New marine species

12 new marine species found in the Dutch Wadden Sea

In 2009, the Dutch Invasive Alien Species Team requested a survey (rapid assessment) of (alien) marine algae and macrofauna of hard substrata in the Dutch Wadden Sea. During this survey 83 localities were searched for native and non-native species. In total 129 species were observed, 29 of which were cryptogenic or of non-native origin. Twelve of these species and one subspecies were found to be new to the Dutch Wadden Sea. One red alga (Ceramiaceae sp.) is probably a new species to Europe. The sea-squirt Molgula socialis is recorded as new for the Netherlands. It is probably widespread, may even be native and misidentified in the past as the non-native American species M. manhattensis.The total number of non-native species in the Dutch Wadden Sea has been raised to 64. The observed (sub)species of an alien or unknown origin in the survey are:

  • Antithamnionella spirographidis (Schiffner) Wollaston, 1968
  • Ceramium cimbricum H.E. Petersen, 1924
  • An unknown Ceramiaceae species
  • Codium fragile ssp. atlanticum (A.D.Cotton) P.C. Silva, 1955
  • Gracilaria vermiculophylla (Ohmi) Papenfuss, 1967
  • Ficopomatus enigmaticus (Fauvel, 1923)
  • cf Neodexiospira brasiliensis (Grube, 1872)
  • Aplidium glabrum (Verrill, 1871)
  • Botrylloides violaceus Oka, 1927
  • Didemnum vexillum Kott 2002
  • Molgula socialis Alder, 1863
  • Caprella mutica Schurin, 1935
  • Jassa marmorata (Holmes, 1903)

All results from this survey can be downloaded here.

For more information please contact Wiebe Lammers on or see