First record of oriental shrimp, Palaemon macrodactylus Rathbun, 1902 in Varna Lake, Bulgaria V. St Raykov, M. Lepage, R. Perez Dominguez To cite this version: V. St Raykov, M. Lepage, R. Perez Dominguez. First record of oriental shrimp, Palaemon macro- dactylus Rathbun, 1902 in Varna Lake, Bulgaria. Aquatic Invasions, 2010, 5 (Suppl 1), pp.S91-S95. 10.3391/ai.2010.5.S1.019. hal-01550575 HAL Id: hal-01550575 https://hal.archives-ouvertes.fr/hal-01550575 Submitted on 29 Jun 2017 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Aquatic Invasions (2010) Volume 5, Supplement 1: S91-S95 doi: 10.3391/ai.2010.5.S1.019 Open Access © 2010 The Author(s). Journal compilation © 2010 REABIC Aquatic Invasions Records First record of oriental shrimp, Palaemon macrodactylus Rathbun, 1902 in Varna Lake, Bulgaria Violin St.Raykov1*, Mario Lepage2 and Rafael Pérez-Domínguez3 1Institute of Oceanology, “Parvi May” Str. 40, P.O. Box 152, Varna 9000, Bulgaria 2Cemagref, 50 avenue de Verdun Gazinet, 33612 Cestas Cedex, Bordeaux, France 3Institute of Estuarine & Coastal Studies (IECS), University of Hull, Hull, HU6 7RX, United Kingdom E-mail: [email protected] (VSR), [email protected] (ML), [email protected] (RPD) Received: 13 April 2010 / Accepted: 14 August 2010 / Published online: 20 August 2010 Abstract In September 2009 a non-native shrimp species was found at two sampling sites in Varna Lake, a brackish coastal water body connected to the Bulgarian Black Sea. Diagnosis based on morphological features confirmed that the examined individuals belonged to the species Palaemon macrodactylus Rathbun, 1902. All specimens found were ovigerous, 2+ year females suggesting the presence of a viable population in the system. Possible ways of introduction and community effects for Varna Lake are discussed. Key words: Palaemon macrodactylus, Varna Lake, Bulgaria, non-native Introduction In the present paper we report the first sightings of P. macrodactylus in Bulgarian Palaemon macrodactylus (Rathbun, 1902) origi- waters. nates from the temperate north-western Pacific: Japan, Korea and China (Holthuis 1980). The Materials and methods species was originally described by Rathbun (1902) and Kubo (1942). P. macrodactylus has Varna Lake (43°11΄25˝N, 27°49΄30˝E – been recorded outside of its native range in the 43°12΄28˝N, 27°53΄00˝E) is the largest by waters of USA (Newman 1963; Jensen 1995), in volume and is the deepest liman along the Black Australia (Davie 2002; Poore 2004; Walker and Sea coast, separated from the sea by a 2km-wide Poore 2003) and Argentina (Spivak et al. 2006). strip of sand. It has an area of 17km², a volume In Europe large populations of P. macrodactylus of 166 million m³ and a maximum depth of 19 m have been recorded in some estuaries on the (Figure 1). Varna Lake is permanently connected southwestern Iberian Peninsula (Cuesta et al. to the Black Sea by two man-made canals. 2004; Chicharo et al. 2009). In 2006, P. macro- Vertical distribution of oxygen and hydrogen dactylus was also reported in the Gironde sulphide (H S), along with temperature, seasonal Estuary, France (Beguer et al. 2007). Ashelby et 2 stratification and the presence of pollutants al. (2004) found P. macrodactylus in the Orwell and Stour estuaries in south-eastern England, determine the abiotic environment of Varna Lake North Sea. More recently, D’Udekem d’Acoz et (Konsulov 1971). A sharp thermocline is a al. (2005) reported the oriental shrimps being common feature during summer months, which caught at different sites along the southern bight prevents oxygen from reaching the bottom layers of the Northern Sea. First observations in under 4-5m, inducing hypoxia and resulting in German waters, and some important conclusions the production of hydrogen sulphide. The about the oriental shrimp presence in other hypoxic and anoxic phenomena result from the estuarine habitats of the North Sea, were decomposition of organic material and lead to published by González-Ortegón et al. (2007). mass mortalities of fish and crustaceans (Dineva P. macrodactylus have recently been recorded in 1999). In recent years a marked improvement of estuarine water bodies along the Romanian coast water quality has been noticed during summer in the Black Sea (Micu and Niţă 2009). months compared to historical records. S91 V.St. Raykov et al. Figure 1. Black Sea with general study area (black rectangle, site of discovery with red asterix); two canals connecting Varna Bay with the Lake and sites of oriental shrimp discovery (red asterix, S1and S2). Picture: Google Earth. Figure 2. General aspect of ovigerous female Palaemon macrodactylus Rathbun, 1902 (scale bar in millimeters). Photograph