These nickel-sized seastars hide beneath rocks during the day and forage at night for small invertebrates such as the margin snail Granulina. Females brood dozens of externally fertilizated eggs beneath their tube feet. Development is direct.
This closeup of a juvenile Pisaster was taken to show details of the seastar's dorsal surface. Blue rings surround pink spines, and tiny yellow pincers, pedicellariae, encircle the rings. Skin gills protrude from dark recesses.
General view of rounded rocky surface, with very colorful organisms. Large 4-leg sea star in foreground. Some small globular sponges, portion of larger white
This seastar is an active predator of snails, bivalves, barnacles, and small chitons. It is not feeding on the anemones it straddles here. Diameter about 45 cm. Depth 18 m.
We found this Pisaster scavenging on the remains of a bony fish near a wharf. A dead fish obviously had been thrown from the wharf and thus became available to a seastar that could not have caught the living animal. Depth 16 m.
With tube feet attached, Pisaster slowly moves its captured prey along one arm toward the mouth. The seastar then turns the snail so it can insert its stomach through the shell's aperture and digest the snail. The shell, with a barnacle attached, later will be discarded. The encounter was set up in our home aquarium.