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Green Sea Urchin Strongylocentrotus droebachiensis


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Green Sea Urchin
credit: Hannah Robinson/CCSA

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Category: Seastars and relatives view all from this category

Description Strongylocentrotus droebachiensis is commonly known as the green sea urchin because of its characteristic green color. It has the longest genus-species names in the animal kingdom. It is commonly found in northern waters all around the world including both the Pacific and Atlantic Oceans to a northerly latitude of 81 degrees and as far south as the Puget Sound (Washington State) and England. The average adult size is around 50 mm (2 in), but it has been recorded at a diameter of 87 mm (3.4 in). The green sea urchin prefers to eat seaweeds but will eat other organisms that float by or even catch small fish. They are eaten by a variety of predators, including sea stars, crabs, large fish, mammals, birds, and humans.

It is commonly found on rocky substratum in the intertidal and up to depths of 1,150 meters (3,770 ft). It uses its strong Aristotle's lantern to burrow into rock, and then can widen its home with the spines. Usually, this sea urchin can leave its hole to find food and then return, but sometimes it creates a hole that gets bigger as it gets deeper, so that the opening is too small for S. droebachiensis to get out. S. droebachiensis has the unique ability to survive in waters that are euryhaline (low salinity). This allows it to flourish in the south Puget Sound. Acclimation and size are important factors as larger individuals have a lower surface area to volume ratio and can handle the increased osmotic tension.

Warning This spiny creature is painful if stepped on.

Habitat Rocks, Algae.

Range Alaska, Mid-Atlantic, Northwest, Eastern Canada, New England, Western Canada.