BIOTIC Species Information for Ensis ensis
|Researched by||Jacqueline Hill||Data supplied by||MarLIN|
|Refereed by||This information is not refereed.|
|Scientific name||Ensis ensis||Common name||A razor shell|
|MCS Code||W1999||Recent Synonyms|
||Feeding method||Active suspension feeder
|Typical food types||Suspended organic detritus||Habit||Burrow dwelling|
|Bioturbator||Flexibility||None (< 10 degrees)|
|Height||Insufficient information||Growth Rate||2-4 cm/year|
|Adult dispersal potential||10-100m||Dependency||Independent|
|General Biology Additional Information||Typical abundance
Abundance of Ensis sp. varies from high to low density. In favourable conditions - such as the lee of rocks, rocks and islands for Ensis arcuatus on the western coast, individuals are found in high densities in 'beds' which interchange individuals with the surrounding areas where they occur in a more dispersed pattern (Fahy et al. in press).
Size ranges Size range given for Ensis ensis. Ensis siliqua males and females up to 20 cm and Ensis arcuatus males and females up to 15 cm.
|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||
|Substratum preferences||Fine clean sand
Coarse clean sand
|Physiographic preferences||Open coast
Strait / sound
Enclosed coast / Embayment
|Biological zone||Lower Eulittoral
|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.
In moderate wave exposure Ensis ensis may be replaced by the larger Ensis siliqua (Holme, 1954).
|Reproductive Season||Summer||Reproductive Location||Insufficient information|
|Reproductive frequency||Annual episodic||Regeneration potential||No|
|Life span||11-20 years||Age at reproductive maturity||3-5 years|
|Generation time||Insufficient information||Fecundity||Insufficient information|
|Egg/propagule size||Insufficient information||Fertilization type||Insufficient information|
|Reproduction Preferences Additional Information||Life span
The life span of Ensis ensis is likely to be in excess of 10 years. The other two British species Ensis siliqua and Ensis arcuatus are also very long-lived, with a life-span up to 18 years (E. Fahy pers. comm.).
Razor shells in Britain do not appear to breed before they are three years old (Henderson & Richardson, 1994). Breeding occurs during the summer but larval settlement is not successful every year, and recruitment of juveniles is irregular (Hayward et al., 1996). Breeding probably occurs during spring and the veliger larvae has a pelagic life of about a month (Fish & Fish, 1996). Studies on razor shells from North Wales showed that individuals of Ensis ensis were mature in July but were spent in August, indicating that spawning had occurred by the middle of the summer (Henderson & Richardson, 1994).