Scientists identify bacterium behind devastating wasting disease in starfish | Marine life

A decade after the start of an epidemic of the decline of the SEA Star (SSWD) considered the greatest ever documented in the wild, the researchers identified the responsible microbial culprit: a bacteria strain Vibrio Pectenicida.

In 10 years, the bacteria has ravaged the starfly starfish (PYLIANTHOIDES PYCNOPODIA), a large starfish or starfish, along the west coast of North America, with a loss of 5.8 billion since 2013 – or 90% of the total world population. The Sunflower Sea Star is part of the International Union for the Conservation of the Red List of the Nature of Criticized Species.

Previous studies had tested V pectenicida in tissue samples and gave non -conclusive results. Instead, by examining the coelomical fluid of the SEA Stars, which acts like blood, the researchers were able to confirm with certainty V pectenicidaThe role of the SSWD because of its strong abundance there.

Infection by V pectenicida The FHCF-3 strain begins with external lesions, leading to the loss and contortion of the limbs, and ultimately kills afflicted individuals by melting their fabrics into a white paste similar to a mucus. The identification of the disease in the distressed starfish was impossible without a known pathogen, because starfish can respond with visual signals similar to other stressors of stress such as low oxygen, variation of salinity and extreme heat. The indirect link between the increase in temperatures in the ocean and the SSWD remains an area of key interest, since V pectenicida is known to proliferate in lukewarm water during seasonal variations and abnormal marine heating events.

Research, published this week in the journal Nature Ecology & Evolution, was headed by Dr Melanie Prentice and Dr Alyssa Gehman, of the Hakai Institute in British Columbia, in Canada, as part of an international collaboration of four years involving the University of British Columbia, the University of Washington and the nature conservance, among other parties.

The decline of the stars of the Sunflower Sea has ramifications for marine ecosystems beyond the loss of a single species. “Identifying the cause of the SSWD is incredibly impactful,” said Prentice. “In the absence of sunflower stars, [kelp-eating] The sea urchins are increasing, which means the loss of Varech forests, and which has large implications for all other marine and human species that count on them. »»

Varech forests offer a habitat for thousands of sea creatures, support local economies through peaches and leisure, and are culturally important to First Nations and tribal communities. They also stabilize sediments, protect storm ribs and are a significant carbon well to sequence carbon dioxide.

Although the epidemic is still in progress, hope is that this breakthrough will help recovery and treatment efforts for various species of starfish around the world and ecosystems affected by their decline. The methods explored include captive reproduction for resistant individuals and the development of probiotic solutions that can be introduced to ecosystems.

“Now that we have found the causal agent of the disease, it gives me hope that we could really do something for the star of Sunflower,” explains Gehman. “We can be really targeted in the way we work with them, and I think it will help us evolve much faster and try to fight the SSWD.”