First Record of Beroe Gracilis Ku¨Nne, 1939 (Ctenophora: Beroida: Beroidae) from Norway, Found in a Mnemiopsis Leidyi A

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Marine Biodiversity Records, page 1 of 5. # Marine Biological Association of the United Kingdom, 2015 doi:10.1017/S1755267215000366; Vol. 8; e60; 2015 Published online First record of Beroe gracilis Ku¨nne, 1939 (Ctenophora: Beroida: Beroidae) from Norway, found in a Mnemiopsis leidyi A. Agassiz, 1865 bloom halldis ringvold1, tamara a. shiganova2, k. emily knott3 and bella s. galil4 1Sea Snack Norway, Bergen, Norway, 2P.P. Shirshov Institute of Oceanology Russian Academy of Science, Moscow, Russia, 3University of Jyvaskyla, Department of Biological and Environmental Science, Jyvaskyla, Finland, 4National Institute of Oceanography, Israel Oceanographic and Limnological Research, Haifa, Israel

In September 2014 an unusual mixture of ctenophores was recorded at Arboretet, south-western Norway and at Flødevigen, near Arendal on the south coast of Norway. In addition to the invasive American lobate ctenophore, Mnemiopsis leidyi, the common northern lobate ctenophore Bolinopsis infundibulum and the cydippid Pleurobrachia pileus, two beroid ctenophores, were noted – Beroe cucumis and Beroe gracilis. The latter species had not been documented before in Norwegian waters.

Keywords: Ctenophora, Beroe gracilis, Beroe cucumis, Pleurobrachia pileus, Bolinopsis infundibulum, Mnemiopsis leidyi, bloom, Norway

Submitted 25 September 2014; accepted 25 March 2015

INTRODUCTION from June to October in Korsfjorden, and to a lesser degree in May–June and September in Fanafjorden (Hosia & Research on gelatinous zooplankton in Norway dates back Ba˚mstedt, 2007). A recent study of cyddipids from Svalbard to 1776 (Kramp & Damas, 1925), yet ctenophores received recorded Mertensia ovum (Fabricius, 1780) co-occuring scant attention until Mnemiopsis leidyi A. Agassiz, 1865 was with Euplokamis sp. and a yet-unidentified mertensiid-like recorded in late 2005 in Oslofjorden and in the following species, though no Beroe spp. (Majaneva & Majaneva, 2013). year near Bergen (Hansson, 2006; Oliveira, 2007). In an exten- A couple of studies examined the trophic and functional sive report on the zooplankton in Trondheimsfjorden, 1963– ecology of the ctenophores P. pileus, Bolinopsis infundibulum 1966, ctenophores were accorded a brief mention: ‘Beroe and Beroe cucumis (Falkenhaug & Stabell, 1996;Ba˚mstedt, cucumis Fabricius occurred frequently at all stations at all 1998; Sørnes & Aksnes, 2004). depths. Pleurobracia pileus occurred occasionally’, though The type locality of Beroe gracilis Ku¨nne, 1939 is they ‘were often damaged during the haul and of the more Helgoland, Germany (Ku¨nne, 1939). It is common in the fragile species only gelatinous material was retained’ North Sea and has been recorded from the coastal waters of (Strømgren, 1973: 118). In zooplankton samples collected north-west Europe (Ku¨nne, 1939; Greve, 1975; Greve et al. with 50 and 200 mm mesh nets at five stations along the 1976; Adema, 1982; Muller, 2004), Skagerrak, (Hansson, Hardangerfjord between April 27 and 4 May 1992, ‘only an 2006; Hosia et al., 2011), Kerteminde Harbour and occasional ctenophore’ was found (Page`s et al., 1996: 71). A Limfjorden, Denmark (Riisga˚rd & Goldstein, 2014; visual investigation of zooplankton in four western Shiganova et al., 2014b), as well as the Bahamas (Wrobel & Norwegian fjords in the summer of 1996 identified the vertical Mills, 2003), the north-eastern Pacific (Mills & Haddock, distribution of some lobate ctenophores, ‘probably Bolinopsis 2007) and from the central Chilean coast (Oliveira et al., infundibulum’ (Gorsky et al., 2000: 131). Swanberg & 2014). However, its presence off the Norwegian coast had Ba˚mstedt (1991: 508) tentatively refer to Beroe in the not been recorded before. Barents Sea: ‘There appear to be two forms or species of This article describes a bloom of ctenophores observed in Beroe in the area; one, which we believe to be B. gracilis.... September 2014 at Arboretet, south-western Norway and at while the other, B. cucumis?’ Seasonal patterns of Bolinopsis Flødevigen, near Arendal, on the south coast of Norway, infundibulum (O.F. Mu¨ller, 1776), P. pileus (O.F. Mu¨ller, and the first record of Beroe gracilis in Norwegian coastal 1776) and Beroe sp. in 2003 were described from fjords in waters. the Bergen area: that year Beroe sp. dominated samples

