Spiral wrack

Spiral wrack

Spiral wrack ©Nigel Phillips

Spiral wrack

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Enw gwyddonol: Fucus spiralis
This brown seaweed lives high up on rocky shores, just below the high water mark. Its blades are usually twisted, giving it the name Spiral Wrack.

Top facts


Length: up to 40cm

Conservation status


Pryd i'w gweld

January to December


Spiral wrack or Twisted wrack is a common wrack seaweed that grows just below the high water mark on rocky shores all around the UK. Living on the upper shore, it is very tolerant of desiccation and can survive out of the water for long periods, although not as long as Channelled wrack. It can live for up to five years.

What to look for

Twisted wrack is a pale olive-brown 'wrack' seaweed, recognised by the spirally twisting fronds with an obvious rib down the middle, and the yellowish, paired swollen tips which are the reproductive structures. It does not have air bladders and the edges are smooth not serrated.

Where to find

Common on rocky shores all around our coasts.

Roeddech chi yn gwybod?

Spiral wrack spends up to 90% of its time out of the water and can survive water loss of up to 80%. To protect itself, it curls up as it dries to conserve moisture and produces mucus to help it stay moist.