Green Sea Urchin (Strongylocentrotus droebachiensis)

Description: Green sea urchins are a member of the echinoderm phylum, meaning that they are relatives of sand dollars, sea star, and sea cucumbers. Their body is encased in a round endoskeleton, covered in spines and tube feet about 9 cm in diameter. Like their name suggests, they are usually green in color, but can have reddish-brown or purple colored spines on occasion. Their spines are relatively short, about 2.5 cm in length and finer than other urchin species. 

Habitat: Green sea urchins range from Alaska to California, and are typically found in sheltered rocky intertidal zones and kelp beds that are protected from direct surge. Although Haystack Rock is included in their habitat range, it is rare to spot them among the tide pools here.

Diet: The diet of a green sea urchins consists of kelp and other algae. They will occasionally scavenge on fish and invertebrates. 

Tide Pool Tidbits:

• Predators of green sea urchins include sea stars, crabs, wolf eels, large fish, and sea otters. 

• Green sea urchins are the only commercially harvested urchins in Alaska. 

• Sea urchin tests (exoskeletons) have an intricate pattern, and are covered in small bumps. These bumps are the pivot point in which the spines move. 

• The spines are used for protection, and can be painful if you are penetrated by them, but they are not venomous. 

References: Biodiversity of the Central Coast