Invasive African clawed frog population increases in Washington


Frogs are considered one of the worst invasive species on earth, according to WDFW. They feed on native insects and feed on food eaten by native species.

ISSAQUAH, Washington – An invasive species consumes and competes with species native to western Washington, including salmon.

Scientists have spotted African clawed frogs in Issaquah, Lacey and Bothell, and the Washington Department of Fish and Wildlife (WDFW) is asking residents to be part of the solution.

The WDFW, the nonprofit Trout Unlimited, and other partners are all working together to combat the growing frog population.

The frogs were first introduced to the United States for use in pregnancy tests, said Max Lambert, principal investigator at WDFW. Although frogs are no longer used for this purpose, they have become part of the pet trade. Although Washington has made it illegal to possess them, some still do. Some who decided not to keep the frogs, and instead released them into ponds and streams, created a problem.

“A few years ago we first found them in Lacey and that’s really where we thought they were for a lot of the time,” Lambert said. “We had occasional examples of this in Bothell, first a single frog in Bothell and a single frog in Issaquah.”

As WDFW began to look into the matter and work with landowners to set traps, the department discovered hundreds of frogs.

“They are considered one of the worst invasive species on earth,” Lambert said. “They’ve been introduced to Europe, Asia, sometimes in large numbers and they’re damn good predators. They eat a lot of native insects, which are good forage for our fish and amphibians, they eat tadpoles from our salamanders natives, and they’ll eat fish. We looked at some of their stomach contents – and they’re full of baby fish.

People working to restore salmon populations worry that frogs will encroach on that progress.

Since Trout Unlimited began trapping in January, the organization has captured about 300 frogs, Rebecca Lavier said. About half of them have been discovered in the past few weeks. They believe this is only a fraction of the general population.

Lavier says she got involved in the work because of the role it could play in supporting populations of native species.

“Native species play a vital role in our ecosystem and we want to protect them,” Lavier said. “They make our region beautiful and it can be healthy – and it can be healthier – if we just take the time to observe and take care of what we have.”

She too asks the illegal owners of the frogs to dispose of them properly or give them to someone else if they can no longer care for them.

“You don’t just take a non-native species and throw it in a pond,” Lavier said. “It’s not their habitat. They’re not supposed to be there and they can really wipe out native species.”

WDFW wants to remind residents that it is not legal to have these frogs as pets. If someone does, they have to keep it for life or click here to learn more about alternative options. To get involved in volunteer projects through Trout Unlimited, click here.


Comments are closed.