After the loss of 90% of the global population in just 10 years, researchers now hope to stop the disease.
Over 5.8 billion sunflower sea stars have been wiped out by this devastating disease in a decade — nearly 90% of the global population of the species.
The sunflower sea star is now listed as Critically Endangered on the IUCN Red List of Threatened Species.
A Silent Catastrophe
The mystery has loomed since 2013, when sunflower sea stars (Pycnopodia helianthoides) — once abundant in the Pacific Ocean — began to disappear.
The disease, known as Sea Star Wasting Syndrome (SSWS), causes lesions, limb loss, deformation, and ultimately the disintegration of the starfish’s body into a white mushy paste.
Researchers then discovered a strong bacterial strain present in diseased sea stars but absent in healthy ones, identified as Vibrio pectenicida.
The findings, published Monday in the journal Nature Ecology & Evolution, represent a major breakthrough in the fight against this marine epidemic.
“Identifying the pathogen finally gives us a starting point to act,” explained Dr. Alyssa Gehman, co-lead author of the study alongside Dr. Melanie Prentice, both affiliated with the Hakai Institute in British Columbia, to The Guardian.
The research linked the bacterium to the disease through analyses of the coelomic fluid — essentially the sea stars’ blood — where a high presence of Vibrio pectenicida was detected in affected individuals.
Impact on Biodiversity
The identified strain, nicknamed FHCF-3, particularly thrives in warm waters, suggesting a possible connection to ocean warming, according to The Guardian.
The decline of this sea star species has caused a disruption in the marine balance. Sunflower sea stars are major predators of sea urchins, which themselves feed on kelp—marine algae that flourish along the shores.
Without their natural predators, sea urchins multiply and attack kelp forests. These ocean “lungs” shelter thousands of species, protect coastlines, store carbon, and support the human communities that rely on them.
Recovery of Sea Stars
Although the SSWD epidemic is still ongoing, this discovery renews hope. Scientists are already considering concrete solutions, such as breeding resistant sea stars in captivity or introducing probiotics into ecosystems.
“Now that we know what we are dealing with, we can act more strategically,” explained Alyssa Gehman. “[And] accelerate recovery efforts.”
