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Diseased ochre sea star

Proactive responses are most effective for fighting marine disease, Oregon State research shows

By Sarah Gravem

The best time to deal with diseases in marine species is before an outbreak occurs, a study by Oregon State University shows.

Researchers in the College of Science and Carlson College of Veterinary Medicine evaluated more than a dozen disease management strategies and found the most promising ones were proactive rather than reactive, such as increasing marine ecosystem health and building marine disease monitoring and response networks.

The findings, published in Ecological Applications, are important because marine diseases can disrupt ecosystems and threaten human livelihoods, and because outbreaks are expected to increase with climate change, said Sarah Gravem, a research associate in integrative biology at Oregon State.

“The ocean environment fundamentally changes how diseases are passed between marine species, which means we must also adapt our wildlife management strategies to successfully respond to disease outbreaks in the ocean,” she said. “The COVID outbreak has shown how devastating disease outbreaks can be in people, and diseases in the marine environment are no different. But we are much less prepared for addressing emerging infectious diseases in wildlife.”

In particular, Gravem said, preventing or controlling outbreaks in marine systems is challenging because pathogens can travel much longer distances at faster rates in water versus air. Also, many marine species, including most invertebrates, do not have immune “memory” like humans, and many species produce larvae that float in the currents and grow up far from their birthplace.

“That means the tools that we use to control outbreaks must be adjusted to meet those circumstances,” she said. “These challenges were highlighted by the outbreak of sea star wasting disease in 2013, which easily transmitted in the ocean currents and spread from Baja California, Mexico, to the Aleutians in Alaska within a couple years, affecting at least a dozen species and often causing severe declines.”

That outbreak, Graven said, prompted scientists to reconsider how to better prepare for and manage marine diseases.

Graven and a team that included multiple graduate students looked at 17 disease management strategies to see how they compared in a marine system versus a terrestrial system. The analysis led them to identify which strategies are potentially the most effective for marine disease outbreak prevention, response and recovery.

Read the full story here.