Scientists have identified the bacterium Vibrio pectenicida strain FHCF-3 as a causative agent of the devastating sea star wasting disease (SSWD) that has killed billions of sea stars along the Pacific Coast of North America since 2013.
Why it matters: The discovery marks a significant milestone in understanding and combating SSWD, which has decimated sea star populations, particularly the sunflower sea star (Pycnopodia helianthoides), leading to uncontrolled growth of sea urchin populations and widespread loss of kelp forests.
The details:
- Researchers conducted exposure experiments using tissue extracts, coelomic fluid, and effluent water from infected sunflower sea stars, observing disease symptoms and mortality in the samples.
- Deep sequencing of diseased sea star coelomic fluid samples revealed a dominant presence of Vibrio pectenicida.
- Vibrio pectenicida strain FHCF-3, cultured from the coelomic fluid of a diseased sunflower sea star, caused disease and mortality in exposed healthy sea stars, confirming it as a causative agent of SSWD.
The identification of the pathogen allows for culture-based experimental research, broad-scale screening for pathogen presence and abundance, and the development of targeted recovery strategies.
What they’re saying:
- “I have been waiting for this for a long time,” said Dr. Christopher Harley, a marine biologist at the University of British Columbia who was not involved with the research.
- “To have one pathogen, V. pectenicida, stand out so clearly as causing the disease was surprising and exciting,” said Dr. Alyssa-Lois Gehman, a marine ecologist at the Hakai Institute in British Columbia and lead author of the study.
- “For me, it’s the discovery of the decade,” said Dr. Drew Harvell, a disease ecologist at the University of Washington and part of the research team, calling the finding “incredibly fulfilling and important” after years of effort.
The impact: The discovery paves the way for more comprehensive efforts to restore affected sea star populations and maintain the delicate balance of marine ecosystems along the Pacific coast. Potential strategies include selecting individual sea stars with the greatest resistance to the bacterium and using probiotics to help sea stars deal with pathogens.
What’s next: Researchers are now investigating how the bacterium is transmitted, whether it is native to the coasts of North America or introduced, and if it accumulates in the food of sea stars. Answering these questions could help prevent future outbreaks and inform ongoing sea star recovery programs.
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