Nederlands Soortenregister

Overzicht van de Nederlandse biodiversiteit

Brakwaterpok Amphibalanus improvisus


Balanidae [familie]
Amphibalanus [genus] (3/2)
improvisus [soort]

Exotenpaspoort ?

Vestigingsstatus Gevestigd
Zeldzaamheid Algemeen
Invasiviteit Potentieel invasief
Invasiviteit (toelichting) This species has been found in European waters including the Baltic Sea for 200 years or more. The species could be considered fully naturalized. In some European countries, e.g. the United Kingdom, the species is now considered native. It is a suspension feeder, it grows very fast, is highly euryhaline, lives in a great number of brackish, marine and sometimes nearly fresh waterhabitats. It is eurythermal and tolerates temperatures as low as -2° C and up to 35° C (Southward, 1957); it is tolerant of low oxygen concentration, of eutrophication and pollution (Jensen, K.R., 2010).
Type introductie Niet opzettelijk
Jaar van eerste introductie 1827
Jaar van eerste melding 1827
Natuurlijke verspreiding
  • Noordelijke Atlantische Oceaan
  • Zuidelijke Atlantische Oceaan
  • Verspreiding in Nederland
  • Friesland
  • Groningen
  • Noord-Holland
  • Zuid-Holland
  • Zeeland
  • Verspreiding in Nederland (toelichting) Wolff (2005) mentions this species as either a European native species or an early immigrant. The first record in the Netherlands is from Waardenburg (1827) who mentions the species - as Balanus ovularis - from the former Zuiderzee. In following years the species was also found in many brackish inland waters and along the coast. Nowadays B. improvisus is a common species in the Netherlands in marine, brackish and sometimes nearly fresh waters (Holthuis, 1961; Huwae, 1985; Van der Gaag et al., 1999).
  • Mariene habitats
  • Estuaria en brakwatergebieden
  • Kustgebied
  • Wijze van introductie
  • Aquacultuur
  • Lifters op of in schip/boot
  • Ballastwater schip/boot
  • Aangroei op scheepsrompen
  • Onderling verbonden waterwegen/bassins/zeeën
  • Impact Concurrentie
    Ecologische impact (toelichting) B. improvisus is a competitor for space, but in the Baltic there was no evidence it has a negative effect on community diversity (Dürr & Wahl, 2004). The species may change the habitat, foulling mussels and oysters. There are no specific data of negative impact on the ecosystem in the Netherlands
    Economische impact (toelichting) The species is part of the fouling community on hulls of ships and other structures. It may form dense layers which attract associate fauna and produces organic debris. The species is known for clogging up pipes of power plants etc. in the Baltic. This may also be the case in for instance the Noorzeekanaal-area, but as yet there are no specific indications of any economic impact in the Netherlands.


    • Dürr, S. & M. Wahl 2004. Isolated and combined impacts of blue mussels (Mytilus edulis) and barnacles (Balanus improvisus) on structure and diversity of a fouling community. Journal of Experimental Marine Biology and Ecology 306: 181-195.
    • Gaag, M. van der, S. Rajagopal, G. van der Velde & H.A. Jenner 1999. Settlement and growth of barnacles, Balanus improvisus Darwin, 1854, in the brackish Noordzeekanaal, The Netherlands. In: J.C. von Vaupel Klein & F.R. Schramm (eds.), The biodiversity crisis and Crustacea. Proc. 4th Int. Crustacean Congress, Amsterdam, The Netherlands, July 20-24, 1998. 663-674. Balkema, Rotterdam.
    • Hoek, P.P.C. 1875. Eerste bijdrage tot een nauwkeuriger kennis der sessiele Cirripediën. 1-94. PhD thesis, University of Leiden.
    • Holthuis, L.B. 1961. Zeepokken. In: H. Boschma, F. de Graaf, L.B. Holthuis & J.A.W. Lucas (eds), Rankpotigen (Cirripedia). 19: 1-27. Tabellenserie van de Strandwerkgemeenschap.
    • Huwae, H. 1985. De rankpotigen (Crustacea - Cirripedia) van de Nederlandse Kust. Tabellenserie van de Strandwerkgemeenschap 28: 44 pp..
    • Jensen, K.R. 2010. NOBANIS – Invasive Alien Species Fact Sheet – Balanus improvisus. In: Identification key to marine invasive species in Nordic waters. [link]
    • Redeke, H.C. (red.) 1922. Flora en Fauna der Zuiderzee. Monografie van een brakwatergebied. Nederlandse Dierkundige vereeniging & De Boer Jr., Den Helder.