Egg wrack

Egg wrack

Egg wrack ©Nigel Phillips

Egg wrack

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Scientific name: Ascophyllum nodosum
This yellow-brown seaweed grows in dense masses on the mid shore of sheltered rocky shores. It is identifiable by the egg-shaped air bladders that give it its name.

Top facts


Length: up to 2m

Conservation status


When to see

January to December


Egg wrack is a common wrack seaweed which grows on sheltered rocky shores, around the mid shore zone. It has long, leathery strap-like fronds with egg-shaped air bladders along the lengths. Egg wrack is a long-lived species, with individuals growing slowly for decades. They do not cope well on exposed shores (those with strong wave action), but they flourish on very sheltered shores to the extent of dominating these environments. The dense masses of Egg wrack provide shelter for many species on rocky shores - lift the fronds out of the way and see what is hiding underneath (but make sure you put them back again afterwards!).

What to look for

Egg wrack has long, yellow-brown, strap-like fronds with air bladders protruding at regular intervals along their length.

Where to find

Common on sheltered rocky shores all around our coasts.

Did you know?

Egg wrack, also known as Knotted Wrack, often bears tufts of a small, reddish epiphytic (plants that live on other plants) algae, Polysiphonia lanosa. This filamentous 'Red Seaweed' forms pom-pom-like structures on the Egg wrack.