Red Sea Urchin
Family: Strongylocentrotidae, a family of sea urchins.
Size: To about 12-13 cm across.
Distribution: I don't think this species is found near Australia at all, though they're in the Sydney Aquarium. Internet sources says the northeast Pacific Ocean from Alaska to Baja California, Mexico. There are many other sea urchin species that are found in Australian waters though.
Status: Safe for now.
Habitat: From shallow waters near the low-tide line to depths of greater than 100 metres.
About the Red Sea Urchin
Lifespan often exceeds 30 years, and scientists have found some specimens to be over 200 years old! They have the ability to regenerate lost spines.
Diet: The Red Sea Urchin has a mouth with special jaws (Aristotle's lantern) located on the bottom (oral) surface. Its preferred diet is seaweeds and algae, which it scrapes off and tears up from the sea floor.
Danger: Many sea urchins, including the Red Sea Urchin, can be dangerous to humans as their sharp spines can penetrate our skin, break off, and get infected. For example, if you walk on one barefoot.
Economics: Red sea urchins are harvested commercially for their reproductive organs, primarily for export to Japan.