MATERIAL AND METHODS

Corresponding author: ′ ′′ B.S. Galil The salinity and temperature at Arboretet (60825 72 N ′ ′′ ′ ′′ ′ ′′ Email: [email protected] 05827 01 E) and Flødevigen (58825 35 N08845 18 E)

1 2 halldis ringvold et al.

Fig. 1. Southern Norway, with bloom sighting locations: 1. Arboretet (60825′72′′N05827′01′′E); 2. Flødevigen (58825′35′′N08845′18′′E).

(Figure 1) were measured with SAIV SD204 CTD and with an Aanderaa Conductivity Sensor 4120, respectively. The surface water temperature at Raunefjorden, near Arboretet, measured on 17 September 2014, was 16.58C, and the salinity was 30.37. The surface water temperature at Flødevigen, measured on 12 September 2014, was 178C, and the salinity varied between 18 and 25, over 24 h. The salinity in this bay may vary due to heavy rainfall, a nearby freshwater outlet or winds pushing surface water outwards to be replaced by the inflow of deeper, more saline water. Eleven specimens of Beroe gracilis were carefully lifted by means of a hand-held glass from the upper 20 cm layer off Fig. 2. Beroe gracilis (Ku¨nne, 1939). Norway, Arboretet, 19 September 2014, Arboretet on September 19 and photographed using a total length 23 mm (photograph by H. Ringvold). Canon PowerShot D30, Zoom lens 5 times IS (Figure 2). To confirm the identity of Beroe gracilis, we analysed a portion of the 18S ribosomal DNA (rDNA) gene from three Carlsbad, CA, USA). The amplified products were cleaned specimens of Beroe gracilis collected off Arboretet on using Exo I and FastSAP (Fisher Scientific, Waltham, MA, September 19 and frozen, as well as a single specimen of USA). Then, they were sequenced in the forward direction Beroe cucumis collected from Flødevigen, on September 12. using an Applied Biosystems’ BigDyew Terminator V3.1 kit, DNA was extracted using a combination of Qiagen’s separated on an ABI 3130xl Genetic Analyser and visualized DNeasy kit (Qiagen Nordic, Helsinki, Finland) and Zymo’s using Sequencing Analysis v.6 software (all from Life Genomic DNA clean and concentrator kit (Zymo Research Technologies, Thermo Fisher Scientific, Waltham, MA, USA). Europe, Freiburg, Germany). The 18S rDNA gene was amplified using the universal primers 18S-F: 5′-ACCTGGTTGAT CCTGCCA-3′ and 18S-R: 5′-TGATCCTTCYGCAGGTTCA C-3′ (Medlin et al., 1988). Amplification was performed in RESULTS 20 ml reactions consisting of 1 U DreamTaq DNA polymerase, 1X DreamTaq Buffer, 2.5 mM MgCl2, (Thermo Fisher On September 7, two specimens of Beroe gracilis were observed Scientific, Waltham, MA, USA), 0.2 mM dNTPs, 0.005% in Arboretet, near a freshwater outlet in the middle tidal zone, bovine serum albumin (Sigma Aldrich Finland, Helsinki), in addition to several small and damaged individuals of 0.5 mM each primer (TAG Copenhagen, Denmark) and Mnemiopsis leidyi, a few Bolinopsis infundibulum and a great approximately 100 ng DNA template. Thermocycling condi- number of Pleurobracia pileus. On September 13–14, one speci- tions included an initial denaturation at 958C for 3 min fol- men of Beroe gracilis was observed amidst a bloom of lowed by 30 cycles of 958C for 30 s, 558C for 2 min, and Mnemiopsis leidyi in Flødevigen. The abundance of M. leidyi 728C for 3 min, after which there was a final extension at at the time was estimated to be 20 ind. m23 (fide Dr Tone 728C for 7 min. Thermocycling reactions were performed in Falkenhaug, Institute of Marine Research, Norway, http:// a BioRad C1000 thermocycler (Bio Rad Laboratories, www.nrk.no/nyheter/1.11925246, viewed 10 September 2014), first record of beroe gracilis from norway 3 