Anadara transversa

Invasion History

First Non-native North American Tidal Record:
First Non-native West Coast Tidal Record:
First Non-native East/Gulf Coast Tidal Record:

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General Invasion History:

Anadara transversa is native to the Northwest Atlantic, from Cape Cod to Texas. It is found on shallow, sandy bottoms, in polyhaline to euhaline waters (Wass 1972; Morris 1975; Gosner 1978; Miller 2000).

North American Invasion History:

Invasion History on the West Coast:

Dead and worn shells of A. transversa were found on Atlantic oyster beds in San Francisco Bay in 1918 (Packard 1918, cited by Carlton 1979), and again at Coyote Point and Palo Alto Harbor in the bay in 1967 (Wicksten 1976, cited by Carlton 1979). Live animals or dead shells of this bivalve were probably introduced with oysters planted in San Francisco Bay, from Long Island Sound, in the late 1800s (Carlton 1979; Miller 2000). There is no evidence that a breeding population existed in San Francisco Bay.

Invasion History Elsewhere in the World:

Anadara transversa was found in Izmir Bay, Turkey, in the Aegean Sea, in 1972 and given the name A. demiri. It was assumed to be an introduction from the Red Sea, by way of the Suez Canal (Cinar et al. 2005; Albano et al. 2009). It was later recognized as the Northwest Atlantic species A. transversa (Albano et al. 2009), and spread into Greek waters by 2007 (Zenetos 2009). In the Adriatic Sea, A. transversa was first found in 2000 on the coast of Italy and was abundant by 2003 (Morello et al. 2004). It now occurs along most of the Italian Adriatic Coast, from Lecce to the Gulf of Venice (Albano et al. 2009). A specimen has been tentatively identified from the Gulf of Tunis (Antit et al. 2011). This bivalve may have been introduced to the Mediterranean from the East or Gulf Coasts of the US in ballast water or hull fouling (Albano et al. 2009).

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Description

Anadara transversa is a marine bivalve with a thick, strongly ribbed shell. The hinge line bears numerous teeth, arranged in a line on both valves. Both valves have prominent beaks which are set close to the anterior end and curved inward. The shell is heart-shaped in a side view. The shell is somewhat oblong, with straight shoulders below the beak. Both shells have about 12 radiating ribs. The shell is white, but it is covered with a brown periostracum. This bivalve does not have a siphon. This shell typically reaches 25 mm. Ark shells occasionally attach to rocks and shells with byssus threads. (Description from: Morris 1975; Gosner 1978).

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Taxonomy

Ecology

General:

Anadara transversa , commonly known as the Transverse Ark, is a suspension-feeding bivalve found in sandy and muddy subtidal bottoms, in polyhaline-euhaline salinities (Wass 1972; Morris 1975; Gosner 1978). Arks occasionally attach to rocks and shells with byssus threads. This bivalve has planktonic veliger larvae (Chanely and Andrews 1971; Miller 2000).

Food:

Phytoplankton

Trophic Status:

Suspension Feeder

SusFed

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Habitats

General Habitat	Unstructured Bottom	None
General Habitat	Oyster Reef	None
Salinity Range	Polyhaline	18-30 PSU
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Vertical Habitat	Endobenthic	None
Vertical Habitat	Epibenthic	None

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Tolerances and Life History Parameters

Maximum Depth (m)	25	None
Minimum Salinity (‰)	10	Experimental, gradual transfer (Castagna and Chanley 1973)
Minimum Length (mm)	25	Morris 1975; Gosner 1978;
Broad Temperature Range	None	Cold temperate-Warm temperate
Broad Salinity Range	None	Polyhaline-Euhaline

General Impacts

Anadara transversa is not established in North America and has had no known impacts there. However, the abundance of A. transversa has increased rapidly in the Adriatic Sea. By 2004, it was a numerical dominant at some locations.

Ecological impacts-In the Adriatic Sea, the rapid increase and numerical dominance of A. transversa is suggestive of competition. The attachment of juvenile A. transversa to snails and bivalves may restrict their movement and habitat use (Morello et al. 2004).

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References

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https://doi.org/10.3390/ su151411384

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Albano, Paolo G.; Rinaldi, Emidio; Evangelisti, Francesca; Kuan, Michela; Sabelli, Bruno (2009) On the identity and origin of Anadara demiri(Bivalvia: Arcidae), Journal of the Marine Biological Association of the United Kingdom 89(6): 1289-1298

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Miller, Alexander Whitman (2000) <missing title>, University of California at Los Angeles, Los Angeles. Pp. <missing location>

Morello, Elisabetta B.; Solustri, Cristiano ; Froglia, Carlo (2004) The alien bivalve Anadara demiri (Arcidae): a new invader of the Adriatic Sea, Italy, Journal of the Marine Biological Association of the United Kingdom 84: 1057-1064

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Wass, Melvin L. (1972) A checklist of the biota of lower Chesapeake Bay, Special Scientific Report, Virginia Institute of Marine Science 65: 1-290

Zenetos, A.; Koutsoubas, D.; Vardala-Theodorou, E. (2005) Origin and vectors of introduction of exotic mollusks in Greek waters., Belgian Journal of Zoology 135(2): 279-286

Zenetos, Argyro and 6 authors (2009) Aquatic alien species in Greece (2009): tracking sources, patterns and effects on the ecosystem, Journal of Biological Research-Thessaloniki 12: 135-172

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