Alleviate Human Toll For A Quarter
Forty years ago, anglers were catching a million Godgiven kokanee a year from Lake Pend Oreille.
Last year, despite the efforts of fish hatcheries, the catch had declined to about 150,000.
Man’s heavy hand on the lake and its tributaries has taken a heavy toll.
The decline of kokanee in Lake Pend Oreille is bad news for anglers, lakeside communities and the world-class rainbow and bull trout fisheries that forage on kokanee.
But there’s good news, too.
Biologists believe the kokanee fishery could be restored to near historic levels for a mere 25-centsa-month increase in the region’s residential utility bills.
Before Albeni Falls Dam was built in 1952, the water level of Lake Pend Oreille generally would drop to 2,048 feet after spring runoff and stay low through the summer and fall.
The wave action on the lake’s deep gravel beds created ideal conditions for kokanee to spawn below this 2,048-foot level, research shows.
The kokanee seem held their own after the dam was built, but the fishery began to decline in the mid-60s.
Originally, the blame fell on three causes:
Cabinet Gorge Dam, which blocked Pend Lake Oreille fish from spawning in Clark Fork River tributaries.
The introduction of mysis shrimp, which compete for the same food needed by young kokanee.
Albeni Falls dam power production, which dropped water levels after spawning and exposed kokanee eggs.
However, research has found that none of those factors can account for the losses of kokanee, said Ned Horner, Idaho Fish and Game Department regional fisheries manager.
The kokanee fishery began its decline before the mysis shrimp took hold, he said. Furthermore, 1980s net-pen studies proved that young kokanee could find enough to eat without being fed.
“The fishery held strong even after Cabinet Gorge blocked a run of 100,000 kokanee that used to spawn in Clark Fork River tributaries,” Horner said. “Losing that run wasn’t a major factor because we had 5 million kokanee spawning on the lake’s shorelines.”
Similarly, post-spawn drawdowns of up to 10 feet at Albeni Falls Dam had only a small impact on kokanee because the deep spawning gravels were still viable, he said.
Over time, however, these deep spawning areas have been lost.
In the mid-60s, the Corps of Engineers began producing more power from Albeni Falls Dam, Horner said. A drawdown of an additional 5 feet was common in the fall.
“The decline in kokanee began in the mid-60s at the same time the deeper drawdowns began,” he said.
“We believe the changes have caused the deep-water gravel beds to fill with sediment.”
Horner says there’s “a ton of science” to show that increasing the lake’s winter water levels would be a boost to the lake’s fisheries.
“If the lake were raised to the historic winter pool level of 2,056 feet, there would be a sevenfold increase in the amount of spawning gravel available for kokanee,” he said.
“We have a goal of boosting the annual catch to 750,000 fish, but we’ll never do that without the spawning habitat,” he said.
Raising the winter levels also would be a boon to bass in the Pend Oreille River, he said.
And all he wants is a chance to prove it.
Last December, the Northwest Power Planning Council endorsed a plan to raise the level of the lake 5 feet during winter. The Bonneville Power Administration tentatively indicated it would fund a study to evaluate the benefits to fish.
However, Idaho’s appointed two new members to the council in January. They could keep the plan afloat - or they could sink it.
Pend Oreille’s 1996 and 1997 kokanee spawning runs are forecast to be record lows.
We’ve procrastinated too long.
“BPA says it would cost $10 million in lost power production to maintain higher winter levels,” Horner said. “Spread that cost over BPA’s $3.5 billion budget and it translates into a quarter a month to the average ratepayer.
“I think people would be willing to pay that much to restore a world-class fishery.”
Mike Field of Boise and Todd Maddock of Lewiston, Idaho’s two new NPPC members, will be holding a public hearing at the Sandpoint Community Center Saturday, 10 a.m. to noon. Info: Idaho Fish and Game, (208) 769-1414.
You can contact Rich Landers by voice mail at 459-5577, extension 5508.