ANGLERS can expect to get skunked at some Sierra lakes this summer as crews kill trout to protect a rare frog.
Officials are eliminating the prized game fish from 22 lakes, mainly in and around Sequoia National Park and the Eastern Sierra. The fish eat mountain yellow-legged frogs and their tadpoles, pushing the amphibian closer to the endangered species list. The frogs have declined by at least 80% since the 1950s.
For anglers, the fish-removal program puts their conservation credentials to the test. While some say losing a few trout to save nature is a fair exchange, others fear it’s the beginning of the end for high-country fishing.
“It makes no sense killing trout to save frogs. It’s environmentalism gone too far,” says Tom Raftican, president of United Anglers of Southern California.
For years, Bob Tanner has been taking anglers to fish via his Red’s Meadow Pack Train near Mammoth Lakes. He says his clients ride mules into the high country to fish; they surely won’t come for frogs. He fears too many environmental restrictions will hurt his business.
But Brett Matzke, native and wild trout manager at CalTrout, a fishing advocacy group, says scientists make a strong case that the fish, among other causes, contribute to the frogs’ declines.
“Endangered species are just that; they’re endangered and need everybody’s help,” Matzke says. “All fishermen are asking for is a conservative approach.”
Roland Knapp, a research biologist with the UC Sierra Nevada Aquatic Research Laboratory, says that where trout were removed from lakes in Sequoia and Kings Canyon National Parks, the frog population increased. At one lake in Kings Canyon National Park, their numbers grew from 165 to 17,600 in three years.
So, National Park Service personnel are removing trout from some lakes in the two national parks while the state Department of Fish and Game eradicates trout from some nearby waters in the eastern Sierra. Crews shock fish with electricity and use gill nets to remove them. Yosemite National Park officials are considering similar measures to protect the amphibians.
So far, brook trout have been removed from two lakes in the Big Pine Creek drainage and from Gable Lakes in the Mt. Tom area west of Bishop. With so few lakes targeted — trout are plentiful in many of the thousands of lakes that dot the Sierra — officials insist many fishing opportunities will remain.
In a change, fisheries managers have learned that planting lakes with trout not only harmed frogs, but also compromised fish populations.
Knapp found that nearly three-quarters of the Sierra lakes that the state stocked have trout populations capable of sustaining themselves.
“Throwing thousands of fish in these lakes makes fish grow more slowly than if there was no stocking,” he says.
Many of the high-country lakes and streams have ideal spawning habitat, but not enough food to grow big fish. In one lake, Knapp says he found a golden trout more than 26 years old that was less than 10 inches long.
Today, state wildlife officials stock fewer fish, partly because of budget constraints, but also because of a change in philosophy. The department increasingly promotes “aquatic biodiversity management plans” for the eastern Sierra to balance native fauna with recreational fisheries.
Fish and Game biologist Curtis Milliron says stocking will be eliminated at many lakes where trout populations are self-sustaining. At the lakes where fish are being removed, officials will manage them to restore native species.
In the trout-free lakes, mayflies and water beetles return, as well as birds such as the gray-crowned rosy-finch and Brewer’s blackbird. And National Park Service aquatic ecologist Danny Boiano found frog legs along the shore, leftovers from blackbirds that eat frog bodies, but not the legs.
Some lakes will be managed so that anglers can expect to catch lots of small fish. Other lakes will be stocked with big trout in hopes they eat the stunted little ones, grow even bigger and build a fishery where catching is more difficult, but the chances for a trophy fish are better.
Whether the measures are sufficient to save the frog is unclear. Knapp says the chytrid fungus, which infects a quarter of the frogs in Yosemite, Sequoia and Kings national parks, poses a serious long-term threat. Biologists suspect wind-borne pesticides that drift into the Sierra from Central Valley farms weaken frog immune systems, making them susceptible to the fungus.
For now, many anglers are showing forbearance, even if it means fewer hookups.
Says Scott Olson of Simi Valley, a Sierra fly-fishing enthusiast: “It’s not reason to extinguish a species because we want to fish. You never know if the frogs might hold the cure for cancer.”