Quills but no ink - marine sea pens

This is an AUV still image showing habitat of the Freycinet Marine Park at ~89 metres, including sandy substrate, sea pens and sponges. Sea pens are colonial marine organisms and each individual pen is made up of many animals. These animals are called polyps and they look like miniature anemones with eight tentacles which they use to catch plankton and other small organisms from the water column to feed. Sea pens typically occur in deeper waters where there is less turbulence, and unlike most soft corals they occur in soft sandy environments, anchoring themselves in the sediment with a bulbous base.