State and federal officials said the widespread coral bleaching event predicted by the National Oceanic and Atmospheric Administration due to warmer ocean temperatures this summer did happen — but not as severely as originally anticipated.
The coral bleaching occurred statewide, and is still occurring, even as ocean temperatures cool down this month. Conditions, however, are improving.
“Conditions for corals are now improving with sea surface temperatures beginning to drop,” said Gerry Davis of NOAA Fisheries in a news release. “While bleaching this year was not as devastating as the events seen across the Hawaiian islands in 2014 and 2015, the Division of Aquatic Resources surveys, along with NOAA observations and reports from ocean users to the Hawai‘i Coral Bleaching Tracker, show there still was substantial bleaching found on all islands.”
Surveys by a collaborative team over two months found that as much as half of live coral was bleached in the most heavily affected areas. The reefs off of Maui took a big hit, as did the reefs off of Windward Oahu, the team reported. Cauliflower and rice corals were most impacted.
“We’ve seen bleaching on all the islands, at different levels,” said Davis.
The team reported the following from its surveys:
>> On Oahu, reefs on the windward side impacted this year include Lanikai, where bleaching covered an estimated 55% of live corals, higher than reported during the last bleaching event in 2015. At Kaneohe Bay, more than 50% of the corals on some patch reefs have turned white.
>> On Maui, the amount of coral impacted was less than in 2014 and 2015, but areas with low coral from previous events were more severely impacted this year. More than 50% of reefs in Molokini’s crater also bleached.
>>On Hawaii Island, an average of 40% of live coral bleached in many survey locations, with the areas most affected along the Kona coast.
Officials emphasized how important “The Coral Pledge” — a pledge highlighting six common-sense actions that residents and tourists alike can take to help reduce stressors on coral — is to the effort to help the reefs. The six actions include letting fish protect reefs, giving corals their space, standing on sand, using reef-safe sunscreen, containing chemicals and anchoring away from reefs.
“Many people think, ‘I can’t do anything about climate,’ but that’s not true,” said Davis. “You can play a major role in making it so corals stand a much better chance of surviving. Corals that survive bleaching have a much better chance of dealing with in in the future.”
The state DAR is targeting, in particular, the visitor industry, which hosts millions of visitors each year. Tour companies are encouraged to share the pledge with their guests before heading into the water. Among those that have signed on are Aulani, a Disney Resort, Trilogy Excursions and the Waikiki Aquarium.
Hundreds of citizen scientists have also contributed to the Hawai‘i Coral Bleaching Tracker over the summer, helping researchers monitor the event in real time, and are encouraged to keep adding their reports to it at hawaiicoral.org.