Sunflower Sea Star

Sunflower Sea Star (Pycnopodia helianthoides)

A Sunflower sea star (Pycnopodia helianthoides) encountered during a site survey at the Endurance Oregon Shelf site (80 meters). Photo Credit: NSF-OOI/UW/CSSF, Dive R1756, V14

This sea star, found in the northeastern Pacific Ocean, is one of the largest sea stars in the world. These echinoderms can reach a diameter of 1 meter and can have up to 24 limbs. They are voracious predators, feeding on sea urchins, bivalves, gastropods, and other small invertebrates. The population was decimated by sea star wasting disease and climatic changes starting in 2013, and is currently classified as Critically Endangered on the IUCN Red List.

They were commonly seen around the Oregon Shelf site, usually near the subtidal and intertidal areas, but sightings have been more rare during recent cruises. They have a soft body, and colors range from yellow, to bright orange, to brown or purple. As they are one of the primary predators of sea urchins, they can help maintain the health of kelp forests and other seaweed communities (which sea urchins can overgraze in the absence of predators), so their population decline is a risk to subtidal diversity in general.