Biodiversity & Conservation

Carrageen - Chondrus crispus

Chondrus crispus

Image Nova Mieszkowska - The seaweed Chondrus crispus. Image width ca 15 cm.
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Distribution map

Chondrus crispus recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

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Chondrus crispus is not listed under any importance categories.

Taxonomy icon Taxonomy Taxon English term
Phylum Rhodophyta Red seaweeds
Class Florideophyceae
Authority Stackhouse
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland Widely distributed on rocky shores on all British and Irish coasts.
Habitat information icon Habitat information Abundant on rocks on the middle to lower rocky shore and in tide pools. It occurs sublittorally to 24 m. It can tolerate some reduction in salinity and can be found in estuaries.
Text page icon Description Chondrus crispus is a small purplish-red seaweed (up to 22 cm long) found on rocky shores and in pools. The fronds grow dichotomously from a narrow, unbranched stipe and are flat and wide with rounded tips. This seaweed is highly variable in appearance depending on the level of wave exposure of the shore and has a tendency to turn green in strong sunlight. Underwater, the tips of the frond can be iridescent.
Identifying features
  • Thallus with discoid holdfast and erect fronds arising in tufts.
  • Un-branched stipe gradually expanding into fan-like blade.
  • Fronds repeatedly dichotomous (up to 5 times) with rounded axils, usually expanding but occasionally tapering towards rounded apices.
  • Female fruiting bodies (carposporangia) occur terminally in cystocarps that protrude strongly as concave-convex swellings 2 mm in diameter.
  • Form highly variable depending on environment.
Additional information icon Additional information Also known as Irish moss. Together with Mastocarpus stellatus, Chondrus crispus is harvested commercially as carrageen to be used in the pharmaceutical and food industries. May be confused with Mastocarpus stellatus, although the latter species has a rounded stipe, channeled fronds and papillate reproductive bodies.

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This review can be cited as follows:

Will Rayment and Paolo Pizzola 2008. Chondrus crispus. Carrageen. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 03/09/2010]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=2971>