Tentacled lagoon-worm

Alkmaria romijni


Tentacled lagoon worm © Phil Smith, Aquatonics

This tiny bristleworm, less than five millimetres long, is scarce in this country.  It lives in a tube made of mud in sheltered estuaries and lagoons.  It has six gills and a number of smooth thread-like tentacles, which it pushes out from around its mouth to gather food from the surrounding mud.   The tentacled lagoon-worm appears to require muddy sediments in brackish water, which is not fully salty.

Tentacled lagoon-worms are included in national conservation legislation because they are scarce and are vulnerable to changes to, or loss of, the habitats in which they live.

Threats to tentacled lagoon-worms include pollution of the mud and seawater; changes in the currents and the nature of the mud; changes in saltiness of the water and mud; and disturbance from dredging and bait-digging.


European distribution

In the UK, the tentacled lagoon-worm is found on the southern shores of the North Sea as far north as the Humber, along the English Channel and round into Pembrokeshire. Around Europe, it is found from the Netherlands to Denmark and in the Baltic Sea.


Conservation status/need

  • Tentacled Lagoon-Worm FactProtected under Schedule 5 of the Wildlife and Countryside Act 1981.
  • Nationally scarce marine animal.
  • The coastal lagoons in which they can be found are a UK BAP priority habitat and are listed on Annex I of the Habitats Directive.


Further information

Marine Life Information Network

Marine Species Identification Portal

World Register of Marine Species