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Could grizzlies be fat and happy without salmon runs?

Author: Ken Olsen Staff writer

Edition: SPOKANE
Section: MAIN NEWS
Page: A1

 

Index Terms:
WILDLIFE MANAGEMENT, STATISTICSSERIES

 

Estimated printed pages: 7

 

Article Text:

The clues are spelled out in 150-year-old bits of skull and skin.

With the help of high-tech science, these pieces of long-dead grizzly bears reveal – almost down to the last supper – the diet of the legendary animals now virtually erased from the Pacific Northwest.

Grizzlies that romped high in the North Cascades, deep in the Idaho wilderness or down in the southeastern Oregon desert depended almost entirely upon salmon, Washington State University scientists have found.

As important: Salmon-eating grizzlies had a significant role in producing the Paul Bunyan-proud trees that lured the timber industry to the Northwest, the WSU researchers say.

While scientists long have known bears eat fish, they were astounded by how important salmon were to both bears and trees.

The research raises questions about how bears would survive if the U.S. Fish and Wildlife Service goes ahead with its plan to reintroduce grizzlies into! Idaho and Washington without first restoring salmon runs.

Scientists also wonder how towering trees can again thrive without the rich influx of nutrients that salmon and grizzlies spread in the forests.

“We are working with the latest high-tech science, from atoms to GPS collars and satellites to document what was probably a Native American parable – that bears and salmon are essential links between oceans and forests,” says Charlie Robbins, who leads the WSU research team.

Fifty thousand grizzlies once roamed the American West, feasting on buffalo and salmon, capturing Native American legends, and serving as a roping animal for sporting Spaniards.

Fewer than 1,000 grizzlies remain in the contiguous 48 states, a handful of them in Idaho and Washington.

Food is basic to whether bears and humans clash, whether bears reproduce and thrive, whether bears and other endangered critters drive each other to starvation.

With that in mind, ! Robbins and his team went after bears killed long ago hoping they coul d learn what sustained grizzlies before their near extinction, and how bears might fare if they return to the Pacific Northwest.

The team unearthed a dozen grizzlies taken in the Pacific Northwest between the 1850s and 1930s and tucked away in collections from New York to Idaho.

They were perfect. One specimen was killed in Idaho’s Lehmi Mountains in 1890, another near Malheur Lake in southeast Oregon in 1930. A third came from the North Cascades.

Sean Farley carefully chipped a whisper of bone from the inside of the skulls – under the watchful stare of curators who had cared for these taxidermic treasures for decades. He also snipped 10 hairs from each hide and made for Pullman with the evidence.

Coaxing answers from bone

Robbins is a wildlife nutritionist, best known for his work on the dietary needs of Morty the moose, who strolled through the opening scenes of the “Northern Exposure” TV series. Long fascinated by grizzlies, Robbins tu! rned from prey to predators in the mid-1980s.

Farley earned his doctorate under Robbins by, among other things, milking grizzly sows to study their butterfat. Grant Hildebrand, a student of grasshoppers and biopesticides as an undergraduate in South Dakota, came to WSU for his doctorate and went chasing live grizzlies.

Until recently, wildlife researchers dug through bear feces to discern diet. The results were uncertain.

Researchers overestimated the importance of vegetation, because it passed through the bears, and underestimated the importance of food like salmon, which was absorbed.

The Robbins team turned to a technique called destructive isotope testing, which was once used to figure out why ancient Egyptian women died much younger than men.

Bones make a lifetime record of what we eat, by accumulating chemicals found in specific foods. Hair makes a similar but more temporary record, showing only what you consume the last season of yo! ur life.

The studies of mummies revealed the pharoah’s men ate meat and wheat, while the women mostly sorghum.

The Washington State team is the first to use the technique in bear studies. By burning bits of skull and hair at high temperatures and analyzing the gases, researchers can pinpoint how much nutrition the grizzlies got from salmon, from other animals, from fruit, or from leaves and other vegetation.

Traces of Columbia River Basin salmon – nitrogen and carbon the fish absorbed from the seas – turned up in every museum bear, even those that lived in the southeastern Oregon desert, 900 miles upstream from the Pacific Ocean.

Idaho’s Lehmi Mountain bear took 90 percent of its sustenance from salmon. Oregon and Washington bears came in a close second.

Robbins and his team also traveled to Alaska to verify their findings with living bears. It’s the only place in the United States that still has both ample grizzlies and salmon.

The evidence is resounding: salmon are the most important meal for many gr! izzlies. And, beyond people with guns, nothing has been more fatal for Pacific Northwest grizzlies than the demise of these fish.

The big sleep

Everyone likes a nap after a big meal. Bears make it a six-month affair. Hibernation is the grizzly’s way of surviving winter’s lean cuisine.

Bears also give birth and nurse their cubs in the den. But if the mother isn’t well-fed when she turns in for the winter, the embryos, fertilized during spring mating, are aborted.

Ample feed also means sows can remain in marginal habitat longer in spring, avoiding male grizzlies who will kill cubs for food or to clear the way for mating.

“Bears would love to be the average American – or at least the one-third that are critically overweight,” Robbins jokes.

