Protecting and growing seagrasses through the deployment of Advanced Mooring Systems (AMS)
Update from the Seagrass and AMS Tevi Challenge Network.
Amanda Goodwin, Tevi Challenge Network Manager.
The aim of this Tevi Challenge Network (CN) is to support the regrowth of seagrass meadows by replacing conventional moorings that scour the seabed with solutions that minimise the mooring’s environmental impact, while still delivering essential mooring performance in terms of vessel security and movement.
Seagrasses, particularly eelgrass, are a crucial part of the marine ecosystem and provide a range of ecosystem services. They are a nursery ground for commercial fish species, a haven for threatened and protected species, a coastal defence and a significant carbon sink – in fact they sequester and store more carbon per unit area than terrestrial forests.
Despite these valuable ecosystem services, it has been estimated that 92% of seagrasses in the UK have been destroyed since the 1930s. This equates to 10.6 MT of stored carbon – worth a carbon trading value of £275million – as well as loss of habitat, food source and shelter.
Advanced Mooring Systems, which come in a variety of designs and from a variety of manufacturers, most notably lift the riser section of the mooring system off the seabed, thus significantly reducing or eliminating the scour issue. Some AMS also replace the anchor section of the mooring with a solution that minimises the zone of interaction of the anchor on the seabed.
Over the course of this Tevi Challenge Network, it has become clear that further evidence is required by harbours and boat owners about vessel security and movement implications posed when transitioning from a traditional concrete block and chain mooring to an AMS. To respond to this need Tevi has conducted a desk based study of all UK AMS trials. This report covers:
- Importance of seagrass
- Public perception of marine environmental issues
- Findings and impact of UK AMS trials
- Costs of available off the shelf advanced mooring systems
- Conclusions and recommendations
Building on the conclusions and recommendations of the report, Tevi is hoping to deliver two further key outcomes from this CN;
- Mapping of seagrass in Fowey Harbour to supplement national datasets and form the foundation of a business case for investment in AMS in Polruan Pool.
- Modelling of the AMS listed within the report, using the average environmental parameters of Cornish harbours and a medium sized recreational vessel, to ascertain the likely movement and performance of AMS within Cornish harbours.
We look forward to continuing to work with all involved in this CN and at this point we wish to extend a special thank you to Natural England’s LIFE Recreation ReMEDIES project team for their many contributions to our report.
Write ups of previous meetings of this Challenge Network can be found here: