Nederlands Soortenregister

Overzicht van de Nederlandse biodiversiteit

Amathia gracilis

Indeling

Amathia [genus] (3/3)
gracilis [soort]

Indeling

Amathia [genus] (3/3)
gracilis [soort]

Exotenpaspoort ?

Exotenstatus Gevestigd
Frequentie Algemeen
Invasiviteit Niet invasief
Jaar van eerste melding 1936
Type introductie Niet opzettelijk
Wijze van introductie Aangroei op scheepsrompen
Vastgesteld in provincies
  • Friesland
  • Groningen
  • Noord-Holland
  • Zuid-Holland
  • Zeeland
  • Habitats
  • Mariene habitats
  • Estuaria en brakwatergebieden
  • Natuurlijke verspreiding Onbekend
    Beschrijving invasiviteit (Engels) This is a cosmopolitan species, of which the origin is considered unclear (Wolff 2005). It may however, prove to be native to the Northern Atlantic or even to the North Sea area. It has been present in Europe for a long time, although in early literature usually under the name of Bowerbankia caudata (Faasse en De Blauwe 2004). In the eastern Atlantic the species occurs from the Arctic into the Mediterranean and perhaps also the Black Sea and the Caspian Sea, in the western Atlantic its range extends from Greenland south to Brazil. There are several factors that contribute to its abundancy and dispersal (or invasiveness). It is highly adaptable to all kins of habitats and substrates, living on solid materials as well as on seaweeds, hydroïds and other species. Its reproduction strategy includes both sexual and asexual reproduction: the colonies consist of replicated series of zooids, each budded asexually from a predecessor. Founding zooids metamorphose from sexually produced larvae. Furthermore the species is considered to be tolerant of a broad temperature-range (eurythermal) and is particularly tolerant of widely ranging salinities (euryhaline): it occurs in brackish and estuarine habitats with highly variable salinities, as well as in marine habitats with high and a stable salinities (Winston 1995). If introduced, it probably arrived on ships’ hulls (Wolff 2005).
    Beschrijving (potentiële) ecologische impact (Engels) B. gracilis is a suspension feeder, capable of filtering rather a large quantity of water. Winston (1995) reported in general that bryozoan colonies located in one square meter of seagrass bed could potentially filter and recirculate an average of 48,000 gallons (approximately 200.000 liter) of seawater per day. If not attached on solid substrates (stones, shells, wood, hulls of boats), also submerged or even floating macroalgae can provide support for the bryozoan colonies. In turn, bryozoans provide habitat for several small organisms like polychaete worms, amphipods and copepods (Winston 1995). Nothing is known about the impact of this species on the environment.
    Beschrijving (potentiële) economische impact (Engels) As there are no reports on economic impact.
    Beschrijving verspreiding binnen Nederland (Engels) This species is already mentioned by Vorstman (1936) from the brackish water in the former Zuiderzee, before this was converted to a freshwater lake. The species is rather abundant at many localities in the province of Zeeland (Lake Grevelingen; Eastern Scheldt, Western Scheldt; Lake Veere; several brackish inland creeks, lakes and ponds; Nieuwe Waterweg; some brackish localities in Zuid-Holland and Noord-Holland. But it is also present along the North Sea Coast in almost every harbour and marina (for instance IJmuiden), on groynes, peers and other coastal constructions and from the artificial reefs near Katwijk-Noordwijk. It is also present in the Wadden Sea (a.o. on the island of Texel, Ouderschild).

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