Saving seagrass in Plymouth
We're protecting seagrass meadows in Plymouth from damaging, traditional moorings.
Widely-used, traditional boat moorings have been found to damage large areas of seagrass, sometimes leaving a 'halo' 5m in circumference. The chains which run from the buoy on the surface to a concrete or metal block on the seabed become slack at low tide, meaning the chain rests on the seabed. As the wind and tide change, the chain is dragged along the seabed, causing destruction in its wake and uprooting valuable seagrass meadows at the same time.
The seagrass project in Plymouth worked to install new mooring systems which lift the chain off the seabed using buoys. The chain is attached to a corkscrew-like mechanism on the seafloor to further reduce potential damage.
Why are we protecting seagrass?
Seagrass and rich sediment inshore seabeds can lock in huge amounts of carbon. Not only that, seagrass also stabilises the sand around exposed coasts, protecting beaches from erosion. They are important nursery grounds for cuttlefish, feeding grounds for bass, crab and snails and they strip the water column of excess nutrients.
In order to make a real difference to the recovery of carbon storage habitats like seagrass beds, we need to repair the ones we have, and grow new beds. We also need the recreational boating community to demand a change to mooring systems that don’t damage the seafloor. We need to make as many boaters as possible aware of the implications of anchoring on seagrass beds to avoid unwanted damage.
We worked alongside Natural England, The Ocean Conservation Trust, The Royal Yachting Association, Plymouth City Council and Tamar Estuaries Consultative Forum as part of the ‘ReMEDIES’ (Reducing and Mitigating Erosion and Disturbance Impacts affEcting the seabed) project to achieve these goals.
For our part in the ReMEDIES project, we raised awareness of seagrass conservation issues through our Sea Champion network and online training and events. The wider ReMEDIES project is tasked with replanting and protecting up to 8 ha of seagrass in five English south coast Marine Protected Areas by the end of 2023.
Update: October 2022
After two and a half years of monitoring the seabed around the moorings, we've found little change in the density of seagrass. We believe there are many reasons as to why there could be such a slow recovery of the seabed, including aspects of poor water quality in the area.
Although we've finished installing Advanced Mooring Systems in the bay, we would like to continue to get funding to monitor recovery of the seabed as time moves on.
We've written a report to highlight the project findings so far:
