the first record of the skeleton shrimp caprella scaura in northwestern europe (crustacea: amphipoda)
Marco Faasse
Skeleton shrimps (family Caprellidae) are highly specialized members of the order Amphipoda. Some body parts have been completely lost and behaviour has changed accordingly, or the other way around. Superficially they look like a marine praying mantis. Their long and thin body clings to the substrate with the hind legs and the claws of the chelipeds at the front end are used to capture prey. The three pleosome segments, used for swimming in other amphipods, are absent, as well as the three urosome segments, originally used for thrusting or steering. Caprellids are promi- nent members of fouling communities in coastal waters, often occurring in high densities. Due to their lifestyle they have a high propensity to be carried elsewhere on ship’s hulls. introduction now been recorded from the Canary Isles and the Caprella scaura (Templeton, 1836) (fig. 1-2) is a Atlantic coast of northern Africa and Portugal as skeleton shrimp occurring worldwide in warm well. According to Ros et al. (2014) it has not temperate waters. Its worldwide occurrence is spread further north along the Atlantic coast than ascribed to transoceanic transports by man (Ros Cascais in Portugal. More northerly records from et al. 2014). It was first recorded from the Medi- Europe have not yet been published. In this terranean Sea (Lagoon of Venice) in 1994 and sub- paper we provide the first record from north- sequently in several widely separated locations western Europe, in the southwest of the Nether- across the mediterranean (Ros et al. 2014). It has lands (Southern Bight of the North Sea).
Figure 1. Caprella scaura, female. Borssele, 21.i.2017. Foto Marco Faasse. Figuur 1. Caprella scaura, vrouw- tje. Borssele, 21.i.2017. Photo Marco Faasse.
faasse ‒ the first record of caprella scaura in northwestern europe 75 identification Caprella scaura differs from other North-West European shallow-water Caprella species in the sharp, anteriorly directed spine on the cephalon, its basis situated behind the eye and not comple- mented with other spines. Several caprellids in North-West Europe have a projection on the cephalon. However, in C. andreae, C. fretensis and C. penantis the cephalic spine is a so-called rostrum, a usually blunt spine on the anterior margin of the cephalon (Guerra-García 2014), unlike its position in C. scaura. Caprella septen- trionalis and C. tuberculata may have a rounded tubercle on the cephalon, not an anteriorly directed, sharp spine. Caprella erithizon has more than one sharp spine on the cephalon behind the eye. An additional characteristic feature of C. scaura is a number of fused proximal seg- ments in the flagellum of the first antenna, up to four in females and up to nine in males (Mayer 1890, McCain 1968). Some authors distinguish several forma’s or subspecies of C. scaura (Mayer 1890, Krapp et al. 2006), which are not recog- Figure 2. Caprella scaura, small male. Borssele, nised by Lowry (2016). Males found in the 23.i.2017. Foto Marco Faasse. Netherlands in January 2017 had a less elongate Figuur 2. Caprella scaura, klein mannetje. Borssele, pereionite 2 than depicted by McCain (1968), 23.i.2017. Photo Marco Faasse. Krapp et al. (2006), Martinez & Adarraga (2008) and Ros et al. (2014). They may not have been fully mature. However, females with eggs in the family caprellidae marsupium were found. The family Caprellidae contains 90 genera, of which the genus Caprella is particularly rich in records from the netherlands species. The genus Caprella Lamarck, 1801 cur- rently contains 183 species worldwide (worms), Four female specimens of C. scaura were collect- seven of which have now been recorded from the ed with the green seaweed Bryopsis plumosa on Netherlands (Nederlandsesoorten.nl), two of them 21 January 2017 near Borssele along the Wester- only washed ashore. Seven species of the family schelde estuary in the southwest of the Nether- Caprellidae have established populations in the lands (n 51°25.835’, e 3°42.626’). On 23 January Netherlands. Two are exotic species: C. scaura and more specimens, including males, were collected C. mutica Schurin, 1935. Two species have recently with B. plumosa. The accompanying fauna extended their distribution to the Netherlands, existed of not yet identified amphipods Jassa C. tuberculata Bate & Westwood, 1868 from the spec., Monocorophium spec., Stenothoe spec., south (Van Moorsel et al. 2014) and C. acanthifera sea spiders Achelia spec., a juvenile isopod Idotea Leach, 1814 possibly from the north (Ligthart spec. and the tanaidacean Zeuxo holdichi 2010). Caprella tuberculata and Pseudoprotella Bamber, 1990. phasma Montagu, 1804 only occur offshore.