Salmon are much more digestible than the berries, tubers, Army cutworm moths and ants that fill the stomachs of the remnant grizzlies of the Rocky Mountains. Salmon also are more abundant than any! other meat source at the most critical time, midsummer through fall.< p=””>

Come mid-July, a 500-pound bear is trying to eat 65,000 calories a day – the equivalent of 75 pounds of salmon – to lay on enough lard to make it through the winter. That gorging may slow to 20,000 calories a day later in the fall.

In either case, if salmon is on the supper table, 80 percent of a grizzly’s weight gain is fat.

“Elk, deer and moose are hit and miss,” Hildebrand says. “With salmon, bears can go to a stream and eat all day.”

That was easy before dams, fishing nets and stream destruction annihilated the 16 million salmon that spawned in the Columbia and Snake River drainages every year, including 4 million in Idaho. Today, when a single sockeye and a few thousand wild chinook make it back to Idaho from the ocean, salmon aren’t on the menu anywhere.

Dam conundrum

Washington’s North Cascades and Idaho’s Selway-Bitterroot/Frank Church Wilderness areas are the two places the U.S. Fish and Wildlife Service would most like ! to reintroduce bears. Because it’s a larger piece of undeveloped territory, the 5,800-square-mile Selway-Frank Church complex is the first candidate.

Hunters, trappers and sheep herders killed as many as 40 grizzlies a year in the Selway-Bitterroot until the 1930s. Scientists believe a 1920s-era dam at Lewiston cut salmon off from that wilderness area and was gunpowder’s major accomplice in eliminating grizzlies.

“With hardly any salmon in the Selway-Bitterroot, it’s a major problem,” says Scott Bosse, a conservation biologist with Idaho Rivers United. “And fire suppression may have drastically altered alternate food sources: pine nuts, grasses and bulbs.”

Chris Servheen, grizzly recovery guru for the U.S. Fish and Wildlife Service, insists there is ample food for the 280 grizzlies his agency wants living in the Selway-Bitterroot within the next 130 years. Grizzlies elsewhere in the Rocky Mountains except Yellowstone National Park survive without fi! sh, Servheen says.

In Yellowstone – the largest concentration o f grizzlies in the continental United States – grizzlies can feast on cutthroat trout and buffalo. Bears in Glacier are much smaller and fewer in number than Alaska bears because of their spare diet.

Robert Bilby, a Weyerhaeuser Corp. salmon researcher for 18 years, says nearly extinct salmon poses the same conundrum in the North Cascades.

“It raises some questions about how successful that (grizzly revival) effort might be because we have changed the system so dramatically,” Bilby says. The number of dams on the Columbia, “present a real challenge in terms of getting salmon back.”

Impoverished outlook

Towering forests also are at stake because of the dependence on salmon, Robbins argues.

Alaska is his proof. In the course of tracking grizzlies across the Kenai Peninsula, Hildebrand is showing each salmon-eating bear spreads 400 pounds of nitrogen and phosphorus a year – in a form much more easily used by trees than commercial fertilize! r.

Salmon absorb the nutrients as they swim the rich ocean, and deliver them to the comparatively sterile rivers and streams of Alaska – as they once did in the Northwest. Grizzlies eat the fish, absorb the fat, convert nitrogen into the most plant-friendly form, and relieve themselves of the nitrogen, phosphorous and possibly other important elements. As they once did in the Northwest.

“Salmon is accounting for 20 percent of the metabolism of the tree,” Robbins says. “The gigantic, old-growth trees that grew along the river courses, that enriched the Northwest and the timber companies, were likely produced not only because they were old, but because of the millions of salmon that died in the streams and were eaten by wild animals that then fertilize the trees.”

Bilby, who recently moved from Weyerhaeuser to the National Marine Fisheries Service, confirms that importance of salmon-delivered nitrogen, although no one has it down to a specific number ! of board feet.

“It is very possible these fish historically ma de a very important contribution to the forests of the Northwest,” Bilby adds. “A lot of big forest products companies (now) fertilize with nitrogen.”

Adds Hildebrand: “It would be a whole lot cheaper to let bears do it.”

Bear optimism

Robbins and other scientists next will probe the remaining large trees of the Pacific Northwest to put an exact number on what grizzlies and salmon do for forests, and to bolster their case for bringing back both.

It may take much more to bring back bears. Grizzly recovery is mired in studies and draft decisions 23 years after the bear hit the endangered species list.

Environmentalists are divided about whether they want grizzlies in their hiking country. Some are expected to file suit this week, arguing the few grizzly bears living in the lower 48 states are being mismanaged.

Congress, meanwhile, tucked a measure blocking money for reintroducing grizzlies in the Selway-Bitterroot into the budget ! bill it hastily passed in late October.

Robbins’ team is undaunted.

“Perhaps someday a logger in the Bitterroot will realize an important part of his living is from salmon and grizzly bears,” Robbins says. “And be proud.”

Caption:
The salmon-bear-forest link surprised researcher Charlie Robbins. Photo by Kathy Plonka/The Spokesman-Review Color Photo; Graphic: Causes of death

 

 

Memo:
Ken Olsen can be reached at (208) 765-7130 or by e-mail at keno@spokesman.com.

This sidebar appeared with the story:

TWO-PART SERIES

Today: The proposal to reintroduce grizzly bears to central Idaho stirs controversy.

Monday: Researchers look to Alaska’s Kenai Peninsula to determine how people and bears get along.

Copyright (c) 1998 The Spokesman-Review
Record Number: 9811300235