This brightly colored sea urchin has short, blunt spines that are not sharp and poisonous like other sea urchin species. They live all over our shallow coral reefs and come in colors from pink, red to reddish brown. They grow to about eight inches and on certain reefs like Koloa Landing in Kauai they can bee seen in large groups consisting of a dozen or more!
They are called red pencil urchins because the Hawaiians many years ago used the dried out spines to write with, much like chalk on a piece of slate. The spines were also carved and used for decorations.
The Hawaiian name means “thick, stubby spines that have a red color.” Like all sea urchins there spines protect their hard skeleton, called a “test.” Their mouths are on the bottom where they have a five-part radial set of jaws for scraping algae off of the reef.
The urchin holds onto the rocky reef with hundreds of small tube feet that have suckers that are so powerful they can hold onto the rocks even in big surf!
Many sea urchin species commonly know as “wana” are eaten by people, but not the red pencil urchin. Many types of fish like to eat them but they have a hard time pulling them off of the reef then flipping them over to avoid their thick spines!
There are male and female urchins and they spawn from time to time by shooting eggs and sperm up into the sea water at the same time, to be fertilized and drift off in the currents. The eggs hatch into tiny larvae that drift at sea for a few weeks then grow into juveniles and settle down onto the rocky reef. A dozen or more red pencil urchins may all broadcast spawn at the same time, and their offspring may drift with the currents for many miles before the young settle down to grow on a whole different reef from where their parents live.
You can visit the marine science educational website to see movies of these beautiful sea urchins at www.underwater2web.com. Also, visit the nonprofit Reef Guardians Hawaii site and check out available summer school marine science programs for kids where students are taken out to seeall the sea urchin species in person and are taught all about coral reef habitats. The nonprofit web is at www.reefguardianshawaii.org.
Terry Lilley, marine biologist, lives in Hanalei. His websites are underwater2web.com and www.gofundme.com/5urrm4zw.
Source: The Garden Island