Tara Gleboff is a second year Recreation, Fish and Wildlife student at Selkirk College in Castlegar.

Tara Gleboff is a second year Recreation, Fish and Wildlife student at Selkirk College in Castlegar.

The Kootenay’s uninvited guest — the American bullfrog

Ecology Comment is written by Recreation, Fish and Wildlife students at Selkirk College

Submitted by Tara Gleboff

The American bullfrog is on the world’s top 100 invasive species list and can now be found in several B.C. locations. While many of us have never seen an American bullfrog, they are easy to identify. They have olive to bright green backs and creamy white underbellies mottled with grey or dark markings. And they’re big. They are North America’s largest frog, growing up to 800 grams and 20 centimetres in length.

The American bullfrog was initially introduced into coastal British Columbia for human consumption as it is known for its meaty legs. This cuisine trend never took off in B.C., and farmers released the frogs into the wild. The bullfrog was also a popular household pet and a favourite for outdoor ponds due to its ease of adaptation to any water habitat. When unwanted, pet owners would release these frogs into ponds and wetlands. These innocent acts of release have contributed to the current environmental issue without knowing the impact it would have. In addition, there have been bullfrogs that have migrated from Washington state into the Kootenays.

In 2015 a newly detected colony was found in the Kootenay region near Creston and reports are indicating they are spreading north. Vancouver Island, the Lower Mainland and the South Okanagan are also reporting colonies. In these new environments, bullfrogs lack their usual predators, like snapping turtles, to keep the population in check. These frogs also release an unpalatable toxic chemical from their skin, protecting them from predators.

While they prefer warm, weedy ponds or lakes, unfortunately they can also thrive in human-disturbed habitats. They are frequently found in ditches and slow-moving streams. These frogs can migrate up to 19 kilometres per year, contributing to the province’s invasive spread.

American bullfrogs can also transfer an infectious disease called chytrid fungus. The fungus thrives in cool, moist environments and feeds on living amphibians. The fungus consumes the keratin in the frog’s skin, causing it to thicken, preventing normal respiration. This fungus is directly responsible for declining amphibian populations. The bullfrog seems to be immune to the fungus.

The difference between the bullfrog and a native frog is that the bullfrog is larger and will eat almost anything that can fit in its mouth. The American bullfrog is an opportunistic predator and ambushes its prey. They are carnivorous and will eat amphibians, fish, rodents, snakes, turtles, songbirds, ducklings, and even each other. Evidence shows that new and increasing bullfrog populations are drastically affecting native and endangered frog species such as the northern leopard frog, the protected Pacific chorus frog, and Columbia spotted frog. They will either eat these protected species or their food.

Bullfrogs reproduce ten times faster than native frogs; therefore, the native frogs are being pushed out of preferred habitats. This is resulting in declining numbers of native frogs which is negatively impacting the ecosystem. These native frogs are an integral part of our ecosystem and food web. The smaller native frogs consume large amounts of insects and their tadpoles eat algae, which keeps waterways clean. These frogs and tadpoles are also an essential food source to predators such as dragonflies, fish, snakes, birds, beetles, and centipedes.

The Central Kootenay Invasive Species Society (CKISS) is just one group that is working to reduce American bullfrog populations. Last year CKISS safely removed many of these invasive frogs along the Kootenay River.

We can all do our part by not possessing, breeding, shipping, or releasing America bullfrogs in B.C. It is also important to not transfer tadpoles of any kind or to stock ponds with frogs from pet stores. When creating an outdoor pond, set up an attractive environment with water, shelter and insects to attract native frog species. Most importantly, raise awareness to avoid further spread into B.C.

Tara Gleboff is a second year Recreation, Fish and Wildlife students at Castlegar’s Selkirk College.

Environmentkootenay

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Interior Health update. File photo.
86 new COVID-19 cases, two more deaths in Interior Health

The new deaths are from Heritage Square, a long-term care facility in Vernon

RCMP responded to a report early Friday morning of a suspect firing a gun at a Salmo home. Photo: Black Press
RCMP arrest woman who fired shots at Salmo home

The woman allegedly discharged a firearm early Friday morning

Summit Ski Hill had a delayed start to the season because of warm temperatures. Photo: Summit Ski Hill
Late season start frustrating for Nakusp ski hill

Summit Ski Hill only just opened Jan. 14

Four friends were heading to their home on Highway 6 just south of Silverton on the evening of Dec. 25, 2020, when the people in the front of the vehicle saw what looked like a “huge, man-like figure” on the side of the road. (Pixabay.com)
Possible Bigfoot sighting shocks, excites Silverton residents

‘I didn’t see the creature myself, I saw the prints’

Police were called after a man was witnessed stabbing tires with the fence post. Photo: Thanh Serious on Unsplash
Trail RCMP eport erratic man, suspicious fire and prohibited driver

Brief from the media release from the Trail and Greater District RCMP detachment

Health Minister Adrian Dix and provincial health officer Dr. Bonnie Henry head for the press theatre at the B.C. legislature for an update on COVID-19, Jan. 7, 2021. (B.C. government)
B.C.’s COVID-19 spread steady with 509 new cases Friday

Hospitalized and critical care cases decline, nine deaths

Seasonal influenza vaccine is administered starting each fall in B.C. and around the world. (Langley Advance Times)
After 30,000 tests, influenza virually nowhere to be found in B.C.

COVID-19 precautions have eliminated seasonal infection

Prime Minister Justin Trudeau listens to a question during a news conference outside Rideau cottage in Ottawa, Friday, January 8, 2021. THE CANADIAN PRESS/Adrian Wyld
Trudeau says Canada’s COVID vaccine plan on track despite Pfizer cutting back deliveries

Canadian officials say country will still likely receive four million doses by the end of March

Jobs Minister Ravi Kahlon shared a handwritten note his son received on Jan. 13, 2021. (Ravi Kahlon/Twitter)
Proud dad moment: B.C. minister’s son, 10, receives handwritten note for act of kindness

North Delta MLA took to Twitter to share a letter his son received from a new kid at school

Lilly and Poppy, two cats owned by Kalmar Cat Hotel ownder Donna Goodenough, both have cerebellAr hypoplasia, a genetic neurological condition that affects their ability to control their muscles and bones. Photo by Alistair Taylor – Campbell River Mirror
VIDEO: Wobbly Cats a riot of flailing legs and paws but bundles of love and joy to their owner

Woman urges others to not fear adopting cats with disabilities

A COVID-19 outbreak at Vernon's Heritage Square long-term care home has claimed seven people. (Jennifer Smith - Morning Star)
Two more COVID-19 deaths at Vernon care home

Heritage Square has now lost seven people due to the outbreak

Chief public health officer Dr. Theresa Tam provides an update on the COVID-19 pandemic in Ottawa on Friday, Jan. 8, 2021. THE CANADIAN PRESS/Sean Kilpatrick
Canada’s top doctor says to avoid non-essential travel as B.C. explores legal options

Premier John Horgan says he is seeking legal advice on whether it can limit interprovincial travel

Martin Luther King Jr. addresses the crowd during the march on Washington, D.C., in August of 1963. Courtesy photo
Government reinforces importance of anti-racism act on Black Shirt Day

B.C. Ministers say education “a powerful tool” in the fight for equity and equality

Andre Robert won $500,000 through a Lotto Extra ticket on Dec. 23, 2020. Photo: Jeanne d’Arc Allard
Creston resident wins $500k through Lotto ticket

“I was surprised. I wasn’t sure if it was true or not.”

Most Read