Researchers with the National Oceanic and Atmospheric Administration have come back with good news after their first expedition to the Papahānaumokuākea Marine National Monument in two years.
NOAA crews sailed to the Northwestern Hawaiian Islands to resume their research and monitoring of marine ecosystems within the nature preserve in July and early August.
During their expedition, researchers found coral reefs around French Frigate Shoals, now known as Lalo, are recovering from storm damage. In 2018, Hurricane Walaka turned the vibrant reefs of Lalo into lifeless rubble.
"Coral reef biologists got to survey the area, and we saw recoupment of different types of corals coming in, as well as the return of the fish — something that they hadn't seen on their original surveys after the hurricane," said Jason Leonard, field operations coordinator at Papahānaumokuākea Marine National Monument.
Leonard says researchers went to several other sites that were severely impacted by Hurricane Walaka, which also showed signs of recovery.
"From their expert opinion, things look promising and making a way back."
Crews also conducted follow-up surveys at Lalo of a shipwreck site discovered by crew and students aboard the Hikianalia and Hōkūleʻa earlier this year. The wreckage is believed to have been from the 1800s.
Elsewhere in the nature preserve, researchers saw more positive signs of reef recovery.
In 2015, the reefs around Kapou, or Lisianski Island, experienced a severe coral bleaching event, killing a majority of corals. To make matters worse, a grounded buoy and chain left scarring on the reef.
"But when we went back there, [researchers were] amazed at how things are making a comeback," said Leonard. "Not anything really fast, but there are signs that a lot of the algae that was overgrowing these corals were looking in better shape, and fish were there."
The expeditions also took researchers to Manawai, or Pearl and Hermes Atoll, where crews followed up on an invasive algae species — chondria tumulosa. The seaweed was first discovered at the atoll in 2019, and poses a threat to corals.
Researchers reported that the amount of algae didn't appear to have diminished since 2019, and may have increased.
Scientists are concerned the algae may spread to other parts of the monument.
Leonard says a recent expedition went to several locations where the algae was likely to grow, and found more positive signs.
"One of the big things we found is it wasn't found outside of Manawai," he said. "That's not to say it's not there, because we weren't able to survey every square inch of the atolls."
While the seaweed is still present around Manawai, scientists collected samples to do more research on how to manage the algae at the atoll.
Researchers also collected samples of limu at every stop, in order to expand our knowledge of the monument's biodiversity and native seaweed. Leonard says not much is known about some species of limu, and the samples collected will give us more insight into them.
He says samples were collected at Kuaihelani (Midway Atoll) that could be new to science.
Despite the good news, Leonard says there is still plenty of work to ensure the ecosystems in Papahānaumokuākea are preserved for future generations.
