It’s raining trout. Should it?

Fall IS A QUIET time on the high Sierra lakes around Mt. Whitney, as circular wakes fan out silently across the water’s surface and then fade to glassiness again. It seems so peaceful. It’s not. The ripples are stirred by insects landing and being pecked at feverishly from below by the golden trout that inhabit many of the high-mountain waters.

Today, golden trout occupy nearly 300 lakes and 200 miles of streams in the Sierra Nevada, mostly above 10,000 feet. Many of these waters are stocked on an irregular basis by state Department of Fish and Game personnel, who drop them as fingerlings from airplanes, much as firefighters drop water on fires. By October, they’re like the bears roaming lower elevations, building up fat and protein reserves before the ice and snow set in.

It’s line-dropping time for fly fishermen, who relish the golden trout for its radiance and for its wariness and fight. “Pound for pound, or ounce for ounce as the case may be, golden trout tend to fight a lot harder” than the hatchery-raised rainbow trout so prevalent in lower areas, says David Moss, a fly-fishing guide based in Mammoth Lakes. “They’re extremely wild. A lot of them never had a hook in them. And some of the fish in the upper lakes are in excess of 12 inches. They put up a fight on 6x tippet. You use anything heavier than that and the fish get spooked and won’t bite.”

For several years now, the Department of Fish and Game has debated whether to continue its aerial planting of golden trout, given the strong evidence that the fisheries can, in most cases, support themselves. There’s also the question of whether the stocking of any species of trout poses as big a threat to the existence of the mountain yellow-legged frog -- which is in serious decline -- as some believe it does.

“There have been trout planted in the Sierra now for well over 100 years,” says Phil Pister, who from 1953 to 1990 was Fish and Game’s lead biologist in the Eastern Sierra. “But the general disappearance of amphibians has been relatively recent, so there are other factors involved.”

Plus, fairly recent DNA testing bolsters a suspicion that some have held for years: that the fish the department plants, grown from eggs collected at Cottonwood Lakes, have somehow become hybridized and contain a small mixture of rainbow trout. Should these fish be dropped from airplanes into lakes containing a purer strain of goldens?

Faced with the dual responsibility of maintaining healthy ecosystems while at the same time providing recreational opportunities, Fish and Game has not announced any big changes in its trout-stocking program and maintains that it plants golden trout only in waters where impure strains already exist.

While some say hybridization has occurred throughout the Sierra, Pister isn’t so sure. “Goldens are very close to rainbows genetically, and the geneticists are now puzzling a bit [over whether] they are seeing impurities or simply stuff that should be there,” he adds. “We feel that there are still places where pure golden trout exist, one of them being in the upper reaches of Volcano Creek, a tributary to Golden Trout Creek.”

Interestingly, few of those fish -- whether hatchery-raised or wild -- belong where they are. Golden trout are native only to the Kern Plateau region. This is one of only three Sierra drainages historically containing any type of trout -- the others being the Truckee River and Carson River drainages.

In the Kern drainage, barriers created by geological forces thousands of years ago isolated what was then a strain of rainbow trout. After countless generations of in-breeding, the fiery golden trout emerged.

Then came humans and a world of change.

At some point in the 1850s or early 1860s, a small number of fish from Golden Trout Creek were placed in Mulkey Creek, a tributary also isolated by natural barriers. In 1876, 13 trout were taken from Mulkey Creek and hauled to Cottonwood Creek, which drains from Cottonwood Lakes to the east -- toward the Owens Valley.

A Civil War colonel who ran a sawmill there ordered the transplant “simply because he wanted something for the stream,” Pister says. “They did really well there, and the guys had lots of trout to eat.”

By 1891, trout from Cottonwood Creek were discovered upstream in Cottonwood Lakes, which begin at about 11,000 feet. Those fish formed the broodstock for Fish and Game’s golden trout-planting operation since 1918, when employees at the Mt. Whitney Fish Hatchery, just west of Independence, collected the first batch of golden trout eggs.

Now, conservation groups such as the Sierra Club are among those looking back with 20-20 hindsight, wishing the fish had never been stocked where they weren’t part of the natural order.

Fortunately for golden trout, some restoration of the natural order came with the establishment of the Golden Trout Wilderness in 1978. That protected all the species’ historic range, or more than 300,000 acres, within the Kern Plateau. Beyond that, as fishermen cast and strip their hoppers, nymphs and various dry flies, efforts to protect the state fish continue.

Roland Knapp, a research scientist with the University of California’s Sierra Nevada Aquatic Research Laboratory, is among those suggesting that the state cancel its aerial stocking program. Knapp recently concluded a study involving 60 lakes that have not received Fish and Game plants in the last five or six years. There was evidence of a successful spawning season in 70% of those waters, which is proof that at least some golden trout fisheries are self-sustaining. “I argue we don’t need fish in every backcountry lake, for the sake of biodiversity.” For another recent study, he donned a wetsuit and snorkel and waited at Summit Lake for the Fish and Game airplane to make its drop. He found that by the end of the day, 50% of the fish had died. “Many died on impact,” Knapp says.

The fish that are still alive will soon hunker down for a long, dark winter. Ice will cover the surface of the lakes. Snow will build atop the ice, providing insulation. The water temperature will hold at about 39 degrees near the bottoms of the lakes and about 32 degrees closer to the surface.

Near that bracing bottom is where these fish will remain, dormant like the hibernating bears, until the warmth of spring and early summer turns them loose again.

To e-mail Pete Thomas or read his previous Fair Game columns, go to www.latimes.com/petethomas.