Oceanologia (2019) 61, 341—349 Available online at www.sciencedirect.com ScienceDirect j ournal homepage: www.journals.elsevier.com/oceanologia/ ORIGINAL RESEARCH ARTICLE Limited success of the non-indigenous bivalve clam Rangia cuneata in the Lithuanian coastal waters of the Baltic Sea and the Curonian Lagoon a,b, a a Sabina Solovjova *, Aurelija Samuilovienė , Greta Srėbalienė , a,c a Dan Minchin , Sergej Olenin a Marine Research Institute, Klaipėda University, Klaipėda, Lithuania b Department of Environmental Research, Environmental Protection Agency, Klaipėda, Lithuania c Marine Organism Investigations, Ballina, Killaloe, Ireland Received 29 January 2018; accepted 29 January 2019 Available online 13 February 2019 KEYWORDS Summary The gulf wedge clam, common rangia Rangia cuneata, with a native origin in the Gulf of Mexico has spread to north European brackish and freshwaters. This semitropical species is able to Semitropical bivalve; survive in conditions of low winter temperatures in boreal environment of the Baltic Sea. Its expansion Coastal lagoon; within lagoons and sheltered bays in the southern and eastern parts of the Baltic Sea appears to be Exposed coast; with natural spread and its discontinuous distribution is likely to have been with shipping, either Winter conditions; within ballast water or as settled stages transported with dredged material. In this account, we report Ballast water; on the occurrence of R. cuneata in Lithuanian waters. We compare habitats of the common rangia in Natural spread. the Curonian Lagoon and in the exposed coastal waters of the Baltic Sea. We notice high mortality of the species in the Lithuanian waters in comparison to the neighboring Vistula Lagoon. Based on finding of small specimens of R. cuneata attached to the spiked watermilfoil Myriophyllum spicatum, we indicate a risk of local spread with movements of fishing equipment and snagged plants on anchors or boat trailers removed from the water. We discuss the possibility of further spread of the common rangia to similar environments in the Baltic Sea and elsewhere in Europe. © 2019 Institute of Oceanology of the Polish Academy of Sciences. Production and hosting by Elsevier Sp. z o.o. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/). * Corresponding author at: Marine Research Institute, Klaipėda University, Universiteto ave. 17, 92294, Klaipėda, Lithuania. E-mail address: [email protected] (S. Solovjova). Peer review under the responsibility of Institute of Oceanology of the Polish Academy of Sciences. https://doi.org/10.1016/j.oceano.2019.01.005 0078-3234/© 2019 Institute of Oceanology of the Polish Academy of Sciences. Production and hosting by Elsevier Sp. z o.o. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 342 S. Solovjova et al./Oceanologia 61 (2019) 341—349 The Curonian Lagoon is exposed to irregular inflows of 1. Introduction marine water, causing abrupt changes in salinity within the Klaipėda Strait and extending up to 40 km within the lagoon, The common rangia Rangia cuneata (G.B. Sowerby I, 1832) where otherwise the average annual salinity is 2.5 (Dailidienė (Bivalvia, Mactridae), has a native origin within the Gulf of and Davulienė, 2008). Due to the shallow depths, the lagoon Mexico and extended its range northwards to the Chesapeake rapidly heats up in spring and remains warmer during the Bay by the 1960s and arrived to the lower reaches of the summer than the surface water of the open sea (Gasiūnaitė Hudson River (Carlton, 1992). It is spreading within north et al., 2008). The lagoon has no seasonal thermocline and in European brackish waters (AquaNIS, 2018; Verween et al., winter there is ice-cover (Table 1) which in recent years 2006; and references therein). It was first found, and well occurs for fewer days on account of warmer winter condi- established, in Belgium during 2005 (Verween et al., 2006) tions. Whereas the Klaipėda Strait is always ice-free. Loca- and has since spread to estuaries in southern regions of the lized anoxia events may take place during ice coverage and North Sea (Bock et al., 2015; Gittenberger et al., 2015; overnight during summer (Gasiūnaitė et al., 2008). The main Kerckhof et al., 2018; Neckheim, 2013; Wiese et al., 2016) sediments within the Lagoon are sand and silt where there and has been found in freshwater in Britain (Willing, 2015). are shell deposits. In the port area of the Klaipėda Strait It entered the south-eastern Baltic Sea about 2010, in the bottom sediments are influenced by constant dredging and waterway leading to the port of Kaliningrad, Vistula Lagoon water flow from being at the lagoon entrance. When com- region in Russia (Ezhova, 2012; Rudinskaya and