COMOX VALLEY RECORD (British Columbia) 01 September 06 Love the frog legs, hate the invasion (Fred Davies)
It’s invasive, voracious, cannibalistic and most likely in a pond near you.
Bullfrogs are spreading across Vancouver Island and the huge amphibian, which wreaks havoc on indigenous frog and fish populations, has firmly established itself in many communities.
The non-native species is thought to have spread mainly due to its large hind legs that are prized as food and resulted in the species being shipped around the continent.
“Once a population is established it’s almost impossible to eradicate,” says Purnima Govindarajulu, who works in the department of biology for the University of Victoria and has studied the frog extensively. “The biggest concern is it’s a generalist predator that can potentially have a negative impact on local frog species.”
The bullfrog ranges in size from eight to 20 centimeters (not including the legs) and can weigh over a pound. Its diet in addition to other frogs can include insects, small birds, rodents, snakes, and, when fully grown, it is beyond the grasp of most local predators. Adult bullfrogs will eat their own metamorphosed tadpoles.
Govindarajulu says the bullfrog’s range has expanded from its traditional stomping grounds of eastern North America and can now be found in Port Alberni, Courtenay and as far north as Merville.
“A population has been established in Errington since the 1960s,” she adds.
Robin Campbell manages the North Island Wildlife Recovery Centre, located in Errington. He describes the frog’s invasion as “a terrible problem. It’s beyond imagination how destructive it can be.” He notes at the recovery centre’s ponds he hasn’t seen a red legged frog for two years saying, “it’s an endless battle for us.”
Expansion of the bullfrog’s range is made possible primarily through human behaviours.
“Please tell people not to move the frogs around,” says Govindarajulu.
Love the frog legs, hate the invasion