Sea Stars Of The Pacific North West

Class Asteroidea
Order Velatida
Family Solasteridae

MORNING SUN STAR

Solaster dawsoni

Identification:
8 to 13, but most often 11 or 12 gradually tapering arms. Aboral surface smooth with small plates. Chocolate brown to orange. To 40 cm (16 in) across.

Range:
Northern Alaska to central California. Also China, Japan and Siberia; intertidal to 420 m (1,378 ft).
Notes:
This voracious predator might better have been named the "DEATH STAR" because it primarily eats other sea stars. Almost every sea star found in the PNW exhibits a dramatic escape response when touched by the morning sun star. Most increase their rate of movement significantly, trying to outrun the predator. But some stars, such as the leather star and the purple star, are “slow pokes” and readily captured. In field studies I carried out in Jervis Inlet, BC, the LEATHER STAR comprised 50% of stars being eaten. This corresponded directly to the high abundance of LEATHER STARS in this area.
Other stars, such as the long-armed rainbow star and velcro star fight back aggressively, coiling pincer-laden arms around the arms of the morning sun star, inflicting thousands of painful nips. The slime star is very slow, so attempting to outrun its attacker is impossible. Instead, it inflates its plump aboral surface, preventing the predator from getting a grip while releasing mucous too*.
Although it seldom reaches even one-third the diameter of a large sunflower star, touch by a morning sun star will elicit an impressive "running" response from a sunflower star. The reaction is based entirely upon the chemical "smell" of the MORNING SUN STAR, since a sunflower star will "run" no matter how small (and in reality, insignificant) the attacker.