Warmer-than-normal ocean temperatures around Hawai‘i this year will likely lead to the worst coral bleaching the islands have ever seen, scientists said recently. Many corals are only just recovering from last year’s bleaching, which occurs when warm waters prompt coral to expel the algae they rely on for food, said Ruth Gates, the director of the Hawaii Institute of Marine Biology (HIMB). The phenomenon is called bleaching because coral lose their color when they push out algae.
Bleaching makes coral more susceptible to disease and increases the risk they will die. This is a troubling for fish and other species that spawn and live in coral reefs. It’s also a concern for Hawaii’s tourism-dependent economy because many travelers come to the islands to enjoy marine life. Gates compared dead coral reef to a city laid to rubble. “You go from a vibrant, three-dimensional structure teeming with life, teeming with color, to a flat pavement that’s covered with brown or green algae,” she said. “That is a really doom-and-gloom outcome but that is the reality that we face with extremely severe bleaching events.“
HIMB researcher Courtney Couch spent a month in the Northwest Hawaiian Islands. She says the data she collected is alarming. “Just mass mortality! I’ve never seen something that fast happen at that level. It really is a wake-up call,” said Couch. Many of the reefs were 85 to 100 percent dead. Climate experts say it’s all thanks to warmer water temperatures brought on by El Niño.