Project Description

These green sea urchin (Strongylocentrotus droebachiensis) shells or tests were collected near Vancouver, BC when I first started diving in the Pacific Northwest.  Tests are made up of calcium carbonate to give them strength.  The many bumps you can see on the tests are where spines were once attached.  A cup-like base to each spine would rest over these bumps.  A living green sea urchin can use muscles and tissue attached to the spines to direct them towards a threat.  These animals were herbivores and ate a wide variety of algae.  The green sea urchin can grow to 3.6 inches (9 cm) across, with a range that is circumpolar and includes Japan, as well as northern Alaska to northern Washington.