Seagrass and Recreational Yachting

The Solent is now centre-stage in an important new initiative, led by Natural England, to find ways to protect critically endangered Seagrass Meadows. The Life Recreation ReMEDIES project (Reducing and Mitigating Erosion and Disturbance Impacts (E) affecting the Seabed) will particularly focus on the threats raised by the mooring and anchoring of recreational boats. Five sites have been chosen along the south coast for the study, the largest and busiest being the Special Area of Conservation, Solent Maritime. It includes areas of Chichester Harbour, Langstone Harbour, the stretch of Coast between Stansore Point and Hurst Castle, and that between Osborne Bay and Yarmouth on the Isle of Wight.

Boat owners are learning what ecologists have known for years, that seagrass meadows are highly important; they stabilise the seabed, absorb carbon, slow climate change and are the natural habitats for a plethora of marine animals, algae, rare seaweeds and are nurseries for many of our commercially valuable fish. They buffer wave energy, reducing erosion of our coastline, always a concern in the Solent. The evidence shows that traditional buoyed mooring chains scour deep abrasions in the sediment, thereby destroying the habitat. Recovery is slow and difficult as the scar will often fill with debris rather than allow the sediment to settle to its previous depth, thus enabling the rhizomes and root systems to re-establish. Evidence of long-term damage to the seabed from anchoring is less apparent but the random nature of the fall of the anchor and chain, whilst not scouring the sea-bed, will ‘harrow’, typically, 40 square metres over the rise and fall of a tide. Seagrass beds flourish in relatively shallow, sheltered bays and alas, enjoy the same merits that make for a good anchorage!

For a generation now, Advanced Mooring Systems (AMS) have been trialled around the world, particularly in North America and Australia. The outcomes have been mixed. The options have usually been different adaptions of a helical screw into the sea floor, rather than a concrete block or an anchor, together with a floating rode, either a chain whose weight is supported by small floats or one made of synthetic elastic or rubber. All of these have proved to work better in waters with a lesser tide range and moderate wave depth. There is no ‘one size fits all’ with AMS; they need to be designed to cope with the specific conditions of the site in question. They are expensive to make and need regular maintenance; the synthetic materials do not weather well and organisms are prone to grow in between the fibres and weaken the elastic. The need for reliability of the installations is emphasised by the high value of the vessels using them and the Insurance implications.

The ReMEDIES project sets out to square the circle by finding solutions to all forms of anthropomorphic damage to Seagrass, exploring the most effective means of preventing it, and then seeking the co-operation of the recreational boating community. To that end The Royal Yachting Association and its environmental programme, The Green Blue, who along with the Ocean Conservation Trust and the Marine Conservation Society
are partners in the Project, are working with many local stakeholders to identify their needs.

Persuading chart makers to plot the Seagrass beds in question on Marine charts is an early initiative already under the microscope.