06/17/2025 | Press release | Distributed by Public on 06/17/2025 13:25
June 17, 2025
MOSS LANDING, Calif., (June 17, 2025) - In a groundbreaking effort, a team of conservation partners froze, thawed, and settled larval giant pink stars (Pisaster brevispinus) into juveniles, the first time this process has been completed with a species of sea star. This success serves as a model for utilizing frozen larvae as a conservation tool for sea star recovery, including the critically endangered sunflower sea star (Pycnopodia helianthoides).
This first-of-its-kind achievement was the result of significant collaborative efforts from numerous partner institutions. Adult giant pink stars were spawned and their gametes cross-fertilized by scientists at the Aquarium of the Pacific, resulting in thousands of viable larvae. These larvae were cryopreserved in San Diego Zoo Wildlife Alliance's Frozen Zoo® by the organization's reproductive sciences team, with the assistance of protocols developed by partners at Omaha's Henry Doorly Zoo and Aquarium. The frozen larvae were transferred to conservation nonprofit Sunflower Star Laboratory, where they were thawed, grown through their larval stage, and settled into juvenile sea stars.
The larval freezing process has since been replicated with larvae from adult sunflower stars held at the Alaska Sea Life Center, and University of Washington's Friday Harbor Labs, with the cryopreserved larvae held at Omaha's Henry Doorly Zoo and Aquarium.
Cryopreservation allows for frozen larvae of these species to be held in storage for extended periods of time, affording more flexibility in creating or expanding efforts to grow sea stars under human care, and increasing the genetic diversity of individuals in the 'biobank', both key factors for accelerating sea star recovery efforts.
This collaboration is part of the Association of Zoos and Aquariums (AZA) SAFE Sunflower Sea Star Program, a multi-faceted program that incorporates objectives related to ex situ aquaculture, research, reintroduction/field work, and education/outreach.
By successfully settling cryopreserved giant pink star larvae, this team laid the groundwork for similar efforts focused on the sunflower star. Sunflower stars are a critically endangered species of sea star that serves as a keystone predator in kelp forest ecosystems, and cryopreservation is a critical tool for enhancing recovery efforts for this species.
Sunflower stars help provide balance to kelp forest ecosystems by eating and scaring urchins and other native species that graze on kelp. In 2013-2014, Sea Star Wasting Syndrome, one of the largest marine disease outbreaks on record, decimated populations of sunflower stars across their former range from Alaska to Baja California, rendering the species functionally extinct in California. In their absence, urchin populations have skyrocketed, and kelp forests have declined precipitously across much of the state, in part due to the impact of urchin overgrazing.
The novel larval cryopreservation and settlement process developed by these partners will accelerate the pace of sunflower star recovery, providing hope for building kelp forest resilience in California and along the Pacific coast.
Sunflower Star Laboratory is a non-profit that leads research and conservation to recover the sunflower star, building kelp forest resilience with our communities. Our organization is actively growing the critically endangered sunflower star and other species in our conservation aquaculture facility in Moss Landing, CA, while coordinating greater sunflower star recovery efforts across North America. We are an integral part of the Pycnopodia Recovery Working Group, a consortium of diverse researchers who are developing recovery management strategies. Sunflower star recovery is an integral part of restoring California's vanishing kelp forests, and Sunflower Star Laboratory's experienced, interdisciplinary team leads groundbreaking work to make this imperative a reality. Head to https://www.sunflowerstarlab.org for more information.
San Diego Zoo Wildlife Alliance, a nonprofit conservation leader, inspires passion for nature and collaboration for a healthier world. The Alliance supports innovative conservation science through global partnerships and groundbreaking efforts at the world-famous San Diego Zoo and San Diego Zoo Safari Park, both leading zoological institutions and accredited botanical gardens. Through wildlife care expertise, cutting-edge science and continued collaboration, more than 44 endangered species have been reintroduced to native habitats. The Alliance reaches over 1 billion people annually through its two conservation parks and media channels in 170 countries, including San Diego Zoo Wildlife Explorers television, available in children's hospitals across 14 countries. Wildlife Allies-members, donors and guests-make success possible.
Consistently ranked as one of the world's top zoos and voted 2025's Best Zoo by USA TODAY 10Best Readers' Choice Awards, Omaha's Henry Doorly Zoo and Aquarium is accredited by the Association of Zoos and Aquariums and operated by the not-for-profit Omaha Zoological Society. The Zoo features immersive exhibits and guest experiences on 160 acres in the heart of Omaha, Nebraska and is recognized nationally for its conservation, animal care and exhibit design. Omaha's Henry Doorly Zoo and Aquarium's mission is to inspire, educate and engage people to serve as lifelong stewards for the conservation of animals and their habitats. More information is available at OmahaZoo.com.
The nonprofit Aquarium of the Pacific is a community gathering place dedicated to connecting people to and conserving nature. The Aquarium's vision is to foster an inclusive community that works together to create our sustainable future. Home to more than 12,000 animals, Aquarium exhibits include Stars of the Sea featuring the Our Living Coastline touchpool exhibit, the Southern California Gallery, Pacific Visions, and Shark Lagoon. Beyond its animal exhibits, the Aquarium offers educational programs for people of all ages, including First Wednesdays featuring a variety of guest speakers. The Aquarium offers memberships with unlimited FREE admission for twelve months and other special benefits. To make a donation to help support the Aquarium, please visit the donation webpage. To visit, reservations are required for everyone and can be made at aquariumofpacific.org or by calling (562) 590-3100.