Coral nursery seeks to restore reefs

The state Department of Land and Natural Resources is establishing a new coral nursery at Sand Island that aims to serve as a sort of “neonatal intensive care unit” to help restore damaged reefs as well as a bank for Hawaii’s native corals.

At the shore-based nursery, located at the Anuenue Fisheries Research Center and operated by DLNR’s Division of Aquatic Resources, coral husbandry techniques will be used to grow small fragments of a coral colony that can be added to large colonies and then transplanted into the field in a fraction of the time it would take the coral to grow in its natural environment.

The “fast-growth protocol” at the 3,000-square-foot Coral Restoration Nursery is poised to help restore reefs affected by pollution, vessel groundings, coastal development and climate change, said Bruce Anderson, administrator of the Division of Aquatic Resources.

The annual coral growth rate in Hawaii — 1 to 2 centimeters in its natural setting — is much slower than coral in other parts of the world. Nursery staff are using techniques designed to increase the growth rate to up to 3 centimeters a year.

The process starts with coral harvested from Hawaii harbors which is cut into small fragments and placed in aquarium-size tanks filled with water that includes minerals to maximize survival. Optimal lighting is hung above the tanks. The growing fragments are later placed in large outdoor seawater tanks where they naturally fuse together.

During a tour of the facility Thursday, the nursery’s manger, David Gulko, said the bigger the coral, the less likely it will be affected by sedimentation and invasive species.

“By putting out larger corals. … We’re more confident that they’re going to do OK in the environments we put them out into,” Gulko said.

Coral grown at the nursery is slated to be used to restore depleted reefs near the runways at Honolulu Airport and in the Waikiki Marine Life Conservation District.

Vessel groundings, sewage spills and invasive species have damaged or destroyed various coral reefs in Hawaii. Coral bleaching — due to warmer temperatures that kill off symbiotic algae — has also been a factor. More coral bleaching events are expected to occur over the next few years because of El Nino-related weather patterns.

In an effort to fend off threats that could wipe out rare species endemic to Hawaii, Gulko said the nursery will maintain a “seed bank.” Among the species in the collection are Irregular rice coral, or Montipora dilatata, and blue rice coral, or Montipora flabellata.

“About 25 percent of the corals in Hawaii are found nowhere else in the world,” Gulko said. “They’re unique.”