BIOTIC Species Information for Chondrus crispus
Researched byWill Rayment and Paolo Pizzola Data supplied byMarLIN
Refereed byDr Stefan Kraan
Scientific nameChondrus crispus Common nameCarrageen
MCS CodeZM345 Recent SynonymsNone

PhylumRhodophycota Subphylum
Superclass ClassRhodophyceae
SubclassFlorideophycidae OrderGigartinales
Suborder FamilyGigartinaceae
GenusChondrus Speciescrispus

Additional InformationAlso 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.
Taxonomy References Fish & Fish, 1996, Dickinson, 1963, Dixon & Irvine, 1977,
General Biology
Growth formTurf
Feeding methodPhotoautotroph
Mobility/MovementPermanent attachment
Environmental positionEpilithic
Typical food typesNot relevant HabitAttached
BioturbatorNot relevant FlexibilityHigh (>45 degrees)
FragilityRobust SizeMedium-large(21-50cm)
Height Growth Rate0.33 mm/day
Adult dispersal potentialNone DependencyIndependent
General Biology Additional InformationSize at maturity
Surprisingly little information was found concerning size at maturity. Pybus (1977) estimated that Chondrus crispus from Galway Bay, Ireland, reached maturity approximately 2 years after the initiation of the basal disc, at which stage, the fronds were approximately 12 cm in length.

Growth rates of Chondrus crispus vary widely according to environmental conditions. Pybus (1977) reported mean growth for Chondrus crispus from Galway Bay of 0.33 mm/day, with little seasonal variation in growth rate. A similar rate of 0.37 mm/day was reported for plants from Maine, USA (Prince & Kingsbury, 1973). Sporelings grew at 0.02-0.08 mm/day in culture, and growth rate was governed principally by temperature (Tasende & Fraga, 1999). Peak growth occurred from May to November in eastern Canada (Juanes & McLachlan, 1992; Chopin et al., 1999). Optimum growth of Chondrus crispus in culture occurred at 10-15°C (Fortes & Lüning, 1980), 15-17°C (Tasende & Fraga, 1999) and 20°C (Simpson & Shacklock, 1979). Kuebler & Dudgeon (1996) reported higher growth rates at 20°C vs. 5°C, in terms of length, biomass, surface area, dichotomy and branch production, for Chondrus crispus from the Gulf of Maine, USA. North Sea plants grown in culture were growth saturated at light intensities of 70 µE/m²/s and growth rate increased up to a 24 hour photoperiod (Fortes & Lüning, 1980). For cultured spores of Chondrus crispus from NW Spain, growth rate increased with salinity between 23 and 33 psu, declined above light intensities of 20 µmol/m²/s and below photoperiods of 16:8 (light: dark) (Tasende & Fraga, 1999).

Supports which species
Chondrus crispus from Galway Bay, Ireland, was a host for algal epiphytes including Ceramium nodulosum, Melobesia membranaceum, Lomentaria articulata, Membranoptera alata, Palmaria palmata, and faunal epiphytes including Alcyonidium hirsutum, Dynamena pumila, Electra pilosa, Grantia compressa, Helcion pellucidum and Spirorbis borealis (Pybus, 1977). Leathesia difformis grew epiphytically on Chondrus crispus in Nova Scotia, Canada (Chapman & Goudey, 1983). In substratum choice experiments in the laboratory in New Hampshire, USA, the bryozoan Alcyonidium polyoum preferentially settled on Chondrus crispus and Fucus distichus, rather than other algae (Hurlbut, 1991). The epiphytes, Ulva sp. (studied as Enteromorpha) and Ectocarpus sp. grew epiphytically on Chondrus crispus in culture, and were in turn grazed by the crustaceans Gammarus lawrencianus and Idotea baltica (Shacklock & Doyle, 1983). Idotea baltica readily consumed Chondrus crispus when no other food was available, whereas Gammarus lawrencianus did not.
Chondrus crispus can sometimes be epiphytic on kelps (S. Kraan, pers. comm.).

Biology References Dickinson, 1963, Dixon & Irvine, 1977, Pybus, 1977, Prince & Kingsbury, 1973, Tasende & Fraga, 1999, Juanes & McLachlan, 1992, Chopin et al., 1999, Fortes & Lüning, 1980, Simpson & Shacklock, 1979, Kuebler & Dudgeon, 1996, Hurlbut, 1991, Shacklock & Doyle, 1983, Chapman & Goudey, 1983, Aguirre-von-Wobeser et al., 2000, Bird et al., 1979,
Distribution and Habitat
Distribution in Britain & IrelandWidely distributed on rocky shores on all British and Irish coasts.
Global distributionSee additional information.
Biogeographic rangeNot researched Depth rangemid eulittoral, exceptionally to 24 m
MigratoryNon-migratory / Resident   
Distribution Additional InformationIn Galway Bay, Ireland, Chondrus crispus occurs in relatively stable conditions. The annual variation in sea surface temperature was 10-16°C and in salinity was 32-35 psu (Pybus, 1977). However, the species is capable of existing in much more variable environments. In New Hampshire, USA, Chondrus crispus formed its most extensive populations on the open coast on massive outcrops and boulders in the shallow subtidal (3 to 5 metres deep) (Mathieson & Burns, 1975). The annual variation in sea surface temperatures was -1 to 19°C. The species also occurred in an estuarine tidal rapid experiencing currents up to 5.5 knots and salinity fluctuations from 16-32 psu (Mathieson & Burns, 1975).

