Kahalu‘u Beach Park will be closed from May 16-21 due to anticipated coral spawning events, according to the county Department of Parks and Recreation.
Cauliflower coral (Pocillopora meandrina) was once abundant on shallow coral reefs along West Hawaii, including Kahalu‘u Bay. However, environmental stressors and very high ocean temperatures impacted West Hawaii in 2015 and again at the end of 2019, leading to catastrophic bleaching and mortality of more than 90% of the cauliflower coral population in Kahalu‘u Bay.
Natural reproduction events are essential to recovering from the loss in the coral population, the county said in a news release. For more than a decade, researchers have observed annual broadcast spawning events for cauliflower corals and can now accurately predict when they will likely occur based on season, solar, tidal and lunar cycles.
During the spawning events, corals emit reproductive cells into the water column, which the tides carry to mix and generate planktonic coral larvae. The high volume of daily visitors to Kahalu‘u Bay may cause harm to larval corals due to physical and chemical disturbances (such as sunscreens and other personal care items) in the bay’s surface waters.
In recent studies, oxybenzone chemicals in sunscreens were shown to cause damage to larval corals and prevent successful settlement on the reef.
Minimizing pollutants and physical disturbances within the spawning period in their natural environment will help ensure that corals can successfully reproduce and settle properly, the county said.
For more information, please contact the Kahalu‘u Bay Education Center at (808) 895-1010.