Hawaii Bonefish Flats Experience Coral Bleaching

Hawaii Bonefish Flats may experience their worst-ever coral bleaching due to high ocean temperatures this summer.
Warmer-than-normal ocean temperatures around Hawaii this year will likely lead to the worst coral bleaching the islands have ever seen, scientists say. 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, according to the Hawaii Institute of Marine Biology. The phenomenon is called bleaching because coral lose their color when they push out algae.

The island chain experienced a mass bleaching event in 1996, and another one last year. This year, ocean temperatures around Hawaii are about 3F to 6F warmer than normal, says the US National Weather Service (NWS) in Honolulu.

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 is also a concern for Hawaii’s tourism-dependent economy. To 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. That is a really doom-and-gloom outcome but that is the reality that we face with extremely severe bleaching events.

30% to 40% of the world’s reefs have died from bleaching events. Hawaii’s reefs generally have been spared such large scale die-offs until now. Most corals bleached last year bounced back, but it will be harder for these corals to tolerate the warmer temperatures two years in a row. You can’t stress any individual, an organism, once and then hit it again very, very quickly and hope they will recover as quickly.

Scientists have reports of bleaching in Kaneohe Bay and Waimanalo on Oahu and Olowalu on Maui. For the Big Island, reports of bleaching have come in from Kawaihae to South Kona on the leeward side and Kapoho in the south-east. Scientists on an expedition to the remote, mostly uninhabited islands in the far north-eastern end of the island chain reported some coral died after last year’s bleaching event. Researchers at the Hawaii Institute of Marine Biology, said a mile and a half of reef on the eastern side of Lisianski Island was essentially dead. Coral further out from the atoll handled the warm temperatures better.

Aquatic biologists with the state department of land and natural resources, said people could help by not adding to the coral’s problems. That meant avoiding fertilizing lawns and washing cars with soap so contaminants do not flow into the ocean. People should avoid walking on coral and boaters should make sure they do not drop anchor on coral. Fishermen should fish responsibly. Scientists have also asked people to help them keep track of bleached coral by reporting sightings to the state’s “Eyes on the Reef” website.

The NWS, said it was not known why waters around Hawaii and other parts of the northeast Pacific were warmer than normal this year. This warm water – nicknamed “The Blob” – is coinciding with El Niño, which is a general warming of parts of the Pacific that changes weather worldwide.

Hawaii is home to 85% of the coral under US jurisdiction, including 69% within the mostly uninhabited islands of the Papahanaumokuakea Marine National Monument. Another 15% of US coral lies among the Main Hawaiian Islands – from Niihau in the north to the Big Island in the south – where the state’s 1.4 million people live.