Anthozoans · Pennatulacea · Pennatulidae

Phosphorescent Sea Pen

Pennatula phosphorea

Not Evaluated

It has not yet been assessed against the IUCN criteria. See full glossary

A sea pen, a colony shaped like a quill driven into the mud: an elongated primary polyp anchors in the sediment and from it grow side branches covered in secondary polyps that filter plankton from the current.

Size

10 cm – 40 cm

Diet

Carnivore

Feeds mainly on other animals.

Social structure

Colony

Lives in large concentrations, often for breeding reasons.

Sighting difficulty

Unknown

OceanCarnivore Colonial Ocean Cnidarian

31countries 45parks 79dive sites

Fun facts

GeneralA feather-shaped colony rooted in the mud, which gives off flashes of light.
It can withdraw entirely into the sediment when disturbed, vanishing from the seabed in seconds.
Its beds form soft-bottom habitats that are protected in Europe and highly vulnerable to bottom trawling.
It is not one animal but a colony: an elongated primary polyp from which side branches bearing the feeding polyps grow, hence its quill-pen shape.
It is intensely bioluminescent, as its name indicates. Touched, it gives off waves of blue-green light that travel up the colony, passing from polyp to polyp.
It can withdraw completely into the mud if disturbed, and emerge again afterwards.
Its sea pen fields form a soft-bottom habitat protected under European legislation, and one that bottom trawling destroys easily.