Eelgrass

There are two species of Eelgrass locally, Common Eelgrass, Zostera marina, and Dwarf Eelgrass, Zostera noltei which is found by Herm and Jethou. They are sub-tidal plants, but with our large tidal range on spring tides, it is quite possible to see areas of Eelgrass from the shore. One such place is Cow Bay on the harbour side of Castle Cornet.

Eelgrasses are not showy, they have long grass-like leaves that sway in the current. This belies its unusual place in shallow seawater as it is a flowering plant, not a seaweed. It cannot rely on pollinating insects to fertilise seed for the next generation. Instead, these plants release long strands of male pollen which the tide disperses. Some of them will become entangled in the female stigma which are hook-shaped. The fertilised seeds are then carried by currents and spread far and wide. They grow in shallow seawater, well-lit from above as they need to photosynthesise.

Eelgrass meadows provide important areas of shelter for young fish and other sea creatures. Under the sand and sediment, a network of rhizomes form a stabilising mat which helps to prevent coastal erosion. The meadows are an important carbon sink as they store quantities of carbon dioxide (and methane). They are helping to combat the effects of climate change.

Brent Geese overwinter in small flocks around our shallow coastal areas and feed on marine weed and eelgrass.