BIOTIC Species Information for Chorda filum
Researched byNicola White Data supplied byMarLIN
Refereed byDr Stefan Kraan
Distribution and Habitat
Distribution in Britain & IrelandAll coasts of Britain and Ireland, but rarer in south east England.
Global distributionSee additional information.
Biogeographic rangeNot researched Depth rangeRock pools down to 5m.
MigratoryNon-migratory / Resident   
Distribution Additional InformationGlobal distribution
Canada (Arctic), Alaska, NW Atlantic from Labrador to New Jersey, Greenland, Iceland, Spitsbergen, Norway, Sweden, Denmark, The Netherlands, Belgium, the Baltic, the Faroes, France, Spain, Portugal, Canary Islands, Greece, China, Japan and south Kurile Islands, NE Pacific and the Bering Strait.

Chorda filum occurs in sheltered bays, estuaries, lagoons and sea lochs. It is rarely found on the open coast and is completely absent from exposed shores. The plants occur in clumps on a range of unstable, small objects such as pebbles and shells. It may also be found on sand and detritus but it will not remain for long on this substratum (S. Kraan, pers. comm.). They are also epiphytic on %Zostera marina% and %Fucus vesiculosus%. During stormy weather, plants may be washed to more sheltered locations where they continue development. Chorda filum has considerable tolerance to reduced salinities and extends into river mouths and the Baltic, where it grows at 3.5 psu. However, plants that grow in fully marine conditions cannot withstand immersion in freshwater for 2 hours (Russell, 1985).

Substratum preferencesMuddy gravel
Gravel / shingle
Physiographic preferencesStrait / sound
Ria / Voe
Isolated saline water (Lagoon)
Enclosed coast / Embayment
Biological zoneLower Infralittoral
Upper Infralittoral
Sublittoral Fringe
Wave exposureSheltered
Very Sheltered
Tidal stream strength/Water flowModerately Strong (1-3 kn)
Weak (<1 kn)
SalinityLow (<18 psu)
Reduced (18-30 psu)
Full (30-40 psu)
Variable (18-40 psu)
Habitat Preferences Additional Information
Distribution References South & Burrows, 1967, Russell, 1985, Norton & South, 1969, Hardy & Guiry, 2003,
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