Identification Photos: Crowned Urchin, Centrostephanus coronatus: The Crowned Urchin is characterized by its very long, slender, serrated, and very sharp dark purple spines which can be up to three times the diameter of the test. The spines are present at a level of twice those found on similar urchins and become brittle when dry.

Crowned Urchins reach a maximum diameter of 6 inches but are normally found with a diameter of 2 inches. They are abundant yet very reclusive, setting up homes below the maximum low tide line in fairly tranquil waters by attaching themselves on the underside of rocks and clearing out large territories for themselves. The Crowned Urchin appears much larger than it is because it is in continuous motion with the outstretched spines moving freely in the water as it feeds continuously.

This is one of the best protected species in the sea with an excellent defense mechanism against all predators as the tips of the spines are exceedingly sharp yet very fragile; in humans, they poke you and then small pieces break off under the skin causing misery.

The Crowned Urchin feeds primarily on algae and corals via five pairs of blunt, light colored spinlets around the underside of the oral plate. Due to the size of the spines, it cannot be confused with other urchins. The Crowned Urchin is found in all intertidal Mexican waters.

Note: the Crowned Urchin is very similar to, and often debated in the scientific literature as being related to or one and the same as the Longspine Urchin, Centrostephanus longispinus, which is found in most areas of the Atlantic Ocean.

The Crowned Urchin is an Echinodermata (which includes Brittle Stars, Sea Cucumbers, Sea Lilies and Starfish) and a member of the Centrechinoida Family. Globally there are 700 known species of sea urchins. They all are spiny, hard-shelled animals that live on the rocky sea floor, normally attached to rocks. They have the ability to move but do so very slowly.

They have a five-sided radial symmetry and their skin has hard, chalky plates that form a shell called the test. The body is globular with long spines that radiate outward. These spines are used for protection, locomotion, and collection of food.

They also have five paired rows of tiny tube feet with suckers utilized for locomotion and attachment to the sea floor.

They do not have a brain. The mouth is located on the underside. It is claw-like with five tooth-like inward pointing plates known as Aristotle’s Lantern. The anus is on the top of the shell.

Sea Urchins feed on plants and animal matter including algae, barnacles, and decaying matter such as dead fish, kelp, mussels, and sponges. They are preyed upon by birds, crabs, fish, sea otters, snails, starfish and humans.

Sea Urchins reproduce via external fertilization with a litter consisting of several million eggs. It takes several months for the juveniles to form and 2 to 5 years to reach adulthood.

In California, Sea Urchins were consumed by Native Americans for thousands of years, and today they are harvested commercially by hand along the Pacific Coast by divers in waters between 5 and 100 feet. The annual harvest reached a maximum of 52 million pounds in 1988 before declining rapidly due to over-fishing and subsequent implementation of harvesting restrictions.

The end-product of interest is Sea Urchin roe, sold primarily in Japan for human consumption.

Note: being gaffed by a Sea Urchin is fairly common and with some species can be a very painful experience. It is important to determine if a piece of urchin remains embedded. If the answer is “yes," then it is important to remove it surgically within the first 12 hours since it can be extremely painful and the human body requires months to dissolve urchin spines.

Crowned Urchin, Centrostephanus coronatus: Collected at El Tule, Km. 17, Los Cabos, Baja California Sur, Mexico, tidal pool, mid-afternoon in 70-degree water, in February 2007. Size approximately 2 inches. Second picture of a dried test with a wide squat profile, 4 cm x 1.6 cm. Description and photos courtesy of John Snow.