Anadara kagoshimensis -

Anadara kagoshimensis is originally found in the western Pacific Ocean and the Indian Ocean, specifically around Korea, China, Japan, northern Australia, India, Sri Lanka, and Indonesia ^[2,3].

First observation in Belgium

Anadara kagoshimensis has not yet been observed in Belgium.

Distribution in Belgium

Anadara kagoshimensis has not yet been observed in Belgium.

Distribution in neighbouring countries

In 1969, this clam was first reported in the Adriatic Sea near Ravenna (though under a different name), and colonised the Venice Lagoon in the 1970s ^[4]. Large populations are now found in numerous locations throughout the Mediterranean region. Following its initial introduction, Anadara kagoshimensis spread through the Sea of Marmara, the Black Sea, and the Sea of Azov ^[3,5-7]. Closer to home, the species was found in 1993-1994 in northwest Spain (Eo estuary) ^[8] and in 2003 near Morbihan in Brittany (France) ^[4].

In the Netherlands, a first fresh specimen was found in June 2021, in the Eastern Scheldt near the Bergse Diepsluis ^[9]. Large numbers of empty shells and fresh valves have since been found there. Additionally, reports have been made of specimens with flesh remains near Scheveningen, both on the beach and between the blocks of harbor piers. Although no live specimens have been found to date, the large numbers and freshness of the found material suggest an established population ^[2].

The species was presumably introduced to the Mediterranean Sea via shipping (as planktonic larvae in ballast water) ^[5,10]. Secondary spread in the Mediterranean region is linked to the natural dispersal of planktonic larvae on sea currents or commercial fishing ^[5]. The occurrence in northwest Spain is attributed to aquaculture, where Anadara kagoshimensis was likely introduced accidentally along with the Manila clam Ruditapes philippinarum via the translocation of shellfish larvae from the Adriatic Sea ^[5], where these species were already widespread ^[11].

Anadara kagoshimensis inhabits waters with a salinity between 14 and 35 psu, but this mollusk has the potential to survive for some time at very low (8 psu) to very high (45 psu) salinities ^[12]. The species also tolerates a broad temperature range, from 3°C (winter) to 28°C (summer), although in its natural distribution area, it has been shown that the shell exhibits signs of physiological stress at such high summer temperatures (i.e., after the spawning period), impacting survival rates and resulting in high summer mortality ^[13].

The species usually lives buried in soft sediment (silt-clay) in the sublittoral zone but also thrives on sandy bottoms. Since they can also attach themselves to hard substrates with byssus threads, they are also found on rocky substrates. They are encountered in both brackish water systems and marine environments, down to about 40 meters depth ^[14-17].

The occurrence of a planktonic larval stage enables the species, once established in a new region, to spread further naturally by drifting on prevailing sea currents ^[5].

Anadara kagoshimensis is listed among the hundred worst invasive species in the Mediterranean region, where it has displaced several native bivalves from their habitats ^[18,19]. For example, densities of up to 120 specimens per square meter have been recorded in the Adriatic Sea, while in the Black Sea, densities have locally reached up to 476 adult specimens or 3,000 juvenile specimens per square meter ^[20-22].

This species has two main competitive advantages over many other mollusks. The presence of hemoglobin in its tissues allows Anadara kagoshimensis to survive for extended periods under hypoxic conditions, unlike other mollusks ^[23]. Additionally, it can attach to all types of hard substrates using byssus threads ^[20], enabling it to behave as both an epifaunal and infaunal species ^[5]. As a result, the species also poses a potential threat to commercial shellfish farming ^[5].

Anadara kagoshimensis is a bivalve that grows up to 50 mm, although specimens up to 95 mm have been reported. The shells are creamy white, yellowish, or light brown on the outside, while the inside is often shiny white. The periostracum is dark brown, fibrous, and wears off quickly, especially in the middle and at the top. The shell is thick, with the left valve slightly larger than the right. The shell has 30 to 35 transverse ribs. They have a taxodont hinge with 55 or more teeth in a continuous row, with the central teeth being the narrowest ^[2].

