Keehi jellyfish
outbreak lessens

The tiny, stinging jellyfish that drove canoe regattas from Keehi Lagoon three weeks ago could hardly be found in the latest lagoon water samples.

Very few of the hydromedusae jellyfish that had been so evident in samples taken June 14 could be seen in samples taken Friday, said Watson Okubo, monitoring supervisor for the state Department of Health Clean Water Branch.

"Lu didn't find any and Jerry found just a few," Okubo said, referring to Bishop Museum invertebrate zoologist Lu Eldredge and Waikiki Aquarium curator Jerry Crow, who examined the samples.

"Apparently there is some kind of seasonality to this (the jellyfish presence at Keehi)," he said. "The numbers just weren't there anymore."

Crow and Eldredge are helping the Health Department try to identify what had been stinging canoe paddlers May 29 and June 5 at Keehi Lagoon regattas.

The Hui Wa'a canoe racing association canceled one regatta and moved several others that would have been held at Keehi until the source of the stings could be figured out.

The Oahu Hawaiian Canoe Racing Association will discuss tonight whether to hold a July 17 regular regatta and its July 24 association championships at Keehi or elsewhere, said association president Hannie Anderson.

The location of July 23 championships for Oahu's other canoe racing association, Hui Wa'a, also remains undecided.

The precise identify of the tiny jellyfish, with bodies no bigger than a pinhead, remains uncertain and their habits unknown. It is possible that they are related to a hydromedusae jellyfish that is believed to cause outbreaks for New Zealand ocean swimmers.

Figuring out what marine organism is causing problems for people takes time, agreed Anita Freudenthal, the retired chief of marine ecology for the Nassau County, N.Y., Health Department who has studied outbreaks of "sea-bathers' eruption," and Swiss jellyfish expert Peter Schuchert of the Museum of Natural History in Geneva.

The Health Department will continue to sample Keehi Lagoon twice a month for several months, Okubo said.

"We're trying to determine what's going on here," he said. "It could be a monthly thing (like the box jellyfish that invade South Oahu beaches) or a seasonal thing."

No one has reported similar stinging at any other Oahu location since the Keehi outbreak, Okubo said yesterday.