LIHUE — The ideal time period for the state’s proposed rat eradication project on Lehua Island has arrived, but the state Department of Land and Natural Resources is still finalizing the plan.
And the estimated $1 million project might not even happen this year, according to representatives from DLNR.
“The decision to implement the project this year has yet to be made and is contingent on finalizing permits,” said Patrick Chee, from DLNR’s Division of Forestry and Wildlife.
In March, the state announced its intent to drop between eight and ten tons of the rodenticide Diphacinone from helicopters onto the 284-acre island sometime this summer, with a July through September time period set.
Lehua Island is about 30 miles west of Kauai and three-quarters of a mile from the island of Niihau.
Rat eradication using Diphacinone would require three applications, 5-10 days apart. While the exact dates of the applications aren’t yet known, the project will happen in August or September, if it is completed this year.
“The July (through) September time period refers to the best biological window which includes considerations of weather, sea conditions, rat population biology, and non-target species,” Chee said.
Those non-target species include the hundreds of endangered birds that use Lehua as their home-base on land.
Community concerns abounded at a Waimea public meeting regarding the project in March, and local fishermen questioned the effects rat poison will have on fish.
The Kekaha Hawaiian Homestead Association issued a public statement in opposition of the plan June 27, because of the potential effects on Niihau and the surrounding waters.
“The narrow channel between Niihau and Lehua, and the waters off west Kauai, are irreplaceable resources for subsistence fishing, life and livelihood for our people,” the statement says.
Members of KHHA pledged to work with policymakers to find less toxic alternatives to the poison drop, and promised to urge greater research into the project before it is launched.
Phoebe Eng, Westside resident who attended the March meeting, said fishermen and subsistence-based Niihauans even asked about the length of a possible fishing prohibition for the proposed drop.
“(At the meeting) the agencies said only that replacement food would be provided to the Niihauans if needed,” Eng said in an email to TGI.
She and other Kauai residents point to a 2012 poison drop on Wake Island when a 942-day fishing ban was recommended by the U.S. Air Force. The island is a coral atoll that measures about 1,800 acres and is located in the western Pacific.
The recommendation throws up red flags, especially for those who rely on fishing in the waters that could be affected by the poison drop.
“If there’s wash-off, the poison that goes in the ocean will just go toward Niihau,” said Kekaha resident Harold Vidinha at the March meeting in Waimea. “I’m concerned about the crabs, the fish and the animals because it’s right next door to Niihau.”
The concerns have prompted a U.S. Geological Survey study on fish and their response to rodenticides, which is ongoing.
“Preliminary results from that study shows that fish clearly avoid eating food containing diphacinone and show very low sensitivity to the rodenticide,” Chee said.
He continued: “The majority of birds present on Lehua are seabirds which would be very low risk of exposure due to their feeding behavior — they are predatory birds that feed out at sea.”
Mitigation strategies to reduce the risk to non-target species have been lined out in the draft Environmental Assessment of the project — those include dropping the poison at specific times to increase rat exposure and follow-up monitoring.
“Regular monitoring of Lehua Island for the presence of rats over several months following the eradication effort is key to verifying the success of the project,” Chee said. “If the eradication is not successful, a follow-up operation will be mounted.”
State representatives didn’t say when the dates for the drops would be finalized, but did say the project would be helpful for the endangered seabirds on the island.
“This investment should be taken in light of the long-lasting benefits the operation could have for biodiversity conservation,” Chee said.