Fragments of Life: Restoring Hawaiian Coral Reefs with Indigenous Wisdom and Community

223 years ago, Hualālai volcano’s final eruption tumbled across the Hawaiian seaside village of Kaʻūpūlehu, coating the bay in molasses-black lava. Today at this heritage site, cooling air suspends the rippling lava field in time at the final fringes of the North Kona coast, where swirling bouts of turquoise water bend and slide into the Island’s igneous crown. This union of newborn rock and clear, warm tropical water provides an ideal stage for coral reefs to take root and flourish. These reefs, torn apart and rebuilt with each new volcanic flow, signify the extreme resilience of Hawaiʻi’s marine ecosystems. Under stress from human activity and climate change, these underwater oases have also come to represent the most vulnerable of the world’s biocultural resources.

The coral reefs at Kaʻūpūlehu make up a portion of the 300,000-410,000 acres of reefs across the main Hawaiian Islands, supporting more than 7,000 marine species and generating $863 million yearly from tourism, recreation, research, and commerce. North Kona coast reefs like those in Kaʻūpūlehu generate $17.7 million per year on their own. Octopuses, lobsters, sea turtles, Hawaiian monk seals, and mystical humpback whales dwell in these coastal waters, depending on the reefs as the islands’ people do. Coral reefs possess the economic power to spearhead tourism, protect beach settlements from wave impacts, and support sustainable nearshore fishing.

Coral structures nullify powerful ocean currents and waves, offer shelter from predators, and create biomass-rich places to feed and breed. Some ecologists identify corals as the keystone species around which reef ecosystems orbit. Others argue that the corals’ calcium carbonate skeletons provide the keystone structures on which communities rely, making corals the foundation species responsible for their underwater world’s very constitution. Coral’s multitude of roles in reef ecosystems makes them challenging to classify and incredibly valuable to protect.

Reefs also hold a profound significance in Hawaiian culture. Stories passed down through Hawaiʻi’s rich oral tradition credit coral, or ko’a, as the common ancestor of the Hawaiian people and the originator of life itself. A creation story known as the Mo‘olelo of ‘Ōpu‘ukahonua explains that coral fragments rose to become the Hawaiian islands after being fished from the ocean. Coral is used as construction material for sacred grounds called heiaus, playing pieces for games like kōnane, and an ingredient in remedies for respiratory ailments. Coral represents a valuable component of Hawaiian history and provides tangible and spiritual resources for Hawaiʻi’s cultural ecosystem.

Local communities honoring their kuleana (responsibility) in service and stewardship of the reefs were among the first to observe the North Kona coast’s declining health. Lineal descendants of Kaʻūpūlehu organized to form the Kaʻūpūlehu Marine Life Advisory Committee (KMLAC), which coordinated with The Nature Conservancy (TNC) to study the reefs. In 2016, TNC reported its findings, partnering with the National Oceanic and Atmospheric Association, SymbioSeas, and Hawaiʻi’s Division of Aquatic Resources. What these groups discovered alarmed them; more than half of Kaʻūpūlehu’s coral cover had declined over 20 years, along with 75% of the island’s primary food fish abundance.

The report identified several culprits responsible for the reef’s decline in health, including coral bleaching. Coral bleaching occurs when the symbiotic partnership between coral and the algae living in its tissues is thrown off balance. Healthy corals extract nutrient products from the photosynthesizing algae living in their tissues, while the algae in turn receive shelter and consume the coral’s waste chemicals. This fragile relationship may be offset by various factors, though warming ocean temperatures from greenhouse gas emissions have contributed significantly to modern bleaching events.

Because warmer water increases the photosynthetic activities of the algae, it also increases the concentrations of potentially harmful photosynthetic byproducts in the coral’s tissues. The coral’s antioxidant system cannot neutralize these chemicals at the rate that algae produce them, causing cell and tissue damage. Expelling the colorful algae is a last resort for stressed corals; temporary relief from algal byproducts costs the invertebrates their main energy and nutrient sources, making them vulnerable and weak. This expulsion strips corals of their colors, veiling their skeletons in an ominous, ghostly white silhouette. The 2016 report oversaw the severity of bleaching’s effect; about half of all corals bleached in 2015 had died by 2016, contributing to a 44% decrease in coral cover across the entire reserve that year.

