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First record of Anadara transversa (Say, 1822) (Bivalvia: Arcidae) in the Bay of Biscay

Authors:
Irene Fernández-Rodríguez at University of Oviedo
Irene Fernández-Rodríguez
Rafael Bañón at Grupo de Estudo do Medio Mariño (GEMM)
Rafael Bañón
  • Grupo de Estudo do Medio Mariño (GEMM)
Nuria Anadon at University of Oviedo
Nuria Anadon
Andrés Arias at University of Oviedo
Andrés Arias
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The occurrence of the alien species Anadara transversa is reported for the first time in the Bay of Biscay, from two estuaries of northern Spain (Villaviciosa and Eo), constituting its northernmost distribution in E. Atlantic to date. We present a detailed diagnosis and illustrations of the species in order to facilitate its differentiation from other native ark clams and the introduced A. kagoshimensis. Furthermore, the potential pathways for its introduction in the area are discussed.
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The transverse ark clam Anadara transversa (Say, 1822)
has a well-documented area of distribution in southern
Europe and the Mediterranean Sea (Fig. 1). The species
was first recorded out of this native area in the
Mediterranean in 1972, from the Bay of Izmir (Turkey), as
Arca amygdalum (Demir, 1977). Two decades later, the
species was reported for the first time in Europe from the
Aegean Sea (Greece) (Zenetos, 1994). In the 2000s the
species reached the Italian shores, establishing populations
across the Adriatic Sea, including both Italian (Morello &
Solustri, 2001; Morello et al., 2004; Mizzan &Vianello,
2007; Crocetta, 2011) and Croatian parts (Nerlović et al.,
2012). Shortly thereafter A. transversa continued its
expansion westwards, being reported from the Gulf of
Naples and the Ionia Sea (Crocetta et al., 2009), Sardinia
(Lodola et al., 2011), Tunisia (Antit et al., 2011) and the
Catalan coasts of the Iberian Peninsula (López-Soriano,
2011). More recently, A. transversa was reported in Ría de
Vigo (Galicia, Atlantic Iberian Peninsula) linked to farming
Ostrea edulis Linnaeus, 1758 in floating structures (Pérez,
2003).
Reçu le 16 décembre 2015 ; accepté après révision le 1 février 2016.
Received 16 December 2015; accepted in revised form 1 February 2016.
Cah. Biol. Mar. (2016) 57 : 277-280
First record of Anadara transversa (Say, 1822)
(Bivalvia: Arcidae) in the Bay of Biscay
Irene FERNÁNDEZ-RODRÍGUEZ1, Rafael BAÑÓN2, Nuria ANADÓN1and Andrés ARIAS1
(1) Departamento de Biología de Organismos y Sistemas (Zoología), Universidad de Oviedo, Oviedo 33071, Spain
Corresponding author: andresarias.rguez@gmail.com
(2) Grupo de Estudos do Medio Mariño (GEMM), Ribeira 15960, Spain
Abstract: The occurrence of the alien species Anadara transversa is reported for the first time in the Bay of Biscay, from
two estuaries of northern Spain (Villaviciosa and Eo), constituting its northernmost distribution in E. Atlantic to date. We
present a detailed diagnosis and illustrations of the species in order to facilitate its differentiation from other native ark
clams and the introduced A. kagoshimensis. Furthermore, the potential pathways for its introduction in the area are
discussed.
Résumé: Premier signalement de Anadara transversa (Say, 1822) (Bivalvia: Arcidae) dans le golfe de Gascogne. La
découverte de l’espèce introduite Anadara transversa est signalée pour la première fois dans le Golfe de Gascogne. Elle
représente la limite nord de leur distribution dans l’Atlantique est jusqu’à présent. Nous présentons des caractères
diagnostiques et des illustrations de cette espèce pour faciliter sa différentiation avec les espèces indigènes d’arcidés et
l’espèce introduite A. kagoshimensis. Enfin, nous présentons une brève discussion sur le possible mode d’introduction dans
cette région.
Keywords: Anadara spp. lArk clam lNon-indigenous species lExotic species lCantabrian Sea lIberian Peninsula
278 ANADARA TRANSVERSA IN THE BAY OF BISCAY
Here we present the first record of A. transversa in the
Bay of Biscay, constituting the northernmost distribution
for this species in the Atlantic European waters.
Furthermore, we give brief notes on the taxonomy and
distribution of the species, and briefly discuss the potential
pathways for introduction to the area.
During a series of surveys carried out along the coast of
Asturias (central Cantabrian Sea) during 2011-2014, seven
live specimens of A. transversa were found intertidally at
two different estuaries of the region. Five specimens were
collected in Villaviciosa estuary (43º31’16.71’’N-
05º23’48.72’’W), two on 22 May 2011, two on 4 April
2013 and one on 18 May 2014 (Fig. 1). Furthermore, two
specimens were found in Eo estuary (43º32’07.11’’N-
07º01’24.02’’W) on 26 August 2013 (Fig. 1). In both cases
the specimens were found as epibiont on Pacific oyster
Crassostrea gigas (Thunberg, 1793) reefs, in the intertidal
zone. Once in the laboratory, all specimens were measured
(total length and width) and its radial ribs were counted in
the left valve.
