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VANCOUVER SUN (British Columbia) 08 July 04 Bullfrog invasion making waves in B.C. ponds: Government cutbacks means lack of cash to control slimy critters (Nicholas Read)
They are the plague that won't go away.
American bullfrogs that can weigh up to 750 grams and grow to the size of dinner plates are spreading through the ponds and streams of B.C., and now, because of government cutbacks, there's no money to control them.
Trudy Chatwin is an endangered species biologist with the B.C. Ministry of Water, Land and Air Protection in Nanaimo. She used to run a program that attempted to manage the proliferation of bullfrogs in the province.
Funding for that program is gone, but the frogs are still around and still spreading.
"In their place, they're fine," Chatwin says of the large, slimy green and brown frogs known for eating anything they can fit in their mouths. "But here they've just gone explosive."
Their place is almost all of the eastern U.S., but back in the 1930s, they were brought to southwestern B.C. by some misguided entrepreneur who wanted to raise them for their legs.
The trouble was that British Columbian palates didn't run to cuisses de grenouilles back then, so the frogs were abandoned to a local pond where they made themselves at home.
After that they remained almost invisible for 40 or 50 years. They were out there somewhere, but hardly anyone knew where.
Then, about 15 years ago, and for reasons no one can understand, they started to proliferate -- and proliferate and proliferate -- to the point that there are now who knows how many thousands of them throughout large portions of Vancouver Island and the southwestern part of the mainland.
"They're all over southern Vancouver Island as far north as Campbell River and as far east as Port Alberni," said Purnima Govindarajula, who is studying the frogs for her PhD thesis in biology at the University of Victoria. "They're also all through the Lower Mainland, in Abbotsford, Langley, Surrey and White Rock. They're also in Sechelt and there is one isolated population in the Okanagan."
The problem is that because they're an invasive species, bullfrogs are taking over habitats from native frog species. Not only that, they're eating native frogs, too.
"They're very opportunistic," says Chatwin. "They eat other frogs, including the red-legged frog, which is now a blue-listed [endangered] species because of it."
But it's not just frogs they consume. Their tastes also include other kinds of amphibians, ducklings, garter snakes, songbirds and even mice.
"They eat anything that can fit in their mouths, and they've got big mouths," Chatwin says.
In Langley, Lisa Burgess-Parker and other members of the Langley Environmental Partners Society (LEPS) have been trying to control their numbers for years. But now their funding has been cut as well.
So all they're left to offer is advice, which is that because bullfrogs like warm, deep water, make sure that any ponds on your property remain shallow and thick with vegetation. Otherwise, you're just extending an open invitation to an enterprising bullfrog to lay its eggs there.
And given that one adult female can lay up to 20,000 eggs at one go, that may be an invitation you'll come to regret, says Burgess-Parker.
Some native predator species, including herons, eagles, ospreys and snakes, will feed on young bullfrogs from time to time, but, because bullfrogs are foreign to B.C. and therefore not part of those predators' staple diet, not enough of them are eaten to keep their numbers in check. So those numbers just keep growing.
Humans can do their part too, says Burgess-Parker, by trying to fish bullfrog egg masses out of ponds before they're allowed to hatch. It's too late for that now -- bullfrog eggs are laid and hatched in May and June -- but next year, should you happen to find one in your pond, she suggests fishing it out and laying it on the ground where it will die.
And how do you go about recognizing such a mass? Chatwin describes them this way: "They're laid in broad, frothy sheets of jelly, and they look like poppy seeds scattered on a patch of slime. They may also be covered with algae."
Bob Espin, who has a hobby farm just east of the Langley airport, has lived uncomfortably with bullfrogs for years.
He's tried to get rid of them with help from LEPS, but they just keep coming back. Last fall he shot one with a .22-calibre rifle on a pond outside his house. But this spring, another one was there in its place.
He's been trying to get a sight on it since.
"I was out there this morning looking for the one that was croaking," Espin said Wednesday. "I know where he should be, but I can't see him clear enough to get a sight on him with a .22.
"They say I should try a fishing rod with a hook on the line and dangle it in front of him. I might try that. Then if I got him, I'd reel him in and whack him somehow."