In East Asia, Anadara kagoshimensis is an important food source ^[24].

[1]          World Register of Marine Species (WoRMS) (2024). Anadara kagoshimensis (Tokunaga, 1906). https://www.marinespecies.org/aphia.php?p=taxdetails&id=504360 (2024-10-18). 

[2]          (2022). Special: Exoten van zoet en brak water. Zoekbeeld: nieuwsbrief van Stichting Anemoon, 12(1B). Stichting Anemoon: Bennebroek. 41 pp. [https://www.vliz.be/en/imis?module=ref&refid=393782] 

[3]          Strafella, P.; Ferrari, A.; Fabi, G.; Salvalaggio, V.; Punzo, E.; Cuicchi, C.; Santelli, A.; Cariani, A.; Tinti, F.; Tassetti, A.N.; Scarcella, G. (2017). Anadara kagoshimensis (Mollusca: Bivalvia: Arcidae) in Adriatic Sea: morphological analysis, molecular taxonomy, spatial distribution, and prediction. Mediterr. Mar. Sci. 18(3): 443-453. [https://www.vliz.be/en/imis?module=ref&refid=393778] 

[4]          Nolf, F. (2010). Anadara inaequivalvis (Bruguière, 1789) (Mollusca: Bivalvia: Arcidae) a new invasive species in the eastern Atlantic waters of W France. Neptunea 9(2): 7, pl. I-VI [https://www.vliz.be/nl/imis?module=ref&refid=200200] 

[5]          Bañón, R.; Fernández, J.; Trigo, J.E.; Pérez Dieste, J.; Barros-García, D.; de Carlos, A. (2015). Range expansion, biometric features and molecular identification of the exotic ark shell Anadara kagoshimensis from Galician waters, NW Spain. J. Mar. Biol. Ass. U.K. 95(3): 545-550. [https://www.vliz.be/en/imis?module=ref&refid=393777] 

[6]          Zaitsev, Y.; Öztürk, B. (2001). Exotic species in the Aegean, Marmara, Black, Azov and Caspian Seas. Turkish Marine Research Foundation: Istanbul. ISBN 975-97132-2-5 . 259 pp. [https://www.vliz.be/nl/imis?module=ref&refid=303166] 

[7]          Sánchez, P.; Sartor, P.; Recasens, L.; Ligas, A.; Martin, J.; De Ranieri, S.; Demestre, M. (2007). Trawl catch composition during different fishing intensity periods in two Mediterranean demersal fishing grounds. Sci. Mar. (Barc.) 71(4): 765-773. [https://www.vliz.be/nl/imis?module=ref&refid=119864] 

[8]          Cigarria, J.; Valdés, A. (1996). Anadara inaequivalvis (Bruguière, 1789) in the North Atlantic. J. Conch., Lond. 35(4): 378-379. [https://www.vliz.be/en/imis?module=ref&refid=393776] 

[9]          Rijken, R.; Mulder, G.; de Bruyne, R. (2022). Aziatische exoot met tanden. Nature Today 7 april: online. [https://www.vliz.be/en/imis?module=ref&refid=393659] 

[10]        Crocetta, F. (2012). Marine alien Mollusca in Italy: a critical review and state of the knowledge. J. Mar. Biol. Ass. U.K. 92(6): 1357-1365. [https://www.vliz.be/nl/imis?module=ref&refid=234289]

[11]        Crocetta, F.; Macali, A.; Furfaro, G.; Cooke, S.; Villani, G.; Valdés, Á. (2013). Alien molluscan species established along the Italian shores: an update, with discussions on some Mediterranean “alien species” categories. ZooKeys 277(277): 91-108. [https://www.vliz.be/nl/imis?module=ref&refid=287736] 

[12]        Kukhareva, T.A.; Rychkova, V.N.; Soldatov, A.A.; Andreeva, A.Y.; Kladchenko, E.S. (2023). Adaptation of Anadara kagoshimensis (Tokunaga, 1906) to hypo- and hyperosmotic environment: hemocyte response. Russ. J. Biol. Invasions 14(4): 581-587. [https://www.vliz.be/en/imis?module=ref&refid=393763] 

