Scientists: Hanalei Bay reef is still ‘hanging in there’

LIHU‘E — Reefs are “amazingly tough,” and Hanalei Bay is “hanging in there,” said Kalaupapa National Historical Park Marine Ecologist Dr. Eric Brown.

Research indicates that coral in the North Shore bay has “stayed surprisingly consistent” for some 20 years, said Dr. Alan Friedlander, fisheries ecologist with the Hawai‘i Cooperative Fishery Research Unit at the University of Hawai‘i at Manoa.

“The take-home message is there are some reefs doing OK,” Brown said. “And the bottom line is that Hanalei appears to be doing fairly well.”

Hanalei Bay is actually “looking very good compared to other places in the world,” agreed marine biologist Dr. Carl Berg.

One explanation could be “corals coming into Hanalei in astronomically high numbers,” Brown said.

Although it is unclear where exactly they are migrating from, Hanalei exhibits “world-class” influx levels of the living organism, he said. Alternative parts of the state — like Moloka‘i where Brown conducts similar work — have about one-tenth the amount of inflow.

“So for us it’s a real eye-opener and could possibly be one reason why Hanalei is able to sustain such heavy wave and human interaction and still be all right,” Brown said.

On the other hand, there are other parts of the state, such as the South Shore of O‘ahu, where “they’ve really packed people in” and the reefs are “doing rather poorly,” Brown said.

“Some of the reefs are subjected to continual abuse and do not have a strong structuring mechanism,” he said. But, Hanalei has a “relatively small population of people” living in the area.

That is not to say there aren’t “localized spots in Hanalei taking a beating,” Brown said.

For example, Hanalei wall is in “very, very poor condition,” said Dr. Greta Aeby, who works for the Hawai‘i Institute of Marine Biology at UH-Manoa.

Hanalei is actually “not in great condition compared to other islands,” she said.

Coral bears the brunt of human activity in the area, such as “excess fertilizer,” and “if we don’t change our ways, we will start to lose our reefs,” Aeby said.

Disease outbreaks are starting to increase which is “worrisome,” she said. And Hanalei Bay is exhibiting a “unique” disease found “no where else in the state.”

“We know our reefs in Hawai‘i are stressed,” Aeby said.

This is a “warning shot,” and “we are starting to see signs that it’s starting to tip,” she said.

But some efforts to curb coral degradation have been developed, such as a research program in Waikoko, where the reef is only a few hundred yards from a stream, said Berg, who heads the program.

“Best-management practices” are created to assist taro farmers in reducing “the amount of pollutants into streams and ditches, while at the same time increasing the production of taro,” he said.

If the amount of sediments can be cut back, then the “corals would be happier,” he said.

The nitrogen from fertilizers, for example, causes seaweed to grow, which tends to “smother the reefs,” Berg said.

“A lot of sediment that comes into the bay affects the corals negatively,” Aeby agreed.

But natural events bring about sediment settling as well, Brown said. The recent flood in November was a prime example of “natural forces” at play.

Other events such as hurricanes and high surf “serve as a refreshing,” he said. This past winter had the “strongest wave patterns in probably a decade.”

Considering Hanalei Bay’s intense North Shore swell and human-induced sedimentation — including a “disturbing” number of cesspools in the area — it is astounding how well the reefs are doing, said Friedlander who visited the island last week along with Brown to conduct studies.

Though data is not available yet, the coral and fish “look pretty healthy,” he said.

But the reef is “at a tipping point,” Friedlander said. Human activities are “incompatible” and it is important to “fix stuff before it breaks.”

“I can guarantee everything won’t be fine if we do nothing,” he said.

Visit www.reefcheckhawaii.org for more information.

• Coco Zickos, business and environmental writer, can be reached at 245-3681 (ext. 251) or czickos@kauaipubco.com.