ambience: bullfrogs
Leopard frogs have been disappearing in Arizona, and the major culprit is apparently a creature that eats virtually anything less than it’s size that crosses its path. I’m Jim Metzner, and this is the Pulse of the Planet. American bullfrogs have been eating their way through the southwestern United States and no one knows quite how to stop them. Bullfrogs were originally found in aquatic environments in eastern parts of North America. It’s believed they were brought over to the west coast by people who wanted to serve them as a delicacy, or see them as live ornaments in their garden pools. Cecil Schwalbe is with the U.S. Geological Survey’s Sonora Desert Field Station at the University of Arizona. He tells us what’s being done to control the American bullfrog population.
“We’ve found no single method that is effective in eliminating bullfrogs because they’re just so adaptable. Some poisons have been tried, and of course, things like rotenone and some other toxicants that are used to kill fish and other gill breeders are effective in killing tadpoles, but they also kill all the other gill-breathing organisms. And so, that’s not preferred, especially when you’re dealing with populations of endangered and threatened fishes, you cannot use such methods. We use a combination of methods. We use hand capture, or with hand nets, or spears called gigs and go ‘frog gigging.’ That’s actually a very effective, as far as taking a certain number of frogs per unit time. We actually even set out so called hoop traps, and we connect them by a long fish net, and then when the frog hits the fishnet, then it goes either way – it ends up in the trap. Those are methods that will catch frogs, but you can almost never eliminate a population that way.”
The bullfrog returns in future programs. Pulse of the Planet is presented by DuPont, bringing you the miracles of science, with additional support provided by the National Science Foundation. I’m Jim Metzner.
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