A very common seaweed, Channelled wrack grows around the high water mark on sheltered, rocky shores. Living on the upper shore, it is very tolerant of desiccation and can survive for up to eight days out of the water. In fact, if it is fully submerged for too long, it may die. Channelled wrack can live for up to four years.
How to identify
A smallish brown 'wrack' seaweed, Channelled wrack can be recognised by the obvious 'channels' that its frond form - produced by their sides being rolled in. Lighter-coloured, bumpy, v-shaped swellings at the ends of the fronds are its reproductive structures. It does not have air bladders.
Did you know?
Channelled wrack is a hermaphrodite, so it has both male and female structures. The gametes are released in August and September from the swollen tips of the fronds (receptacles) and are fertilised externally in the water. They settle as tiny sporelings, developing through the winter.
How people can help
Seaweeds provide a vital link in the food chain for many of our rarer species. Our seas and coastline are in need of protection if we are to keep our marine wildlife healthy. The Wildlife Trusts are working with fishermen, researchers, politicians and local people towards a vision of 'Living Seas', where marine wildlife thrives. Do your bit for our Living Seas by supporting your local Wildlife Trust or checking out our Action pages.
