HONOLULU — Most of Hawaii’s species of coral is unlike other coral around the world in that it grows very slowly, making restoration projects for endangered reefs in the state difficult.
But officials in Hawaii have come with a plan to grow large chunks of coral in a fraction of the time it would normally take. In doing so, they hope to create a stock of replenishing species to build up damaged or unhealthy reefs in the future.
State officials gave a tour of their new coral nursery on Thursday, showing off their “Fast-Grow Protocol” and a rare coral seed bank.
Hawaii’s average coral grows about one centimeter per year, while the dominant species of coral around the world, mostly in warmer waters closer to the equator, grows at up to 30 centimeters a year, Division of Aquatic Resources Coral Nursery Manager David Gulko said.
The way Hawaii’s coral grows makes it difficult to have a traditional replenishment program, he said, because they are usually housed in natural settings, meaning it would take decades to make large enough coral specimens to start to rebuild reefs.
“The larger the coral, the more space it provides for fish and invertebrates and the all things that are important,” he said. “That means recovery takes a really long time. You can’t replace a hundred-year-old coral in less than a hundred years — until now with what we’re doing.”
With the process they are using, Gulko said they will have a volleyball-sized chunk of coral in about one year, a fraction of the time it would take to grow naturally.
“Bigger coral is much more important,” he said. “If a coral this size is important to keep the shoreline from eroding, it can’t wait a hundred years. We need faster techniques.”
The way they are doing this is to take harbor coral that is not part of the natural reef, so they don’t harm those ecosystems, quarantine it to ensure it is healthy and has no invasive species, then chop it up into tiny portions that grow the fastest.
They then take those small pieces of healthy coral and expose them to optimal conditions in specially designed tanks. Once grown, the genetically identical chunks are then fused back together to make a single large portion of coral that they can transplant back onto reefs.
When they first begin growing these specimens, they are put in artificial seawater that is closely monitored for optimal health. They carefully expose them to light that would mimic their natural depths in the ocean and provide certain minerals to ensure the fastest-growing coral possible.
Once they have been in that setting for long enough, the coral is moved into a natural seawater tank, still controlled but more closely resembling natural conditions, and assimilated back to their natural ocean reefs.
Zac Forsman, a coral-recovery specialist with the state who has helped develop the technique they are using, said the project needs to be data-driven to find the best combination of conditions to grow the coral as fast as possible.
“Human beings, we manipulate our ecosystems. We’ve done it with forests, we’ve done it with planting trees. We’ve done it with farms and greenhouses. With the oceans we haven’t done any of that,” Forsman said. “It’s all been just kind of decline. We’ve impacted it negatively but we haven’t really tried to go the other way.”
Bruce Anderson, the administrator of Hawaii’s Division of Aquatic Resources, said the facility is unique in that it’s an applied research facility where they can actually see what it takes to maintain and manage their reefs.
“We’re not growing enough coral here to make a huge difference immediately,” Anderson said. But he hopes the project will help them better understand what it takes to “grow coral faster and plant out more reefs” in the future.
The facility also houses several rare coral tanks that the team is using to create a seed bank for threatened species. It acts as their insurance policy against losing those species altogether, Gulko said.
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