B.C. fears invasion of killer frogs

Glenda Luymes, Canwest News ServicePublished: Thursday, March 27, 2008
DELTA, B.C. -- Fears that a major B.C. wetland area could be overrun by killer frogs has local politicians hopping.
"They're big and they're ugly and we can't let them get a hold in Delta's wetlands," said Delta Coun. Vicki Huntington Wednesday about the plague of American bullfrogs in Burns Bog, the largest bog of its kind on the West Coast.
Huntington became aware of the problem when an environmental assessment for a development near the edge of the bog indicated the species was in the area.
American bullfrogs mean bad news for other frogs, fish and baby ducks, all of which become food for the ill-tempered toads that are even known to eat their own species -- or anything else that will fit in their huge mouths.
"It's not just the bog," said Huntington. "These frogs can take over an entire ecosystem very quickly."
The American bullfrog is the largest frog in North America and females can lay as many as 20,000 eggs in spring. As tadpoles, the frogs can grow to the length of a hand, and as adults, to the size of a dinner plate.
The frogs, which are native to eastern Canada, were imported to B.C. in the 1930s to supply restaurants with frogs' legs.
It is believed some of the frogs were released into the wild, where they expand their range by about five kilometres each year, endangering local species like the red-legged frog.
University of B.C. zoology professor Jonathan Shurin said the ill-tempered frogs are especially prevalent in California and on Vancouver Island. "I haven't heard of it on the (Lower) Mainland," he said. "But it's not at all surprising."
Shurin said efforts to eradicate the frogs are often unsuccessful because the tadpoles are hard to eliminate. "You'd have to take pretty drastic measures," he said.
Metro Vancouver parks spokesperson Mitch Sokalski said he was not aware the frogs had been found near the bog, but added: "Wherever there are bullfrogs, there's a concern for us.
"They are very predacious. They'll eat all the other local frogs." http://www.californiaherps.com/frogs/pages/r.catesbeiana.html