Researchers from NOAA who are investigating the mat-forming alga Chondria tumulosa in the Papahānaumokuākea Marine National Monument have observed its proliferation, which is negatively impacting Hawaiian coral reefs.
"Invasive and nuisance species are some of the most serious threats to our native ecosystems," the organization said. "This alga has the potential to negatively impact entire island-scale coral reef ecosystems."
According to NOAA scientists returning from a 23-day research expedition in Papahānaumokuākea Marine National Monument confirmed the first record of the mat-forming alga Chondria tumulosa at Hōlanikū, or Kure Atoll, about 1,350 miles from Honolulu. In 2016, when NOAA divers initially identified the alga, it was present in relatively low quantities and had not yet spread widely. However, by August 2019, this algae had proliferated, forming abundant mats that covered more than 100,000 square feet each at Manawai (Pearl and Hermes Atoll), effectively outcompeting the species that typically inhabit these ecosystems. Subsequently, Chondria was also observed in the vicinity of Kuaihelani (Midway) in both 2021 and 2022. The recent confirmation of its presence at Hōlanikū means that Chondria is now confirmed to be present at all three of the monument's northernmost atolls
According to the NOAA, the algae has the ability to create extensive, dense mats that suffocate native corals and virtually all other life forms beneath them. Interestingly, the origin of Chondria remains a mystery, and there is minimal knowledge about its ecological aspects, physiology, or any potential factors driving its biology. The species is new to science, only officially being identified in 2020, and thus far has only been recorded within the confines of the Papahānaumokuākea region.
"Marine nuisance and alien species are notoriously difficult to get rid of once they become established," said Kim Fuller, marine invasive species specialist with the Department of Land and Natural Resources. "Prevention is the most time-effective and cost-effective solution for protecting our marine resources from invasive and nuisance species."
Fuller conducted experiments to verify the effectiveness of best management practices designed to mitigate the dissemination of Chondria to other islands or atolls. As a precautionary measure to prevent any unintentional transport of Chondria to O‘ahu, the team thoroughly immersed all equipment used in the water, including their diving and research gear, in a potent bleach solution. Additionally, they applied a bleach spray to the small dive boats and the deck of Kahana II before heading back.