Watch Baby Sea Stars Grow in Shedd Aquarium’s Care with Debut on Exhibit

Tucked in a small habitat in Shedd Aquarium’s Polar Play Zone, a group of tiny orange-brown sea stars tell a much bigger story. Over the past year, Shedd has been raising critically endangered sunflower sea stars (Pycnopodia helianthoides) as part of the Association of Zoos and Aquariums (AZA) Saving Animals From Extinction (SAFE) program. Now, guests have the chance to spot the growing sea stars on exhibit and learn about how these animals serve as ambassadors for the threats facing their wild counterparts.

The sunflower sea star is one of the largest species of sea stars in the world, growing up to three feet in diameter with up to 24 arms. Yet in their larval form, the sea stars are microscopic in size. Since arriving in early 2024, the animals grew over 16,000% and are currently around two inches in diameter.

In the beginning, the microscopic larvae floated through the water and ate tiny phytoplankton, a food source grown at Shedd that guests can see in the Plankton Revealed exhibit. Over a month later, the sea stars settled on the bottom of their habitat and began growing arms. The juvenile sea stars are now eating pieces of salmon, caviar, fish, shrimp, clams and squid.

“While you might not picture it when looking at these young animals, sunflower sea stars are actually voracious predators and play a major role in controlling the urchin population in kelp forests,” said Rachel Zak, senior aquarist of aquarium sustainability and institutional representative on the sunflower sea star SAFE program at Shedd.

Sunflower sea stars are a keystone species in kelp forests, meaning they are vitally important to the health of the ecosystem. The sea stars eat urchins, which prevents the urchins from overgrazing and destroying the kelp. In other words, sunflower sea stars help protect the habitats of animals like sea otters, leopard sharks, giant sea bass and many others. Plus, kelp forests provide benefits to people too by supporting fisheries, enabling ecotourism, reducing coastal erosion and capturing carbon.

"Kelp forests support a diverse array of marine life, much like coral reefs do, and these sunflower sea stars serve as a reminder of how the delicate balance of nature is facing a number of threats that can have a rippling effect on an important ecosystem,” said Zak.

Sunflower sea stars are critically endangered and have experienced significant declines across much of their range, primarily due to sea star wasting disease. This mysterious disease causes sea stars to rapidly decay in just a few days and has reduced the global population of the species by over 90%.

Shedd is leveraging its unique expertise in larval rearing – raising young animals through the early stages of development – to contribute to the collaborative SAFE program to save sunflower sea stars from extinction. The program utilizes the skills, resources and facilities of accredited partners like Shedd to support the recovery of the species through research and restoration work. The sunflower sea star is one of 28 species that Shedd has committed to safeguarding through the aquarium’s Reverse the Red Day pledges to reverse, or at least halt, the decline of endangered species.

By raising these larval sunflower sea stars, Shedd has already collected valuable data about the optimal conditions the sea stars need to survive and will continue to learn more as the sea stars develop. At Shedd, the animals also serve as powerful advocates for their species as guests can come face-to-face with the sea stars, learn about their plight in the wild and be inspired to take action for sunflower sea stars’ protection.

“This is just the beginning, and our work is far from over,” said Zak. “We know we have the skills and equipment to raise sea stars and similar species from a microscopic level, allowing Shedd to play a crucial part in saving species from extinction.”

Guests can plan a visit to Shedd and look for the juvenile sunflower sea stars on exhibit in the Polar Play Zone. It sometimes takes a close eye to find them, as the sea stars may be tucked at the top of the habitat or behind an object. Another action people can take is to donate to help fund the Sunflower Sea Star SAFE program.

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Photo/Video Credit: ©Shedd Aquarium