Ensis directus Conrad, 1843
American jack knife clam
Couteau de l'Atlantique
Ensis directus
photo by Harvey-Clark, Chris

Family:  Pharidae ()
Max. size:  26 cm TL (male/unsexed)
Environment:  benthic; brackish; marine; depth range 0 - 73 m
Distribution:  Western Atlantic Ocean: from Nova Scotia, Canada to Florida and southern Gulf of Mexico to Campeche, Mexico. Introduced in the Northeast Atlantic from UK (England and Wales), the North Sea to southern Norway and southern Baltic Sea to Spain in the southern Bay of Biscay. Tropical to temperate.
Diagnosis:   
Biology:  Comprise communities and assemblages throughout the Mid-Atlantic Bight (Ref. 80354). Inhabits littoral and sublittoral sediment (Ref. 1314). Found in areas influenced by estuarine outflows (Ref. 96507). Swims backward (Ref. 80328).
IUCN Red List Status: Not Evaluated (N.E.) Ref. 123251)
Threat to humans: 
Country info:  Introduction may be accidental via ballast waters or by larval dissemination from neighboring populations. Colonization likely to be related to its southwest expansion from the Scheldt estuary (Belgium and Netherlands). Also in Ref. 96507. O: Ref. 96507.

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