Clam, Razor, clams

Ensis spp.

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

Sustainability rating five info

Sustainability overview

Illegal razors known as razor fish or spoots. There are two commercially important species found in Scottish waters Ensis arcuatus, (called bendies) and the larger pod razor Ensis siliqua. They are a very valuable shellfish stock and there is a revalent illegal market and it is believed that almost all razor clams have been caught by fishing with electricitya. The main market is for the live E. siliqua, exported to the Far East, predominantly China.

Electrofishing entails small boats trailing live electric cables, directing electric charge to stun the razor clams, causing them to emerge from the substrate, where a diver collects them. Electrofishing is more popular than other harvest methods because it is far more efficient than hand pulling and salting and yield a higher quality, more valuable product than dredging.

The main concerns relate to the illegality of the fishery, high and unreported exploitation rates and health and safety risks (causing deaths and serious injury and food safety violations). Electrofishing catches around 500-600kg of razor clams per day (compared with around 1-2kg a day by legal boats). The criminal fishery was believed to be making upwards of 65,000 pounds a day more lucrative than the illegal drugs trade! Current enforcement has been insufficient. To mitigate this, the Razor Clams Order was introduced in April 2017. Permits are granted and vessels can be physically inspected but equipment is illegally dumped, preventing convictions.

The stock status of razor clams in this area is unknown, trials to determine their population is underway. Electrofishing may lead to over-harvesting and depletion of razor clam beds, especially since they have slow growth rates and their populations take a long time to recover. It presents limited impacts to the habitat and is very selective but long-term impacts on the ecosystem are unknown.


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. 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: 1 info

Stock Area


Stock information

There are no assessments to determine the abundance and fishing mortality. The abundance and level of fishing on the stock is unknown. It is too early to tell if the abundance of razor clams is lower than historical levels (Fox, 2018), however, exploitation levels and illegal fishing rates have been high. Therefore, there is concern for biomass and fishing mortality and resilience is high.


Criterion score: 1 info

Despite efforts to reduce illegal fishing, there is insufficient enforcement in place to show that illegal fishing has reduced. Therefore, the fishery is red-rated.

There a few measures to protect the razor clam fishery; there are no catch limits. There is a minimum landing size (MLS) of 100 mm applied to the genus for all European stocks, but this is often lower than the size at which they mature.

Illegal fishing of razor clams has been widely reported in Scottish seas via electrofishing. There are an estimated 40 vessels fishing illegally in Scotland for razor clams.

In 2014, the Scottish Government introduced Razor Fish Licences and deployed Marine Protection Vessels into inshore areas to deter illegal activity. Enforcement was declared insufficient in 2017 because the fishery is so profitable, there are important data gaps and it is very difficult to convict fishers who illegally dumped fishing equipment when detecting patrol vessels.

Marine Scotland implemented the Razor Clams Order in April 2017. This prohibited fishing for and landing razor clams in Scottish waters, except i) for scientific investigation authorised by Scottish Ministers; and ii) for traditional hand gathering of razor clams from the shore (where taking 30 razor clams per day is permitted). Marine Scotland Compliance works with other authorities to target illegal fishers: there has been one manslaughter conviction, one 1 criminal investigation of tax fraud, 50 civil tax evasion investigations and 14 cases reported to prosecutor for fishing violations.

The expansion of enforcement activity has been proven to have some success: in 2016, when the Marine Protection Vessel Minaa monitoring razor clam fisheries, landings or razor clams fell significantly, resuming when the vessel departed.

Capture Information

Criterion score: 1 info

Electrical fishing for razor clams is illegal. Electrical fishing was banned in the EU in 1998 to prevent irresponsible and dangerous fishing practices (including: electrical fishing, explosives and poison). Electrical fishing works by using electrical currents to produce a response in the target species. The intense electrical field, emitted by electrodes towed slowly across the seabed, stimulate Ensis to temporarily leave their burrows. They are then collected most commonly by a diver following the fishing vessel, or alternatively by a dredge drawn across the surface of the seabed.

In a recent study (2014), electrofishing for razor clams was considered as a relatively benigna harvesting method compared to other conventional methods, such as dredging. The survey concluded that the electrofishing did not impact short-term (5 days) survival in razor clams, surf clams, starfish or hermit crab, however, the fishing method stunned sandeels (which recovered within 10 minutes) and may have increased the organismsa susceptibility to predation (particularly from shore crabs and squat lobsters Munida rugosa). Electrofishing-induced predation may be lower than that caused by mechanical dredge methods. However the study did not assess the long-term effects of electrofishing, the razor clam stock, nor consider appropriate harvesting levels of razor clams. A trail electro-fishery will allow these wider impacts to be studied but there is currently insufficient information to determine the true impact of electrofishing on the ecosystem.


Marine Scotland Compliance Team Pers. Comm. 2016

North Atlantic Fisheries Intelligence Group. 2017. Illegal trading Scottish Razor Clams. Available at:

Marine Scotland. The Razor clams (PROHIBITION ON FISHING AND LANDING) (SCOTLAND) ORDER 2017. 2017. SSI 2017/419. Available at:

Marine Scotland. 2017. Final Business and Regulatory Impact Assessment. Available at:

Fishing News. 2017. LECTROFISHING RAZOR CLAM TRIALS IN SCOTLAND. 10.04. 2017. Available at:

Seafood Source. 2015. Illegal razor clam fishers caught in the act. 21.09.2015. Available at:

Marine Scotland. 2017. Electrofishing for Razor Clams. Available at:

BBC. 2017. Illegal clam fishermen 'track' fishery protection vessels. 18.04.2017. Available at:

Appleby, T. and Harrison, J. (2017) Brexit and the future of Scottish fisheries key legal issues in a changing regulatory landscape. Journal of Water Law, 25 (3). pp. 124-132. ISSN 1478-5277 Available from:

Fox, C. 2017. To Develop the Methodology to Undertake Stock Assessments on Razor Fish Using Combinations of Video Monitoring and Electrofishing Gear. Fishing Industry Science Alliance (FISA) Project 09/15. Scottish Marine and Freshwater Science 8, 6. Marine Scotland Science, Aberdeen.

Murray F, Copland P, Boulcott P, Rovertson M, Bailey N. 2014. Electrofishing for razor clams (Ensis siliqua and E. arquatus): Effects on survival and recovery of target and non-target species. Scottish Marine and Freshwater Science 14, Marine Scotland Science, Aberdeen, 50 pp.

Fox, C. 2018. Report on Razor Clam Surveys in the Sound of Harris and the Ayrshire Coast of the Clyde (Girvan to North Bay) Scottish Marine and Freshwater Science Vol 9 No 3.

Constantino, R., Gaspar, M. B., Pereira, F., Carvalho, S., Cardia, J., Matias, D. and Monteiro, C. C. (2009), Environmental impact of razor clam harvesting using salt in Ria Formosa lagoon (Southern Portugal) and subsequent recovery of associated benthic communities. Aquatic Conserv: Mar. Freshw. Ecosyst., 19: 542-553. doi:10.1002/aqc.995 .