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up to 40 cm


all kinds of color: pink, brown, green


small benthic animals


shorebirds, fish, worm fishermen



  • Dut: Zager (zeeduizendpoot)
  • Lat: Nereis spp., Alitta virens
  • Eng: Ragworm (King rag, estuary ragworm)
  • Ger: Seeringelwurm
  • Dan: Børsteorm
King rag, foto fitis, sytske dijksen


Ragworms are predator worms with strong jaws; a large ragworm can produce quite a bite! They have lots of small legs, which explains why they are also called marine centipedes in Dutch. They emerge out of the sea bottom to mate in the spring. Deep-sea fishermen like to use ragworms for bait because fish like to bite into them. However, these worms are more difficult to dig up out of the mudflats, making them more expensive than lugworms. That is why ragworms are cultivated. There are various kinds of ragworms. The king rag can grow as long as 40 centimeters. The estuary ragworm grows to 20 centimeters.

On Texel

The king ragworm (Alitta virens), the estuary ragworm (Nereis diversicolor) and the catworm (Nephtys hombergii) are common on the mudflats by Texel. The estuary ragworm even lives on the landside of the dikes, in salty ditches by the Petten.

  • Distribution and habitat
    Estuary ragworm, Oscar Bos, Ecomare

    Ragworms live in tunnels which they dig in the bottom of the Wadden Sea, the delta waters and North Sea, as deep as 30 cm. They are found particularly near stones, mussel banks and peat banks.

  • A Dutch native?

    It's very likely that the ragworm hasn't lived in Dutch waters for very long. The first reports of ragworms found on the borders of the North Sea were only in the 20th century. The first time was in 1903, when one was found in the Oosterschelde. Twelve years later, the first one was reported in the Wadden Sea. It is not known where ragworms actually originated. It's possible that they gradually expanded their habitat from the Arctic region. Via Norway, along the British west coast and along the Straits of Dover in the southern North Sea, it's possible that in this way they eventually reached the Wadden Sea.