Scientists seek cause of fish disease

HONOLULU — Red rice coral hit by blue-green algae off Kauai’s North Shore has responded well to a treatment involving marine epoxy, according to state and federal scientists, but they’re still trying to find out what is causing skin problems in nearby Hawaiian puffer fish.

“Something’s going on on that North Shore,” Greta Aeby, assistant researcher at the University of Hawaii Institute of Marine Biology, told the Honolulu Star-Advertiser.

Researchers in October photographed sites of dying coral in Anini. Trying to slow growth of algae, they applied marine epoxy, a material like clay, to bacteria on eight colonies of red rice coral. Eight nearby colonies were not treated.

University of Hawaii and U.S. Geological Survey researchers returned two months later. The determined that 4.4 percent of each treated colony was affected by the disease. In contrast, about 65.9 percent of each of the untreated red rice coral colonies had been wiped out by the bacteria.

“(The epoxy) basically slowed the disease a lot, so that’s good,” Aeby said. She called the disease “fairly lethal.”

During the October field work, researchers first noticed lesions on puffer fish.

In an attempt to determine cause and prevalence of the disease, researchers from May 29 to June 5 surveyed five areas — three in Anini, one off Charo’s in Hanalei, and Makua Lagoon.

No fish were seen at one site in Anini. At another Anini site, 22 fish were spotted and five, or 23 percent, were detected with the skin disease, Aeby said. In all, 70 fish were seen at four of the sites. Researchers plan to return to the sites in July, Aeby said.

The blue-green algae, or cyanobacteria, is also affecting ringed rice coral and blue rice coral, and both have been proposed as threatened species. Marine epoxy will be applied to the other affected coral species next month.