A Big Island beach that’s one of Hawaii’s most popular snorkeling spots will temporarily close to support the reproduction of cauliflower coral.

Kahaluu Beach Park in Kailua-Kona will be closed from May 23 to May 31, according to a Hawaii County news release Friday.

The public is asked to refrain from swimming, snorkeling and surfing in Kahaluu Bay during the closure to aid coral spawning and resettling in new reef areas and to give the popular bay a period of rest.

More than 400,000 people visit Kahaluu Bay annually, many of them to observe marine life and ancient coral colonies up close in shallow, nearshore waters.

Cauliflower coral was once abundant on shallow coral reefs along West Hawaii, including in Kahaluu Bay, according to the state Division of Aquatic Resources.

Marine heatwaves in 2015 and 2019 caused catastrophic bleaching and mortality of more than 90% of the cauliflower coral population, according to DAR. The state instituted yearly rest periods in 2018.

The annual beach closures have allowed cauliflower coral to return to the reef and begin to recover. 

“We fully support this voluntary measure as natural reproduction events are critically important,” said DAR administrator Brian Neilson in a news release.

Research indicates it can take as little as 24 hours for cauliflower corals to successfully reproduce and resettle in new reef areas.

“This yearly closure has directly contributed to the strength and vibrancy of the coral reefs in and around Kahaluu Bay. We would like to send our heartful mahalo to all who continue to honor this closure for the betterment of future generations,” said Mayor Mitch Roth in the release.

Civil Beat’s coverage of environmental issues on Hawaii island is supported in part by a grant from the Dorrance Family Foundation.