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.
How to identify
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.
Distribution
Common on rocky shores all around our coasts.
Did you know?
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.
