Our team used a combination of snorkel and SCUBA surveys to visually assess the extent of bleaching, collect digital imagery of the reef, and install temperature loggers that will remain underwater to track water temperature at the reef surface.
The Hawaiian Islands Humpback Whale National Marine Sanctuary generously partnered with our team, offering the research vessel R/V Koholā as well as their inflatable small boat to help us access numerous reefs along the leeward side of Maui. A warm mahalo to their team for embodying what we like to call the “One NOAA” philosophy!
Among the 51 sites we surveyed, we saw evidence of bleaching at every reef. An average of 26 percent of the live corals we visually observed between 7 and 64 feet showed some level of visual bleaching stress. Most corals become visually pale or white when they lose their symbiotic algae as a result of heat stress. Other colonies, particularly Pocillopora meandrina, showed signs of fluorescing bright yellow or purple. Fluorescent pigments may serve as protection for coral tissues in environments with intense light, functioning as a sort of “sunscreen” and reducing bleaching stress.