Sea Stars Of The Pacific North West

Class Asteroidea
Order Valvatida
Family Goniasteridae

COOKIE STAR

Ceramaster patagonicus


Identification:
Broadly pentagonal, rigid, body flat or occasionally swollen. Aboral surface with small flat-topped plates. Arms and disc bordered by large marginal plates. Yellow to pink-orange, no red patches. To 16 cm (6.3 in) across.


Range:
Bering Sea to Cape Horn, South America; 10 to 245 m (33 to 1,785 ft).
Notes:
This species was first described from the trawled collections of the research vessel Challenger in the Straits of Magellan, near Patagonia--hence the name. Common in BC fjords. Eats sponges, including the CLOUD SPONGE Aphrocallistes vastus *and the CHOCOLATE PUFFBALL SPONGE Latrunculia (Biannulata) austini*. This COOKIE STAR is usually larger than the ARCTIC COOKIE STAR and is never red. This star is also much more common than the ARCTIC COOKIE STAR and is found throughout the Strait of Georgia, especially in mainland fjords such as Jervis Inlet and Knight Inlet. It is not uncommon to see several on a single, moderately deep dive in Agamemnon Channel, at the entrance to Jervis Inlet*.
In lab experiments I observed that when attacked by a MORNING SUN STAR, a COOKIE STAR puffed itself up and did not attempt to escape by running away from trouble (a doubtful strategy since the COOKIE STAR is so slow). Later, I found the MORNING SUN STAR with its rays curled far back over its aboral surface, the stomach everted and the tube-feet extended. It was almost as though the attacker had been poisoned. The MORNING SUN STAR recovered in two to three days and attacked again, with the same results. Although four COOKIE STARS were held for over two months in a tank with several hungry MORNING SUN STARS, none was ever eaten. It seems that the COOKIE STAR has some sort of chemical defence that is very effective against sea star predators. But exactly what this compound is and how it works is unknown.