html> Sarabellum: Wet and Salty

Green Sea Urchin
(Strngylocentrotus droebachiensis)

Dedicated to Dan Morris ("Ursas and urchins...") Good luck on the MCATs Dan!

green and spiky

The green sea urchin is an extremely voracious predator, scouring algae off the rocks of the Atlantic from the Arctic to New Jersey and the Pacific from Alaska to Puget Sound. They are extremely vulnerable to environmental stress and bird predation however, which restricts them to subtidal regions or deep tide pools. They aren't very common in bays and estuaries where saliniy varies, due to their inability to osmoregulate well. They eat soft algae by using a mechanism called Aristotle's Lantern, a group of 5 teeth with amazing range of motion. Huge "fronts" of urchins can clear huge areas, leaving them devoid of all but the hardest coralline algae. Aside from birds,cod, and occasionally sea stars, their other major predator is man, who harvests them for their eggs, which are a delicacy in Japan. Sea otters also eat a lot of them on the Pacific Coast. Sea urchins are echinoderms, which means they have a hard exoskeleton (echinoderm means "spiny skin"), and a water vascular system which is used to move and articulate both tube feet and spines.

Take me back to the Species of the Week!
Take me back to the Main Page!