The main diagnostic features of A. transversa (Fig. 2A)
are as follows: inequivalve, inequilateral, subrectangular in
outline (longer than higher) shell; left valve ostensibly
larger than right valve (left valve overlaps right one). Shell
length of about 30 mm. Slightly protruding umbo at
anterior third of shell length, sometimes with a slight
depression. Sculpture consisting of 29-35 radial ribs with
wide interstices at each valve. Taxodont hinge in straight
line, narrower in middle and becoming wider at edges. Ribs
slightly wrinkled. Velvety, brown periostracum formed by
appressed lamellae with erect bristles, covering most of
valve surface. Internal margins with crenulations
corresponding with external radial ribs. Outside of shell
whitish under greenish brown periostracum; inner side
white. Live animals light yellow to salmon colored.
Alcohol preserved animals have turned whitish. Anadara
demiri (Piani, 1981) is considered a junior synonym of A.
transversa (Albano et al., 2009).
Collected specimens of Anadara transversa ranged from
28.46 to 34.85 mm in length, with a mean of 32.25 (N = 6;
SD = 2.42) and from 18.96 to 25.60 in height, with a mean
of 21.85 (N = 6; SD = 2.51). Their shell sculpture consisted
of 32–35 radial ribs (X = 32.83; SD = 1.06). All collected
individuals presented perforated shells, caused by the
spionid polychaetes of the genus Polydora Bosc, 1802.
Anadara transversa (Fig. 2A) can be easily
distinguished from the native Arca tetragona Poli, 1795
(Fig. 2C) and Striarca lactea (Linnaeus, 1758) (Fig. 2D) for
its more rectangular shape, major size, absence of keel
(present in A. tetragona) and in that its left valve is larger
Figure 1. Anadara transversa. Distribution map of occurrence
in Europe and the Mediterranean Sea. Squares: present study
localities; circles: localities from bibliography data. Date of first
species record for each locality is included.
Figure 2. Anadara transversa. Comparison with other ark
clams that occur in the Bay of Biscay. A. Anadara transversa. B.
Anadara kagoshimensis. C. Arca tetragona. D. Striarca lactea.
Right: external view of right valve; left: dorsal view.
I. FERNÁNDEZ-RODRÍGUEZ, R. BAÑÓN, N. ANADÓN, A. ARIAS 279
than right valve, overlapping this one (Fig 2A). On the other
hand, A. transversa differs from the also exotic A.
kagoshimensis (Tokunaga, 1906) (Fig. 2B) by its not inflated
shape, lesser size, ribs without conspicuous and regular
nodules (present in A. kagoshimensis), umbones more closer
to the anterior part and although its left valve is larger for
both, it is far more readily apparent in A. transversa
(Fig. 2A).
The native distribution area of A. transversa ranges from
the NW Atlantic coasts of Canada to the Gulf of Mexico,
including the Caribbean Sea (Rosenberg, 2015). It lives in
both rocky hard and muddy/sandy-muddy substrates
(Nerlović et al., 2012; Zenetos et al., 2004). Anadara
transversa stands successfully in polluted habitats and
degraded ecosystems (Zenetos, 1994; Crocetta et al., 2009).
The introduction pathway of A. transversa to the
Mediterranean remains unclear, but some authors agree that
it can be linked to shipping, through fouling and ballast water
and by means of aquaculture (Lodola et al., 2011; Zenetos et
al., 2004). In this case, the arrival of A. transversa in northern
Spain may be explained by the unintentional co-transport of
their larvae and/or juveniles into commercial bivalve
cultures, mainly clams and oysters from the Mediterranean
Sea. The two estuaries with presence of this alien species are
locations of intensive mariculture with high traffic of exotic
aquaculture species (Arias & Anadón 2012 & 2013). The
same hypothesis has also been suggested to the introduction
of Anadara kagoshimensis in Spanish and French Atlantic
areas (Cigarria & Valdés, 1996; Nolf, 2010; Bañón et al.,
2015).
Anadara transversa has been included in the list of the
100 worst invasive species in the Mediterranean Sea
(Streftaris & Zenetos, 2006). This species is considered an
ecosystem engineer species, since it may generate habitat
modification through bioturbation and bioconstruction
processes (Smith et al., 2014). Furthermore, high population
densities of the species may also affect both benthic and
pelagic habitats due to the increase on sediment erosion and
resuspension rates (Smith et al., 2014). Anadara transversa
certainly has the potential to become invasive. Its preference
for living as epibiont on oysters may turn this species into a
plague on oyster cultures and aquaculture facilities,
competing with oysters for food. Further research is needed
in order to ascertain how widespread is this species within
the Cantabrian Sea, as well as the implementation of
monitoring studies to evaluate the dynamics and viability of
A. transversa population in both Cantabrian estuaries.
Acknowledgements
We thank the anonymous reviewers for their careful reviews
and helpful remarks. This is a contribution from the Marine
Observatory of Asturias (OMA).