Global distribution
Occurs in Iceland, the Faroes, the western Baltic Sea, from northern Russia to southern Spain, the Mediterranean, Portugal, the Azores and West Africa. In north America it occurs in Alaska and from Labrador in Canada to New Jersey in the USA. Also occurs in the Bering Sea (East Asia).

Substratum preferencesBedrock
Large to very large boulders
Small boulders
Physiographic preferencesOpen coast
Strait / sound
Enclosed coast / Embayment
Biological zoneMid Eulittoral
Lower Eulittoral
Sublittoral Fringe
Upper Circalittoral
Upper Infralittoral
Lower Infralittoral
Wave exposureExposed
Moderately Exposed
Tidal stream strength/Water flowStrong (3-6 kn)
Moderately Strong (1-3 kn)
Weak (<1 kn)
Very Weak (negligible)
SalinityFull (30-40 psu)
Variable (18-40 psu)
Habitat Preferences Additional Information
Distribution References Fish & Fish, 1996, Dickinson, 1963, Hiscock, 1986b, Dixon & Irvine, 1977, Pybus, 1977, Mathieson & Burns, 1975, Hardy & Guiry, 2003, Mann, 1972, Guiry & Nic Dhonncha, 2002,
Reproduction/Life History
Reproductive typeAlternation of generations
Developmental mechanismSpores (sexual / asexual)
Reproductive SeasonInsufficient information Reproductive LocationAs adult
Reproductive frequencyAnnual protracted Regeneration potential No
Life span6-10 years Age at reproductive maturity1-2 years
Generation time1-2 years FecunditySee additional information
Egg/propagule sizeInsufficient information Fertilization typeInsufficient information
Larval/Juvenile dispersal potentialInsufficient information Larval settlement period
Duration of larval stageNot relevant   
Reproduction Preferences Additional InformationLife span
The fronds of Chondrus crispus typically have a life of 2-3 years (Taylor, cited in Pringle & Mathieson, 1986) but may live up to 6 years in sheltered waters (Harvey & McLachlan, 1973). The holdfast is much longer lived (Taylor, cited in Pringle & Mathieson, 1986) and is capable of regenerating new fronds after disturbance (Mathieson & Burns, 1975; Dudgeon & Johnson, 1992).
Fernandez & Menendez (1991) reported that reproductive capacity was similar for both gametophytes and tetrasporophytes in northern Spain, the estimated number of spores being 8 x 1010/m²/year. The greater number of fertile gametophytes was counterbalanced by the high numbers of tetrasporangial sori and tetraspores.
Timing of reproduction
Dickinson (1963) reported that Chondrus crispus was fertile in the UK from autumn to spring, but that the exact timings varied according to local environment. Similarly, Pybus (1977) reported that although carposporic plants were present throughout the year in Galway Bay, Ireland, maximum reproduction occurred in the winter and estimated that settling of spores occurred between January and May. In northern Spain, Chondrus crispus had reproductive capacity all year round but was greatest for gametophytes between November and March and for tetrasporophytes in April (Fernandez & Menendez, 1991). In Nova Scotia, Canada, cystocarps and tetrasporangia have been recorded on Chondrus crispus all year round with a reproductive peak from August to October (Scrosati et al., 1994). However, spores failed to germinate below 5°C and so winter temperatures in Nova Scotia are unsuitable for spore germination. It was suggested therefore that simple counts of spore production do not adequately model reproductive potential (Scrosati et al., 1994). Scrosati et al. (1994) also commented that viability of spores was low (<30%) and suggested that reproduction by spores probably does not contribute much to maintenance of the intertidal population of Chondrus crispus in Nova Scotia, compared to vegetative growth of gametophytes.
Reproduction References Dickinson, 1963, Dixon & Irvine, 1977, Pybus, 1977, Prince & Kingsbury, 1973, Tasende & Fraga, 1999, Juanes & McLachlan, 1992, Chopin et al., 1999, Fortes & Lüning, 1980, Simpson & Shacklock, 1979, Kuebler & Dudgeon, 1996, Mathieson & Burns, 1975, Dudgeon & Johnson, 1992, Pringle & Mathieson, 1986, Harvey & McLachlan, 1973, Fernandez & Menendez, 1991, Scrosati et al., 1994,
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