though the lead author (H. Ringvold) observed patchy con- been recorded before from Norway. This report is the first centrations estimated to be up to 100 ind. m23 comprising documentation of the species’ presence in Norwegian adult and juvenile M. leidyi and P. pileus, as well as a single waters, although, it is likely not a new species to the area, specimen of Beroe cucumis. On September 18, a bloom of but one that has been previously overlooked. Similarly, it M. leidyi was sighted off Arboretet, with concentrations was recently recorded from Kerteminde Harbour, Denmark, estimated to be 8–10 ind. m23, where several Pleurobracia where it may have been ‘present for years, misidentified as pileus specimens were also recorded. On September 19, a young stages of B. cucumis’ (Shiganova et al., 2014a, b: 5). mixed bloom of M. leidyi (8 ind. m23), Pleurobracia pileus Scientific records of Ctenophora are sparse due to the high (3 ind. m23) and Beroe gracilis (1 ind. m23) were observed temporal and spatial variation in ctenophore populations, off Arboretet, as well as two specimens of Beroe cucumis. poor sampling and preservation methodologies and limited The 2014 bloom of M. leidyi was first observed in search effort, even in countries such as Norway, which have Flødevigen, near Arendal, on the south coast of Norway and a rich tradition of marine research (i.e. the marine biological a week later in Arboretet, Bergen, south-western Norway. research station at Flødevigen, established in 1882, and in We consider the bloom to be a single event, notwithstanding Bergen, near Arboretet, in 1892). The arrival of Mnemiopsis the geographic distance between the sites. It has been shown leidyi in Norwegian waters was followed by its inclusion that toxic algal blooms that had first been recorded in among the ‘High Risk’ nonindigenous species on the ‘2007 Skagerrak spread with the Norwegian coastal current Norwegian Black List’, though ‘it is uncertain what impact it (Prymnesium polylepsi (Manton & Parke) Edvardsen, will have in Norwegian waters’ (Gederaas et al., 2007: 71). Eikrem & Probert, 2011, in Edvardsen et al., 2011; fide Dahl The 2008 killing of farmed fish in Norway, http://www.nrk. et al., 1989). Similarly, Beroe gracilis may have spread with no/hordaland/denne-har-tatt-livet-av-tusener-1.6241751, helped the prevailing current along the Norwegian coast. raise awareness of the importance of comb jellies to the envir- In summary, five ctenophore species were identified in our onmental and economic viability of the marine ecosystem. survey: the invasive M. leidyi and the native Prymnesium Alien ctenophores were unknown in Nordic waters until pileus, Bolinopsis infundibulum, Beroe cucumis, in addition late 2005, when the highly invasive M. leidyi was first recorded to Beroe gracilis, which had not been recorded before in in the Oslofjorden (Oliveira, 2007), and subsequently found in Norwegian waters. The identity of Beroe gracilis was con- Skagerrak, Kattegat and the Baltic Sea (Hansson, 2006; firmed with molecular data. Sequencing yielded a 587 bp frag- Javidpour et al., 2006,Kubeet al., 2007). As gelatinous plank- ment of the 18S rDNA gene. The sequences were identical to ton plays a pivotal role in marine food webs and elemental each other and shared 99.8% identity with a known sequence fluxes, M. leidyi’s potential impact on the trophodynamics of Beroe gracilis available in GenBank (AF293696.1). Only a of the Norwegian fjords should be of major concern, since 451 bp fragment of the 18S rDNA sequence could be reliably commercially important