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280 ANADARA TRANSVERSA IN THE BAY OF BISCAY
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  • Jul 2014
Smith C, Papadopoulou N, Sevastou K, Franco A, Teixeira H, Piroddi C, Katsanevakis S, Fürhaupter K, Beauchard O, Cochrane S, Ramsvatn S, Feral J-­‐P, Chenuil A, David R, Kiriakopoulou N, Zaiko A, Moncheva S, Stefanova K, Churilova T, Kryvenko O (2014) Report on identification of keystone species and processes across regional seas. Deliverable 6.1, DEVOTES Project. 105 pp + 1 Annex. In managing for marine biodiversity, it is worth recognising that, whilst every species contributes to biodiversity, each contribution is not of equal importance. Some have important effects and interactions, both primary and secondary, on other components in the community and therefore by their presence or absence directly affect the biodiversity of the community as a whole. Keystone species have been defined as species that have a disproportionate effect on their environment relative to their abundance. As such, keystone species might be of particular relevance for the marine biodiversity characterisation within the assessment of Good Environmental Status (GEnS), for the Marine Strategy Framework Directive (MSFD). The DEVOTES Keystone Catalogue and associated deliverable document is a review of potential keystone species of the different European marine habitats. The catalogue has 844 individual entries, which includes 210 distinct species and 19 groups classified by major habitat in the Baltic Sea, North East Atlantic, Mediterranean, Black Sea (EU Regional Seas) and Norwegian Sea (Non-­‐EU Sea). The catalogue and the report make use/cite 164 and 204 sources respectively. The keystones in the catalogue are indicated by models, by use as indicators, by published work (e.g. on traits and interactions with other species), and by expert opinion based on understanding of systems and roles of species/groups. A total of 74 species were considered to act as keystone predators, 79 as keystone engineers, 66 as keystone habitat forming species, while a few were thought of having multiple roles in their marine ecosystems. Benthic invertebrates accounted for 50% of the reported keystone species/groups, while macroalgae contributed 17% and fish 12%. Angiosperms were consistently put forward as keystone habitat forming and engineering species in all areas. A significant number of keystones were invasive alien species. Only one keystone, the bivalve Mya arenaria, was common to all four EU regional seas. The Mediterranean Sea had the largest number of potential keystones (56% of the entries) with the least in the Norwegian Sea. There were very few keystones in deep waters (Bathyal-­‐Abyssal, 200+ m), with most reported in sublittoral shallow and shelf seabeds or for pelagic species in marine waters with few in reduced/variable salinity waters. The gaps in coverage and expertise in the catalogue are analysed at the habitat and sea level, within the MSFD biodiversity component groups and in light of knowledge and outputs from ecosystem models (Ecopath with Ecosim). The understanding of keystones is discussed as to when a species may be a dominant or keystone with respect to the definition term concerning ‘disproportionate abundance’, how important are the ‘disproportionate effects’ in relation to habitat formers and engineers, what separates a key predator and key prey for mid-­‐trophic range species and how context dependency makes a species a keystone. Keystone alien invasive species are reviewed and the use of keystone species model outputs investigated. In the penultimate sections of the review the current level of protection on keystone species and the possibilities for a keystone operational metric and their use in management and in GEnS assessments for the MSFD are discussed. The final section highlights the one keystone species and its interactions not covered in the catalogue but with the greatest impact on almost all marine ecosystems, Homo sapiens.
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First record of Anadara transversa (Mollusca: Bivalvia: Arcidae) in Croatian waters (Adriatic Sea)
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  • Jun 2012
Six specimens of the alien bivalve Anadara transversa (Say, 1822) were found on the muddy bottom at a depth of 4.4 m in the innermost part of Lim Bay in June 2011; this species is being newly reported from the Croatian part of the Adriatic Sea.
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First Record of Mercenaria mercenaria (Bivalvia: Veneridae) and Ensis directus (Bivalvia: Pharidae) on Bay of Biscay, Iberian Peninsula
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  • Feb 2012
We present the first record of two nonnative Bivalvia species originally from North America, Mercenaria mercenaria and Ensis directus, in the waters of the Iberian Peninsula (southwest of the Bay of Biscay). This constitutes the southernmost distribution for these species in the northeast Atlantic to date. We provide notes on the relative abundance, depth range, and substrate preferences of the species in their new habitat. The bivalve E. directus has became the dominant Ensis species along the Cantabric sandy shores it has colonized.
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