Fast Facts: Purple Sea Urchin

  • The Purple Sea Urchin is one of the most common Sea Urchins found on Sydney’s Coast;
  • Are endemic to Australia;
  • Body colour ranges from white to green, pink, purple and black and the spines are typically different in colour;
  • Due to this colour diversity, it was once thought that the Purple Sea Urchin were three separate species;
  • They live on intertidal rocky shores and in coastal waters to a depth of 35 meters;
  • Are commonly found in waters shallower than 10 meters;
  • As benthic animals, they are often found attached to rocky reefs, stones, seagrass beds, in crevices and burrows and on sandy mud bottoms;
  • They seem to prefer areas not fully exposed to wave motion;
  • Their external skeleton surrounding their body is called a test;
  • Can reach up to 24 centimetres in test;
  • They possess a hard exoskeleton with numerous sharp, solid spines that taper to a point;
  • They have tube feet and the mouth is located on the underside of the body;
  • They feed by actively grazing rock surfaces and by trapping algae or seagrasses;
  • To protect themselves from predators and the elements, they cluster together and use their sharp spines to burrow into the rock;
  • You often see them borrowed inside their self-eroded rock surfaces;
  • They are often seen with parts of shells and sand covering its body;
  • This species is sometimes eaten by humans; and
  • In Sydney, there are bag limits and certain rock platforms have been designated Aquatic Reserves where collecting is not permitted.

References:; and personal experience.

Published by Karina Teuma Karina Teuma is a Passionate Marine Biology Enthusiast, Environmentalist, Snorkeller, Freediver, Scuba Diver and more.

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