Project Description

While diving I noticed this retracted orange sea pen (Ptilosarcus gurneyi).  It’s amazing that this large colony has the ability to expel water so that it can retreat into the sand or mud for protection.  The orange sea pen was named after an old-fashioned quill pen which it resembles.   Each sea pen is a colony of polyps (small anemone-like individuals) working together for the survival of the whole.  Each polyp is specialized and one even develops into a rigid central tall stock that supports the other polyps and provides an anchor to the ocean floor.  The orange sea pen grows to around 18 inches (48 cm) tall, with a range from northern Alaska to northern Mexico.