Eelgrass
Eelgrass (Zostera) and its grass-like relatives are true flowering plants that grow and thrive submerged in seawater. If you walk down to Grebe beach or any other cove between Durganand Toll Point on the north shore of the Helford River at very low tide you might glimpse the green strands of eelgrass swaying in the water just offshore. Sprouting from a sandy sea floor with occasional seaweed covered rocks, these estuarine beds are very special as they provide shelter from strong currents and predators and play host to so many different sea creatures.
Why is eelgrass important?
- Eelgrass roots stabilise sand and prevent it from being washed away
- Eelgrass beds are home to a huge array of animals including the rare seahorse
- Eelgrass beds act as a refuge for juvenile fish species such as pollack and bass
- Eelgrass beds provide important breeding grounds for cuttlefish and sea hares
- Eelgrass is rare in the UK and is declining in abundanceHow you can help
Eelgrass is the only British flowering plant to be found growing in the sea. Tufts of green leaves arising from underground stems provide important shelter for crabs, anemones and young fish whilst cuttlefish, sea hares and sea lemons use it to anchor their eggs. Perhaps one day the fascinating little seahorse will be seen again within the underwater meadows. Recently concern has arisen that boat anchors are contributing to bare patches, so attempts are being made to persuade boat owners to anchor elsewhere in the estuary.
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 the 1980s 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.