DLNR: Search and destroy mission combats non-native corals

Expecting to only remove two species of non-native coral, a team from the DLNR Division of Aquatic Resources (DAR), ended up extracting four coral colonies from one of the longest and widest fringing reef in Hawai‘i on Thursday.

The five-member DAR team snorkeled against powerful currents to locate two target colonies they’d previously sighted and marked.

“We went out for two and we got four. It’s a good thing and a bad thing,” said Dr. Heather Ylitalo-Ward, the aquatic biologist leading the team. “We are happy we removed four, but it’s also disappointing that there’s still non-native coral out there.”

First detected by the Reef Guardians nonprofit in 2021, the team believes the non-native corals resulted from someone dumping the contents of a saltwater aquarium into the ocean.  

“Coral is not legal to import without a permit,” said DAR Outreach and Education Specialist Aaron Swink. “If you have a saltwater aquarium, you can have limu in it, you can have different kinds of aquatic life, live fish, and invertebrates. You can’t have coral. You should never dump anything in the ocean.”

Some of the original colonies, removed three years ago, were affixed to the reef with zip ties and string. Those removed yesterday appear to be fragments that rooted and started growing or possibly spread from the first colonies. DAR says it had not previously seen one of the species, meaning it could have been planted in 2021 and remained undetected until Thursday.

After mapping and surveying the area around the colonies, Ylitalo-Ward used a chisel and hammer to free the non-native corals from the rock.

“[There were] three different species as near as we can tell, and we’ll take DNA samples to confirm,” said Ylitado-Ward. “They all appear to be Indo-Pacific species, which are not native to Hawai‘i. Our concern is that they could spread disease and we don’t want them proliferating across the reef. They appeared to be quite healthy.”

Swink added that non-native corals could spread quicker in Hawaii than its native species. “Hawai‘i’s corals are built for Hawai‘i’s environment,” Swink said. “That means big surf, big surge. The non-natives, allowed to grow larger, could shatter and spread fragments everywhere.”

The non-natives are not yet considered invasive because they’re isolated to a relatively small area and are small, and the DAR team plans to keep it that way. In addition to citizen reports, the team surveys the entire area off of Anini Beach Park, twice each year.

Both Ylitalo-Ward and Swink said they were thankful for the community members who alerted them to the presence of the non-native corals. They encouraged anyone who sees something ‘weird’ to note the location, take photographs, and contact them.

“It was the keen eyes of the Reef Guardians who kept this from becoming another invasive species situation,” Swink concluded.