Visitors can help through 'reef etiquette,' filing reports, even adopting a coral head

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MAUI, Hawaii — If you love to snorkel and dive, this October is a ghostly month in more ways than one for visitors to Maui.

On my visit this week to gather material for upcoming Seattle Times travel stories, I’ve witnessed first-hand the unprecedented coral bleaching this fall off the beaches of Maui, resulting from record-setting ocean temperatures of past months.

“This is the worst we’ve ever had, it’s pretty ghostly,” said Darla White, a Maui-based reef specialist with Hawaii’s Division of Aquatic Resources.

White’s agency and the National Oceanic and Atmospheric Administration (NOAA) issued a statewide coral-bleaching alert for this fall, with the phenomenon expected to last into November and December. Bleaching weakens coral and severe cases can kill it. Global warming combined with a significant El Nino event are being blamed.

Coral bleaching is a phenomenon often tied to warming waters in which coral eject the symbiotic algae that usually live in the coral and photosynthesize oxygen and sugars that feed coral polyps. The loss of the algae leads to loss of color, causing a bleached, ghostly appearance of the coral heads.

Hawaii’s coral reefs saw a small event of coral bleaching in 2009, with a repeat last fall, when bleaching was worst around Oahu and the northwestern islands of Hawaii. “This time Maui and the Big Island are getting hit, and we’re starting to see mortality now,” White said.

She was sobered by a snorkel-dive inspection tour on Monday at the Mile Marker 14 dive site, near Olowalu in West Maui, site of a reef covering almost 1,000 acres. White calls it “our jewel, the mother reef,” because the large old corals typically provide reproductive stock for reefs around West Maui and neighboring Lanai.

“This was one of the first places I snorkeled when I came here 20 years ago, and it’s completely different now,” she told me as we swam from one large bleached coral head to another. “Being here, all I’m seeing is death.”

Waters are beginning to cool, however, and corals can recover from bleaching, White emphasized. There was some evidence of recovery in a few coral heads at Olowalu. However, daytime air temperatures reached into the low 90s most days of my visit.

I also saw bleaching of more than half of corals observed Sunday during a boat trip to the popular Molokini crater dive site, a few miles off West Maui.

Even after some recent cooling, water temperatures were still hovering around 80 degrees, usually the maximum in the area, said Yoshi Koketsu, skipper of the Trilogy V catamaran.

It’s no reason to cancel a visit, but there’s reason to be aware. White said visitors can help in a few important ways:

  • The reefs’ compromised health underscores the importance of “reef etiquette” for divers and snorkelers — not touching or standing on coral, which can kill it with or without bleaching; not feeding reef fish, which disrupts the natural ecosystem that depends on fish and sea urchins for cleaning excess algae growth from coral; and using reef-friendly sunscreens based on titanium oxide or zinc oxide, which can be purchased at dive shops, rather than sunscreens with benzophenone-2, or BP-2, a sunscreen chemical that is highly toxic to corals, according to NOAA. (It’s also found in many soaps, cosmetics and body fragrances.)
  • Report sightings of bleached coral by filling out a report form at Hawaii’s Eyes of the Reef website, a community reporting network. Such reports contribute data to research on causes and cures.
  • Adopt a coral head, and report on its health every time you visit Hawaii. It’s a new program soon to be featured on the Eyes of the Reef site.