Help a scientist collect invasive bullfrogs, get free beer
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FRUITA, Colo. — It's 8:50 p.m. on Thursday, August 7. The sun has slipped into the desert beyond Interstate 70, and a handful of volunteer scientists turn on their headlamps and spread out around a pond near the Colorado River in Fruita.
Denita Weeks, a biology professor at Colorado Mesa University, forgot her folding table on this trip to Snook's Bottom, the slightly slimy lake surrounded by cattails just outside of town.
Everything besides the table is ready to collect bullfrogs from the volunteers who just ventured out to catch the amphibian, which is invasive in much of the western United States. This community science effort helps Weeks with her research on diseases that affect aquatic life in western Colorado.
"[Bullfrogs] unfortunately can be reservoirs for two different diseases, so I like to survey for that and see what kind of threats they currently pose to our native amphibians," she said.
Video: Joshua Vorse, Rocky Mountain PBS
The invasive bullfrogs eat native amphibians, rodents and snakes, and can carry chytrid fungus and ranavirus, which are harmful to other animals in the ecosystem.
Weeks has done these collection events for the past five years. Volunteers receive a voucher for a drink at their favorite brewery for participating. It’s called "Bullfrogs for beers," and over the years more than 100 participants have removed 300 bullfrogs from wetland areas along the Colorado River in the Grand Valley, Weeks said.
"[It's] definitely a different way to spend your evening, but it's exciting to be part of a conservation effort," said Sarah Finley, one of the volunteers.
"If I can catch one," she added.
Weeks weighed and measured each bullfrog, swabbed them to see if they're carrying the fungus, then euthanized them with a special tranquilizer, absorbed through the frog's skin as they sat in a container.
"It's as humane as possible, but I still don't enjoy it," said Weeks, of the euthanasia process.
After she collects data from each bullfrog, she donates the specimens to elementary or middle school science classes to continue the research. Students catalog the stomach contents of the frogs for Weeks, giving her more information about the impact they’re having on the landscape.
Later in the evening, volunteer Erik Kopperud spotted a leopard frog — one of the native amphibians that bullfrogs prey on — as he waded out into three feet of water to look for the invasive species.
He spotted one in the cattails, training his headlamp on it. The light sets off a freeze response in the creatures, letting Kopperud inch close enough to grab the frog with a blue-gloved hand.
"If we were at Connected Lakes, this would be a real big one. But they’re all this size or bigger here," he said after grabbing the bullfrog. Connected Lakes is a section of the Colorado River State Park, another location Weeks has held collection events at over the summer. If Kopperud wasn’t catching frogs under the supervision of a scientist, he’d need a fishing licence from Colorado Parks and Wildlife.
Participants wear gloves, changing them between each catch, to make sure there’s no cross contamination between samples.
Kopperund contributed 50 percent of frogs collected at the August 7 event. The next day was the last event of the summer. Volunteers caught 30 bullfrogs in total this season, Weeks said.
Collecting this much data with just a few research students working each summer would be impossible, Weeks said.
"I think people often think of science as being inaccessible or something that they can't do. And it actually is extremely helpful for a lot of people to come out on the same mission and help collect this data," she said.
If the volunteers don't like beer, they could also choose a coupon to a local pizza place, or, long-time favorite for homemade ice cream, Graff Dairy.
Type of story: News
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources. To read more about why you can trust the journalism of Rocky Mountain PBS, please visit our editorial standards and practices page.
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources. To read more about why you can trust the journalism of Rocky Mountain PBS, please visit our editorial standards and practices page.