Giant Spined Sea Star
Pisaster giganteus

Physical Description

• Large, five-pointed sea star.
• Red, brown, tan, or purple coloring.
• Light blue circles around base of each white spine.
• 14-19 inches in diameter.
• Sexes look identical.

Range

• British Columbia to southern California.

Habitat

• Live in low and subtidal regions.
• Mostly found in protected coastal areas.
• Found on pier pilings, sand, and rocks.

Reproduction

• 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).

Diet

• Barnacles, snails, mussels, limpets, ornate tubeworms, California piddock bivalve.

Predators

• Sheep crab, sea gulls, sea otters.

Interesting Facts

• 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

Photo: David R. Andrew