protect it and the seahorse population, Studland Bay was designated as a Marine Conservation Zone (MCZ) in 2019.
During 2020, when Covid restrictions prevented recreational boating, the charity that campaigns to protect seahorses, the Seahorse Trust discovered that there was an increase in the growth of seagrass and consequently an increase in the population of seahorses in Studland.
The first official move in December 2021 was to introduce a voluntary no anchor zone for boats in the area of seagrass close to South Beach in Studland. From Wednesday 1st June 2022 this area will be extended to protect a larger area sensitive to damage from boat anchors.
Voluntary no anchor zone marked out by blue line was introduced on 17th December 2021. The area of green is the seagrass meadow
Voluntary no anchor zone marked out by blue line to be introduced from 1st June 2022
To provide an alternative for boat owners who wish to stop in Studland Bay, 10 eco-moorings have been deployed in the bay by the company Boatfolk and the Seahorse Trust.
These, unlike traditional moorings and anchors, don’t drag along the seabed damaging the seagrass with metal chains. It’s hoped that eventually 100 will be installed.
Installation of 10 eco moorings in July 2021 in Studland Bay
Assess the extent and health of the seagrass beds
Now the new project by the team from the University of Southampton will assess the current extent and health of the seagrass beds in the Studland Bay MCZ. They’ll be doing this using robotic vessels that can operate underwater and on the sea’s surface.
The work is being undertaken in conjunction with the Studland Bay Marine Partnership which is made up of organisations including Studland Parish Council, National Trust, Dorset Coast Forum, The Seahorse Trust, Royal Yacht Club and Planet Purbeck.
A Sparus II autonomous underwater vehicle, similar to the one that will be
used in this project. Here it is being deployed in Spain by researchers from the University of Southampton and the University of the Balearic Islands
“Camera-equipped robotic submersibles and autonomous boats”
Project lead and lecturer in ocean engineering at the University of Southampton, Dr Hachem Kassem said:
“Scientists and engineers will conduct a series of surveys over the summer using state-of-the art monitoring technologies, such as camera-equipped robotic submersibles and autonomous boats to map the seagrass and monitor their recovery from past anchor damage.
“By building a comprehensive picture of the bay and its subtidal habitats, we will be able to better advise on the implementation of nature-based solutions at Studland and identify safe, unvegetated access routes for vessels.”
The view from the beach across Studland Bay to the Old Harry Rocks
Work expected to start soon
The long term plan is to reduce boat anchor damage, giving the seagrass and local biodiversity a chance to thrive, while also allowing the sailing and recreational activities to continue in the bay.
The work to start mapping the seagrass in Studland is expected to start at the end of May 2022.
- More about the Studland Bay Marine Conservation Zone and the voluntary no anchor zones is on the Marine Management Organisation website