In wake of wasting disease, scientists on San Juan Island rear sunflower sea stars in captivity
Seven years ago, a wasting disease began killing sea stars all along the West Coast. The largest and hardest-hit species, the sunflower sea star (Pycnopodia helianthoides), is now critically endangered, reduced in numbers by some 90 percent. Scientists with the International Union for Conservation of Nature (IUCN) put it on their “red list” last week. But researchers at Friday Harbor Labs on San Juan Island say there’s reason for hope.
“You know, if somebody is drawing a picture of the seashore, there's a really good chance that there's going to be a sea star in that picture,” says Jason Hodin, the senior research scientist in charge of the first-ever attempts to breed huge sunflower sea stars in captivity.
His team started out with thousands of tiny embryos in April 2019, cultivated from adult stars that divers found around Friday Harbor on San Juan Island. The adults and their offspring are kept in aquaria in Hodin’s lab.
His team has been figuring out which cultures work best for breeding and how much to feed the babies. More than 18 months into this experiment, they have 14 small stars left.
“Nobody had ever done this before. We didn't even know if we were going to get any to survive,” Hodin says. “We faced all kinds of challenges of rearing these juveniles.”
They eat lots of clams. And he says they’re growing fast. They’re now about the size of a quarter.
“Which seems kind of small,” he says.
“But if you consider the fact that they started out at like less than 1/32nd of an inch in diameter, they basically have grown – in the course of a year or so – from the equivalent of a human baby (…) to the size of like, a really tall giraffe.”
Sunflower stars can grow as large as about three feet in diameter. They have the most legs of all sea stars and are known for being the fastest. Still, more of their kind succumbed to the wasting disease than any other. And some of the most robust populations remaining are in the Pacific Northwest.
If they can be successfully bred in the lab, the hope is to eventually release the offspring into the wild. But the program is a feasibility study, with many hurdles to clear before reintroductions can happen. The research is backed by The Nature Conservancy and the University of Washington.
CORRECTION, Dec. 17: This story has been updated. The correct location of Friday Harbor and Friday Harbor Labs is on San Juan Island.