Seeing coral reproduce requires careful timing
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Guidelines for watching coral spawn
By Katherine Nichols
Advertiser Staff Writer
Darkness thickened around Coconut Island in Kane'ohe as 20 people donned wetsuits, masks and snorkels and eased into the glassy ocean to watch the reef procreate and rebuild itself.
They floated across the lagoon over sea cucumbers three feet long and a variety of corals to find clumps of rice coral, typically identified by little rice-shaped bumps on their surfaces. After a brief wait, the coral began to spawn, firing bundles of eggs and sperm into the water. The divers' initial feelings of voyeurism gave way to awe.
Importance of coral spawning
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May occur once or twice each year and are the only opportunities for the creation of new corals. If humans disrupt the spawning, new coral colonies may not form. Few of the swimming larvae produced by spawning will survive to grow into new coral colonies.
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Given the relatively slow growth of Hawaiian corals and the limited amount of coral reef space available, new corals are important in maintaining the fragile living reef environment.
Adapted from "Reef Renewal: Hawaii's Unique Coral Spawning Events"
"Corals in Hawai'i are unique in that they don't all spawn at the same time," said Athline Clark, aquatic resources planner for the state Division of Land and Natural Resources. Summer, she said, "is a very important time in terms of reef renewal." In many cases, spawning happens only once or twice a year.
But the summer excitement is not over. For instance, experts predict that mushroom coral will spawn on Sunday. Mushroom coral (also known as razor coral) primarily spawns June through September, one to four days after a full moon, between 5 and 7 p.m. The corals, which are male or female, erupt with mushroom-shaped clouds of eggs or sperm.
If you can identify the coral, you may be able to view the event yourself. But naturalists strongly recommend that people attempt to view coral spawning only under the guidance of a marine expert, and follow some important guidelines (which are listed on Page E3).
Both the Waikiki Aquarium (which arranged a "Coral Spawning and Reef Romance" program) and the Maui Ocean Center recently held separate events in honor of the rice coral spawning.
But at the spawning at Coconut Island, only community leaders and students from Windward Community College,
under the guidance of Dave Krupp, associate professor of marine and biological sciences, were able to see the coral spawn in its natural environment.
The purpose: to educate people who would return to their neighborhoods and share the information with others who use the ocean. The message: Corals are living creatures, not just inanimate objects on the sea floor. And summer is their most productive time.
In rice coral, this rejuvenation process is visible between 8 and 10 p.m., two days after a new moon. Primary spawning for this species occurs in June and July.
Brochure available
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The state Department of Land and Natural Resources, with assistance from the Waikiki Aquarium, Maui Ocean Center and money from Hawaii's Coastal Zone Management Program, has published a new brochure called "Reef Renewal: Hawaii's Unique Coral Spawning Events."
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It's available at the DLNR Division of Aquatic Resources offices on all islands, and at the Maui Ocean Center and Waikiki Aquarium.
On Coconut Island, Jeff Kuwabara, education specialist with the Hanauma Bay Education Program through the University of Hawai'i's Sea Grant Extension Service, was one of the first to spot the egg/sperm bundles rising to the surface. He and Krupp helped people distinguish between these and the zooplankton swarming toward the flashlight beams.
Rice coral, which was the only coral spawning that night, is hermaphroditic. This means both male and female sexes are contained in the same structure.
Before the dive, Krupp, who has researched coral spawning since 1981, told his audience that people should learn from ancient Hawaiians, who understood the value of the reefs. In fact, the Hawaiian creation chant mentions coral polyps. "Born the coral polyp/ Born of him a coral colony emerged," a translation of the chant says. And, as Krupp pointed out, a long time passed before humans appeared.
Krupp is one who sees inestimable value in our surroundings. "Ka-ne'ohe Bay is my laboratory," he said with a smile. But his coral research is not just about his love for the ocean. His purpose is much broader. Reefs, he said, "are an important economic resource to the state that need to be managed properly."
