Apparent waste attributed to natural coral spawning

By Jan TenBruggencate
Advertiser Science Writer

When Hera Guillermo walked out onto the Waikane Pier on Memorial Day weekend, the view was disgusting.

"There was a scum line. There were hundreds of pieces of feces," she said.

Her attention immediately went out to what was upwind.

"It was Memorial Day. The whole entire horizon was filled with sailboats, and there was a huge military boat out there," Guillermo said.

She made the assumption the stuff in the water was sewage, oil or possibly other filth from the folks enjoying the holiday on the water, the military ship and maybe some from the Waikane Stream, which flows into the bay nearby.

She wasn't alone.

"I received several calls from folks living vicinity of Waiahole-Waikane shoreline—worries about possible sewage spill, dumping from Kualoa Ranch activities, human waste, pineapple slices—the stories got better with each telling," said John Reppun, community developer with the Kualoa-He'eia Ecumenical Youth Program.

But laboratory tests and checks with scientists determined that a large part of the apparent pollution was entirely natural. The pinkish scum was most likely the results of coral spawning and mucus that corals form during exceedingly low tides.

During nights of the new moon in summer, rice coral, known to science as Montipora capitata, spawns, and Memorial Day weekend had a new moon. The corals release packets of eggs and sperm, said coral researcher Fenny Cox at the Hawai'i Institute of Marine Biology. She said there's a lot of rice coral in Kane'ohe Bay.

The spawn material floats to the surface. Fertilized eggs become larvae and swim away, but unfertilized material, pinkish in color, drifts on top of the water.

Additionally, if it has been an exceedingly low tide, exposed corals produce mucus to protect themselves, and this mucus can also drift away as the water rises, mixing with the coral spawn material.

"There might have been some kind of wind pattern that took it all to shore," Cox said.

Kane'ohe residents should know that the corals may have a couple of spawns left this season.

"They'll do it again the 30th (of June) and maybe on the July new moon as well," Cox said.

Reppun said he called on Kaipo Faris, an independent water quality monitor, who took a sample of the feces-like material and brought it to the AECOS laboratory in Honolulu. AECOS owner Ric Guinther conducted tests free of charge. The result, according to lab director Snookie Mello, was that it was probably turtle poop.

"It looked like it had pieces of algae in it," and a bacteriological test showed it was not from a mammal, she said.

"The upshot of story is that while us humans were so worried about the threat to our SUV-laden world, some very natural phenomena were at play," Reppun said.

Guillermo said she accepts the theory that some of that day's pollution was natural, but not all of it.

"There were also boat oils. You can see it every day. There was all this shiny stuff on the water. And as for the feces, some was turtle—you can see the algae in it—you can see the contents. But some of it wasn't turtle. It was really bad," she said.

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