Gray sea pen

WHAT DOES IT LOOK LIKE?

The feather-like outline is formed by a central axis and small side portions carrying the polyps, the animals living together in this sea pen. The shape narrows below into a peduncle, the smooth portion beneath the branching area.

Several sea pens share this feather-like appearance. The general outline alone does not reliably distinguish them.

WHERE DOES IT LIVE?

The gray sea pen lives on soft seabeds, mainly sandy or muddy ones, sometimes in relatively calm areas where organic particles are abundant.

It can be seen alone or in small groups on sedimentary plains. When disturbed, it can partly withdraw into the substrate.

WHAT DOES IT EAT?

Food-bearing water passes through the sea pen’s plume. Feeding polyps on the expanded parts open their tentacles and retain small planktonic prey with help from stinging cells. Catches nourish a colony of individuals connected by an internal network. Feeding is distributed among numerous specialised units. A close look reveals tentacle crowns, the capture points on this seemingly single animal.