Animal Sex in the City

Rebecca Albright, an Academy curator of Invertebrate Zoology, is almost literally a doctor of coral love. As ocean warming and climate change cause coral reef bleaching across the world, Albright and Academy scientists are testing their resilience and encouraging their growth at the Coral Regeneration Lab (CoRL).

Under Albright’s supervision, the Academy became the first aquarium in the United States to spawn coral in a lab setting—and they’ve recently bred a second generation of coral from those original spawns.

Creating a coral family tree is no easy process, requiring some intensely monitored mood-setting. Because corals use environmental cues to reproduce, Albright and scientist Elora Lopez-Nandam will adjust an enclosure’s water temperature and change lighting to simulate natural seasonal and lunar cycles, all factors that trigger coral spawning.

Once the team sets the mood, the spawning event unfolds: Corals release tens of thousands of tiny, couscous-sized gamete “bundles”—packets of sperm surrounded by unfertilized eggs—into surrounding water. These bundles burst, mingle and fertilize, and then transform into free-swimming larvae in search of a place to call home.

Steinhart Aquarium is home to nearly 60,000 plants and animals—at least 2,000 of which are fish. Though some are imported from far-off oceans and partner aquaria across the country, the Academy has a Fish Egg Catalog Project that encourages the strategic reproduction of fish in the aquarium and their sustainable collection across the globe. It is part of the Academy’s broader Larval Rearing Program.

As animals who reproduce through a process called broadcast spawning, many of the Academy’s fish will release unfertilized eggs straight into the water column, where these microscopic eggs either fertilize and float—or are left alone to sink and be eaten. Love hurts.

“The egg catalog is so important because it provides data about the complete life cycles of particular animals—it gives you the ability to aquaculture species of interest to an institution,” said Kylie Lev, one of Steinhart Aquarium’s curators. “This reduces the amount of animals you take from wild sources, and we share these resources with other zoos and aquariums.”

Sunflower stars are incredibly important keystone predators in California’s kelp forest. Sometimes as heavy as 20 pounds—the weight of a hefty watermelon—these massive, multi-armed stars were particularly hard-hit by sea star wasting disease.

“An estimated 90 percent or more of Pycnopodia died during the wasting event,” Lev said. “Our long-term goal is to breed sunflower stars and reintroduce them to the wild—especially at a large enough scale to regrow their population in the Pacific.”

The Academy’s Larval Rearing Program collaborates with several organizations to breed sunflower stars, which are notoriously difficult to reproduce in an aquarium setting. AZA organizations such as the Aquarium of the Pacific, Henry Doorly Zoo, and Birch Aquarium have successfully spawned sunflower stars and are working to raise awareness about their conservation challenges.

The Academy is excited to bring the echinoderm lovefest back to San Francisco this Valentine’s Day, when biologists plan to hold their next sunflower star spawn.

Even the spikiest among us procreate: The Academy also raises several types of sea urchins, another broadcast spawner and keystone species for our aquarium ecosystems. While biologists in the Larval Rearing Program will raise the urchins to adulthood, Academy veterinarians are responsible for helping them reproduce.

“With urchins, they require vigorous shaking or rotating, stimulating the kind of movement they’d naturally get from the ocean’s waves,” said Lana Krol, DVM, an Academy veterinarian. “We do the urchin dance, holding them in our hands and shaking them until the urchins spawn eggs and sperm.”