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Rare corals discovered in waters off Kona

Aresearch team with the state Department of Land and Natural Resources Division of Aquatic Resources discovered off the South Kona Coast a species of coral new to the main Hawaiian Islands.

In a release issued Wednesday, the DLNR reported the team members came across a large number of coral colonies they had never encountered before while doing reconnaissance scuba dives in April along the South Kona Coast.

“These robust finger-like colonies didn’t even look like they were related to any other corals in the vicinity of the main islands,” the release stated.

The team returned the next day to photograph and document the colonies, and tentatively identified the species as Acropora gemmifera.

The species is common in shallow, tropical reef environments in the Red Sea, Australia, the Indo-Pacific and central and western Pacific, but there are few records from the Northwestern Hawaiian Islands. It can be found, however, at Johnston Atoll, approximately 900 miles southwest of Hawaii.

The colonies vary in color from tan/brown to green, blues and even purples, according to the release.

“Not only is this the first record of A. gemmifera in the main Hawaiian Islands, it’s the first record of any Acropora species occurring around the island of Hawaii,” the release reads.

The team’s visual identification of the coral was subsequently confirmed through genetic sequencing performed by Narrissa Spies of the Richmond Lab at the Kewalo Marine Laboratory, Pacific Biomedical Research Center in Honolulu.

“The presence of these coral colonies is a significant contribution to our understanding of local reef diversity and opens up speculation about what other rare corals may be found on the reefs of Hawaii Island,” said Dr. Bill Wash, senior biologist with the DLNR.

In a Wednesday interview, Walsh called the discovery “a bit of good news for a change” compared to the usual dire warnings coral reefs are endangered because of pollution, bleaching and other events.

“This is something people can be excited about and happy about,” he said. “It’s pretty amazing. It’s definitely a rare occurrence.”

In a paper published Oct. 14 by the scientific journal Coral Reefs, Walsh and his team explained they found no historical reports of any Acropora species occurring around Hawaii Island, “nor were any observed in over 4,300 coral reef monitoring/research dives over the past 14 years.”

The team reported finding a total of 75 individual colonies along an approximately 50-meter stretch of reef in depths ranging from 3 to 9.8 meters. Based on established growth rates for a similar species found in the Red Sea, the team estimated the colonies had been present in the area for “at least 80 years.”

Walsh said there is plenty of work to be done after the initial finding, including finding out how the coral got here.

“The next stage is to look and determine if we can specify where it came from,” he said.

Walsh said his best guess is the coral wafted into the area on an underwater current from the Johnston Atoll, where the species is quite plentiful. He hopes to compare samples from the atoll with the samples found in Kona, and see how close they are.

“I think that’s something we’ll be able to nail down,” he said.

Walsh added information concerning the exact location of the colonies of Acropora is on a “need-to-know” basis, in order to protect the rare corals from divers who might damage them. But, he said, if divers happen upon other locations that might have the species, he and his team would love to hear about it.

“It’s kind of amazing to think that this is the only place they can be found,” he said.

The DLNR release added the discovery of the rare species in Hawaii “emphasizes the need for local marine and land-use conservation practices. Members of this genus have a low resistance and low tolerance to bleaching and disease, which can be made worse by pollution, overfishing and climate change.

They are also a coral species preferred by Acanthaster planci, the crown-of-thorns starfish, which is a coral predator.

If divers happen upon A. gemmifera, they are asked to take photos and document the location, and provide the information by calling the Division of Aquatic Resources at Honokohau Harbor at (808) 327-6226, or by emailing darofc@hawaiiantel.net.

Email Colin M. Stewart at cstewart@hawaiitribune-herald.com.

 

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