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Deadly Sea Star Disease May Devastate Subtidal Ecosystems

Joanna Lawrence
26th October, 2016

Scientists have found that sea star wasting disease is affecting more species than previously believed. The fatal disease is killing subtidal sea stars in the Salish Sea, including the ecologically important sunflower sea star. The new study raises concerns about worldwide sea star populations. The details are in a paper that was just published in the journal PLOS One. Sea star wasting disease is a serious disorder that affects sea star species all over the globe. The infected sea star begins to develop lesions and body tissue starts to degrade. Eventually, entire limbs fall off and the sea star dies within days. The disease is caused by a virus called the sea star-associated densovirus but environmental factors may also play a role. Most research has been conducted on intertidal species since they’re the easiest to study. As a result, scientists weren’t sure how the disease was affecting subtidal sea stars. A team of researchers studied sea stars in the Salish Sea, a network of waterways that stretches from northwestern Washington state to the coast of British Columbia in Canada. The team used scientific databases plus information from the Reef Environmental Education Foundation, a citizen science project. The team found that while a few species were slowly declining, the sunflower sea star (Pycnopodia helianthoides) was severely impacted. Sunflower sea stars, major predators in the local ecosystem, were quickly disappearing. Sunflower sea stars are important predators that keep urchin populations in check. As sea stars continue to fall prey to sea star wasting disease, urchins may begin to multiply. Sea urchins eat kelp, a staple food for other animal species, and high numbers of urchins can negatively impact the entire ecosystem. The team believes that the sunflower sea star should be listed as a species of concern. The team’s findings point to the importance of studying sea star wasting disease in subtidal species. The sunflower sea star is dying out, potentially resulting in negative consequences for the ecosystem. The study highlights the urgency of researching the fatal disease, which is continuing to wipe out sea stars across the globe. REFERENCE Montecino-Latorre et al. Devastating Transboundary Impacts of Sea Star Wasting Disease on Subtidal Asteroids. PLOS One (2016).