Very interesting plant seen in the shallow water
EELGRASS is an interesting plant. It is a native flowering plant and while it does have long, green, ribbon-like leaves, it is a grass lookalike rather than being a true grass. Its connection with eels is that it grows on the seabed and is one of our very few plants to flower underwater. Its distribution is patchy in Ireland, but it grows all around our coasts and is reported to be locally abundant.
The recent heatwave prompted me to go snorkelling to renew my acquaintance with my local stand of Eelgrass. The sea was shallow at low water of the spring tide, both the air and the water were much warmer than normal, there wasn’t a breeze and the sea-surface was flat calm; the clarity underwater from the bright sunlight was amazing.
Eelgrass grows best rooted in muddy sand in sheltered conditions. That particular habitat combination is characterised by the presence of Lugworms. Recent casts get washed away by the action of the sea but the combination of the worms extruding fresh casts and the sea eroding them resulted in the seabed having a hummocky surface like that of an egg tray.
The Eelgrass grew plentifully in my local patch. Its 40cm-long, hairless, shiny, dark green leaves swayed gently with the motion of the sea. Fish were common as were good-sized Spider Crabs. The big change since my last visit was the great profusion of Japweed in the stand of Eelgrass; Japweed had taken over leaving no continuous sward of the seagrasses.
Japweed, an alien brown seaweed from Japan, was first recorded in Irish waters in 1995. It is now very common and widespread on my local stretch of coastline. The Japanese government does not take kindly to the name ‘Japweed’ and favours its alternative name ‘Wireweed’. It is not known if the presence of the alien seaweed in the beds of Eelgrass has a positive or negative, or any, impact.
Eelgrass is a perennial plant. It reproduces by making new plants along rhizomes creeping out from a parent. It also reproduces sexually, producing large numbers of seeds enclosed within fleshy nutlets on flowering spikes. The seeds may be dispersed by the action of waves or by waterfowl feeding on the seagrass.
In my neck of the woods, when Brent Geese arrive in winter, they up-end at low water over the stands of Eelgrass reaching down to grab the nutritious leaves growing upwards from the muddy sand below.