Kahalu`u Beach Park Partially Closes Due to Coral Spawning

Hawai‘i County Department of Parks and Recreation is informing the public that Kahalu’u Beach Park will be closed from 7 a.m. to 12 p.m. on May 1 and May 2, due to anticipated coral spawning events.

According to the Division of Aquatic Resources and Eyes of the Reef Network, cauliflower coral (Pocillopora meandrina) was once abundant on shallow coral reefs along West Hawai’i, including Kahalu’u Bay.  However, a global thermal stress event resulting in very high ocean temperatures struck West Hawai’i in the fall of 2015, and caused catastrophic bleaching and mortality for more than 90 percent of the regional population of cauliflower coral.

To recover from this event, natural reproductive and replenishment activities of corals are critically important.  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 broadcast spawning events, corals emit reproductive materials (“gametes”) into the water column, and these materials are carried by the tides to mix and generate planktonic coral larvae.  During this time, physical disturbance of corals and pollutants in the water (e.g. oxybenzone in many sunscreens) must be minimized to help ensure that corals are successful.