[13]        Kang, H.Y.; Seong, J.; Kim, C.; Lee, B.-G.; Lee, I.T.; Kang, C.-K. (2022). Seasonal energetic physiology in the ark shell Anadara kagoshimensis in response to rising temperature. Front. Mar. Sci. 9: 981504. [https://www.vliz.be/en/imis?module=ref&refid=393758] 

[14]        Crocetta, F. (2011). Marine alien Mollusca in the Gulf of Trieste and neighbouring areas: a critical review and state of knowledge (updated in 2011). Acta Adriat. 52(2): 247-260. [https://www.vliz.be/nl/imis?module=ref&refid=288245] 

[15]        Zenetos, A.; Gofas, S.; Russo, G.; Templado, J. (2003). CIESM atlas of exotic species in the Mediterranean: 3. Molluscs. CIESM Publishers: Monaco. ISBN 92-990003-3-6. 376 pp. [https://www.vliz.be/nl/imis?module=ref&refid=59205] 

[16]        Rinaldi, E. (1985). Rapana venosa (Valenciennes) spiaggiata in notevole quantità sulla spiaggia di Rimini (Fo). Boll. Malacologico 21(10-12): 318. [https://www.vliz.be/en/imis?module=ref&refid=393757] 

[17]        Despalatovic, M.; Cvitkovic, I.; Scarcella, G.; Isajlovic, I. (2013). Spreading of invasive bivalves Anadara kagoshimensis and Anadara transversa in the northern and central Adriatic Sea. Acta Adriat. 54(2): 221-228. [https://www.vliz.be/en/imis?module=ref&refid=393756]  

[18]        Streftaris, N.; Zenetos, A. (2006). Alien marine species in the Mediterranean - the 100 ‘worst invasives’ and their impact. Mediterr. Mar. Sci. 7(1): 87-118. [https://www.vliz.be/nl/imis?module=ref&refid=208858] 

[19]        Kolyuchkina, G.A.; Miljutin, D.M. (2013). Application of the morpho-functional analysis of hydrobionts (Anadara sp. cf. Anadara inaequivalvis Bivalvia) to environmental monitoring. Oceanology 53(2): 169-175. [https://www.vliz.be/en/imis?module=ref&refid=393748] 

[20]        Ghisotti, F.; Rinaldi, E. (1976). Osservazioni sulla popolazione di Scapharca, insediatasi in questi ultimi anni su un tratto del litorale romagnolo. Conchiglie 12(9-10): 183-195. [https://www.vliz.be/nl/imis?module=ref&refid=255173] 

[21]        Micu, D.; Micu, S. (2004). A new type of macrozoobenthic community from the rocky bottoms of the Black Sea, in: Ozturk, B. et al. International Workshop on Black Sea Benthos, April 2004, Istanbul - Turkey . pp. 70-83. [https://www.vliz.be/en/imis?module=ref&refid=393746]  

[22]        Chikina, M.V.; Kucheruk, N.V. (2004). Contemporary dynamics of coastal benthic communities of the north Caucasian coast of the Black Sea, in: Ozturk, B. et al. International Workshop on Black Sea Benthos, 19-23 April 2004, Istanbul - Turkey . pp. 155-160. [https://www.vliz.be/en/imis?module=ref&refid=393697] 

[23]        Shiganova, T. (2008). Introduced species, in: Kostianoy, A.G. et al. The Black Sea environment. The Handbook of Environmental Chemistry, 5.Q: pp. 375-406. [https://www.vliz.be/en/imis?module=ref&refid=394257]  

[24]        Tanaka, T.; Aranishi, F. (2014). Genetic variability and population structure of ark shell in Japan. Open Journal of Marine Science 04(01): 8-17. [https://www.vliz.be/en/imis?module=ref&refid=393691]

VLIZ Alien Species Consortium (2024). Anadara kagoshimensis. Introduced alien species of the Belgian part of the North Sea and adjacent estuaries anno 2024. Flanders Marine Institute (VLIZ). 5 pp.