Clam, Razor, clams

Ensis spp.

Method of production — Caught at sea
Capture method — Manual harvesting
Capture area — North East Atlantic (FAO 27)
Stock area — UK
Stock detail — All Areas
Picture of Clam, Razor, clams

Sustainability rating three info

Sustainability overview

Avoid eating clams harvested using illegal methods such as electrical fishing. Choose clams harvested in the wild by sustainable methods such as hand-gathering only. Avoid eating undersized animals (less than 10cm) and wild clams harvested during the spawning season (May - September).

Biology

Razor clams are bivalve molluscs. There are 6 species found in British intertidal waters. 2 are of commercial importance, namely Ensis siliqua and E arcuatus. E directus was introduced to European waters probably in 1978 through tanker ballast water. Spawning occurs in summer. Fertilised eggs develop into mobile larvae hours after fertilisation. The larval phase includes several stages and lasts for about 3-4 weeks, during which time they drift with the current. The larval phase ends when larvae settle, attaching themselves to sand or shell by byssal threads. At around 0.5cm length juveniles burrow into sand. Relative to other commercially important bivalves Ensis are long-lived, slow growing, and attain sexual maturity late in life. They may survive to 10-15 years and an average adult can reach a size of 12.5cm, although growth will cease by age 10. E.siliqua and E.arcuatus can live in excess of 20 years. Maturity is reached at sizes above 100mm. They are filter feeders and normally lie vertically in the sediment with 2 small siphons, through which they feed, visible on the surface. Razor clams burrow into the sediment around the extreme low water mark and in the shallow subtidal and are capable of rapid burrowing if disturbed.

Stock information

Stock Area

UK

Stock information

Widely distributed in intertidal waters throughout UK and temperate waters.

Management

Various bodies e.g. Natural England, Cefas, Sea Fishery Committees, Local Authorities etc. have responsibility for their protection or management in UK coastal waters.

Capture Information

Clams may be harvested by hand-gathering or manual digging or raking, or by mechanical methods e.g. suction or hydraulic dredge. Manual harvesting methods cause less disturbance to sediment than mechanical methods. Choose clams harvested in the wild by sustainable methods only (such as hand-gathering, raking and manual digging). Avoid wild clams harvested during the spawning season (May - September). Razor clams are often harvested as juveniles before they have reached maturity. Avoid eating undersized animals, always choose or collect razor clams above 10cm, the current EU Minimum Landing Size. A MLS of at least 130mm has been recommended to ensure Ensis are not harvested before reaching maturity.