Dozens of people gathered in East Oahu Saturday to clean up Maunalua Bay.

Forty volunteers gathered in partnership with Malama Maunalua and Pono Pacific to remove invasive algae from nearshore waters along the bay.

While doing so, they also got to learn about Hawaii’s native marine environment.

“Due to sediment and invasive runoff, invasive species have kind of taken over this native ecosystem, and by removing the algae, we’re helping to heal the bay and bring the native system and species back,” said Molly Mamaril, assistant project manager, Pono Pacific.

Mamaril held up a thick cluster of algae recently pulled from the water.

“At the bottom of all of this is leather mudweed, which is kind of the main problem in the bay. It’s really smothered the native ecosystem. As you can see the roots are really thick, and it holds onto sediments and pollutants that come down from the mountains,” she explained.

Hawaii Kai resident John Kauhi said he volunteered because “this is like my background over here. I learned how to surf, I learned how to swim, everything out here.”

Kauhi says he can see the change in the environment over time.

“It’s gotten really bad because where we come across by Kuliouou Stream, it was like 10 feet deep. Now it’s got a sandbar that’s there forever. All that soot just came in and covered the whole reef out here,” he said.

Organizers say they expect to pull close to 2,000 pounds of invasive algae, which is given to local farmers to use as soil fertilizer.