BIOTIC

BIOTIC Species Information for Ensis ensis
All Taxonomy Biology Distribution Reproduction

Researched by	Jacqueline Hill	Data supplied by	MarLIN
Refereed by	This information is not refereed.
Distribution and Habitat
Distribution in Britain & Ireland	Common on all British coasts.
Global distribution	From Norway to the Atlantic coast of Spain. Ensis ensis and Ensis siliqua found in some parts of the Mediterranean.
Biogeographic range	Not researched	Depth range	to a depth of 60m
Migratory	See additional information
Distribution Additional Information	Habitat Ensis spp. Occur virtually everywhere inshore but favourable conditions, such as the lee of reefs, rocks and islands make for high densities known as 'beds' which interchange individuals with the surrounding areas where they occur in a more dispersed pattern. Ensis ensis beds do occur at extreme low water of spring tides but the species is much more common in depths of about 10m (Holme, 1954). Single specimens have been collected from depths of 60m in the Plymouth area. Ensis arcuatus lives in coarser sediment than either Ensis ensis or Ensis siliqua. Migration Henderson & Richardson (1994) observed a distribution of razor clam size classes on a shore in north Wales which may indicate that there is a gradual down-shore migration of juveniles into the adult population. They suggest that juveniles become established further up the shore because the low water mark is exposed to the strongest tidal currents. Wave exposure In moderate wave exposure Ensis ensis may be replaced by the larger Ensis siliqua (Holme, 1954).

Substratum preferences	Fine clean sand Coarse clean sand	Physiographic preferences	Open coast Offshore seabed Strait / sound Enclosed coast / Embayment
Biological zone	Lower Eulittoral Sublittoral Fringe Upper Infralittoral Lower Infralittoral Upper Circalittoral Lower Circalittoral	Wave exposure	Sheltered Very Sheltered Extremely Sheltered Ultra Sheltered
Tidal stream strength/Water flow	Moderately Strong (1-3 kn) Weak (<1 kn)	Salinity	Full (30-40 psu)
Habitat Preferences Additional Information	Habitat Ensis spp. occur virtually everywhere inshore but favourable conditions, such as the lee of reefs, rocks and islands make for high densities known as 'beds' which interchange individuals with the surrounding areas where they occur in a more dispersed pattern. Ensis ensis beds do occur at extreme low water of spring tides but the species is much more common in depths of about 10 m (Holme, 1954). Single specimens have been collected from depths of 60 m in the Plymouth area. Ensis arcuatus lives in coarser sediment than either Ensis ensis or Ensis siliqua. Migration Henderson & Richardson (1994) observed a distribution of razor clam size classes on a shore in north Wales which may indicate that there is a gradual down-shore migration of juveniles into the adult population. They suggest that juveniles become established further up the shore because the low water mark is exposed to the strongest tidal currents. Wave exposure In moderate wave exposure Ensis ensis may be replaced by the larger Ensis siliqua (Holme, 1954).
Distribution References