Light blue circles around base of each white spine.
14-19 inches in diameter.
Sexes look identical.
British Columbia to southern California.
Live in low and subtidal regions.
Mostly found in protected coastal areas.
Found on pier pilings, sand, and rocks.
They reproduce by broadcast spawning (releasing sperm and eggs into the water column).
Spawning season is March-April.
Larvae start life bilaterally symmetric (meaning there is one line where they can be divided into a mirror image) and then settle into adult form as pentaradially symmetric (there are five lines where they can be divided into a mirror image).
Barnacles, snails, mussels, limpets, ornate tubeworms, California piddock bivalve.
Sheep crab, sea gulls, sea otters.
They can detach a limb to escape a predator and can regrow that limb later. If they are cut in half, they can grow into two sea stars!
Sea stars are considered keystone species, because if they are removed from an ecosystem, the entire ecosystem can end up out of balance, with certain species taking over and out-dominating other species.
The giant spined sea star can be trained to associate a light stimulus with food.
Sources: Wildcoast; Encyclopedia of Life; biology.fullerton.edu; UC Irvine Biology; SIMoN