The lowdown on Lehua

LIHUE — Those involved in the Lehua Island rat eradication project are meeting with members of the community one-on-one instead of holding a community meeting to answer questions.

“We’re here looking for concrete communication conduits into the community,” said Heath Packard, director of communications for Island Conservation, one organization partnering with the state in the plan.

Packard and other representatives of Island Conservation met with The Garden Island on Thursday afternoon, along with Division of Forestry and Wildlife Director Sheri Mann, to talk about the project, which they believe has about a 90 percent chance of success.

The goal of the Lehua Island rat eradication project is to eliminate all of the invasive rats from Lehua Island through aerial broadcast of the rodenticide diphacinone in bait pellets from a helicopter.

The first of three tentatively scheduled bait drops was set to occur on Aug. 8. However, the project is on hold for a few reasons.

A National Oceanic and Atmospheric Administration Section 7 concurrence letter and a Hawaii Department of Agriculture aerial application permit are the last two steps until the project gets the governmental go-ahead.

Scott Enright, head of HDOA, said he has not signed off on the aerial application permit because he shares some of the community’s concerns on the impacts the project will have on the environment.

While the paperwork is pending, project representatives are on Kauai.

“We’re meeting one-on-one with people out here, doing talks on the radio, and hoping to answer questions through these methods,” Mann said.

Three community meetings were held concerning the Lehua project. The first two meetings were civil and productive, Mann said, but the third wasn’t.

“We, unfortunately, weren’t able to get out the information that we wanted to,” she said.

The third meeting was a courtesy to the public and not required by law, Mann said.

“There is a lot of detailed information and it’s a hard project to explain to a big group of people with questions,” Mann said.

Impacts to the marine environment and the details of the operation were the main points of clarification for the group.

The 285-acre, horseshoe shaped island is about 18 miles from the west coast of Kauai and three-fourths of a mile away from the island of Niihau.

It’s currently the nesting site for 17 different species of seabirds and historical records indicate more species nested there in the past. Bird populations number in the thousands on Lehua, according to Island Conservation.

Invasive rats are prominent throughout the entire island. Researchers with Island Conservation declined to give a ballpark number of rats and said what’s more important than the number of rats on the island is the fact that they’re widespread over the entire landmass.

Marine concerns

Island Conservation representatives said the rodenticide used won’t have an impact on the fish or monk seals around Lehua, after completing scientific studies on the interactions between the poison and the animals.

Gregg Howald, Island Conservation director for North America and the Caribbean, cited studies done on triggerfish that show fish consume the uncontaminated bait, but spit out contaminated bait.

There are no documented impacts of diphacinone on corals, triggerfish, or monk seals, he said.

“Even if they (monk seals) did feed on contaminated fish, because of their size, the risk to monk seals is low,” Howald said.

A fishing moratorium was proposed as a potential option in the beginning stages of planning for the Lehua project, researchers said, but is not in the current plan.


The project’s staging area will be on Niihau and helicopters used in the aerial drops will be refueled while still running in a procedure called “hot refueling.” It’s a standard practice and trained personnel will complete the procedure.

Bait pellets will be distributed through a modified agricultural hopper, and in conditions with a maximum wind speed of 25 miles per hour. Bait won’t be delivered if wind speeds exceed that.

Aerial application is the only way to completely rid the island of rats, experts and organizers say, because the island’s terrain is too dangerous for hand applications and too complicated for bait stations.

Bait stations using diphacinone are between 90 and 95 percent effective, but broadcasting poising isn’t quite as sure of a thing.

“One of ten operations are not successful the first time,” Packard said.

What next?

A year after the operation, Island Conservation and partners will be back to test for the presence or absence of rats using live traps, chew tags and motion sensors.

That’s because it takes about a year in the tropics for populations to rebound to detectible levels if the rats are still on the island.

Once it’s established whether the project worked, the next step is to either repeat the bait drop or work on the revitalization of Lehua Island in partnership with the National Tropical Botanical Garden.

Part of the restoration project will be finding out what plants are still on Lehua Island, what plants can grow there, and how the island can be used to bolster native Hawaiian plant species.

If rats still live on the island, the project may be repeated using the poison brodifacoum, which has a higher rate of success but has more risks to the environment.

“We’re dedicated to safety, to communication, and to caring for our public trust resources,” said Suzanne Case, chair of the state Board of Land and Natural Resources. “We’re optimistic that we’ll be successful.”


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