Nuisance algae threatens native coral reefs at Papahanaumokuakea

Published: Aug. 16, 2021 at 4:11 PM HST
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HONOLULU (HawaiiNewsNow) - Native coral ecosystems in the Papahanaumokuakea Marine National Monument are being threatened by an invasive species that’s become a big problem in a short amount of time.

Researchers recently completed a 20-day expedition to the Northwestern Hawaiian Islands and were alarmed to see how the monument’s reefs are being impacted by a mysterious algae.

“It’s never been recorded anywhere before,” said Brian Hauk, Joint Institute for Marine and Atmospheric Research resource protection specialist. “There’s no record of it in scientific publications or journals or research books, any of that kind of stuff. Nobody knows what this stuff is.”

Little is known about the nuisance algae classified as “chondria tumulosa.”

Chief Scientist Brian Hauk says it was first detected at Manawai Atoll in 2015 and six years later, it’s infesting the coral habitat.

“You have these reefs that were originally covered in coral that are now getting overgrown with this alga and as it overgrows, it can form very thick mats,” Hauk said. “It grows up to six to eight inches thick and just smothers kind of everything underneath it. It blocks off the light, cuts off the waterflow, and eventually kills everything underneath it.”

Furthermore, there are no natural enemies as fish in the area don’t appear to have a taste for it.

“This alga is either unpalatable to them or they don’t like it,” Hauk said. “Maybe it has something that smells, tastes bad or is toxic. That’s what we need further research on.”

Right now, there are no definitive explanations for its origin, but Hauk suspects it may have floated in on marine debris and researchers are racing to keep it from spreading throughout the sanctuary.

Vacuuming it out has been discussed, but that has its hurdles.

“From an operational standpoint, the logistics of trying to pull something off all the way out there, a thousand miles away and how extensive its already spread everywhere, I don’t have a lot of optimism that that’s gonna be a meaningful way to deal with it,” Hauk said. “I think it’s really, we have to isolate it to that atoll and keep it from spreading anywhere else.”

Researchers are now continuing to analyze the algae and planning a return expedition next year.

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