populations may be affected. scored from the sample of Beroe cucumis, which was 99.8% Notably, our finding of Beroe gracilis in a M. leidyi bloom indi- identical to sequences of Beroe cucumis in GenBank cates that there may be significant interactions between native (AF293695.1 and AF293699.1). As noted by Podar et al. and invasive ctenophore fauna. For example, predation (2001), there is very low variability in the 18S rDNA sequence among gelatinous zooplankton is well documented and may among different ctenophore species, and in the gene region we play a major role in regulating populations, e.g. Beroe ovata sequenced, Beroe gracilis differs from Beroe cucumis at only and M. leidyi (Finenko et al., 2003; Shiganova et al., 2004, three sites. The sequences we obtained showed the same 2014a). Predation by scyphomedusans such as the Atlantic three differences as in the published sequences. The sequences sea nettle, Chrysaora quinquecirrha (Desor, 1848), the reported in this paper have been deposited in the Nucleotide compass jellyfish, Chrysaora hysoscella (Linnaeus, 1767), the Sequence Database (GenBank Accession numbers: Beroe lion’s mane jellyfish, Cyanea capillata (Linnaeus, 1758) and gracilis KP334109, Beroe cucumis KP334108). Pelagia noctiluca (Forsska˚l, 1775) on M. leidyi have been Fully developed specimens of Beroe gracilis have a slender experimentally quantified (Purcell & Cowan, 1995; Hosia & cylindrical body, are milky or pale pink in colour and may Titelman, 2011; Tilves et al., 2012). A recent study also experi- reach 30 mm in length, though the total length of our speci- mentally quantified predation rates and interrelationships mens was approximately 23 mm. The body is moderately between Beroe gracilis and M. leidyi of different sizes: Beroe compressed. The eight meridional canals have few diverticulae gracilis fed on smaller M. leidyi but only partially consumed and they extend inwards toward the stomodeum rather than larger specimens, whereas, the latter fed on young Beroe gra- in the plane of the body surface. Ciliary comb rows, equal in cilis. The experiment suggested a minor Beroe gracilis preda- length, extend from the aboral pole to about three quarters tion impact on the M. leidyi population (Hosia et al., 2011). of the distance towards the mouth. The aboral pole is Changes in distributions and abundances of ctenophores fringed with a row of branched papillae on the polar plate are plausibly linked to increasing temperatures, which may (Ku¨nne, 1939). impact the ecosystem in ways we neither expect nor understand, Examination of the photographs of five specimens of Beroe and which may be more significant than their obvious economic gracilis showed that they were all heavily parasitized, and impacts (Greve, 1981;Schlu¨ter et al., 2010; Dinasquet et al., roughly 30–40 parasites were counted on each specimen, 2012). Already, the seasonal localized blooms and longer-term which were situated mostly on the 2/3 rear end (Figure 2). persistence of M. leidyi may indicate that under favourable con- ditions it may constitute a potential threat to fisheries through resource competition with fishes (CIESM, 2015)thatmay DISCUSSION bring about changes in the structure and function of the ecosystem in Norwegian waters. The establishment of a coor- Beroe gracilis is well known from the North Sea and adjacent dinated regional monitoring programme of gelatinous plank- waters, as well as the Barents Sea, but surprisingly it has not ton is needed. 4 halldis ringvold et al.

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