LIHUE — No detectable levels of rat poison were found in the five pilot whales that died on Kauai in October, according to a Tuesday state announcement.
Frozen liver samples were taken from the whales during post-stranding necropsies immediately after the mammals were moved off Kalapaki Beach in response to concerns the whales could have come in contact with the rodenticide diphacinone.
The rodenticide was dropped on Lehua Island in late August and early September as part of a rehabilitation project to make the island a sanctuary for seabirds.
“Three preparations of each whale’s livers were extracted and analyzed last Thursday,” a Tuesday release from the state Department of Land and Natural Resources said. “No observed concentration of diphacinone was detected in any of the 15 samples.”
Kauai pathologist and veterinarian Jade Fisher helped with the October necropsies and said she helped take the samples, though she wasn’t convinced the whales died from diphacinone-related issues.
“We took the samples to satisfy the public and (look into) every possibility,” she said.
State Rep. Dee Morikawa (D-16) has expressed concerns about the rodenticide permeating the food chain surrounding Lehua Island and has questioned the role of the poison in the whale deaths, as well as the investigation relating to the beaching.
Tuesday she said she’s still not confident with DLNR’s monitoring efforts following the Lehua Island rat eradication project and is still concerned about the results, which came from U.S. Department of Agriculture’s National Wildlife Research Center in Fort Collins, Colorado.
“’No observed concentration’ worries me because any trace, no matter how small, would prove an effect,” Morikawa said. “However, no humans have been affected, and I am thankful for that.”
The DLNR, National Oceanic and Atmospheric Administration’s Pacific Islands Regional Office and the University of Hawaii cooperated in the necropsies (postmortem examinations) conducted on the pilot whales, and so far have been unable to determine a conclusive cause of death. Additional testing continues, according to DLNR.
Monitoring continues in relation to the Lehua Island restoration project, and since the final drop of diphacinone on Lehua in early September, monitoring has shown no presence of the rats it was meant to kill.
However, the partners of the Lehua Seabird Restoration Project have stated that they cannot declare the island “completely rat free,” until one year after the final rodenticide application, according to DLNR.
“We remain hopeful that the rat-removal project will be declared a success in 2018. As conservationists committed to preserving wildlife, we were deeply saddened by the October pilot whale mortalities,” said Patty Baiao, Hawaii program director for Island Conservation, the not-for-profit conservation organization that assisted DLNR and other partners with the invasive rat removal project.
“We are heartened by today’s announcement, which reaffirms the body of science suggesting rodent-removal projects can be done with little to no risk to marine mammals.” she said.
Morikawa said she thinks waiting a year to evaluate the success of the project is too long of a time frame.
“They should be on it sooner and continue to manually eradicate what they can,” she said. “I’m hoping they don’t need to go back with a stronger rodenticide to be dropped aerially again.”