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Live coral sex
stars at Waikiki
Aquarium

The annual spawning of
rice coral is expected
to occur in time for
the Fourth of July

By Leila Fujimori
Star-Bulletin

Sparks will be flying underwater this Fourth of July when the Waikiki Aquarium presents live coral sex.

The fireworks are expected when rice coral, both in the wild and at the aquarium's Edge of the Reef exhibit, engage in their once-a-year spawning.

The event occurs two to four days after the new moon in June or July. This year, July's new moon happens to fall on July 1, so aquarium officials hope for lots of activity on the Fourth.

Courtesy of Waikiki Aquarium
Coral spawning resembles "snowing upward." The
white spots are the egg-sperm bundles that float to
the surface before breaking up to release sperm.

The spawning resembles "snowing upward," said Carol Hopper of the Waikiki Aquarium.

The coral release 1/8-inch bundles of both eggs and sperm, which resemble volleyballs under a microscope, Hopper said.

The bundles then float to the surface and break apart, releasing sperm, which fertilizes eggs of other coral heads, Hopper said.

Rice coral, named for the rice grain-like projections on its surface, are believed to be found only in Hawaii and limited areas of the Pacific, Hopper said. The brown coral, occasionally with white edges, grows broad fans -- sometimes with knobby towers -- in quieter waters on reef slopes or in calm, shallow waters such as Kaneohe Bay.

"Corals are alive and have sex," Hopper said, which reminds people they are animals, and that the reefs are experiencing renewal.

The exhibit's nocturnal fish such as aholehole and squirrel fish sometimes feed on the egg-sperm bundles. But some of the surviving eggs are fertilized and develop into larva. Some larva will eventually settle on a suitable surface.

A single larva will develop into the first polyp, depositing limestone to form a supportive skeleton, and will asexually reproduce by dividing and redividing into a colony.

The aquarium's rice coral colonies started 13 years ago from small coral heads and have grown four to five times the original size.

"Imagine office desks, two of them, curved round to form a rough U-shape," Hopper said describing the colonies in the reef exhibit.

Cindy Hunter, a zoologist specializing in coral biology, will conduct a class on July 4, which will include a presentation on coral ecology, a gallery tour and coral spawning, from 7 p.m. to 9:30 p.m.

Because of limited viewing space, the class is limited to 30.

Fees are $15; $10 for aquarium members.

For reservations, call 923-9741.

For those who miss the live action on July Fourth, videos are shown at the aquarium year-round.