An innovative University of Hawaiʻi at Mānoa team spent 22 days this past summer exploring new ways to combat Chondria tumulosa, an invasive red algae that has spread across reef habitats in Papahānaumokuākea, including Kuaihelani (Midway Atoll).
In June, five UH Marine Option Program alumni reunited aboard the R/V Searcher for a 22-day expedition into Papahānaumokuākea. Equipped with autonomous marine robots, hyperspectral cameras and aerial drones, the team worked to better detect, map and understand the spread of Chondria.
Why is this important? Chondria can form dense mats that smother native algae and coral. Traditional removal relies heavily on divers and is extremely labor-intensive—an especially difficult challenge in the remote Northwestern Hawaiian Islands. The goal of this research is to develop technology that can help scientists find and map infestations over large areas, identify priority locations, and eventually make control and removal efforts more targeted and efficient.
Researchers are also investigating ways to actually control the alga, including treatments that can kill Chondria fragments and prevent them from spreading. Hawaiian green sea turtles (honu) have even been observed grazing on Chondria at Kuaihelani, although researchers are still determining whether this could play a useful role in controlling the invasive algae without contributing to its spread. Chief Scientist Keolohilani H. Lopes Jr., a MOP alumnus and UH Mānoa natural resources and environmental management PhD candidate, says,
“We have a unique opportunity to work with brilliant marine roboticists to develop tools to help combat one of Hawaiʻi’s most mysterious and potentially devastating marine macroalgae species, Chondria tumulosa.”
The 2026 June expedition is an important step toward a larger goal: moving beyond simply finding Chondria to developing practical, scalable ways to protect reef ecosystems from its continued spread.
For Kuaihelani and the rest of Papahānaumokuākea, better tools for detecting and managing this invasive alga could make a vast difference in protecting these remote and extraordinary reef ecosystems.
Jeff Kuwabara, the expedition photographer, not only took incredible photos of corals surrounding Kuaihelani, but also of the beautiful birds living on the island. Mahalo, Jeff, for sharing these photos with us!
