Coral recovery project completed on Hawai‘i Island

Conservation divers have successfully removed and relocated nearly 11 years’ worth of coral growth from a decommissioned offshore fish farm pipe ring that was towed into Honokōhau Small Boat Harbor last week on Hawai‘i Island.

Divers from the Department of Land and Natural Resources’ Division of Aquatic Resources, The Nature Conservancy and Arizona State University then teamed up to remove hundreds of large, healthy, native coral heads from the ring, which supported the teepee-like structure used to raise Hawaiian Kanpachi (greater amberjack). Four of the fish pens remain in operation and visible just off a runway at the Ellison Onizuka Kona International Airport.

“Essentially, this pen has been in the water for 11 years, since 2013, and in that time, just natural recruitment of coral has happened to the point that now it’s time to take the pen out of the water. And there’s a whole, you know, 11 years’ worth of coral on the pen,” explained Julia Rose, the coral restoration program manager for The Nature Conservancy.

The partners have been working closely together over the past couple of years to build capacity for coral restoration and for emergency response.

“Opportunities like this are actually really, valuable, because the amount of time and effort and money that it would take to grow 11 years’ worth of coral that’s on these offshore pens, is huge,” Rose said. “Any amount of coral that we can save from these pens today, is so valuable. It’s the biggest bang for the buck that you can get.”

The coral removal was a complex, but well-orchestrated three-day long operation. Corals on top of the pipe were not recovered as prolonged exposure to air kills them, but most everything below the water line was removed using chisels and hammers.

Those corals sank to the bottom of the harbor where divers collected them in milk crates that were lifted onto boats. Large coral heads were gingerly placed into water-filled coolers, while smaller ones were bubble-wrapped and placed in coolers.

Zachary Craig, the Division of Aquatic Resources’ Coral Restoration coordinator on Hawai‘i Island, said: “These structures are fantastic areas for these corals to settle on. Great in the short run, but in the long run, they need a proper reef home to survive. This is one of the largest mature colony collections that I’ve ever heard of on Hawai‘i Island.”

The larger corals were taken by boat back to the reef, in-shore of the fish pens. Then the full crates were lowered to the ocean floor by divers. The smaller, wrapped corals were taken to a new coral nursery at the National Energy Laboratory of Hawai‘i.

“In the nursery, we can give them a kind of an intensive care unit for those corals that we’re rescuing and know that we’re giving them the absolute best conditions. We can also use that nursery to do other types of research to address the causes of coral stress,” according to Arizona State University restoration scientist Grace Klinges.

The ʻĀkoʻakoʻa Coral Restoration Nursery opened in May and is the first large, land-based coral nursery on Hawai‘i Island and is thought to be the biggest nursery of its type in the Pacific.

The dive teams collected hundreds of healthy colonies. Klinges said: “It’s great to be responding to something in a positive way where, you know, these corals would die otherwise. We think that we can save a fair number of them by working together. This is such a massive effort. I don’t think we even knew how big it was going to be until we got in the water and saw it. But I think we’ve made a monumental impact. The coral that we’ve been able to move to the nursery so far, they’re doing pretty well, and we hope they’ll continue to thrive over there.”

The coral heads returned to the ocean will be affixed to existing reef structure this week using a special marine epoxy.

Blue Ocean Mariculture is the company operating the kampachi aquaculture farm.

Chief Executive Officer Dick Jones said: “We are deeply committed to the health and resilience of Hawaiʻi’s marine ecosystems, so we’re honored to partner with the DLNR and the other partners on this coral reef restoration initiative. By providing reef samples from our net pens off the Kona Coast, we can help support the regeneration of vital species in our coral reefs, reinforcing both environmental sustainability and the balance of Hawaiʻi’s coastal waters. This collaboration is a natural extension of our team’s dedication to Hawaiʻi’s ocean ecosystems and to preserving their vitality for future generations.” 

Added Tyler Korte, Blue Ocean Mariculture vice president of Marine Operations, said: “Our offshore team is on the open ocean every day, witnessing firsthand how marine life, including coral and other reef organisms, naturally establish on our net pens off the Kona Coast. Being able to share these samples for Hawaiʻi’s reef restoration efforts is something we’re proud of, as it contributes directly to the work in regenerating healthy reef ecosystems.”