These starfish face extinction. Scientists are helping them mate. | ET REALITY

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Over the past decade, the sunflower starfish has gone from being a powerful predator on the bottom of the Pacific Ocean to being on the brink of extinction. natural conservation Dear All that 5.75 billion sunflower starfish died in the span of three years, a global decline of 94 percent.

The cause, scientists say, is largely climate change and warming waters, driven by what they now call wasting starfish disease. Scientists have raced to figure out how to bring these creatures, whose 24 limbs can extend up to four feet, out of the abyss.

Hope is slowly on the horizon.

The Scripps Institution of Oceanography’s Birch Aquarium near San Diego successfully spawned three sunflower starfish earlier this month, the latest success story in an extensive cross-institutional collaborative effort to help sea stars thrive. reproduce and eventually reintroduce them into nature.

“There are a lot of opportunities for good genetic diversity across the board with all of our different institutions working together,” said Melissa Torres, an aquarist at Birch Aquarium who is leading the project.

Despite their “charismatic” nature, Torres said, sunflower sea stars move quickly and decisively in kelp forests, feeding on sea urchins and other types of invertebrates that feed on the kelp beds. But starting in 2013, millions of starfish began dying along the Pacific coast, from Mexico to Alaska. That was the same year that parts of the Pacific Ocean became unusually warm as part of a broader marine heat wave, dubbed the Blob.

The starfish began to form white lesions on their limbs that would dissolve the surrounding flesh and eventually lead to their death. Researchers found that the disease affected dozens of species of starfish, but particularly harmed sunflower starfish. In California and Oregon, the species is believed to be functionally extinct, meaning the population has declined to the point that it no longer serves an ecological role or function.

Last March, federal officials recommended that sunflower starfish should be protected under the Endangered Species Act.

Without enough sunflower starfish, urchins have destroyed nearly all of California’s kelp forests, what marine biologists call “the lungs of the ocean.”

Meanwhile, researchers at various zoos and aquariums Across the United States they have been working frantically to restore the population, led in part by the Aquarium of the Pacific in Long Beach, California, and the Henry Doorly Zoo and Aquarium in Omaha.

The Birch Aquarium, located at the University of California, San Diego, has five sunflower starfish, one of the largest populations of captive sunflower sea stars in California. But until recently they didn’t know who was female or male. To determine sex, the researchers induced spawning.

In nature, starfish spawn in water (males freely release sperm and females release eggs), where they mingle and hopefully fertilize spontaneously. In the aquarium, the researchers administered hormones to the legs of three sunflower stars, about 50 inches in diameter, and waited.

After several hours, the starfish began to rise from their flat position in what the researchers described as a downward dog position, like in yoga. The eggs and sperm slowly began to appear and the researchers carefully collected them with glass pipettes. Immediately afterwards, the genetic material was cryogenically frozen.

Torres said more testing was needed to determine whether the offspring could survive diseases or parasites. Once determined, the aquarium can begin the fertilization process. And since the aquarium now knows the sex of all of their sunflower starfish, they can pair them accordingly or even share the starfish between aquariums for breeding.

He said the aquarium was thrilled to be able to “pass these genetics on to everyone else who doesn’t have the population size they need or the ability to get these genetics.”

Creating multiple generations of new sunflower-type starfish is the ultimate goal, one that has been successful at Friday Harbor Laboratories in the San Juan Islands. It took three years for the lab’s juvenile sunflower-like starfish to mature enough. but last februaryThe researchers helped the starfish complete their full life cycle.

Jason Hodin, a marine biologist who directs Friday Harbor’s sunflower starfish project, described Birch’s success as “a pretty big breakthrough.”

Now Dr. Hodin shares with Birch his secret to success, or what he calls “our cookbook for raising a starfish.”

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