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maximum 1 centimeter


transparent with gray tints


maximum 1 year


diatoms and bacteria on the mud particles


shelducks, young eiders, waders, fish



  • Dut: Slijkgarnaal
  • Lat: Corophium volutator (C. arenarium)
  • Eng: Corophium
  • Ger: Schlickkrebs
  • Dan: Slikkrebs
Corophium, Wim de Bruin


If you are on the tidal flats on a quiet day, you can hear the corophium wallowing in the mud. They make a remarkable dry crackling sound. Corophium are very common inhabitants of the muddy flats. In the summer, their population can reach densities greater than 10,000 per square meter. They dig tunnels, from which they gather food with their long tentacles, consuming as much as 4000 diatoms per day. This amount of diatoms must be processed and therefore corophium eject wastes up to 1000 times a day.

  • Distribution and habitat

    Corophium is common on the higher lying mudflats of the Wadden Sea and delta waters. They live in U-shaped tunnels in the mud. Corophium doesn't just dig its tunnel anywhere. Searching for a suitable neighborhood is serious business. The grain size of the mud is very important for the firmness of the tunnel and it is important for the corophium to know that food will stick to the grains. In addition, corophium is an animal that lives in groups: the more neighbors, the better. It sometimes moves its home daily, so that it is not unusual for us to see them crawling on the tidal flat bottom.
    Corophium may be fussy when it comes to its tunnel, but when it comes to natural conditions it can endure a lot. It survives well in brackish water as well as water saltier than the sea. In addition, corophium is not easily put off by low temperatures. During very cold winters, it simply freezes up during low tide and usually goes on living after defrosting.

  • Influence on the tidal flats

    Corophium is an important species in tidal regions. Many birds, such as shelduck and avocets, and young fish are crazy about this crustacean.

    Other animals are less happy with corophium. All that digging and raking of the bottom produces loose mud particles in the water. They wash away more readily, making the water more turbid. Animals that filter the water for food, such as mussels and cockles, ingest more mud. Plants are unable to take root on the tidal flats if the bottom is constantly being dug up by corophium. Without plant growth, the mudflats are as we usually see them: extensive muddy and sandy stretches without plants but with lots of benthic animals.