BIOTIC Species Information for Fucus spiralis
Researched byNicola White Data supplied byMarLIN
Refereed byDr Graham Scott
Scientific nameFucus spiralis Common nameSpiral wrack
MCS CodeZR383 Recent SynonymsNone

PhylumChromophycota Subphylum
Superclass ClassPhaeophyceae
Subclass OrderFucales
Suborder FamilyFucaceae
GenusFucus Speciesspiralis

Additional InformationA number of discrete forms of this species have been recorded. In the UK, a diminutive form Fucus spiralis nanus is relatively common.
Taxonomy References Howson & Picton, 1997, Fish & Fish, 1996, Anderson & Scott, 1998, Scott et al., 2000,
General Biology
Growth formFoliose
Feeding methodPhotoautotroph
Mobility/MovementPermanent attachment
Environmental positionEpifloral
Typical food typesNot relevant HabitAttached
BioturbatorNot relevant FlexibilityHigh (>45 degrees)
FragilityIntermediate SizeMedium-large(21-50cm)
HeightUp to 40 cm Growth Rate1.1 cm / month
Adult dispersal potentialNone DependencyIndependent
General Biology Additional InformationFucus spiralis spends up to 90 percent of the time out of the water. It can tolerate a high level of desiccation, being able to survive 70 to 80 percent water loss. Distinct varieties of Fucus spiralis have been recognised, such as Fucus spiralis forma nanus, which is a dwarf form present on exposed shores. Fucus spiralis also hybridises with Fucus vesiculosus providing considerable difficulty in identification.
Biology References Niemeck & Mathieson, 1976, Fish & Fish, 1996, Scott et al., 2000,
Distribution and Habitat
Distribution in Britain & IrelandAll coasts of Britain and Ireland
Global distributionIceland, Norway, Denmark, Netherlands, UK, Ireland, Atlantic coast of France, Spain, Morocco, Azores, East coast of America from New Jersey to Nova Scotia and isolated reports in the Northern Pacific.
Biogeographic rangeNot researched Depth rangeLower littoral fringe
MigratoryNon-migratory / Resident   
Distribution Additional InformationFucus spiralis favours rocks with many cracks and fissures, which probably provide some protection for developing zygotes and adult plants. It can extend into estuaries up to the 10 psu isohaline. The presence or absence of suitable substrata is considered to be one of the most important factors determining the distribution of Fucus spiralis.

Substratum preferencesBedrock
Large to very large boulders
Small boulders
Physiographic preferencesStrait / sound
Ria / Voe
Biological zoneLower Littoral Fringe
Wave exposureModerately Exposed
Very Sheltered
Tidal stream strength/Water flowStrong (3-6 kn)
Moderately Strong (1-3 kn)
Weak (<1 kn)
Very Weak (negligible)
SalinityReduced (18-30 psu)
Variable (18-40 psu)
Full (30-40 psu)
Habitat Preferences Additional Information
Distribution References Niemeck & Mathieson, 1976, JNCC, 1999, Norton, 1985, Hardy & Guiry, 2003,
Reproduction/Life History
Reproductive typeVegetative
Permanent hermaphrodite
Developmental mechanismInsufficient information
Reproductive SeasonJuly to August Reproductive Location
Reproductive frequencyAnnual episodic Regeneration potential No
Life span3-5 years Age at reproductive maturity1-2 years
Generation time3-5 years FecundityInsufficient information
Egg/propagule sizeInsufficient information Fertilization typeInsufficient information
Larval/Juvenile dispersal potentialInsufficient information Larval settlement periodInsufficient information
Duration of larval stageInsufficient information   
Reproduction Preferences Additional InformationFucus spiralis is hermaphroditic. Receptacles are initiated during late January to February, gametes discharged during July and August, and the receptacles shed by November, although exact timing of reproduction depends on location and the form of the plant. Young plants usually reach a length of 8 to 10 cm or more before they form receptacles. Reproduction usually begins before or during the second years growth. Vegetative recruitment occurs by the formation of new fronds from existing holdfasts. This form of reproduction is important in existing stands of the population, whereas recruitment by eggs is more important in disturbed areas or in areas where germlings are protected e.g. rock crevices.
Reproduction References Niemeck & Mathieson, 1976, Robertson, 1985, Scott et al., 2000, Vernet & Harper, 1980,
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