Coral Reefs

An animal similar to a sea anemone, with thousands of tiny polyps living together in a colony. Corals build calcium skeletons, which build the structure and foundation of coral reefs.

In the Kumulipo, the Hawaiian creation chant, the coral polyp or ko‘a was one of the first living organisms created along with Kumulipo and Pō‘ele, the first man and woman.The ko‘a was then followed by the creation of urchins, sea cucumbers, sea stars, and so forth. Documentation of the ko‘a as one of the first life forms reveals how Hawaiians hundreds of years ago already recognized the importance of coral reefs and their role in sustaining marine ecosystems and themselves.

Healthy coral reefs are some of the most biologically diverse and economically valuable ecosystems on earth, providing food for fish, jobs, recreational opportunities, coastal protection, cultural significance, and other important services.

Corals use their tiny tentacles to catch and eat microscopic animals swimming in the water called zooplankton. They also get energy from symbiotic algae living in their tissue through photosynthesis.  

The Division of Aquatic Resources (DAR) is responsible for managing, conserving and restoring the state’s aquatic ecosystems and resources for present and future generations, including both marine and freshwater environments. Through programs such as fisheries management, ecosystem protection and public education initiatives, DAR works to ensure sustainability for future generations, and a part of that is restoring our living corals. 

Corals in Hawai‘i are some of the slowest growing on the planet, and up to 20% are endemic, which means they are not found anywhere else in the world. The loss of these corals would devastate our ocean’s ecosystem. Corals are also a fundamental part of Hawaiian culture, and are the first organism created in the Kumulipo creation chant. 

Different types of corals have different growth rates. Typically branching corals, most common in other areas of the world, are faster growing, at 10 – 15 centimeters per year, compared to bouldering corals, most common in Hawai‘i, which grow 1 – 2 centimeters per year. Hawai‘iʻs bouldering corals are better able to withstand the high wave energy Hawai‘i is known for. Even the branching corals found in Hawai‘i have incredibly dense skeletons, which take more time for the coral to build. 

The Hawai‘i Coral Restoration Nursery (HCRN) was created to mitigate planned and unplanned reef impact events that can kill coral by removing them before the event or rehabilitating them after impact. In providing these services, the HCRN has developed industry-leading methods. 

To keep Hawai‘i ocean waters healthy, it’s necessary to nurture, grow and outplant these living corals. The process includes feeding the coral, providing optimal lighting and water conditions. While at HCRN, these corals are protected from ocean predators and disease to ensure they grow as quickly as possible for replantation into the ocean.

Many of our reefs are suffering from the effects of climate change, rising ocean temperatures and pollution, each of which can cause coral bleaching or mortality. Our unique restoration process gives at-risk corals a better chance of survival in adverse conditions.

Coral bleaching occurs when the algae living inside the coral are expelled due to stressful conditions, causing the coral to lose its color and turn white. Usually bleaching is caused by unusually warm temperatures or high levels of pollution. Bleaching can occur at the coral nursery, but we take preventive measures if stressful events are forecast, primarily higher temperatures.

We’re able to offer these living corals a controlled and monitored environment so they may grow faster and be replanted into the ocean. 

From the ocean waters around O‘ahu. We collect small pieces and help them grow in a controlled environment so they can be replanted back on the reef as larger, more resilient corals with a higher chance of long-term survival.

We try to maximize the corals’ growth by growing them indoors in a controlled environment on a concrete pyramid module. Clean water, food, stable temperature, stable lighting and constant care over a period of time help the corals grow quickly to fully cover a concrete module in a shorter amount of time.

Depends on the restoration site needs, but we focus on reef-building corals (corals that contribute to reef structure) and corals that are or were present in the restoration area. 

We cut corals using a process called microfragmentation, which does not harm the corals. Fragmentation, when coral pieces naturally break off, is actually one of the ways corals reproduce in the ocean. The broken or cut edges of these coral fragments display an accelerated growth rate that helps the colony repair itself. 

The shape allows the module to have a lower center of gravity, the sloping sides allow water movement/energy to flow around it, and there are no horizontal flat surfaces to allow sediment (gravel, sand, silt) to accumulate on the top to possibly smother the coral tissue.  

We do not remove the coral from the concrete pyramids as they are firmly attached and cover the entire pyramid module. To plant them, we start by selecting a site on the reef; we then prepare the site by cleaning it off, and use epoxy to attach the module directly onto the reef.

We use a reef-safe marine grade two-part epoxy that cures underwater and does not harm corals. This epoxy has historically been used in the state of Hawai‘i for attaching corals on reefs and in public aquariums, does not impact coral growth and reproduction, and can hold-up to the high-energy wave action commonly seen in Hawaiian waters. 

We are in the process of determining target sites for this project and are seeking input from O‘ahu residents. To give your input, please take the survey at  https://forms.gle/Sq9TL8ZVXmu3mxuH8. 

Coral anywhere can be damaged by humans, and we carefully survey coral outplant sites to minimize this risk. 

Yes. We monitor corals the day after they are outplanted, every three months for the first year, and every following sixth months for four more years. In total, most of our corals are monitored for five years to ensure long-term success. We will take action if our outplanted corals face health problems.

Approximately 89% survival for all coral outplants on O‘ahu since 2019. 

We have a few volunteer positions open throughout the year, and post openings on our website and social media pages. While we do not have community workdays, some of  DAR’s coral reef restoration partners offer ways for citizens to help restore coral reefs such as Kuleana Coral Restoration, Malama Maunalua, Sustainable Coastlines, 808 Cleanups, Waimanalo Limu Hui, etc.

As an individual of the general public, unfortunately not. According to regulation HAR 13-95-70, you need to obtain a Special Activity Permit to perform any work with corals. If you see damaged corals, please report it to DAR and/or DOCARE at (808) 643-DLNR (643-3567).

Healthy coral reefs serve as a nursery ecosystem for many near-shore fish species. Healthier reefs will lead to healthier fish populations to feed both people and larger, off-shore fish.

Although coral bleaching and other stressors are threats to our coral, we’re doing all we can to fight back and help these native animals to survive and rebuild their environment.

No, we are looking to restore reefs in areas that will not impact popular surfing spots around O‘ahu.