Gusev, 2012). pared with the exposed coast, the lagoon is more eutrophic In 2011 it was recorded in the Polish part of the Vistula by having seasonal phytoplankton blooms and high accumu- Lagoon (Janas et al., 2014; Warzocha and Drgas, 2013; lations of organic carbon in bottom sediments (Remeikaitė- Warzocha et al., 2016). It was in 2013 when it was recorded Nikienė et al., 2016). at an early stage along Lithuanian coastal waters (Solovjova, 2014), and further to the north in Pärnu Bay, Gulf of Riga, fi Estonia (Möller and Kotta, 2017). In 2015 it appeared on the 2.2. Morphological identi cation German Baltic coast (Wiese et al., 2016) and in a Swedish Baltic fjord in 2016 (Florin, 2017). In this account, we R. cuneata can be confused with the Baltic clam Limecola < present data on the first record and spread of R . cuneata balthica (Linnaeus, 1758) especially for specimens 10 mm in Lithuanian waters. We compare habitats of the common shell length (Fig. 1). These two species can be distinguished fi rangia in the Curonian Lagoon and in the exposed coastal based on the identi cation descriptions of the common waters of the Baltic Sea, and discuss the possibility of its rangia (Abbott and Morris, 2001; Janas et al., 2014; Leal, further spread to similar environments in the Baltic Sea and 2000; Verween et al., 2006): (a) a thicker and more convex elsewhere in Europe. shell; (b) the prominent and anteriorly curved umbo; (c) internal ligament of the left shell with chondrophore, typi- cally with two fused cardinal teeth forming an 'inverted V'. 2. Material and methods 2.1. Study area 2.3. Molecular identification The Baltic Sea area along the exposed coast of the Curonian For molecular identification DNA was extracted from a speci- Spit is mesohaline, with a stable salinity (Table 1). From June men, which was clearly identified by morphological features to September where the epilimnion extends down to 20— as R. cuneata (shell length 27 mm) using InnuPREP DNA Mini 30 m (Olenin and Daunys, 2004). In winter, ice usually occurs Kit (Analytik Jena AG, Germany) according to manufacturer's along this shoreline, but does not extend offshore where instructions. The identification was performed using a spe- wedge clam rangia is found. Coastal currents in the south- cies-specific molecular marker developed by Ardura et al. eastern Baltic are usually from south to north and on account (2015) for R. cuneata. For amplification of a 205 bp long of its exposure the seabed is well oxygenated (Olenin and fragment of the 16S rRNA gene the R. cuneata-specific for- 0 Daunys, 2004) and is densely packed with fine sand at all ward primer RC-16Sar: 5 -AATTTCTTCTAATGATGTGAGG-3 0 stations with the exception of an admixture of mud near the (Ardura et al., 2015) and universal revers primer 16Sbr: 5 - 0 Curonian Lagoon outlet. CCGGTCTGAACTCAGATCACGT-3 (Palumbi, 1996) were used. Table 1 Environmental parameters at stations with living and vacant Rangia cuneata in 2013—2018. Parameter Exposed coast Curonian Lagoon Depth range [m] 13—17 0.3—11.2 Salinity [PSU] 6.40—7.48 0.18—7.27 Temperature [8C] 1.05—20.35 0.52—21.76 Duration of ice cover, days per year None 30—64 À1 Dissolved oxygen [mg L ] 4.44—13.28 4.70—14.64 Oxygen saturation [%] 40—119 48—126 Salinity, temperature, dissolved oxygen, and oxygen saturation are indicated for the near bottom layer. (Lithuanian Environmental Protection Agency (LEPA) monitoring data.) S. Solovjova et al./Oceanologia 61 (2019) 341—349 343 Figure 1 A view of small (<10 mm) shells of Rangia cuneata (two above rows) and Limecola balthica (row below) under dissecting microscope (Photo: S. Solovjova). Amplification was carried out in six replicates of R. cuneata 10—15 cm at the coastal stations and to ca. 10—20 cm within using InnuTaq DNA polymerase (Analytik Jenna AG, Germany) the Lagoon. Three to five samples were taken at each station, in 20 ml reactions containing 2 ml of DNA, 2.5 mM MgCl2, each separately sieved using a 0.5 mm mesh size. Retained À1 250 mM of each dNTP, 1.25 mg ml BSA and 0.7 pmol of each material was fixed in a 4% formaldehyde solution and later primer. The PCR protocol consisted of a denaturation at 958C examined using a stereomicroscope at 7.8Â to 120Â, accord- for 3 min followed by 35 cycles at 958C for 30 s, 548C for 30 s, ing to the procedure of HELCOM (2014). In total, approxi- 728C for 45 s followed by a final extension at 728C for 5 min mately 230 Van Veen grab samples were taken in the and a 48C hold. PCR products were visualized on a 1.5% Lithuanian part of the Baltic Sea and 140 in the Curonian agarose gel stained by SybrSafe. To exclude the possibility Lagoon were the common rangia was expected to occur.