- 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: Australian.museum; dpi.nsw.gov.au and personal experience.
