Hawaiian Coral Nursery and Propagation

The UH Hilo Marine Option is conducting coral propagation activities to provide students with hands-on experience in coral husbandry and to provide specimens for research and conservation activities on Hawaii Island. Work is being done in coordination with the Hawaii Department of Land and Natural Resources Division of Aquatic Resources (DLNR DAR), and may include larval rearing, mitigation of reef damage from boating accidents, and other conservation and research activities. The project is highly student-oriented, and mainly aims to facilitate training for students who will continue this type of work in their careers in Hawaii and abroad.

Interesting in participating? Volunteering opportunities are available for UH Hilo students. Activities include system maintenance, animal care and feeding, coral fragmenting, specimen collection, and more. Contact the MOP Staff Coordinator to learn how to get involved!

Project Activities

All activities described below require and are authorized by a Special Activity Permit granted by the Hawaii Department of Land and Natural Resources. Any person or entity conducting such activities with regulated organisms must have the proper permits and approvals.

Corals of Opportunity

Corals in the wild occasionally become imperiled due to human activities or natural forces. This often results in small fragments that will likely perish if left alone. Examples of such cases include anchor damage, high surf, and corals attached to temporary man-made structures or marine debris. Such "corals of opportunity" are preferentially collected for propagation in the MOP coral nursery due to the fact that they may not survive on their own and it allows an increase in stock without impacting Hawaii's fragile marine environment.

Coral fragments on racks Coral in parasite bath

In October, 2018, DAR staff collected 216 fragments from damage caused by a boat anchor. These fragments were glued to tiles and placed on racks in the tank (left) for propagation. The intent was to replace the corals at the damaged site once they recovered. All corals are soaked in a parasite removal bath prior to being placed in the tank (right).

gluing coral fragments closeup of gluing fragments

To secure coral fragments, they can be glued to bits of tile or other material. Students and staff can be seen here gluing fragments from anchor damaged corals to smashed tiles. While super glue (used here) is effective, better alternatives exist. Future corals will be glued with glues specifically designed for use in securing coral fragments.

Coral being measured Coral in tank

This small Montipora capitata fragment was collected in Hilo for propagation in the tank. Measurements are taken to track growth and for reporting purposes(left). The same coral can be seen in the tank amongst the live rock (right).


Corals are colonial animals. While they may look like colorful rocks from afar, if you look at them closely you can see hundreds, or even thousands, of individual polyps living on the outer surface. If a coral colony is fragmented, the smaller pieces can survive and continue to grow. "Fragging" is the practice of breaking captive corals into small pieces and growing them to increase the number of colonies. This can be useful for research projects, such as subjecting different colonies to different levels of nutrients, environmental pollutants, or other stressors. One purpose for the MOP coral propagation project is to provide specimens for faculty, graduate, or undergraduate research projects, and fragging will help produce the number of specimens needed.

Corals before fragging Corals after fragging

The corals shown here were recovered from a portion of a Fish Aggregating Device (FAD) that broke loose and was recovered by DAR staff. The photos show corals before (left) and after (right) fragging. Four coral colonies were fragged to create a total of nine colonies.

Coral Spawning

Coral spawning is driven by lunar, tidal, solar, and seasonal cycles. As such, it is often possible to predict when spawning activities will occur as precisely as the nearest half hour. Many corals are broadcast spawners, meaning that large quantities of gametes (eggs and sperm) are released into the water column to be mixed by seawater with gametes from other colonies. By precisely timing the release, corals increase the chance of successful reproduction. In May, 2019, a joint effort between MOP, the Division of Aquatic Resources, The Kohala Center, and Pacific Planktonics was made to collect gametes in Kahalu`u Bay and raise coral through the larval stage. Unfortunately, the effort was unsuccessful due to poor fertilization rates and predation on settled larvae by tank inhabitants.

Coral egg

The image to the left shows one of the collected coral eggs under a microscope. Given the steep decline of Pocillopora meandrina in West Hawaii during the 2015 bleaching event, a high rate of spawning success is as important as ever. In May 2018 and 2019, The Kohala Center worked with the County of Hawaii to close Kahalu`u Bay during spawning times to allow the larvae to develop and settle. More information about the purpose of this closure can be found here.

Tank Set Up

All activities are currently taking place in a 125-gallon aquarium at the Pacific Aquaculture and Coastal Resources Center in Keaukaha. While corals are simple animals, they have very specific needs for healthy growth. The tank system includes features like multiple light fixtures, heaters, a chiller, a protein skimmer, a GFO reactor, wavemakers, and filter socks, all managed by a controller that allows for remote observation of tank parameters. Tests are done weekly to check for nitrites, nitrates, calcium and alkalinity levels, and more. Ultimately, the corals will be grown in a larger system with wide, shallow tanks for easy access to individual colonies and better distribution of light. Development of the larger system is currently underway and will allow for growth of close to 700 specimens.

live rock invertebrates for cleanup crew

Live rock (left) plays a critical role in maintaining water quality because microbes within the many pores help cycle nutrients and process waste created by the animals in the tank. Invertebrates (right) also play a critical role in reducing algae and cycling nutrients in the tank.

Donated supplies

Mahalo nui loa to our sponsors!!

We would like to extend our greatest appreciation for the sponsors of this project. Without their generosity, these opportunities for students and conservation work would not have been possible.

Interested in supporting this project? Please visit our DONATE page for information on monetary gifts or to donate equipment and supplies!