by V.Raykov. Figure 3. Palaemon macrodactylus Rathbun, 1902 eggs stage III of maturation with visible compound eyes. Photographs by V.Raykov. S92 Palaemon macrodactylus in Varna Lake Sampling stations and sampling method At the deeper station (S2), the temperature at the bottom (8 m) was 22.7°C and the salinity was In the period 31 August - 4 September 2009, 16.2 psu. Surface temperature was 24.2°C and nine fyke nets and fourteen beam trawl stations salinity 15.7 psu, respectively. comprising a total of 32 sampling events in the Varna Lake and adjacent Varna Bay were examined (Figure 1). The fyke nets were double Results with two facing trap nets jointed by a central panel 5.50m in length and 0.55m in height. The At S1, one ovigerous female was caught and fyke nets had a 12mm mesh size (stretched identified on board as Palaemon macrodactylus mesh) and were left fishing overnight (ca. 10 to and this identification was subsequently 18 hours). The 1.50m wide and 0.50m height confirmed in the laboratory (Figure 2). In the beam trawl equipped with one small tickle chain same fyke nets, ten individuals of P. elegans was fitted with a 10mm mesh (stretched mesh) in Rathke, 1837 were caught. At station S2 (Annex the codend. The beam trawl was towed for 1) two P. macrodactylus were found along with approximately 10 min covering an area of three specimens of Rhitropanopeus harisii approximately 450 to 500m2. (Gould, 1841), 2 P. elegans and two Upogebia pusilla (Petagna, 1792). Most of the separated eggs had clearly visible Habitat compound eyes, and were assigned to stage III of The fyke net sampling stations (Figure 1) were development, following Fisher and Clark Jr, located in the north-eastern part of Varna Lake (1983) (Figure 3). The eggs were oval in shape, (S1). This area was characterized by a soft and had an average length of 0.46mm, and width muddy bottom with a high content of decaying of 0.37mm. organic matter. Typical vegetation found between 0.7 to 1.2 m (Fyke placement) is Morphology identification composed of mixed communities of Potamo- geton natans (Linnaeus, 1753), P. perfoliatus The morphological characteristics of the caught (Linnaeus, 1753), P. crispus (Linnaeus, 1753) ovigerous females in Varna Lake are undoubted- and P. pectinatus (Linnaeus, 1753). Deeper areas ly those of the species P. macrodactylus. are dominated by tape grass Vallisneria spiralis Rostrum with 10-12 dorsal teeth (including (Linnaeus, 1758). Native Palaemon elegans postorbital teeth but not the superior tooth of the (Rathke, 1837) populations are often found in apical cleft), of which 2 or 3 teeth are on these habitats across all depths and among the carapace behind orbit; shorter ramus of the outer canopy of common reed Phragmites australis flagellum of antennula fused for about 20% of its (Cav.) Trin. ex Steud. bordering the shores of the length to longer ramus; chela of P2 with fingers lake. Other water plant species, such as Typha ≈0.7× as long as palm. The described angustifolia Linnaeus, Typha latifolia Linnaeus, identification keys are with agreement with those and Schoenoplectus lacustris Linnaeus (Palla) described by González-Ortegón and Cuesta are also present in this lake margin habitat. 2006; D’Udekem d’Acoz et al. 2005; Ashelby et At the second sampling site (S2) (Figure 1), al. 2004). the specimens were caught with a beam trawl, at depths of up to 8m. This area contains a mixture Discussion of Cladophora vagabunda (Linnaeus) Van Den Hoek; Ulva intestinalis (Linnaeus, 1758) and Palaemon macrodactylus, already has well Ulva compressa (Linnaeus, 1758). The nature of established populations in the Romanian Black the sediment is silt, containing rich organic Sea and, taking into consideration the invasion matter. record and the ecology of this species, it is very likely that it will successfully invade the whole Temperature and salinity of the Black and Azov Seas and the adjacent estuaries, deltas and limans (Micu and Niţă At the shallower sampling station S1, the bottom 2009). water temperature was 23.5°C and the salinity There are two alternative sources of was 16.3 psu. Surface temperature and salinity at introduction of P. macrodactylus in Bulgarian the site were 24.4°C and 16.2 psu, respectively. waters: S93 V.St. Raykov et al. a) natural expansion from the close-by, Conclusion already well-established population in Romania, The presence of ovigerous individuals and their and state of maturation indicated that the species can b) artificial introduction via shipping reproduce naturally. Most probably, it is activities from already established European expanding naturally or has been introduced from populations.