Bullfrogs found in the Uinta Basin

Biologists also concerned about bullfrogs in other parts of Utah

ROOSEVELT - Acting on information provided by a local golfer, biologists for the Utah Division of Wildlife Resources verified his claim that a population of the American bullfrog had been illegally introduced into the Uinta Basin.

Bullfrog Biologists are concerned about the discovery of American bullfrogs in the Uinta Basin this summer.
Photo by Ron Stewart

"This is the first report we've had about bullfrogs in the Uinta Basin," says Trina Hedrick, project leader for the DWR. "According to individuals associated with the Roosevelt Golf Course, this population was introduced into one of their ponds about three years ago. From there we know some have moved, or have been moved, to other areas near the golf course and around the valley.

"One of our biologists recently found one in the Uinta Mountains, just inside the National Forest Service boundary.

"This isn't good news."

And the Uinta Basin isn't the only place in Utah where bullfrogs could harm the state's native species. Bullfrogs and other animals pose a threat statewide. (*Please see the section Other animals also pose a threat at the end of the news release for information about other animals that pose a threat in Utah.)

Why the concern?

"Bullfrogs are voracious predators. They'll eat almost anything, including snakes, worms, insects, crustaceans, fish, frogs, toads and salamanders," Hedrick says. "They will even eat fish and frog eggs. They've also been known to take small birds and mammals.

"In their native range, the bullfrog can be part of a healthy ecosystem. But they are extremely harmful to native species in areas where they have been introduced," Hedrick says. "For example, they are very harmful to native frog and toad populations, including the northern leopard frog found here in the Uinta Basin. Bullfrogs are very aggressive; besides eating leopard frogs, they out-compete them for food and habitat.

"The decline and elimination of native leopard frog populations due to bullfrogs has been documented in Colorado," she says. "They are also believed to be a significant contributing factor in the decline of many species of leopard frog in Arizona, including the endangered Chiricahua leopard frog. They've also contributed to the decline of many other frogs, toads, and salamanders in California and other Western states."

The American bullfrog is native to the Eastern United States and Canada. Their range used to extend only to the Rocky Mountains, but now it goes well beyond. By the early 1900s, bullfrogs had been introduced into many parts of the Western U.S. and Mexico. They have also been introduced into parts of Europe, South America and Asia.

More reasons for concern

Bullfrogs are aquatic for the first few years of their life. It often takes them two or three years to metamorphose into their terrestrial phase. It takes another two years before the frog is officially "mature." Most bullfrogs live seven to nine years. But as with most animals, they live even longer in captivity.

The Bullfrog is an invasive species to Utah
The Bullfrog is an invasive species to Utah
Photo by Ron Stewart

Another reason they're often more successful than native species is that they have less palatable eggs. They also produce larger egg masses that are filled with exponentially more eggs than those produced by native frogs. Humans have also altered natural habitats and created areas of warmer water. Bullfrogs thrive in these areas.

"Because of their potential to devastate populations of native species, they are a prohibited species in Utah," Hedrick says. "It is illegal to collect, possess, transport or import a live bullfrog (either an adult, juvenile or tadpole).

"Moving just two bullfrogs could expand their range and increase the risks to our native species through predation, competition and the potential spreading of amphibian illnesses.

"If you see one, please contact me or any division employee," Hedrick says. "Please let us know when and where you saw the bullfrogs.

"Pictures are good, but not necessary."

You can reach Hedrick at (435) 781-5315 or the DWR's Northeastern Region office at (435) 781-9453.

In other areas of the state, you can call the nearest DWR office or the DWR's Salt Lake City office at (801) 538-4700.

Other animals also pose a threat

"Bullfrogs are not the only amphibian that has been imported to Utah to the detriment of Utah's native species," says Ron Stewart, conservation outreach manager with the Utah Division of Wildlife Resources. "Frogs, toads and salamanders are commonly picked up and carried across state lines with the intention of making it a pet or novelty. Other sources include pet shops and the live frog and salamander kits offered by schools and pet supply stores.

"While bought with good intentions or for their educational value, these amphibians can become a major problem because they are often released into the wild," Stewart says.

"The frog kits usually contain the African clawed frog or the southern leopard frog, neither of which is native to Utah. The clawed frog is like the bullfrog it can get quite large, and it has a voracious appetite. It is also a real survivor because it can retain or change its sex, depending on the sex of the other members of its species that it encounters.

"If these released individuals survive and breed, one or more native species in Utah could be facing increased predation, competition for resources, alteration of the habitat and/or the introduction of new parasites and diseases.

"The kind-hearted person who released them may have just struck the death bell for some of Utah's native species."