Sea Grass-friendly moorings
From Port of Jersey
18th April 2023
Ports of Jersey’s project to restore Jersey’s largest area of seagrass in St Catherine’s Bay is entering a significant phase. Seagrass is known for its blue carbon, calculated to absorb 35 times more carbon than tropical rainforests. Traditional moorings, made up of significant lengths of chain, have been scouring bare patches in the seagrass beds, but specially designed moorings are being trialled to prevent this.
Ports of Jersey is deploying moorings (today, 18 April) which can tolerate Jersey’s extreme 12 metre tidal range while also protecting the sea floor. The moorings have been designed with Jersey’s tidal range at the forefront of their engineering. Other environmentally sensitive moorings are commercially available and are used in places around Australia and the Mediterranean, but they are not designed to cope with such an extreme rise and fall in tide.
The Head of Maritime Operations, Louise Stafford, said: “Our project aims to prevent the damage caused by traditional moorings and anchoring by trialling new mooring systems which protect the seagrass and prevent erosion. This is an exciting phase of the work, and we will be watching its impact carefully. Hopefully we can then deploy the successful system to all boat-owners in St Catherine’s Bay.”
Three different types of mooring will be deployed: one has been developed by Blue Parameters, an environmental and sustainability consultancy based in Guernsey; the second by TEMANO, a French company based in Brittany; and the third has been designed by Ports of Jersey’s Marine Services team.
Once the moorings have been deployed, they will be monitored using a camera attached to a remotely operated vehicle (ROV) to observe how they sit within the water column and how they interact with the sea floor. Once it is established that they prevent, or substantially minimise the impact on the seagrass beds, Ports of Jersey will consider how the new systems can be rolled out to all moorings in the bay.
Seagrass provides shelter for marine fauna and at low water is an important feeding ground for wildfowl and other birds. It is also recognised for its blue carbon, calculated to absorb 35 times more carbon than tropical rainforests.
Studies have highlighted that traditional mooring chains and anchoring cause significant damage to the seagrass and erosion to the seabed.