Story by Alexander Salkever
Once a month Daniel Wagner dons diving gear and takes a deep plunge off of Lahaina, Maui, to peek into the secret sex life of Hawai‘i’s official gemstone. Wagner, a research specialist with the National Oceanic and Atmospheric Administration, is one of the world’s leading experts on Hawaiian black coral, an animal so beautiful and rare that raw it fetches $35 to $50 per pound, and finished pieces can cost thousands of dollars. Harvested by fewer than a dozen divers statewide, black coral has a lustrous obsidian shade. When polished and finely carved, Hawaiian black coral makes a prized element in gold jewelry.
The coral’s ecological and cultural value is just as great as its worth in dollars. On the deep reefs around Hawai‘i, between 90 and 350 feet, black coral affords foraging and shelter for sea creatures, including dozens of species of fish and even Hawaiian monk seals. Native Hawaiians have long used black coral (‘ekaha ku moana) to treat lung diseases and mouth sores.
Yet very little is known about the lives of these creatures. “Because they live in remote places and people haven’t been successful in putting them in tanks or aquariums, information we get about them is only a snapshot,” says Wagner. “We don’t even know their basic life history, like how fast they grow or how long they live.”
Wagner has made some progress in illuminating the secret life of black corals. He’s identified several new species and located two species never seen in Hawai‘i’s waters. He’s determined that black corals spawn over several days, unlike shallowreef corals, which spawn mostly on a single day. He’s also discovered that algae live on the corals, which surprised him. “Most black corals are found at depths with very little light—not enough light to support photosynthesis,” says Wagner.
As new diving technologies allow more people to access the deep reefs, the future of Hawaiian black coral is uncertain. For Wagner, time is of the essence to solve the many mysteries that remain: Why does the algae live on the black coral? How often do different species of black corals form hybrids? To answer these and other questions, Wagner continues to brave the bends.