BIOTIC

BIOTIC Species Information for Littorina littorea
All Taxonomy Biology Distribution Reproduction

Researched by	Angus Jackson	Data supplied by	MarLIN
Refereed by	Dr David Reid
Distribution and Habitat
Distribution in Britain & Ireland	Found on all British coasts, though rare or absent in the Isles of Scilly and Channel Isles.
Global distribution	Distributed from northern Spain to the White Sea (northern Russia).
Biogeographic range	Not researched	Depth range	60 m
Migratory	Seasonal (environment)
Distribution Additional Information	The species is found most commonly on the lower shore and shallow subtidal but in ideal conditions may be found up to the high tide line. However, the lower limit is poorly defined and will depend on factors such as predation, latitude etc. Therefore, the species may be found in the infra- and circalittoral zones. However, in deeper water the species is only found as isolated individuals in very low densities. At least in northern Britain Littorina littorea migrates down shore as temperatures fall in autumn (to reduce exposure to sub-zero temperatures) and up shore as temperatures rise in spring; migration depends on local winter temperatures. When exposed to the air, the species usually remains inactive unless conditions are very moist.

Substratum preferences	Bedrock Large to very large boulders Small boulders Cobbles Pebbles Gravel / shingle Muddy gravel Sandy mud Muddy sand Mud Salt marsh	Physiographic preferences	Open coast Estuary
Biological zone	Upper Eulittoral Mid Eulittoral Lower Eulittoral Sublittoral Fringe	Wave exposure	Moderately Exposed Sheltered Very Sheltered Extremely Sheltered Ultra Sheltered
Tidal stream strength/Water flow	Strong (3-6 kn) Moderately Strong (1-3 kn) Weak (<1 kn) Very Weak (negligible)	Salinity	Variable (18-40 psu) Reduced (18-30 psu) Full (30-40 psu)
Habitat Preferences Additional Information
Distribution References	Hayward et al., 1996, Campbell, 1994, Hayward & Ryland, 1995b, Graham, 1971, Fish & Fish, 1996, Newell, 1958, Fish, 1972, Fretter & Graham, 1994, Rutherford, Web pages, Gendron, 1977, Gardner & Thomas, 1987,