How the American bullfrog is eating its way into BC

Like a horde of slimy green zombies, the incredibly invasive American bullfrog is hopping the border into the West Kootenay.

Carling Grey and Michaela Gebhart

Carling Grey and Michaela Gebhart

Second year students in the Recreation, Fish and Wildlife Diploma program at Selkirk College write an article for a localnewspaper as part of their studies. We will be running several over the next few months, each by a different pair of students.

Carling Grey and Michaela Gebhart

Like a horde of slimy green zombies, the incredibly invasive American bullfrog is hopping the border into the West Kootenay, and eating everything that can fit into its mouth along the way.

It’s an awfully big frog with a very big mouth.

Dissection of bullfrog stomachs has revealed fish, birds, rodents, snakes, small turtles or hatchlings, salamanders, bats, otherspecies of native frogs, tadpoles, and even other bullfrogs.

The species was detected last year just south of the Creston Valley Wildlife Management Area, as well as in the Pend OrielleRiver near the Nelway border crossing.

While many species of amphibians are in decline in Canada, the American bullfrog has been spreading rapidly in BC andoutcompeting, and at times devouring, other native frogs and wetland species.

Native to eastern Canada as well as central and eastern United States of America, the American bullfrog was introducedaccidentally to the western United States and parts of western BC during trout stockings.

They were also introduced intentionally for sport and pest control. Frog farmers who attempted to harvest their legs for profitalso had a hand in their introduction as did some people who kept them in ornamental gardens.

They can now be found in Victoria and as far north as Campbell River. Very recently, they were also found in West Vancouver.

The American bullfrog can reach up 20 cm in length and weigh up to 800 g (almost 2 lbs).

They are generally pale green with brown spots, and mature males usually have bright yellow upper abdomens while onfemales this area is cream coloured.

They are incredibly adaptable, being able to survive in temperate regions where they hibernate to survive below freezingtemperatures, as well as in tropical regions that can reach up to 40 degrees Celsius.

Females lay up to 20,000 eggs at one time and live up to 15 years

Most potential bullfrog predators find the frogs, their tadpoles, and their eggs unpalatable which only increases the success ofthis species.