By Timothy Hurley
Advertiser Staff Writer
Noisy populations of Caribbean frogs have exploded on the Big Island, but state wildlife officials are hopeful theyve found an effective way to fight back.
A concentrated form of caffeine used as a spray has emerged as the best frog killer in field testing of more than 30 over-the-counter compounds, said Fred Kraus, alien species coordinator with the state Department of Land and Natural Resources.
|Caribbean frogs on the Big Island have increased and spread to 150 locations.
Photo courtsey Hawaii Biological Society
"Weve had close to 100 percent knock-down success with one application, Kraus said.
Field testing is required before the U.S. Environmental Protection Agency will allow use of the compound as a control agent against the frogs.
But is it too late for eradication? Kraus said the Big Island frogs have expanded to 150 locations from about eight just three years ago.
In their native Caribbean islands, the frogs, Eleutherodactylus coqui, live in populations of up to 8,000 an acre. Females can produce more than 200 eggs a year, with each frog reaching sexual maturity in just eight months.
The frogs arrived in Hawaii during the past five years as hitchhikers in nursery materials. Scientists say theyre a threat to Hawaiis native forests and export nursery industry. Their loud calls also can be a source of irritation.
There are 40 populations on Maui and a few on Oahu, but the Big Island has the worst problem by far.
State wildlife biologist Fern Duvall said he and a few colleagues observed an enormous frog infestation last year at the Big Island's Lava Tree State Park in Pahoa. He described the din as "deafening and "mind-boggling, and estimated that population at 10,000.
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