Aquatic biologists from the state Department of Land and Natural Resources today and Friday watched light coral spawning at Waialea Bay’s Hapuna Beach State Recreation Area.
Every year, with spring tides and the full moon, corals spawn by sending millions of gametes into the water column. The gametes fertilize nearby colonies, float to the surface of the water, and produce larvae in a day or two. The larvae then help reseed reefs with new corals.
Scientists have observed active spawning over the past five years, but the annual event can be disrupted.
“A lot of factors come into play,” said Lindsey Kramer, a fish and habitat monitoring planner for DLNR’s Division of Aquatic Resources, in a statement. “Water temperature and salinity are important. Rain events can cause the colonies to wait until the next lunar cycle. The moon cycles are the primary drivers of these spawning events of cauliflower corals.”
The biologists were watching for the spawning of cauliflower corals, which were heavily impacted by the 2015 coral bleaching event in Hawaii.
“We’re down to about 5% of the population of this species in West Hawaii. Cauliflower coral are especially susceptible to bleaching, so with that 95% loss of cover these spawning events are vitally important,” Kramer said. “We need to do everything possible to help these reefs recover through this natural reproductive cycle.”
DLNR worked worked with Hawaii County and Kahuluu Bay Education Center to close the bay’s parking lot from Friday through June 5 to aid in coral recovery.
The public was also asked to avoid going into the water before noon.
“It’s good to let them do their thing without people around as hopefully that allows more settling later on,” said Chris Teague, a DAR aquatic biologist, in a statement.
It can be difficult to see the coral spawn.
“Some are carried off-shore and it could be a couple of months before they’re back down on the reef. They might settle back at Waialea, but the spawn could go elsewhere within the region or even across the state,” Teague added.
As tourism recovers in Hawaii, coral experts are asking those who use the ocean to be aware of their impacts on marine environments.
Touching, sitting or walking on corals and using harmful types of sunscreens can be damaging to them.