TIMES COLONIST (Victoria, British Columbia) 12 July 04 Invasion of the bullfrogs (Ian Dutton)
Local biologist Stan Orchard has a plan he says can eradicate invasive American bullfrogs from Capital Region wetlands.
The bullfrogs, pernicious invaders from the eastern U.S. who eat their own young and local species besides, are currently plaguing most lakes in the region.
Only the work of diligent volunteers who mount nightly patrols hunting the amphibians has prevented the wholesale spread of the animals to all of our lakes, Orchard said.
"They're very keen and they've been working on a local level trying to kill frogs coming into these small lakes in the Highlands, but it's no way to eradicate them," he said.
Karel Roessingh, Highlands mayor and part of the frog patrol at his lake, said there's great enthusiasm for the project.
"Volunteers started this lake stewardship program in an effort to keep the frogs out of local lakes and it's been quite successful," Roessingh said.
"As they spread, the people who have been at this the longest help out those whose lakes are just starting to be invaded."
Orchard said the spread of the frogs is now reaching crisis proportions, because of their enormous reproductive capacity, few predators and a lack of funding for control measures.
He said he contacted the province and CRD Parks looking for funding for a pilot project to prove his technique is effective, but neither level of government was prepared to shell out the needed cash.
He received $1,500 in seed money from Saanich municipality, he said.
Orchard said the pilot plan would need about $1,500 in materials and about $10,000 in staffing costs to put in operation.
"The costs of the pilot project would be reduced because I have a Zodiac (inflatable boat) and other equipment but to develop the project fulltime you would need teams and each team would require that basic equipment," he said.
Tracy Fleming, a biologist with CRD parks, said the agency is interested in seeing if Orchard's scheme will work. However, there is no funding to support it this year.
She also said that the parks' mandate is terrestrial, and that jurisdiction over the lakes in the parks -- and presumably any costs relating to the lakes -- would need input from other levels of government.
Orchard -- a self-described "biologist for hire" -- wouldn't describe in detail the process used on the frogs, citing intellectual property rights and the fact that he's learned from experience not to put forth ideas without some commitment for payment.
But he did say the techniques are eco-friendly and species-specific. A full-scale eradication program would take about six years, he said, and would attack tadpoles and adult frogs simultaneously.
Purnima Govindarajulu, a UVic student who has spent seven years studying the frogs and who is currently writing her doctoral thesis, said an eradication project -- if it's done right -- would be worthwhile.
"But it would have to be done very carefully," she said. "If it were not done thoroughly, it would be a waste of conservation dollars, which are very scarce."
Govindarajulu said otter, mink, eagles, herons and garter snakes will eat the frogs, but the predators "are just learning about this new food source."
She also said dragonfly larvae feed on the tadpoles. "But when we stock lakes with fish, they eat the (dragonfly) larvae and reduce insect diversity. It's a very tangled web."
Orchard agreed the struggle is a difficult one.
"The frogs) are diabolical ecologically. The tadpoles are distasteful to fish and so there are huge survival rates and they set up their own ecosystem," Orchard said.
"They've been known to swallow small alligators, snakes, turtles, frogs and when their density gets quite high it's like setting up a rat trap every couple of metres around a lake.
"Birds that come down to get water at the lakes' edge can be picked off by them, shore birds that nest can have their fledglings picked off by them, but once they've stripped all of those resources, they don't really require anything else because they set up their own ecosystem.
"The tadpoles, as they transform into juvenile frogs, are eaten by the adults. You have these vegetarian tadpoles converting algae into animal protein, which is then consumed by the adult."
Orchard said spending money on eradication now would pay off in the long run.
"It's like the Alberta program with Norway rats," he said. "That started in 1950 and within five years 75 per cent of the rats were gone.
"By 1990 there were no rats at all. They maintain a corridor 610 kilometres long by 35 kilometres wide. They spend $100,000 a year and they estimate they save $65 million a year in crop damage and so on.
"In the case of the bullfrog it wouldn't require anything like that."
Invasion of the bullfrogs