Eelgrass (Zostera marina)
Zostera marina, to give the scientific name, is a flowering
grass that grows submerged in seawater. The tufts of leaves arise from
creeping underground stems from which roots reach down into muddy sand.
They are easily dislodged by anchors ropes or chains. The broken sections
float away with the current and can be seen dying on the strand-line.
Colourful anemones, seahorses, fan worms, cuttlefish, strange
sea-slugs and delicate hydroids all shelter and feed amongst
the swaying eelgrass.A host of small fish - dragonets, pipefish, various gobies and
wrasse as well as many juvenile fish of other species swim and
feed in the beds.
In recent years all the eelgrass has been lost from the intertidal beds in the river below Helford Passage, Treath, Calamansack and Gillan. This is why the remaining beds off Grebe beach are so important. Since 1994 these beds have been recorded and photographed regularly. They are being watched for signs of disease or damage, to see what animals and plants use them and whether the beds are changing.
Surveys of the Helford Eelgrass 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.
The Eelgrass beds off Durgan and Grebe are currently regularly observed by a local diver to check on their condition, and it is hoped that the extent will soon be estimated once again to compare against an extent survey in the late 1990s.
Help to preserve the eelgrass beds
Please do not anchor on the eelgrass between Durgan and Toll Point.
The area marked on the postcard shown is all that is left of the once extensive eelgrass beds in the Helford Estuary.
The beds have been badly damaged by anchors and anchor chains; these dislodge and break up the underground stems, which then get washed away and die. These cards can be obtained by contacting the HMCG coordinator.
Also see:
- Hidden habitats of the HVMCA -Eelgrass beds
- Eelgrass – flourishing in the Helford
- Eelgrass monitoring