Sabella spallanzanii - Fanworm
European Fanworm (Sabella spallanzanii Gmelin, 1805) is a polychaeta ringworm from the Sabellidae family, vaguely resembling an antozoo from the outside but actually belonging to a completely different type of animal.abella spallanzanii Fanworm Spirografo intotheblue.it
In the video we see him at the mercy of a current generated by the wave motion in a few meters of depth, totally everted from the tube that protects it, filtering debris in suspension and plankton of which it feeds.
It lives inside a tube of paper consistency, produced by the animal, in which it withdraws in case of danger. It is equipped in the cephalic zone with filiform gills covered with cilia and mucous glands, whose function is to mix food particles. These have a color that alternates between yellow-brown, dark brown and white.
The European fanworm is a rather successful organism whose larvae can easily disperse to new locations. As an invasive species and a filter feeder, it competes with native species and with farmed oysters and mussels for food. Its presence in an area can alter water flows and sedimentation. In seagrass meadows it may grow on and weigh down leaf blades. There may be a reduction in the population of cumaceans, harpacticoid copepods and ostracods in the sediment and an increase in amphipods, barnacles and other species of tube worms on the tubes.
European fanworm is able to bioaccumulate bacteria and has a profound effect on the marine bacterial environment. Microbes build up in the worm and are present at much higher concentrations in its tissues than in the surrounding water and this means the worm can be used as a bioindicator. It is efficient at filtering out Vibrio spp. bacteria that are pathogenic to fish and shellfish and can cause foodborne illness in man. It can also potentially be used for remediation of polluted water near sewage outlets.