AquaNISInformation system on aquatic non-indigenous and cryptogenic species |
Species | Ensis leei [WoRMS] | |
Authority | M. Huber, 2015 | |
Family | Pharidae | |
Order | Adapedonta | |
Class | Bivalvia | |
Phylum | Mollusca | |
Synonym (?) | Ensis americanus (Gould, 1870) Ensis arcuatus var. directus Ensis directus (Conrad, 1843) Solen directus (Conrad, 1843) Solen ensis americana (Gould & Binney, 1870) References (not structured): Von Costel R, Gofas S (2011) Ensis directus (Conrad, 1843). Accessed through: World Register of Marine Species.http://www.marinespecies.org/aphia.php?p=taxdetails&id=140732 Accesed November 18 2011 Comments: Species can be found in BINPAS database as 'Ensis Americanus' |
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Sub-species level (?) | Not entered |
Native origin (?) | Country: USA --> LME: 6. Southeast U.S. Continental Shelf --> LME: 7. Northeast U.S. Continental Shelf References (not structured): Bousfield EL (1960) Canadian Atlantic Seashells. National Museum of Canada Ottawa, 72 pp. Gosnel K (1978) Atlantic seashore. New York: Harcourt, Brace and Company. Comments: NW Atlantic. Ensis directus lives in sandy bottoms in the intertidal or subtidal zones along the Atlantic coast from Labrador to South Carolina. It is usually found in colonies. E. directus is not migratory and remains in its habitat year round |
Life form / Life stage (?) |
References (not structured): Kindersley D, Molluca-Anatomy online. Accessed 10 November 2011 at http://www.chardikala.com/~gurtej/hmwk/bio/mollusca/. Amos G. Winter V, Robin LH Deits &Hosoi; AE, (2012). Localized fluidization burrowing mechanics of Ensis directus. J Exp Biol. 215:2072-2080. |
Sociability / Life stage (?) |
References (not structured): Amos G. Winter V, Robin LH Deits &Hosoi; AE, (2012). Localized fluidization burrowing mechanics of Ensis directus. J Exp Biol. 215:2072-2080. Comments: E. directus can be colonial in adult phase. |
Reproductive frequency (?) | Iteroparous References (not structured): Sullivan CM, (1948). Bivalve larvae of Malpeque Bay, P.E.I. Fish. Res. Bd. Canada, N°77 Kenchington E, Duggan R, Riddell T (1998) Early life history characteristics of tile razor clam (Etzsis directus) and the moonsnails (Euspiru spp.) with applications to fisheries and aquaculture. Can. Tech. Rep. Fish. Aquat. Sci. 2223: vii + 32 Comments: Most E. directus individuals will be sexually mature between the third and seventh growing season. Mating can occur between May and September and is associated with the water temperature. |
Reproductive type (?) | Sexual References: Sullivan CM, (1948). Bivalve larvae of Malpeque Bay, P.E.I. Fish. Res. Bd. Canada, N°77 http://creationwiki.org/Atlantic_jackknife_clam Ensis directus Atlantic jackknife clam(Also: Atlantic jackknife; common jackknife clam) Camponelli, K. 2001. "Ensis directus" (On-line), Animal Diversity Web. Accessed 19 November 2011. Comments: Ensis directus has separate males and females. The males release their sperm into the water and the sperm enters the females through openings. The eggs are fertilized in the interior of the gill and the newly fertilized zygotes develop into larvae, which are released in the water. There are two larval stages. The first stage is the trocophore stage that has small larvae that are free swimming. They are pear shaped, translucent and cilicated. The second stage is the veliger stage, which is also freeswimming. Ensis directus has a very long pelagic or plantonic stage, which means that the larvae can spread over greater distances. After the larval stage, the species settles onto the sand or mud and begins the development to adult stage. |
Developmental trait (?) | Planktotrophy Spawning References: Sullivan CM, (1948). Bivalve larvae of Malpeque Bay, P.E.I. Fish. Res. Bd. Canada, N°77 Comments: First larval stage: ciliated trocophore larvae Second larval stage: veliger larvae Adult: benthic |
Characteristic feeding method / Life stage (?) |