76 neder 48 ‒ 17 discussion acanthifera (Leach, 1814): nu autochtoon op onze Conditions at the collecting location are not kust (Crustacea, Amphipoda, Caprellidea). typical for the Atlantic coast of Europe. Due to – Het Zeepaard 70: 82-89. the shallowness of coastal waters of the Nether- Lowry, J. 2016. Caprella scaura Templeton, 1836. lands, maximum water temperatures in summer – In: T. Horton, J. Lowry,C. De Broyer, are higher than most of the coastal waters of D. Bellan-Santini, C.O. Coleman, M. Daneliya, France, Spain and Portugal, i.e. above 20 °C. J.-C. Dauvin, C. Fišer, R. Gasca, M. Grabowski, Furthermore, the skeleton shrimp was collected J.M. Guerra-García, E. Hendrycks, J. Holsinger, from the cooling water discharge of a power L. Hughes, D. Jaume, K. Jazdzewski, J. Just, station, with raised water temperatures in all R.M. Kamaltynov, Y.-H. Kim, R. King, seasons. It is therefore uncertain whether and T. Krapp-Schickel, S. LeCroy, A.N. Lörz, how far it will disperse in northwestern Europe. A.R. Senna, C. Serejo, B. Sket, A.H. Tandberg, J. Thomas, M. Thurston, W. Vader, R. Väinölä, The power station and the collection location are R. Vonk, K. White & W. Zeidler. World Amphi- situated along the densely navigated Westerschelde poda Database. Accessed through: World Register estuary, leading to the international port of of Marine Species at www.marinespecies.org/ Antwerp and at a distance of only a few kilometers aphia.php?p=taxdetails&id=236551 on 27.i.2017. from the harbour of Vlissingen. Water tempera- Martínez, J. & I. Adarraga 2008. First record of ture and intense shipping activity combined may invasive caprellid Caprella scaura Templeton, 1836 have contributed to the large ‘jump’ of C. scaura sensu lato (Crustacea: Amphipoda: Caprellidae) from southern Europe to the Westerschelde along from the Iberian Peninsula. – Aquatic Invasions 3: the Southern Bight of the North Sea. 165-171. Mayer, P. 1890. Die Caprelliden des Golfes von Neapel Ports and harbours are the main entry points of und der angrenzenden Meeres Abschnitte. – Fauna alien marine species and consequently should be und Flora des Golfes von Neapel 17: 1-55. focal points of monitoring new introductions, McCain, J.C. 1968. The Caprellidea (Crustacea, together with sites of artificially raised water Amphipoda) of the western North Atlantic. temperatures. – Bulletin United States National Museum 278: 1-116. references Ros, M., J.M. Guerra-García, C. Navarro-Barranco, M.P. Cabezas & M. Vázques-Luis 2014. The Guerra-García, J.M. 2014. Caprellidea. Identification spreading of the non-native caprellid (Crustacea: guide to British caprellids. – nmbaqc workshop Amphipoda) Caprella scaura Templeton, 1836 into 2012: 1-17. southern Europe and northern Africa: a compli- Krapp, T., C. Lang, A. Libertini & R.R. Melzer 2006. cated taxonomic history. – Mediterranean Marine Caprella scaura Templeton 1836 sensu lato (Amphi- Science 15: 145-155. poda: Caprellidae) in the Mediterranean. Van Moorsel, G.W.N.M., M.A. Faasse & W. Lengkeek – Organism Diversity and Evolution 6: 77-81. 2014. [The skeleton shrimp Caprella tuberculata Ligthart, A.H.M. 2010. Een aanwinst voor de in Guérin, 1836 on a wreck in the Nederlands]. Nederland voorkomende Caprellidae: Caprella – Het Zeepaard 74: 66-70. [in Dutch]
faasse ‒ the first record of caprella scaura in northwestern europe 77 samenvatting Eerste waarneming van de spookkreeft Caprella scaura in Noordwest-Europa (Crustacea: Amphipoda) Op 21 en 23 januari 2017 werd het exotische vlokreeftje Caprella scaura verzameld bij Borssele (provincie Zeeland). Dit zijn de eerste waarnemingen in Noordwest-Europa. Caprella scaura is een vertegenwoordiger van de familie van de spookkreeftjes (Caprellidae). Deze vallen op van- wege de afwijkende, bidsprinkhaanachtige lichaamsbouw. Ze hebben een lang, dun lichaam, met achterpoten waarmee ze zich aan het substraat vasthouden en voorpoten met klauwen waarmee ze prooien vangen. Spookkreeftjes kunnen talrijk aanwezig zijn in zogenaamde ‘fouling communities’ op scheepsrompen, havenconstructies en dergelijke en kunnen zo gemakkelijk in nieuwe gebieden geïntroduceerd worden. Caprella scaura is bekend van ver- scheidene warm-gematigde gebieden in de wereld. Kort voor de eeuwwisseling werd ze geïntro- duceerd in de Middellandse Zee en de kreeftjes zijn ook aangetroffen aan de westkust van Portugal en op de Canarische Eilanden. De vindplaats bij Borssele betreft de koelwateruitlaat van elektriciteitscentrales, een plek met een kunstmatig hoge watertemperatuur. De soort zal zich mogelijk in Noordwest-Europa niet veel verder kunnen verspreiden, omdat de water temperatuur daarvoor te laag is.
M.A. Faasse Naturalis Biodiversity Center ecoast Marine Research Voltaweg 11c 4382 ng Vlissingen
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