In recent years, corals in Hawaii have experienced widespread bleaching and mortality events due to warmer than average ocean temperatures. According to the Fourth National Climate Assessment (NCA4), they will be under continued threat from rising ocean temperatures and ocean acidification as temperatures warm, with annual bleaching events expected by 2040. Coral reefs also face pressures from pollution, disease, coastal development, and vessel accidents/groundings. In Hawaii and across the Pacific, coral reef ecosystems provide jobs and opportunities for recreation, contribute greatly to tourism, support subsistence fishermen and their families, and provide the vitally important function of protecting vulnerable coastlines (NCA4). Disappearing coral reefs mean significant economic losses, as well as damaging ecological and social impacts. 

Pacific RISA’s Dr. Victoria Keener and Krista Jaspers recently visited the Hawaii Division of Aquatic Resources – Coral Restoration Nursery, which is attempting to mitigate human impacts on Hawaiian coral reefs by growing indigenous corals in an ex-situ environment, and out-planting nursery-grown corals to restore valuable habitat. The nursery aims to get more healthy coral into the ocean as soon as possible in areas where it is most needed after experiencing significant damage or losses. This can be from a vessel grounding, an oil spill, or to mitigate the effects of coastal development. In the future, the Coral Nursery could work as a sort of mitigation bank, where those responsible for loss of coral cover could pay for the damages by buying coral credits, supporting the work of the nursery to restore damaged areas. 

The Coral Restoration Nursery is crucial to mitigation and restoration efforts because Hawaii has over 70 coral species, most of which are slow growing (only 1-2 cm/year on average).  In cases where coral has been damaged or areas where there has been significant decrease in coral cover, it can take decades to recover naturally, if at all. The Hawaii Coral Nursery has managed to “skip” ahead 20-25 years of growth by using a “Fast-Growth Protocol,”  which involves thinly slicing quarantined coral fragments on modules to get rid of old coral skeleton and less healthy past growth, and concentrating very recent, healthy growth in the precise environment of the coral nursery on 40cm modules (Photo 4 below). When the modules have grown out and are healthy and hardy, they are outplanted and monitored for growth and health.  According to DAR Coral Biologist David Gulko, “The technique makes use of non-coral reef source material (harbors, etc.), and provides protection from disease, water quality issues, aquatic invasive species, predation and competition to create re-combined coral colonies in a fraction of the time it would take to grow these corals naturally” (https://dlnr.hawaii.gov/blog/2016/02/11/nr16-30/).

The valuable research and establishment of best practices for growing Hawaii’s endemic corals at the nursery is just one way to approach the problem of future loss due to climate change. Other researchers in Hawaii (see http://gatescorallab.com/) are experimenting with growing “supercorals” that are more resilient to the effects of future climate change, that would be able to survive catastrophic bleaching events and other environmental stressors.

For more information about the Hawaii Division of Aquatic Resources – Coral Restoration Nursery, please contact Norton Chan at nchan@hawaii.edu.