UNION-TRIBUNE (San Diego, California) 15 December 07 Captive breeding eyed for imperiled wildlife (Mike Lee) {Excerpt}
Federal biologists planned for weeks to rescue a rainbow trout whose genes were considered among the purest in Southern California. They made visits to a remote canyon in the Cleveland National Forest.
The researchers wanted to prevent the landlocked fish from being wiped out by debris that would flow into the canyon's pools when heavy rains hit the landscape, which had been charred by wildfires in October. They also aimed to breed a reserve population of the trout so they could repopulate river basins across the region.
Both goals were dashed. Before the biologists could obtain regulatory approval, a recent downpour filled the trout pools with charred wood and mud.
“It's sad. . . . There was nothing living except two water beetles,” said Robert Fisher of the U.S. Geological Survey in San Diego, who recently visited the canyon in the hope that some fish had survived.
Fisher and other biologists said October's infernos highlighted the urgent need for captive-breeding programs to protect various native species from being wiped out by future fires, diseases, off-road recreation and other threats.
That topic was the focus of an international meeting hosted this week by the San Diego Zoo. Wildlife experts, including those specializing in population management, gathered to discuss how to improve captive-breeding programs for amphibians.
“We need some quick rules of thumb that are going to safeguard us so that people 20 years from now won't look back and say, 'Those guys missed the boat,' ” said Dr. Robert Wiese, director of collections for the Zoological Society of San Diego.
After the 2003 fires, the zoological society donated space for what is now a collection of mountain yellow-legged frogs, one of several imperiled amphibians worldwide.
Efforts around the globe to create “Noah's ark” populations are growing because of threats such as deforestation and development, Wiese said. Government agencies and nonprofit groups collaborate on a wide range of programs – some elaborate and others established under emergency conditions.
The full ecological impact of the recent blazes in Southern California won't be known for years. Several biologists said the rains that eradicated the trout in the Cleveland forest are starting to rejuvenate other habitat areas, improving the outlook for many species.
But their concerns have grown for at-risk creatures such as trout in Pauma Creek, arroyo toads, tidewater gobies, Laguna Mountains skippers, coastal California gnatcatchers and cactus wrens. Some of these animals aren't suitable for captive breeding or rearing.
Scientists and environmentalists generally don't relish such work even if they find it necessary. Most of them believe rescue operations should be considered mainly when humans have pushed species so far toward extinction that one catastrophic event could wipe them out.
“It bothers me to do it because it just seems like admitting failure” to sustain species in the wild, said Jim Peugh, a longtime activist with the Audubon Society in San Diego. But in some cases, he added, “it's all we can do.”
Certain creatures facing extinction – most famously the California condor – have been bred in captivity. But the process is filled with risk and uncertainty.
Management of captive species can require large financial investments, though some programs are run on shoestring budgets and the good will of biologists who don't want to see the species disappear. It also relies on reducing threats, such as habitat destruction, in the face of urban sprawl.
“Captive breeding is considered a last resort because you are taking a species that has adapted to very specific wild conditions and bringing it into an artificial situation,” said Jane Hendron, spokeswoman for the U.S. Fish and Wildlife Service in Carlsbad.
“What you have done is potentially just depleted the very small numbers that were in the wild, and if they don't successfully breed, recovery is that much more difficult,” she said. “It's a weighing and balancing of the greater benefit that the species could receive from captive breeding.”
Attempts to find that balance lead to vexing questions: What's the best way to select breeding pairs? How many members of a species are needed for captivity? When is it better to leave a species in the wild? How can scientists mark and track small creatures with numerous offspring?
Other challenges for biologists handling captive populations include managing diseases, maintaining the instincts of wild animals and making sure that creatures have enough habitat once they're released.
“We are trying to meet what we think is natural and maintain genetic diversity, but often our picture of what that is is not really natural,” said Fisher of the U.S. Geological Survey.
…
Captive breeding eyed for imperiled wildlife