Sunflower Sea Star Facts

Sunflower sea stars (Pycnopodia helianthoides) are marine invertebrates also called starfish by some and asteroids by scientists, that belong to the same family as as sea urchins, sea cucumbers, and sand dollars. Sunflower sea stars play a critical role in our marine ecosystem because they are natural predators of sea urchins, which are notorious for destroying kelp forests. However, sunflower sea star populations have declined to critically low levels from a disease called Sea Star Wasting Syndrome. This disease has killed 99.2% of the overall population of Pycnopodia spp. in Washington state.

DID YOU KNOW?

• Sunflower sea stars are carnivores that feed on both living and dead prey with a diet consisting of opalescent squid, clams, spiny dogfish, herring, sea urchins, mollusks, and even other sea stars. 

• The adult sunflower sea star can have up to 24 limbs, each covered in extremely powerful, tiny suction cups that allow them to move along the sand climbing over rocks and other marine terrain. 

• Sunflower sea stars are important for maintaining a healthy marine ecosystem. In some places, the decline of sunflower sea stars caused by Sea Star Wasting Syndrome has resulted in a 311% increase in medium-sized sea urchins, which has decreased kelp forest densities by 30%.

• When working to hunt or find dead food, they perceive light, chemical, and mechanical changes in their environment using the outer ends of each arm that function as sensors.

• In 2020, they were placed on the International Union for Conservation of Nature (IUCN)’s critically endangered species list due to Sea Star Wasting Syndrome. This listing, which affords sunflower sea stars legal protection measures, happened with the help and collaboration of more than 60 different organizations, including SeaDoc Society.

FURTHER READING

• Iconic Sunflower Sea Star Listed as Critically Endangered 

• Falling Stars: Once Abundant Sea Stars Imperiled by Disease Along the West Coast

• Serious Concern for Sunflower Sea Stars

• Devastating Transboundary Impacts of Sea Star Wasting Disease on Subtidal Asteroids

• Disease epidemic and a marine heat wave are associated with the continental-scale collapse of a pivotal predator (Pycnopodia helianthoides)