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The Honolulu Advertiser

Posted on: Monday, March 7, 2005

Seaweed invading site of reef damage

By Jan TenBruggencate
Advertiser Science Writer

A quick-invading, low-growing yellow seaweed has already moved into the scars caused by last month's grounding of the 555-foot cargo ship Cape Flattery off Kalaeloa.

"One of the things we're seeing is a very interesting yellow turf algae growing on the scar," said John Naughton, a NOAA fishery biologist.

"From our experience, this is a normal occurrence after extensive reef damage. This species moves in quickly after an event like this, but it should only last a month or so before other algae begin moving in."

It will take considerably longer before corals re-establish themselves on the damaged reef, and that's one reason why researchers are working hard to save the overturned, but still living, coral heads around the wreck site.

The ship, with a cargo of dry cement on board, hit the reef while approaching Kalaeloa Barbers Point Harbor on Feb. 2. It was not removed until eight days later, when most of its fuel and much of its cargo had been off-loaded to lighten the vessel.

An investigation into the cause of the grounding is proceeding on several fronts, and emergency dive crews have been actively cementing topped coral heads back onto the reef before they die or become undersea bowling balls and topple other corals.

Naughton said that by the end of the week, more than 200 coral heads a yard or more in diameter had been reattached to the reef floor. Crews were to be back in the next week or two to try to set upright and cement down at least 200 more.

The Cape Flattery did most of its direct damage in a fairly compact area that was directly under its hull, but anchors and tugboat cables used in the ship's removal effort broke off big coral heads for hundreds of feet around.

Those large corals give the reef a three-dimensional character that provides hiding places and habitat for much of the life on the reef.

The two main big coral-head species in the recovery effort are the sturdy lobe coral, Porites lobata, and the more fragile antler coral, Pocillopora eydouxi (pronounced eye-dewey).

Naughton said divers often can simply set a lobe coral head onto a pad of cement and leave it, but the antler corals generally have many more broken limbs. They put the core piece into the middle of the cement, and then poke broken smaller pieces in around the base.

"We say we're building flower arrangements," he said.

The recovery teams are looking forward to seeing how well the corals respond to the cementing process.

"It's going to be real interesting to monitor these sites over the next year or so," he said.

Naughton said it may be the first time coral reef reconstruction has been attempted at the depths at which the Barbers Point divers are diving — 30 to more than 60 feet. They are using techniques developed in the Florida Keys National Marine Sanctuary, but most of the work there is done in much shallower water.

"This is all new stuff," he said.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com or (808) 245-3074.