Atlantic jackknife clam

Taxobox
name = Atlantic jackknife clam

---

image_caption = Empty shell of "Ensis directus"
regnum = Animalia
phylum = Mollusca
classis = Bivalvia
ordo = Veneroida
familia = Solenidae
genus = "Ensis"
species = "E. directus"
binomial = "Ensis directus"
binomial_authority = Conrad, 1843

The Atlantic jackknife , "Ensis directus", also known as the American jackknife clam or razor clam (but note that "razor clam" sometimes refers to different species), is a large species of edible marine bivalve mollusc, found on the North American Atlantic coast, from Canada to South Carolina as well as in Europe.

This clam lives in sand and mud and is found in intertidal or subtidal zones in bays and estuaries. Because of its streamlined shell and strong foot, it can burrow in wet sand very quickly, and is also able to swim.

At low tide the position of the Atlantic jackknife clam is revealed by a keyhole-shaped opening in the sand; when the clam is disturbed, a small jet of water squirts from this opening as the clam starts to dig. This species' remarkable speed in digging can easily outstrip a human digger, making the clam difficult to catch. Thus the species is not often commercially fished, even though it is widely regarded as delicious.

Predators of "Ensis directus" other than humans include birds, such as the ring-billed gull ("Larus delawarensis") in North America and the Eurasian oystercatcher ("Haematopus ostralegus") in Europe, and the nemertean worm "Cerebratulus lacteus" [http://links.jstor.org/sici?sici=0009-3262(197612)17%3A4%3C299%3APOTRCE%3E2.0.CO%3B2-5] .

The Atlantic jackknife clam is now also found in northwestern Europe, where it is regarded as a harmful exotic species. It was first recorded in Europe in 1978/79, in the Elbe estuary.

References

* The Long Island Shell Club, 1988. "The Seashells of Long Island", the Long Island Shell Club Inc, New York State

External links

* Kenchington, E., R. Duggan and T. Riddell. 1998. [Early life history characteristics of the razor clam ("Ensis directus") and the moonsnails ("Euspiru" spp.) with applications to fisheries and aquaculture. Can. Tech. Rep. Fish. Aquat. Sci. 2223: vii + 32 p. [http://www.dfo-mpo.gc.ca/Library/226108.pdf]
* Camponelli, K. 2001. "Ensis directus" (On-line), Animal Diversity Web. Accessed August 27, 2006 [http://animaldiversity.ummz.umich.edu/site/accounts/information/Ensis_directus.html] .
* [http://www.gollaschconsulting.de/download/Ensis_p1.pdf Gollasch Consulting. Exotics Across the Ocean - EU Concerted Action. "Ensis directus"]