Spirobranchus cariniferus, commonly known as the blue tubeworm or spiny tubeworm, or by its Māori name toke pā, is a species of tube-building polychaete worm endemic to New Zealand.[1] [2] [3]
This species forms patchy, belt-like colonies of hard, white, triangular tubes, each containing a bright blue worm. These are cemented to the shaded side of rocks in the lower to mid-tidal zone. It may also inhabit hard objects such as dead shells and small stones. When submerged, it puts out a fan of dark-blue tentacles to feed, which it retracts during low tide.[4]
Individuals living in Dunedin's Otago Harbour are the only polychaetes known to host gregarine parasites. Little is known about their impact on the worms, but it is likely to be a negative one.[5]
Adult worms can grow to 40 mm long and 3 mm wide.The tube is hard, white, and triangular in cross-section with a ridge running along the top. This extends from above the tube opening to form a sharp protective spine. The operculum is a flat, calcareous plate. Its stalk is flat with prolonged wings.Its body is a yellow to orange colour towards the posterior and a bright blue at the anterior. Radioles are a bright to dark blue with some white bands.
The blue tubeworm is a surface filter feeder. It feeds on plankton and organic particles, which it filters from the water using its fan of tentacles.[6] [7]
It is found throughout New Zealand. Its tube layers can be up to 30 cm thick in the cooler climate of the South Island.