LIHUE — Feral cats have been added to Hawaii’s list of most impactful invasive species, and advocates of trap-neuter-release (TNR) say the state should reconsider.

Feral cats were among little fire ants, rapid ohia death, pigs and other species on a list of some of the most impactful invasive species in Hawaii, submitted to the Western Governors’ Association by Gov. David Ige.

Hawaii’s list was added to those of the rest of the Western states, and those species were distilled into the Top 50 Invasive Species in the West list, released last week.

“Feral cats are a non- native species that is known to cause harm in natural resources, including terrestrial and aquatic wildlife,” said Cindy McMillian, communications director for the Governor’s Office.

She continued: “Parasites carried by cats also present human health concerns.”

Feral cats are avid hunters of Hawaii’s native wildlife and eat native birds and insects, including the endangered Hawaiian petrels, Newell’s shearwaters and Koloa ducks.

Cats carry toxoplasma gondii, which is a parasite that can impact birds and mammals, and the species is the principle threat to 8 percent of critically endangered birds, mammals and reptiles, according to the Hawaii Invasive Species Council.

Pet cats are not included under the listing, but TNR cats — also known as community cats — are.

Basil Scott of Kauai Community Cat Project (KCCP), which operates a TNR program on the island, says TNR cats should not be included on the list, and the current listing should contain a distinction between feral mountain cats and feral urban cats.

The cats within KCCP’s TNR program don’t target the same species that feral mountain cats do, Scott said, and many times they are far less dangerous and more tame than “truly feral cats.”

“We do TNR in our communities, not in wild areas containing sensitive species’ habitat,” Scott said.

KCCP has done TNR on 5,400 cats in the past decade and reduced the community cat population by 18 percent, or 2,200 cats, according to Scott.

He pointed out that trapping and euthanizing 23,000 cats during that same time reduced the community cat population by 10 percent.

That percentage has been calculated by taking the total euthanasia numbers of feral cats documented over the past decade in Kauai, subtracting the number of cats adopted from the number of cats surrendered.

“Even if you hate the cats, TNR is helping more than traditional methods,” Scott said. “That’s why that reference should not be on the governors’ list.”

Feral cats landed at No. 13 out of the top 25 invasive terrestrial species in the West. Feral hogs were listed as No. 6, coqui frogs were No. 19, and little fire ants came in at No. 25.

The terrestrial invasive species list submitted by Ige to the WGA is Hawaii-specific and includes rapid ohia death, miconia, mosquitoes, rats, albizia, goats, deer, coconut rhinocerous beetle, strawberry guava, Hawaiian ginger and snails on Hawaii’s terrestrial invasive species list.

None of Hawaii’s invasive aquatic species made it on the WGA’s top 25 list. However, Ige submitted 15 species for consideration: mangrove, giant salvinia, rice noodle bryozoan, buffalo grass, gorilla ogo, armored catfish, tilapia, hookweed, apple snails, upside-down jellyfish, Australian mullet, pickleweed, leather mudweed, prickly seaweed and Asiatic clam.

“The rankings produced by the WGA reflect submissions from across the West, including some that we share with others states and some that are currently found only in Hawaii,” McMillian said.

Ige chose to be part of the WGA initiative, which provides the first list of its kind for the West Coast states, as a way to help strengthen Hawaii’s biosecurity efforts.

“Strengthening our biosecurity protocols at ports of entry with our partners on the continental United States through the Western Governors’ Association allows us to take further steps to protect our precious natural environment,” Ige said in a statement to TGI about the WGA list.

He continued: “Protecting our environment is vital to our state’s economy and livelihood of all Hawaii’s people.”

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Jessica Else is the environment reporter at The Garden Island. She can be reached at jelse@thegardenisland.com.