Zoo freezes sunflower sea star larvae in conservation first

How it works: The Frozen Zoo stores and preserves biological materials, including sperm, for future fertilization and reproduction.

• In January, a female sunflower star at Birch Aquarium began her natural spawn, and her eggs were fertilized using frozen sperm from the zoo.
• Once they developed into larvae, researchers used cryopreservation techniques to save 170 vials of those baby sea stars.

Between the lines: Zoo researchers tested 100 different methods over a year to perfect the protocol for cryopreserving the larvae, according to Carly Young, research laboratory manager at San Diego Zoo Wildlife Alliance.

Threat level: About 15 years ago, local divers used to be able to find sunflower sea stars in La Jolla, but now they're functionally extinct in California, Young told Axios.

• The population has been decimated by a wasting disease that's amplified by warming oceans.

• More than 90% of the sunflower sea stars died along North America's west coast, from Baja, Mexico, to Alaska.

Zoom in: While you won't see these sea stars in San Diego's tide pools, five juveniles are on display at Birch Aquarium.

• The adults are about the size of extra-large pizzas. One has 26 arms.
• But right now they aren't available for viewing because of population management.

Yes, but: The young ones on display range in size from a sliced mushroom to a large pepperoni and they'll continue to get bigger and grow new arms.