References (not structured): Ensis directus Atlantic jackknife clam(Also: Atlantic jackknife; common jackknife clam) Camponelli, K. 2001. "Ensis directus" (On-line), Animal Diversity Web. Accessed 19 November 2011. Comments: E. directus is a filter feeders that draws its food from the water around it. When feeding, E. directus will stay close to the surface and expose its siphons. Cilia covering the gills pull the food particles into the shell. As the food passes along the gills (ctenidia) they combine with mucous and become trapped. The cilia along the gills then move the food towards the digestive tract. E. directus mainly feeds upon small phyto- and zooplankton. |
Mobility / Life stage (?) |
References (not structured): Luczak C, Dewarumez JM, Essink K, (1993) First record record of the american jack knife clam Ensis derictus on the French coast of the North Sea. Mar. Biol. Assoc. 73, 233-235. Swennen C, Leopold MF, Stock M (1985) Notes on growth and behavior of the American razor clam Ensis directus in the Wadden Sea and the predation on it by birds.-Helgoländer Meeresunters. 39, 255-261 Leewis R (2002) Flora en fauna van de zee [Marine flora and fauna] Veldgids, 16. KNNV Uitgeverij: Utrecht, The Netherlands. ISBN 90-5011-153-X. 320pp Comments: The free-swimming larvae are distributed by currents in spring. Secondary dispersal of post-larval stages in summer. First larval stage: free swimming Second larval stage: free swimming The very long pelagic or planktonic larval stage, allow the larvae to spread over larger distances. Adult: E. directus are very rapid burrowers with short siphons and usually live near the surface but are able to disappear rapidly to great depths when disturbed. Remark: E. directus is also able to swim or use byssus threats for drifting. They show a diurnal rhythm, being more abundant in the water column at night. |
Salinity tolerance range (?) | Exact range: 7 - 32 References: Maurer D, Watling L, Aprill G, (1974). The distribution and ecology of common marine and estuarine pelecypods in the Delaware Bay Area. The Nautilus. 88(2): 38-46 |
Habitat modifying ability potential (?) | Allogenic ecosystem engineers Autogenic ecosystem engineers References: www.cabi.org (accessed June 2012) Comments: Ecosystem engineer Ecosystem engineer: The species is remarkable in both the speed in which new areas are colonized and its dominance in abundance over all other shellfish species, causing competition for food and space. If its population in an area becomes very large, it can affect the overall structure of the benthic community. The fact that these clams dig burrows for themselves can, in areas with dense populations, influence the character of the sediments and hence the habitats of other species. |
Toxicity / Life stage (?) | Unknown Comments: Not available. |
Bioaccumulation association (?) | Unknown Comments: Not available. |
Known human health impact? | Not known Comments: Not available. |
Known economic impact? | Not known Comments: Not available. |
Known measurable environmental impact? | Known References: Gollasch, S., Kerckhof, F., Craeymeersch, J., Goulletquer, P., Jensen, K., Jelmert, A., and Minchin, D., 2015. Alien Species Alert: Ensis directus. Current status of invasions by the marine bivalve Ensis directus. ICES Cooperative Research Report No. 323. 32 pp. https://doi.org/10.17895/ices.pub.5491 Witbaard, R., Duineveld, G.C.A., Bergman, M.J.N., Witte, H.I.J., Groot, L., and Rozemeijer, M.J.C., 2015. The growth and dynamics of Ensis directus in the near-shore Dutch coastal zone of the North Sea. J. Sea Res. 95, 95-105. https://doi.org/10.1016/j.seares.2014.09.008 Comments: Impacts on species and habitats, potentially also ecosystem functioning (Gollasch et al. 2015 and references within). |
Included in the Target Species list? | Yes Comments: Assessed by the COMPLETE project experts (2021), included in target species list. |
Association with vessel vectors (?) | Ballast waters Tank sediments References: Kerckhof F, Haelters J, Gollasch S, 2007. Alien species in the marine and brackish ecosystem: the situation in Belgian waters. Aquatic Invasions, 2(3):243-257. |
Last update by | Monika Pelėdienė, 2022-01-18 |