Hidden habitats of the HVMCA -Eelgrass (Zostera marina) beds

Rebecca House surveyed part of the HVMCA Eelgrass beds within the Fal and Helford Special Area of Conservation as part of her MSc project and this is what she found.

Past surveys had mapped Zostera marina within the HVMCA and showed that there had been considerable variation in the extent and health of these shallow water eelgrass beds with good light penetration. More detailed recording during the late 1990s showed eelgrass extending over approximately 6.5km2 off the Helford Grebe shore and from about 1996 onward casual observations suggested that the bed was extending westwards from Grebe beach to Durgan beach and beyond. Eelgrass has been seen even amongst the rock-pools to the west of Durgan.

Rebecca made a map of this area for future reference and any necessary management. She identified potential problems:

• Anchors and chains dragging through the eelgrass beds.
• Damage from scouring of boat hulls as well as s propeller chop. .
• Trampling due to visitor pressure.
• Competition from other species or algal dominance.

There is wealth of marine life using these beds including sea anemones, crabs, cuttlefish, sea snails, fan worms and many different fish including juveniles of deeper water species so there is every reason to protect them from damage. Currently the South West Biodiversity Action Plan is focusing on eelgrass bed conservation and Natural England has produced warning buoys to encourage boats to avoid the main beds. This plan has been generally successful and the beds are currently flourishing.

Extract from HVMCA newsletter No.32 Spring 2006

Other items that may be of interest:

• Eelgrass