The signals are subtle. First, a fat full moon droops through the hot heavy clouds of a tropical summer night. Below the ocean's surface, coral polyps swell slightly. The experienced eye knows how to read the signs: it's time for the coral to spawn. It happens every summer, April-September. Many corals thrive here in the Hawaiian Islands. Cauliflower, antler, lobe, and finger corals are most commonly seen. These species may fill the surrounding clear tropical waters with tiny pearl-like eggs and smoky sperm during sexual reproduction.
Hawaii is the only place in the world where coral spawning can be observed during daylight hours.
Coral spawning is an amazing thing to observe. During this annual event, the wonders of the reef are even more amazing. Oftentimes other critters join the action and spawn as well. There is a good chance you can witness sponges, brittle stars, and marine worms spawn at the same time. In addition, a myriad of tiny fishes swarm to the area to feed on the spawn. This draws bigger fish hoping to feed on the smaller fish, and an entire food chain may be observed in a microcosm. Catching sight of coral spawning in the wild is, in many ways, a guessing game. But our researchers say observers stand the best chance with the following species on the specified dates and times.
Cauliflower or Rose Coral (Pocillopora meandrina): April -- May, at full moon and/or 2-3 days after, around 7:30 in the morning. Profuse spawning can reduce visibility from 100 ft. to fog in about one hour. This one is a "don't miss"!
Mushroom Coral (fungia scutaira): June -- Sept. on the first full moon and as much as three nights later, between 5 and 7 p.m.. Rice.
Rice Coral (Montipora verrucosa): June -- August, 3-5 days after a new moon between 8 and 10 p.m.. This spawning may be the easiest to see.
Finger Coral (Porites lobata): June, July and sometimes August, two to three days after a full moon, around midnight. Kind of hard to see, looks like a haze. Lace.
Lace Coral (Pocillopora damicornis): Year-around, with all phases of the moon. This coral releases larvae throughout the day, but mostly at night.
Book reservations well in advance for Wild Side's popular coral spawning snorkel charters. Rates are $105 per person for approximate four-hour charters which take place near, and include, visiting the resting grounds of Hawaiian spinner dolphins. Email Us for more info