Walking knee-deep off a remote, rocky beach in Resurrection Bay, I lost sight of my booties in the gray, milky water. At that point in our search for sunflower sea stars in Alaska, it had been raining for about a week, with more in the forecast. The second the sun came out, we took a chance on a water taxi from Seward to Fox Island.

We came up to Alaska from California to search for sunflower sea stars (Pycnopodia helianthoides) after more than 90 percent of the population disappeared due to sea star wasting disease (SSWD), an underwater pandemic that caused these meter-wide stars to twist their arms, develop lesions and essentially melt. The Nature Conservancy estimated several billion sunflower stars died between 2017 and 2020. Scientists still don’t know exactly what causes wasting, but among about 20 other sea star species, sunflower stars were one of the hardest hit.

When the sunflower stars died, the population of their prickly prey exploded—purple sea urchins started mowing down kelp forests like a herd of hungry cows, leaving urchin barrens where kelp forests once flourished.

Marine ecologist Sarah Gravem and other scientists compiled evidence to get the sunflower star listed as Critically Endangered on the IUCN Red List in August 2020. Sunflower stars have also been declared functionally extinct in California and Mexico, a huge portion of their historic range from the Aleutians down to Baja California. But stars in the colder northern waters fared better. To find these surviving stars, we packed our cameras and headed to Alaska.

Dive Alaska in Anchorage tipped us off to a few spots where divers had seen the sunflower stars recently, and that, combined with iNaturalist observations, gave us some clues as to where to look. But diving in Alaska is cold and logistically complicated—and with no fine scale, long-term population data, I began to feel like we would come up empty-handed in our search.

Swimming cautiously off the beach, staring at my dive watch, I almost crashed into the small shipwreck our water taxi captain had pointed us toward. In about 10 feet of water, I still couldn’t see my fins. Reluctantly, we swam deeper, hoping to make the best of the dive, when suddenly, the cloudy layer of grayish water disappeared. Below 15 feet we could see thick bands of sugar kelp (Saccharina latissima) draped like ribbon candy over a sloped, sandy bottom. Adorning the brown blades were small, fuzzy stars—juvenile sunflower stars.

The young stars were more spindly and skinnier than the adults and quite colorful too, ranging from bright orange and brown to dark purple and pink. I floated and watched them cruise around, gliding with ease on their thousands of tube feet—far from being a sedentary sea star, they’re one of the fastest: the cheetahs of the intertidal.

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When they first settle from their spaceship-like larval stage, they have five arms like a stereotypical sea star, but within the first few weeks, they start to add more. A full-grown adult can have upward of 20 arms. They’re fuzzier than your typical sea star too, their surface lined with tiny cauliflower-shaped pedicellariae (tiny jaws or clamps used for defense) and papillae or “skin gills.”

Gravem, the marine ecologist at Oregon State who spearheaded the Red List efforts, has been studying these “multi-armed ocean Rumbas” just south of Seward in Sitka, Alaska. Her research has demonstrated that sunflower stars keep the kelp forest ecosystem healthy both because they eat the kelp-grazing urchins and because they create a “landscape of fear” for their prey.

“The presence of the sea star, especially if it’s moving, is enough to cause reactions 3 or 4 meters away,” says Gravem. Her recent studies showed that once prey such as red and green urchins were scared by the scent of a pycno, they stayed in hiding for up to three days, meaning they ate less kelp.

In Sitka, she stocked 5-by-5-meter underwater pens with stars and used GoPros to film their behavior in an experiment called “Star Track.” The pycnos cleared paths through the reef as urchins scattered. With so few pycnos left in the wild, urchins are mowing down the kelp worry-free.

Farther south in British Columbia, marine disease ecologist Alyssa Gehman has been studying the stars at Hakai Institute’s Calvert Island field station, where fjords are home to refuge populations of sunflower stars.

“We never would have known they were there because we weren’t looking,” says Gehman. “The way we initially found out about them was through connections and collaborations with the Central Coast Indigenous Resource Alliance (CCIRA) research team.” They were doing rockfish surveys all over the central coast and reported back to Gehman that they were seeing big pycnos in the fjords. Now, she surveys the sites in collaboration with CCIRA.

It turns out a layer of glacial runoff at the surface, similar to what was clouding our dive at Fox Island, may be key to maintaining these remnant populations.

According to Gehman, in the spring and summer, glacial runoff creates a 1- to 5-meter-deep freshwater river at the surface of the fjords. She likens it to the lid on a cooler—when the water warms, only this fresh surface water warms, and the deeper, saltier waters stay colder. Sea stars don’t do well in low-salinity water, so when the freshwater lens comes through, they move deeper.

Gehman says staying in cooler water throughout the summer likely lowers disease transmission.

“It’s not that there’s no wasting, but I think that when you have outbreaks, instead of every single individual getting sick and dying, the amount of transmission of disease per individual is low enough that a couple get sick and die but the rest don’t. That’s very different than what we’ve seen basically everywhere else there is a disease outbreak.”

“IT’S RISKY TO HAVE THE ENTIRE ALASKAN POPULATION IN ONE LOCATION.”

Gehman and others believe that larvae from these fjord populations are replenishing those on outer islands too, although out at the islands with no glacial runoff and higher disease transmission, they’re not surviving past reproductive age (about 3 years old).

“There’s a lot of reasons for me to be worried about these populations, especially coming from the disease perspective,” says Gehman. “I feel mostly worried, but I also think betting against an animal with such a long larval time frame is never a good bet, because there are some aspects to how they produce and spread larvae that could still lead to recovery.”

After our starry dive at Fox Island, we lugged our gear and tanks via water taxi back to Seward and walked to where we knew finding sunflower stars was a sure bet: the Alaska SeaLife Center. Winding our way up to the second floor, we came to a sunny room with floor-to-ceiling windows overlooking the Steller sea lion habitat and a mountainous backdrop. It was stunning, but the first thing we noticed was a clear circular tank with an open top in the middle of the room. Carpeting the bottom of the tank was a pile of about two dozen sunflower stars in a rainbow of colors. There are more stars in this tank than in the state of California.

Early next year, senior aquarist and co-chair of the AZA SAFE Sunflower Star group Ben Morrow will come up from Omaha’s Henry Doorly Zoo and Aquarium to work with the roughly 36 stars at the Alaska SeaLife Center, one of the biggest captive populations in the world.

The first order of business when he arrives will be to spawn all the stars so they can determine the sex. Some of the sperm and eggs will combine to form larvae that can be shipped out to collaborators since “there’s very limited access to brood stock in general,” Morrow says. He and his collaborators will also cryopreserve sperm, eggs, and larvae so they’re ready for future breeding efforts and take tube foot samples that will travel to a genetics lab at the University of California, Merced, for genome sequencing.

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Some of the female stars will even take their first flight to new homes. “It’s risky to have the entire Alaskan population in one location, so the goal is to spread that out a little bit,” says Morrow. That way, collaborators across the country can start breeding stars too.

In the future, given permits, funding, and logistics, some of these stars could end up back in the ocean. Gravem says reintroducing stars is “a risky proposition, just because of the disease still being out there,” but compared to removing urchins or planting kelp, “it’s the only one that could actually be a long-term solution” to kelp forest recovery. “I don’t know that it will work, but I think it’s probably the most likely to work permanently. So I think it’s worth a try.”

Until then, if you see a sunflower star while you’re diving, be sure to upload it to the iNaturalist app to help scientists like Gravem and Gehman continue to track the population.