Green urchin

Strongylocentrotus droebachiensis

Green urchin

Strongylocentrotus droebachiensis

Rocky Coast

At the Aquarium

Rocky Coast

Appearance

This sea urchin is green but often has reddish brown tones. It has short, sharp, crowded spines that are each about 1 inch long. The tube feet are darker than the spines.

Habitat

Brackish waters, and lower intertidal to subtidal depths of 984 feet, but most common in the shallow subtidal in kelp beds and rocky areas to depths of 164 feet.

Diet

Omnivorous grazer: primarily eats kelp and other algae, but will eat sponges, bryozoans, snails, or bivalves, especially blue mussels.

Life History

Green sea urchins reproduce by broadcast spawning in spring, in response to a protein released during phytoplankton blooms. Males first release sperm, which start swimming as soon as they hit the water, and then the females release their eggs. The larvae start life as plankton. Warmer water temperatures speed up development. When they settle, they undergo metamorphosis into a tiny urchin as small as 0.1 inches across. They can grow up to 3.6 inches wide and may live for 45 years.

IUCN Status

Not Evaluated

Ecosystem & Cultural Importance

These urchins are commercially harvested for their roe, called uni, a delicacy in many cultures.

Green sea urchins are eaten by a variety of fish and invertebrates and even by polar bears and walruses. In the NE Pacific, they have many predators, including a variety of fish: stout eelblennies, flounders, and wolf eels; a variety of invertebrates: giant pacific octopuses, oregon hairy triton snails, king and snow crabs, and various sea stars (including sunflower and leather stars), and many different kinds of birds: glaucous-winged and American herring gulls, various eiders, harlequin ducks, and albatrosses, and finally, sea otters.

Northeast Pacific: Alaska to Oregon, Atlantic Ocean and Baltic Sea

You can find sea urchins all over rocky coasts.

Their mouth has 5 strong and sharp teeth that they use to scrape diatoms and coralline algae off of rocks.

Citations & Other Resources

Dvoretsky, Alexander G., and Vladimir G. Dvoretsky. inchesAquaculture of green sea urchin in the Barents Sea: A brief review of Russian studies.inches Reviews in Aquaculture 12.4 (2020): 2080-2090.
Aquarium of the Pacific
Global biotic interactions website
Invertebrates of the Salish Sea
Puget Sound Museum of Natural History

Green urchin

Green urchin

At the Aquarium

Appearance

Habitat

Diet

Life History

IUCN Status

Ecosystem & Cultural Importance

Citations & Other Resources

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