Why scientists want to ban pet salamander imports

About 20 years ago, biologists tried to limit the spread of a fungus that ultimately wiped out more than 200 species of amphibians. Now a related fungus called Bsal threatens more salamander extinctions in North America, they warn.

Courtesy of Tiffany Yap
The Ensatina salamander (Ensatina eschscholtzii), a lungless salamander common along the west coast of the US, is one of hundreds of species of salamanders endemic to North America threatened by an emerging infectious pathogen.

The salamander pet trade faces a surprising adversary – fungus.

Batrachochytrium salamandrivorans, or Bsal, an infectious fungus fatal to many salamander species, has caused significant die-offs in Asia and Western Europe. In a report published Thursday in Science, researchers urged US officials to ban salamander imports. Because salamanders are so popular in North America, researchers say the fungus could run rampant here, causing severe population declines and even extinctions.

Researchers first described Bsal in 2013. At the time, the fungus was found to cause lethal skin lesions in fire salamanders, native to Europe. Since then, the pathogen has affected salamander species in Germany, Belgium, and the Netherlands.

“Some die from infection, some are infected and are able to recover, and some do not get infected at all,” says lead author Tiffany Yap, a PhD candidate at UCLA. “More testing is needed. There are three species from Asia that have been identified as Bsal carriers, and what's worrisome is that they are common in the international pet trade.”

The three species – the blue-tailed fire-bellied newt (Cynops cyanurus), the Japanese fire-bellied newt (Cynops pyrrhogaster), and the Tam Dao salamander (Paramesotriton deloustali) – are endemic to China, Japan, and Vietnam respectively. As such, some scientists believe that Bsal may have Asian origins.

Alarmingly, the Cynops and Paramesotriton genera account for more than 90 percent of pet salamanders imported to North America.

While an outbreak would certainly be bad news for the international pet trade – hundreds of salamander species could be at risk – there are much greater implications for the spread of Bsal. Wild salamanders play a key role in their ecosystems, and population loss could negatively impact local biodiversity.

“Salamanders are important in food chains and in the carbon cycle,” Ms. Yap told the Monitor. “They are important predators of insects, and they provide an important food source for larger predators, such as birds, mammals, and snakes. They also help facilitate carbon sequestration by eating invertebrates that enhance the release of carbon into the atmosphere. In some woodland ecosystems, they are the most abundant vertebrates.”

To prevent the further spread of Bsal, researchers are calling for state-sponsored importation bans. But according to Yap, who studies fungal pathogens at UCLA, government intervention is difficult to secure.

“There is a lack of international infrastructure that facilitates rapid responses to emerging infectious disease in wildlife,” Yap says. “The US, which is home to a significant portion of the world’s salamanders, could call an immediate ban. But it has not done so, purportedly because of the lack of data on Bsal. The US should protect American species and should work with the international community to control the spread of this deadly pathogen.”

Two organizations, the Center for Biological Diversity and Save the Frogs, have petitioned the US Fish and Wildlife Service (FWS), requesting action under a conservation law called the Lacey Act. Title 18 of the act prohibits importation and interstate transport of species deemed “injurious.” But while the FWS states that the fungal strain is “of great concern” to the agency, they claim legal precedents prevent government action.

“[T]he Lacey Act is a workhorse for wildlife conservation that we use to prevent the introduction and spread of damaging non-native species and to halt the illegal trade in wildlife and wildlife products,” says Laury Marshall Parramore, a spokeswoman for the FWS, but "the act does not include a provision to list injurious species on an emergency basis."

In other words, the law is not a rapid-response tool.

Scientists have raised a similar alarm before. In 1998, researchers first described Batrachochytrium dendrobatidis (Bd), a rapidly spreading pathogenic fungus closely related to Bsal. It took seven years to implement limited preventative measures, at which point the damage was already done. Bd has been called a “global pandemic,” and is responsible for the extinction of over 200 amphibian species.

“Bd represents the worst case in recorded history of a single pathogen affecting vertebrates,” Yap says. “With Bsal, we have an amazing opportunity to act early and prevent an ecological crisis if we can stop it from spreading.”

And according to Yap, there are many small ways to do so. These measures can’t substitute for federal regulation, but they can help.

“Anyone can have their animals tested for Bsal,” Yap adds. “Some treatments have been shown to clear Bsal infections, and these should be used if any animals are found to be infected with Bsal. The Bsal pathogen was recently discovered in the pet trade in the UK, so time is of the essence.”

[Editor's Note: An earlier version of this story suggested that Ms. Yap and colleagues had petitioned the FWS. In fact, the petition was filed by two organizations, The Center for Biological Diversity and Save the Frogs.]

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