Overslaan en naar de inhoud gaan

Paalworm Teredo navalis


Teredinidae [familie]
Teredo [genus] (1/1)
navalis [soort]

Exotenpaspoort ?

Reële kans op vestiging? Ja
Betrouwbaarheid beoordeling Grote mate van zekerheid (meerdere bronnen)
Vestigingsstatus Gevestigd
Zeldzaamheid Algemeen
Invasiviteit Niet invasief
Invasiviteit (toelichting) T. navalis may be native to the North East Atlantic Ocean, or even to the Western European (and Dutch) coast. There are records of fossil 'Teredo spec' and even wood with boreholes from the area and there is therefor no reason to consider the species as non-indigious (De Bruyne et al., 2013). This and other Teredo-species have spread around the world, most probably as passenger of wooden ships in earlier centuries. Factors favouring the invasiveness of T. navalis are a.o. the broad range of temperature (it is found in temperate and tropical seas and oceans worldwide), the wide salinity range (it also lives in brackis water with a salinity of 0,9 promille), its adaptability to different habitats (it lives in brackish waters as well as the open sea), its high fertility (a female can produce over 5 million eggs a year) and the fact that the larvae can swim in the water for up to 21 days before settlement.
Type introductie Niet opzettelijk
Jaar van eerste introductie 1660
Jaar van eerste melding 1943
Natuurlijke verspreiding
  • Europa
  • Noordelijke Atlantische Oceaan
  • Onbekend
  • Verspreiding in Nederland
  • Friesland
  • Groningen
  • Noord-Holland
  • Zuid-Holland
  • Zeeland
  • Verspreiding in Nederland (toelichting) T. navalis has been present in the North Sea for at least several centuries and might well be indiginous. Around 1730 the wooden components of Dutch dikes around the former Zuiderzee were seriously affected by these boring bivalves. To prevent the land being flooded, many dikes had to be replaced with heavy stones. In these days the species was particularly abundant (Van Benthem Jutting, 1943). With the diminishing of wooden structures, the occurrence of the species was effectively reduced. The species however continued living in the brackish Zuiderzee (Redeke 1922), probably until 1932, when it was converted into a freshwater lake. Nowadays the species is found mainly in marine habitats, i.e. the open North Sea, living in submerged wood (of a.o. shipwrecks). Since 1985 the number of records, even in washed up wood, has decreased (De Bruyne et al. 2013).
  • Mariene habitats
  • Estuaria en brakwatergebieden
  • Wijze van introductie
  • Aangroei op scheepsrompen
  • Onderling verbonden waterwegen/bassins/zeeën
  • Impact Sociaal-economisch
    Ecologische impact (toelichting) The species drills tunnels into underwater piers and pilings. Timber raspings, together with some microalgae, are extracted from the water passing through the gills, which contain symbiotic nitrogen-fixing bacteria. These bacteria produce enzymes that help to digest the cellulose in the wood. Apart from breaking down submerged wood (wrecks) the species has no large impact on the environment.
    Economische impact (toelichting) This and other Teredo-species can cause major damage to submerged timber structures and the hulls of wooden boats. There are many references to damage of shipworms in the last centuries. At least in 1660 an epidemic occurrence was recorded in the Netherlands. As nowadays most structures are made of different materials, the risk of destruction is relatively small, compared to a few centuries ago. There are no data of specific large-scale damage in the Netherlands caused by T. navalis in the last decades.