Content on this page requires a newer version of Adobe Flash Player.

Get Adobe Flash player
 

  • Nederlands
  • Deutsch
Search in the Encyclopedia

Dieren en planten

Plants   Brown seaweed   Japanese sargassum   Marine flora   Flora of the sea floor   Seaweeds   Flora of the sea dikes   

Water en land

Rocky coasts   Sea dikes (biotope)   

Japanese sargassum

size:

multiple side branches, each up to 10 centimeters long

shape:

thready, bushy, branched

  • Dut: Japans bessenwier
  • Lat: Sargassum muticum
  • Eng: Japanese sargassum, japweed, wireweed
  • Ger: Japanischer Beerentang
  • Dan: Sargassotang
print print
Japanese sargassum, foto fitis, sytske dijksen

Japanese sargassum

As decorative as this brown seaweed may be, it is considered a big nuisance. Japanese sargassum grows quickly and massively, causing lots of problems in harbours (jammed screws), on beaches (stink inconvenience when it dies) and for those that use seawater (cool-water admission, saltwater aquariums). Just like the name indicates, Japanese sargassum comes from Japan. Scientists think that it arrived in the North Sea via Japanese oysters and attached to ships. At any rate, it has been present in the North Sea region since 1973 and in Dutch waters since 1980. Because this species contains many small gas bladders, it is not uncommon for plants to lift up their stony base and drift to other places. 

  • Washed ashore
    Japanese sargassum., Ivo Mol / Morfa

    It is seldom that entire Japanese sargassum plants to wash shore. Usually, only the ends are found. However in this photo, you see the tip of the plant above and the base below. This entire plant was more than one meter long. The top part contains 'berries' (gas bladders) and small leaves. The base has larger leaves and no berries. This seaweed is usually found along rocky coasts. Strange enough, in Japanese waters this seaweed doesn't grow longer than a couple of meters. However in European waters, it grows quickly and long: as much as 10 cm per day and up to 16 meters long!