Earlier this week, a scientist in the San Juan Islands tweeted: “Best day ever." What triggered her joy? Sea stars. Hundreds of healthy, colorful sea stars.

A few years ago, a mysterious disease started killing multiple species of sea stars along the West Coast at devastating rates. This was concerning to scientists because sea stars are voracious predators — they are able to control populations of other sea creatures like mussels, clams and urchins. But some sea stars in the Pacific Northwest appear to be recovering. A species known as ochre sea stars, the orange and purple ones you might have spotted at low tide, seem to be stabilizing around the San Juan Islands.

Best day ever. We counted 481 adult Pisaster ochraceous at one of our sites on Orcas Island, #SanJuanIslands and no #seastarwasting. TONS of big orange stars, which have been rare after the epidemic. Kudos #CORALS2019 @CornellCALS @edyong209 @SeaDocSociety pic.twitter.com/5Q0leaswqr — Drew Harvell (@DrewHarvell) April 24, 2019



Drew Harvell, an ecology professor at Cornell University and an affiliate professor at the University of Washington, said they’re finding stable populations at multiple sites being monitored in that area. “And virtually all of the stars, except for maybe one or two, were healthy. So that was really good news,” she said.

What really made Harvell happy was what she found at a site on Orcas Island that was home to thousands of ochre stars before the outbreak. Her team counted nearly 500 ochre stars at the site and saw a resurgence in orange stars. Harvell said different colored stars have died more rapidly than others during this epidemic and at quite a few sites it seemed the orange stars were taking a hit. “At most of our sites we only have the purple ones left,” Harvell said. “But at this one site there were just so many of the orange ones that we were happy to see them and happy to see that they had obviously survived or re-migrated back following the epidemic.” Harvell said it’s a relief to see that ochre stars seem to be pulling through okay after the outbreak.