Scientists pinpoint the cause of mysterious sea star disease

After a decade-long search, scientists have identified the cause of sea star wasting disease as a killer bacterium that melts sea stars and has wiped out entire populations across more than 20 species from Mexico to Alaska.

This bacterium, Vibrio pectenicida, was revealed in a new study published in Nature Ecology and Evolution. For years, researchers have hypothesized that the cause may have been a viral infection. The study details how scientists collected biological samples from infected sea stars and then analyzed the genetic material to determine the microorganisms present. They found a high proportion of V. pectenicida in the infected sea stars compared to healthy ones. The infection was then recreated in the lab, confirming the cause.

Sea star wasting disease has killed billions of sunflower sea stars (Pycnopodia helianthoides), among other species. This has led to a domino effect as urchins—a common sea star prey species—have increased in numbers and wiped out the kelp forests important for many other species.

Researchers will now be able to explore linkages between sea star wasting disease, higher ocean temperatures and heat waves. Scientists hope this discovery will enable recovery efforts for sea stars and the ecosystems affected by their decline through the ability to conduct culture-based experimental research and broad-scale screening for pathogen presence and abundance in the field.