Purple sea urchins are found mainly in kelp forests in the Pacific Ocean along the west coast of North America from Mexico up to Canada where they are quite common. I hope that you found these facts interesting and learned something new. Similar to what has happened in B.C., tens of millions of voracious purple sea urchins have chomped their way through towering underwater kelp forests in California. Common Name: The Purple Sea Urchin; General Information: The purple sea urchins are equipped with a test which is made up of calcium carbonate and then covered with skin which protects the sea urchins internal organs. Part of the sea urchin’s scientific name, Strongylocentrotus, literally means “spiky creature.” Check out this scary video about Sea Urchins… Pacific purple sea urchins are easily identifiable on the ocean floor because of their distinctive purple color. Sometimes sea urchins' spikes are soft and chalklike, while other times, they are hard and covered by a shell-like structure. Identification. The Purple Sea Urchin is one of the most common sea urchins found on Sydney's coast. Introduction. Colours can vary so dramatically in this species, from light olive green to pink to a dark purple, that the Purple Sea Urchin was once thought to be three separate species. Sea urchins, the round and spiky creatures that hang out on the bottom of the ocean floor, can be found in both shallow and deep waters. Are there any other interesting facts that you would like to share about purple sea urchins? FUN FACTS: You can tell if a sea otter preys on purple sea urchins because the otters’ teeth and bones actually turn a tell-tale purple. They are covered in pincers, tube feet, and purple spines that move via ball-and-socket joints, using these spines to grab food and protect themselves from predators.