Pisaster ochraceus

Phylum Echinodermata

Class Asteroidea

Order Forcipulatida

Suborder Asteriadina

Family Asteriidae

(http://www.sanctuaries.nos.noaa.gov/pgallery/pgolympic/living/living_3.html)

Description: Pisaster ochraceus range anywhere up to 25 cm with white spines across their aboral side. They range in color from vibrant purple to bright orange as well as shades of brown and red. They have stiff arms and are rigid, not slimy and soft like Pisaster brevispinus.

Habitat: Pisaster ochraceus is found in marine waters in the intertidal zone up to depths of 100 meters. They can often be found on rocky shores and pilings within the Puget Sound. In Boston Harbor they can be found right on the docks. Their distribution is from Baja, California to Prince William Sound, Alaska.

Prey: Pisaster ochraceus consist mostly on bivalves and gastropods (Mytilis californiamus, Tegula funabralis). Pisaster ochraceus feeds by prying its prey apart using the suction of their tube feet, then exerting their stomach into the shell of its prey to digest it.

Life span: Sea stars don’t have an expected life span; they will keep aging until they are physically disabled. Sea star can also regenerate their limbs and tube feet.

Physiology: When Pisaster ochraceus is outside of the water, its body composition is stiff and rigid to withstand the environment (waves, current, etc). When inside the water, it is more fluid and flexible. Because Pisaster ochraceus has such a heavily calcified skeleton, it doesn’t move as fast compared to Pycnopodia helianthoides or Pisaster brevispinus.

Sources

Kozloff, Eugene N. Seashore Life of the Northern Pacific Coast; An Illustrated Guide to Northern California, Oregon, Washington, and British Columbia. University of Washington Press: Seattle, 1993.

http://www.sanctuaries.nos.noaa.gov/pgallery/pgolympic/living/living_3.html (Picture in the top right.)

Lambert, Philip. Royal British Columbia Museum Hand Book, Sea Stars of British Columbia, Southeast Alaska, and Puget Sound. UBC Press: Vancouver, 2000.

Links

http://www.calacademy.org/science_now/archive/wild_lives/ochrestar.html

Http://www.nwmarinelife.com

Produced by: Tara Cockerill, 5/18/04