Seventeen Types of Coral Disease on Hawaii Reefs, Star Bulletin, 12/25/05
By Diana Leone
Article Source: Honolulu Star Bulletin
Scientists have found diseased coral in the ocean off Maui, Oahu, the Big Island and Kauai, and even in the remote and pristine Northwestern Hawaiian Islands.
And in some places, disease seems to be spreading.
Coral disease shows itself in the form of abnormal growths (tumors) or discoloration, some nicknamed "zits" by researchers; by the loss of algae that live in the coral (bleaching); and by death of the coral animal itself, leaving behind only its calcium skeleton.
"Coral is a very simple animal. There's no cough or runny nose. We can't ask it, 'How are you feeling, dear? You look a little pale,'" said Greta Aeby, a University of Hawaii Institute of Marine Biology coral disease specialist.
Looking for coral disease is just a few years old in Hawaii. But it's important, because damage from coral disease can be severe.
In the Florida Keys, for example, nearly 90 percent of the most significant reef-building coral type (the genus Acropora) has died of disease.
Aeby saw the destruction firsthand in Florida while working on her post-doctoral research. Since then, other scientists' research in Australia has shown increases in coral disease there, she said.
Now she's among Hawaii scientists developing baseline information about how much disease is "normal" here and what causes the diseases they are seeing.
Hawaii's main reef-building coral genus (Porites) is different from the one affected in Florida and early checks show disease at a much lower level, but Aeby said, "We can learn from the Florida Keys' past experience."
Aeby said she hopes that "we as a people can take better care of our reefs, especially in the main Hawaiian Islands, to ensure that disease does not become a problem as has happened in other regions."
Scientists in Hawaii began specifically looking for coral disease in the Northwestern Hawaiian Islands in 2002, around Oahu in 2004 and around Maui this year. Other observations of coral disease by scientists doing other projects on the Big Island and Kauai have been incorporated.
How to Look for Coral Disease
On a work trip in June to Maui, co-researchers Greta Aeby (University of Hawaii Institute for Marine Biology), Thierry Work (U.S. Geological Survey wildlife disease specialist), Steve Coles (Bishop Museum) and lab technician Dave Albert (collecting samples for UHIMB co-researcher Teresa Lewis) demonstrated the techniques used to look for coral disease.
Underwater dives lasted about two hours per site.
Work and Aeby each carefully noted the species and amounts of coral found 1 meter on either side of a 25-meter-long stretch of tape measure, laid as straight as possible on the ocean bottom. They also noted, and photographed, any coral disease within 3 meters of the tape measure.
Coles took underwater photographs using a frame that allows a computer program to later calculate the amount and type of coral over a wider area.
Albert collected samples of diseased and healthy corals, and the water immediately around them. Lewis analyzes the samples in the lab to determine what kinds of bacteria, viruses or other organisms are present in the vicinity of healthy and diseased corals.
On Maui, the team surveyed coral for disease at Olowalu, Honolua, Kahekili, Kanahena, Molokini, Puamana, Mala Wharf, Maalaea and Sugar Beach. On Oahu in 2004, the team surveyed coral for disease at Kaneohe Bay, Hanauma Bay, Pupukea and Kahe.
The sites were selected because they had good coral cover, Aeby said. In some cases they were sites for earlier coral research on other subjects.