Sea urchins nestle at Ahihi Kinau
Sea urchins, or wana, nestle in rock fissures at an Ahihi Kinau tide pool Wednesday afternoon. According to the Maui Ocean Center website, urchins are the close relatives of sea stars and sea cucumbers. There are about 75 known species in Hawaiian waters, with 22 common in shallow waters. Sharp spines protect them from predators and can provide a painful sting to unwary humans. They use tube feet to cling to rocks and move. Using mouths on the underside of their bodies, urchins graze on algae.