Other threats to Kaʻūpūlehu’s reefs include overfishing and ocean acidification. Absorbed carbon dioxide from the atmosphere breaks apart water’s chemical bonds and forms a new compound called carbonic acid in seawater. The chemical process responsible for this compound’s formation also sends free hydrogen ions into the water, making it more acidic. Corals build their protective skeletons using a compound called calcium carbonate, which is less abundant in more acidic seawater. As calcium carbonate becomes more difficult to extract, corals cannot efficiently construct their structures, resulting in malformed and fragile reefs.

The Nature Conservancy also identified pollution as a source of coral death in Kaʻūpūlehu. Runoff from towns and farms can send harmful chemicals into reef waters. Even sunscreen has the potential to poison a reef: a study performed in 2016 by Downs et al. found that the popular sunscreen ingredient oxybenzone damages coral cell DNA and causes expulsion of the coral’s algae. However, not enough is known about UV filters and their components for governments and companies to push consumers with certainty toward one “reef-safe” product or another, suggesting the need for further research in this developing field.

The report’s findings kindled immediate action. In 2016, the state of Hawaiʻi’s Aquatic Resources division established the Kaʻūpūlehu Marine Reserve, effectively banning all fishing activities in the region until 2026. In 2020, another report published by TNC concluded that the fishing ban greatly improved fish abundance and biomass in the protected area and around its outer perimeter. Mature adult fish in the protected area increased in abundance by 612% within just four years. Even local coral recovery appeared to trend positively as an indirect benefit of the Reserve’s foundation. The state declared Kaʻūpūlehu a priority area for reef restoration in 2022, hopeful that restoring the reef would further solidify the positive changes heralded by the 2016 fishing ban. The site became an even more promising target for restoration after the state banned oxybenzone and octinoxate sunscreens in 2021. In 2023, the much-anticipated restoration began.

Launched October 30, 2023, TNC and KMLAC’s Kanu Koʻa project intends to honor Hawaiian livelihood and unite scientists with community members to restore Kaʻūpūlehu’s reefs. Community members and lineal descendants of Kaʻūpūlehu selected the project’s target species and experimental plot locations following traditional land divisions known as ahupuaʻa. The descendants, alongside TNC divers, search the Marine Reserve’s waters and beaches for corals damaged by recent storms. A double-hulled Hawaiian sailing canoe named Waʻa Kinikini brings damaged specimens to the project’s base camp, where scientists cut the corals into 1-inch fragments and plant them on epoxy and cement plates. The plates rest on the seafloor in a designated plot of healthy coral coverage where they grow under supervision. To avoid the risk of introducing invasive species to the reef and the fragments, divers only re-plant corals in plots closest to where they were found. This procedure, known as coral stabilization, represents one of two active strategies chosen for the project by native lineal descendants. The other, a procedure known as coral gardening, involves growing fragments in nursery environments away from the reef. This allows the fragments to regain strength and grow more efficiently into new coral colonies.

In 2016, Kīluea volcano spat molten rock into the sizzling Kamokuna ocean entry. Sinking lava boiled the sky and buried the reef below, incinerating it instantly. While new generations of corals may eventually rise from their ancestors’ quiet black caskets, changing environmental conditions and human impacts threaten to entomb Hawaiian reefs forever. The beautiful and volatile life cycle of coral reefs provides a fateful reminder of how fragile ecosystems may be in the face of sudden change. However, the resilience of these ecosystems also provides hope for restoration projects and new climate policies. Firmly founded in ancestral knowledge and community kuleana, the Kanu Koʻa project represents a positive step forward for global restoration initiatives as they seek to protect and preserve cherished economic, cultural, and ecological resources.

Works Cited:

https://dlnr.hawaii.gov/dar/announcements/marine-reserve-established-at-kaupulehu-west-hawaii/

https://dlnr.hawaii.gov/dar/habitat/coral-reefs/

https://www.coris.noaa.gov/portals/pdfs/hicesar.pdf

https://link.springer.com/chapter/10.1007/978-3-319-23763-3_7#Sec4

https://www.nature.org/content/dam/tnc/nature/en/documents/WHI-2015-16-Coral-Bleaching-Recovery-Surveys.pdf

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7020446/

http://oceans.mit.edu/research/oceans-and-climate/human-influences/ocean-acidification.html#:~:text=Acids%20and%20Bases&text=This%20reduces%20the%20concentration%20of,construct%20their%20shells%20and%20skeletons

https://www.nature.org/en-us/get-involved/how-to-help/places-we-protect/kaupulehu/

https://nap.nationalacademies.org/read/26381/chapter/10#189

https://oceanservice.noaa.gov/news/sunscreen-corals.html

https://enveurope.springeropen.com/articles/10.1186/s12302-021-00515-w