Clam, Razor, clams

Ensis spp.

Method of production — Caught at sea
Capture method — Diver-caught
Capture area — North East Atlantic (FAO 27)
Stock area — Cornwall
Stock detail — 7e, 7f, 7g, 7h
Picture of Clam, Razor, clams

Sustainability rating four info

Sustainability overview

For more information about this rating please visit:

Cornwall Good Seafood Guide Cornwall Good Seafood Guide

Biology

Razor clams are bivalve molluscs. There are 6 species found in British intertidal waters. 2 are of commercial importance: Ensis siliqua and E arcuatus. Spawning occurs in summer, and 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. They then 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. They can live in excess of 20 years. E. arcuatus reaches sexual maturity between 73 and 130 mm and E. siliqua mature between 118 - 140 mm in Scotland. 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

Criterion score: 0.5 info

Management

Criterion score: 0.75 info

Capture Information

Criterion score: 0.25 info